CHRIS HOWARD’S ASTRO JOURNAL

 

I'm an amateur astronomer and astrophotographer in coastal New Hampshire, working in narrowband and RGB color, focusing mostly on deep space objects—nebulae and galaxies, with some intermittent planetary and solar photography, because our sun's the nearest star and the planets and our moon are simply beautiful. I post finished and processing-in-progress shots here, and my equipment setup information (pics of my scopes and lenses, imaging train layouts with focal distances, focus wheel filter order, lens and scope backfocus, etc.) on the Equipment page. I'm always building and devising better ways to automate and remotely operate my gear, and I post related stuff on my Astro Automation page. Unless specified, everything you see in my Journal is from my equipment in my backyard, which is about a 4 on the Bortle Scale (SQM: 20.62 mag/arcsec)—on a clear night I can still see M33. We live in a town with very few street lights, and the sky glow we get is usually low on the horizon, Hampton to the south, and Portsmouth to the north. Email me here: chrishoward.author@gmail.com or see the links below to my other sites. And here for my 2015 - 2016 Astro Journal Posts   

 

October 12, 2018
Wide-field of the Wizard Nebula surrounding the open star cluster NGC 7380 in the constellation Cepheus, about 7,200 lightyears aways from us. I reduced the saturation so that you hardly notice the differences in the RGB mix, mostly R and B because this is a bi-color set with Ha and OIII. I think I prefer this reduced color or even a completely desaturated (grayscale) version. There are so many stars in this image and I'm not a fan of the off-color red and blue stars you get with narrowband. Also in this shot, I particular like the dark band at the top left. These "dark fog" or dark nebula regions consist of interstellar gas and dust that absorb the light from surrounding stars, and the constellation Cepheus has some famous dark cloudy areas, B 174, 150, and several around IC 1396. (16 x 300 second exposures in Ha and OIII, Atik 414EX mono CCD, Astronomik 12nm Ha, OIII filters, William Optics ZS61 + WO Flat F6A f/4.7, CEM25P EQ mount, Orion OAG + ZWO ASI120MM-Mini guide cam, Stellarmate OS (INDI/KStars/Ekos) running on Raspberry Pi 3b+).

 

July 18, 2018
Here's NGC 281 ("Pacman Nebula") in the Hubble Palette (SII, Ha, OIII -> RGB). NGC 281 is an emission nebula, about 9,200 lightyears away in the constellation Cassiopeia. I re-stacked and reprocessed some hydrogen-alpha, oxygen-3, and sulphur-2 image data I shot several months ago, and I'm happier with this latest result than I was then. It's called the Pacman Nebula because it sort of looks like the classic video game character. (6 x 1200 second exposures in Ha, 5 x 1200 sec OIII & SII with 16 dark frames, Atik 414EX mono CCD, Astronomik 12nm Ha, OIII, SII, William Optics GT81, CEM25P EQ mount, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control).

 

July 9, 2018
I recently bought the William Optics FLAT 6A II, and finally made it out under the stars to take some sub-exposures. I paired it with my GT-81 and ZWO ASI071MC color CMOS camera. The FLAT 6A II is a 0.8x reducer/field flattener; it's adjustable for different focal lengths, and so far, with my limited use, it appears to be quite a leap over the old William Optics F6-A I've used for a few years. The ASI071 has an APS-C sized sensor, and anyone with a large sensor astro camera or DSLR knows if you don't want field curvature with your refractor you need some sort of flattener. The FLAT6AII design makes it easy to dial in the correct distance for the scope you're using. The old reducer/flattener worked, but I had to test out a dozen different flattener to sensor distances, and still had to do some cropping and processing to fix the corners. This new FLAT 6AII provides a fairly flat field across the entire view. Equipment: William Optics GT-81 + FLAT 6A II 0.8x reducer f/4.7, ZWO ASI071MC-Cool color CMOS camera - gain 0 offset 8, ZWO ASI120MM-S Guide Cam + 130mm guide scope.

Testing:
With the GT81 and ASI071 I get a 3.54° x 2.35° field of view, and I can capture some big chunks of the night sky. Here are three from the last two nights: [1] the Pelican Nebula (IC 5070) and the edge of the North America Nebula (NGC7000) at the bottom, [2] IC 1396 nebula with the Elephant's Trunk at the top and the Garnet Star bottom left, and [3] M31, our galactic neighbor, the Andromeda Galaxy.



Pelican Nebula image info: ZWOASI071MC 39 x 240 second color subs stacked in DSS, processed in PSCC2018


IC 1396 region image info: ZWOASI071MC 21 x 300 second color subs stacked in DSS, processed in PSCC2018


The Andromeda Galaxy. The last time I photographed Andromeda (M31) was 2015, maybe fall of 2014? It's been a while. I was using a DSLR--that was the only camera I had, and I had it on a terribly-used Celestron CG-5 equatorial mount with some aftermarket RA/DEC motors. By "terribly-used" I mean you could drive a truck through the gear backlash. Even so, I still managed to get some decent 30-second exposures of Andromeda, Orion Nebula, and other big bright targets in the sky. Well, I'm back with our galactic neighbor, and with much better gear: 192 x 120-second sub-exposures stacked in DSS, processed in PSCC2018, ZWO ASI071MC camera at -10C, William Optics GT81 APO, iOptron CEM25P EQ mount.


 

July 7, 2018
Our galactic neighborhood, looking toward the center, with 13 stacked 15 second exposures, Nikon D750, Rokinon 10mm f/2.8 lens. What's crazy is this is with a decent DSLR camera, lens, a tripod, and some free image stacking software (DSS). I did the stretching in Photoshop CC--"stretching" is when you adjust contrast, intensity values, to bring out the features of whatever you're shooting--in this case the north end of the Milky Way Galaxy, our home. Let me point out some interesting features: starting at the left, that vivid red star is the "Garnet Star" (Mu Cephei), and that's right next to some cool nebulosity that includes the Elephant's Trunk Nebula (IC 1396), a little ways along, you see that blocky reddish region? That's the North America Nebula (NGC 7000) with the star Deneb (19th brightest star in the night sky). Deneb forms the northernmost (leftmost in this shot) point of the famous "Summer Triangle". The other two points are Vega, the 5th brightest star in the night sky (to the right and above the Milky Way core in this shot), and Altair (12th brightest) a little more to the right and below the Milky Way core. Moving along the galaxy to that bright region on the bottom side of the core, about halfway between Altair and the powerlines--if you really zoom in, you'll see the Wild Duck Cluster (M11). Now look just left of where the powerlines cross, those grayish-pink cloudy areas? That's where you will find the Eagle Nebula (Messier 16, NGC 6611) and the Swan Nebula (M17). That bright point of light in the middle of the powerlines is the planet Saturn, which is moving along the ecliptic and right now it's in a pretty good place for viewing. Just right of that are a few more cloudy areas. That's where you would look for the Lagoon Nebula (M8, NGC 6523) and Trifid Nebula (M20, NGC 6514). Somewhere along the Milky Way--this is where you will mostly likely find me focusing my telescope all the through the summer and fall. I almost see this shot as a map of places to visit from afar, and the cool thing is you really don't need to setup the astro gear for this. You can create your own galaxy map, as long as your camera can handle long exposures (not that long, only 15 seconds) and you have it on a tripod with a remote shutter control. And this is only part of the sky from where I'm standing on our little planet! Another way to put this image in perspective is here in the northern hemisphere, around 43° latitude, I don't have enough of a view south (blocked by hills and trees) to see Sagittarius A*, which marks the center of our galaxy, and this far north there's a sky full of other galaxies, a large section of our own galaxy, nebulae, and other deep space objects that I can't ever see from here--that I would have to travel below the equator to see. Some day!

 

July 3, 2018
The Dumbbell Nebula (M27, NGC 6853), also called the Apple Core, is a planetary nebula in the constellation Vulpecula. I setup the AstroTech with 1350mm focal length, paired with the Atik 414EX mono CCD. This gives me .98" / pixel resolution and oversampling, but still managed to get some detail out of the nebula. (Imaging info: 63 x 90 second subs in OIII, 96 x 60 sec. subs of Ha. + 20 dark frames stacked in Nebulosity, processing in PSCC2018. Equipment: AstroTech AT6RC f/9 Ritchey-Chrétien, Atik 414EX mono CCD, 7nm Optolong 2" Ha filter, 8.5nm Baader 2" OIII filter, Orion Atlas EQ-G Mount, ZWO ASI120MM-S Guide Cam + WO 50/200mm guide scope)

 

June 30, 2018
The Eagle Nebula (Messier 16, NGC 6611, Star Queen Nebula) is an open star cluster and emission nebula in the constellation Serpens, about 7000 lightyears away from us. Imaging Info: 96 x 240 sec. Ha + 42 x 240 sec. OIII frames stacked in DSS, processed in PSCC2018. These frames were taken over several nights. You can see the numbers are a bit unbalanced, but the clouds moved in during the OIII sequence last night, and there was nothing I could do. I went ahead and stacked and processed them as they are. I'll probably come back to this one in the future with more oxygen-3 (and maybe sulphur-2) to achieve something like the actual proportional levels of light from the nebula across these bandpasses. Equipment: William Optics ZS61, Atik 414EX mono CCD, 12nm Astronomik Ha filter, 12nm Astronomik OIII filter, CEM25P EQ Mount, ZWO ASI120MM-S Guide Cam + Orion TOAG, INDI/KStars/Ekos control software. Location: Stratham, New Hampshire, Bortle: 4, SQM: 20.62 https://www.astrobin.com/353803

 

June 22, 2018
The view from my backyard, with the right equipment focused on a particular part of the sky: Cygnus Wall region of NGC 7000, the North America nebula, imaged in narrowband Ha and OIII. The way narrowband imaging works is by filtering out all light except for an allowed narrow bandpass at specific locations in the electromagnetic spectrum. A hydrogen-alpha (Ha) filter will only allow light to pass through to the camera sensor around 656 nanometers, which is out at the red end of the spectrum, and an oxygen-3 (OIII) filter will only allow light to pass through around 501nm, which is in the middle of the blue and green ranges. When I say red, green, blue, I'm talking about where these bandpass lines fall within the scope of the visible spectrum, which starts around 390 and goes to 700 or so (for humans). I shot the oxygen-3 sub-exposures last week, and the hydrogen-alpha subs last night. When you process these separately filtered images into one color image, you may get the Ha coming out vivid red to rust red, and the OIII coming out in blues and greens. The Cygnus Wall is that bright, rolling line across the middle where you have a lot of concentrated star formation, but this area of NGC 7000 also has lot of dust and debris drifting in front of it--the dark reddish-brown regions across the top and right side. (Imaging info: 42 x 300 second subs in OIII, 40 x 300 sec. subs of Ha. + 20 dark frames stacked in DSS, processing in PSCC2018 + Astronomy Tools actions & Annie's Astro actions. Equipment: William Optics ZS61, Atik 414EX mono CCD, 7nm Optolong 2" Ha filter, 8.5nm Baader 2" OIII filter, CEM25P EQ Mount, ZWO ASI120MM-S Guide Cam, https://www.astrobin.com/352528).

 

June 16, 2018
It was narrowband time last night in the backyard. I took a couple hours of hydrogen-alpha (Ha) sub-exposures of M17, the Swan Nebula in the constellation Sagittarius. M17 is about 5,500 light-years away. It's also called the Omega Nebula, Checkmark Nebula, and sometimes the Horseshoe Nebula, but all I see is a swan--with a black beak, neck arched forward, and wings outstretched. The bright region in the middle is the swan's chest. I started to take a few OIII frames on the 16th, but by that time M17 was heading back toward the southern horizon, and so I jumped over to the "Cygnus Wall" in NGC 7000 (North America Nebula). I captured several hours of OIII data there, amazing stuff, and I've already posted the finished image in Ha and OIII. I came back to M17 on the 21st, and took another 40 x 300 second subs in OIII. (M17 info: Ha 16 x 300 second + 82 x 120 second exposures + 20 dark frames, OIII 40 x 300 second exposures + 20 dark frames, stacked in DSS, William Optics ZS61, Atik 414EX mono CCD, 7nm Optolong 2" Ha filter, 8.5nm Baader 2" OIII filter, CEM25P EQ Mount, QHY5III178 guide cam with the Orion TOAG, https://www.astrobin.com/352947).

UPDATE: The Swan Nebula (M17) bi-color narrowband with the WilliamOptics ZS61 and the Atik 414EX. I shot the hydrogen-alpha frames on June 16th (16 x 300 second exposures + 82 x 120 second exposures) and I came back on the 21st to shoot 40 x 300 second exposures in oxygen-3. I decided not to shoot sulphur-2 frames based on the wonderful result with bi-color for my Cygnus Wall image set (6.8 hours of Ha + OIII). For the Swan Nebula (this post) and Cygnus Wall (last post) images I used the Hydrogen-alpha/Oxygen-3 bi-color process developed in an article by Travis Rector, et. al. in The Astronomical Journal here: https://doi.org/10.1086/510117, and detailed here: https://www.starrywonders.com/bicolortechniquenew.html

 

June 8, 2018
How about a little Voldemort with your Astronomy? Here's Barnard 104, the Fish Hook Nebula (backward checkmark nebula was already taken?), just left of the star beta Scuti in the constellation Scutum--along with several other absorption nebulae in the Barnard Catalogue, 113, 111, 110, 107, and B106. (See the image below). These are the dark cloudy regions across the middle, which stand out against the glow of a billion stars in this area of the Milky Way Galaxy. (Okay, I'm being a bit deceptive with the drama there. It's probably more like 5 or 10 billion). Oh, and let's not forget NGC 6704, the open star cluster toward the bottom in the center. A note on the "Barnard Catalogue", which is what I've always called it: I just found out the official name for it is the very Harry Potter sounding, Barnard Catalogue of Dark Markings in the Sky. Go home, Death Eaters! The star gazing geeks got here first! (ZWO ASI071MC cooled CMOS camera at -10°C, iOptron CEM25P EQ mount, William Optics ZenithStar 61 f/5.9, 12 x 120 sec. sub exposures, stacked in DSS. Location: Stratham, New Hampshire, US. Bortle 4).



So, all in all, a successful night of astronomy stuff, even with the clouds rolling in around 2 am. Here are a couple more wide-field shots from the session, the Eagle Nebula and the Sadr Region--the diffuse nebula (IC 1318) around gamma Cygni, also called Sadr (center star in the constellation Cygnus).


I spent a few hours last night dialing in the Orion "TOAG" or Thin Off-Axis Guider, which I bought a couple years ago, but have never been able to get working properly. I've tried seven or eight times, added it to my imaging train a couple times a year, attempting to get things working without success. Well, I went at it again last night, and you know what? It came together. I still have some weirdness to tinker with--to work out, but for the first time I wasn't guiding with a separate scope. I was guiding at the same focal length as the ZS61 using a pick-off prism that directs a portion of the field of view up into the guide camera. Here's the setup I used last night to dial-in the distance between the primary camera and guide camera, and then bring everything into focus. I ended up with some pretty cool shots, but my main purpose was to get Off-Axis Guiding (OAG) adjusted and working--and that was with me slewing around the sky to clear areas between banks of clouds to find some halfway interesting targets. In this setup I'm using my trusty ZWO ASI120MM-S for guiding, and the ZWO ASI071MC cooled color camera for the primary. The goal here is to be able to guide (track the motion of the earth against the star field to a very fine degree, and make small incremental adjustments to the EQ mount) so that I can take long exposures without worrying about the external guidescope issues I know all of you care deeply about, like field rotation and differential motion between a guide scope and imaging telescope. I have been able to take 20 minute exposures with a guidescope and camera, but the stars are not as sharp as I would like--think pressing down the button of your camera and holding the shutter open for 20 or 30 minutes and have everything in the field of view remain in sharp focus. That's essentially what the guiding system accomplishes, taking continuous images of the stars and feeding them to some pretty sophisticated software that controls the motion of the equatorial mount (that's the white z-shaped device with the black boxes on which the telescope is fastened and balanced).

 

June 2, 2018
The Crescent Nebula (NGC 6888) with two channels, hydrogen-alpha and oxygen-three. 4 x 1200 second exposures for the Ha (mostly red channel), and 10 x 600 second exp. for the OIII (mostly blue channel). I didn't get nearly enough of the blue halo around the Crescent as I would have liked. I'll probably need to go to 20-minute exposures in OIII next time--or more 10 minute ones.

 

May 30, 2018 Narrowband imaging on the cheap?
It's tempting to say "here's what you can expect from a $129 Hydrogen-alpha filter", but it's never as simple as that, is it? Perspectives and opinions vary, but I consider this a pretty good H-alpha narrowband shot of the Crescent Nebula (NGC 6888), with some great contrast--the Crescent structure itself stands out, and I still managed to bring in a lot of the surrounding dust and clouds of ionized hydrogen. I used an Astronomik 1.25" 12nm Ha filter, an Atik 414EX mono CCD, iOptron CEM25P EQ mount, and I took 4 x 1200 second subs + 15 dark frames, all stacked in DSS. I shot these frames from my backyard, on a clear night with good seeing (Bortle 4, SQM: 20.62 mag/arc sec² according to https://www.lightpollutionmap.info). I've never shot deep space objects with 6, 5, or 3nm bandpass filters, but a 2" Baader 7nm used to be my primary Hydrogen-alpha filter--and I loved it. When I started out in astrophotography I was thinking long-term and went with 2" filters for everything--and it cost me a bunch. A couple years ago I switched to 1.25" filters, both for cost savings and pairing with the smaller Atik 414EX sensor--2" wasn't necessary. It also allowed me to get the Atik EFW2 with the 9-position filter wheel, so I can run with LRGB, Clear, Ha, OIII, SII, near-IR all in one neat motorized package. Because I was looking to save to money I went with a cheap Ha filter--the Astronomik 12nm H-alpha runs around $130 USD. Very inexpensive when compared to the $300 2" Baader I used to use regularly, and nowhere near the $900+ Astrodon 3nm 2" filter. I'm sure the Astrodon kicks ass--they're one of the premier filter manufacturers. But do you need a $900 filter to shoot narrowband? If you have fairly dark skies in your neighborhood (or within driving distance), I would say absolutely not. Will it make things easier when it comes to increasing SNR in light polluted skies? Absolutely. Will it make things easier when it comes to increasing contrast and pulling in those fainter wisps of dust and hydrogen? Probably. But I wouldn't hold off on narrowband imaging just because you can't afford the best. There are just too many cool targets in the night sky that you're not going to pick up with RGB. And that's one of the advantages of our hobby. You can shoot forty subs tonight, stack, process, and post them, and then come back tomorrow, next week, or next year and reshoot the same target with a different camera, faster scope, or better filters. Some targets never get old, and if they do, there are mysterious absorption nebulae and integrated flux nebulae--and even crazier things in the night sky to pursue. Beyond that, there are always interesting new wonders below the horizon--or above, depending on which hemisphere you spend most of your time.

Short thread on this topic at Cloudy Nights: https://www.cloudynights.com/topic/612314-7nm-vs-12nm-h-a-filter

The general conclusion is get the narrowest bandpass you can afford, which is the right answer, especially if you have any light pollution problems.

 

May 24, 2018
Fourteen stacked frames through the powerlines: The Lagoon Nebula (M8, NGC 6523) and Trifid Nebula (M20, NGC 6514). We have a couple sets of transmission lines running east-west south of our property, and unfortunately they interfere with the amazing stuff in the constellation Sagittarius, which is even lower on the horizon than Serpens (also amazing). Transit for M8 is 23°, compared with 33° or so for the Eagle Nebula. We really need to take a trip south to get a better view of these beautiful ionized hydrogen structures. At the middle and lower left I also captured two globular clusters, NGC 6544 and NGC 6553. That's a very bright section of the milky way lighting up the whole lower left of the frame. Yes, there are stars running through the long bands of power lines, because over the 16 or so minutes of exposure time the earth rotated about four degrees. So, those stars were not obscured by the lines in some of my exposures, but when I stack them all together, aligning all the stars, they're going to appear where they were when camera caught them. That's also why the powerlines appear blurry--they're actually smeared out across the frame. They are much narrower and sharper than that in the individual subs. What's funny--to me, anyway--is that I was shooting the Eagle Nebula, and after 30 or so exposures I started to wonder if I had a chance to get the Lagoon Nebula. I slewed even lower toward the horizon, took a test frame, and saw the powerlines running through it...and thought what the hell, maybe the lines will look kind of cool in the foreground.



North America Nebula (NGC 7000) 50 stacked frames from the ZWO071MC camera.

The Eagle Nebula, Messier 16, sometimes called Star Queen is a diffuse nebula in the constellation Serpens. M16 was only 22° above the horizon to the southeast when I was taking these subs, low enough to have the atmosphere and some light pollution from Hampton affect the result. Even so, I'm here in New Hampshire at 43° latitude, and I'll take any chance I can get to shoot the Eagle Nebula.

Swan Nebula (M17, Checkmark Nebula, Omega Nebula, NGC 6618) is another H II region in the constellation Sagittarius.

The Great (and powerful) Globular Cluster in the constellation Hercules (M13) with a hint of the spiral galaxy NGC 6207 at the top. Last night was my first night out with the William Optics ZenithStar 61, and as I expected, it's just a brilliant little refractor. Paired with the ZWO ASI071MC cooled camera and the WO 0.8x Flat/Reducer F6-A, you get a spectacular 4.7° × 3.1° field of view--that's a big chunk of the sky. If you're looking for a pretty fast widefield apochromatic, this is it. It's not the best choice for the Hercules cluster, but I was just slewing all over the sky, taking pictures, and waiting for the North America Nebula to get above 30 degrees.

 

May 18, 2018
We have not had a really clear night for a month, and last night was still fairly poor for imaging. Even so, I set up the ZWOASI071C paired with a Nikon 24-85mm lens to see what I could capture for a wide-field shot centered on the star Deneb in the constellation Cygnus. This area of the Milky Way just happens to be surrounded by some distinctive clouds of ionized hydrogen, including the North America Nebula (NGC7000) and the Pelican Nebula (IC 5070). Both of these are pretty faint, but they are large, so if you stack enough frames you can bring out enough to see why NGC7000 was given its name. For size comparison, the North America Nebula is four times the size of a full moon. (122 stacked 30 sec. frames, ZWO ASI071MC cooled CMOS camera, iOptron CEM25P EQ mount, Nikon 24-85mm F/3.5-4.5 ED lens @ 85mm. Location: Stratham, New Hampshire, US. Bortle ~4)

 

May 7, 2018
Last night I tested out an inexpensive super-wide-angle 6mm C-mount lens hooked up to my QHYIII178 color CMOS camera (without the IR cut filter, which is why the trees are a bit odd looking). It was pretty cloudy to start and the whole view was fogged in by 3am, but I still managed to get the Milky Way as it was sweeping up and across the sky. This camera + lens would make a nice all-sky type setup, but I'm thinking about using this to capture the full night sky when we have meteor showers--the Lyrids, Perseids, Geminids. This shot is from one of the third-floor windows, facing east. (Our attic is finished). I can stick the camera with a long USB3 cable on the end of an 8-foot length of PVC pipe--out the same window--to get it above the roof of the house and get the whole sky in view. Then I can use SharpCap (https://www.sharpcap.co.uk) to capture several thousand 10-second frames over the course of the night, and bring them together into a video.


Now with video and me talking! Night Sky Video test with the QHYIII178C CMOS camera and 6mm wide-angle lens--with me yapping about the camera and other equipment, explaining settings and other interesting stuff about this all-sky setup. My plan is to use this the next time our planet's orbit takes us through the path of some comet's orbit. (one of the ways we get seasonal meteor showers).

Watch the full video:

 

April 22, 2018
Although the skies were clear last night, the "seeing" wasn't great--"seeing" refers to the amount of atmospheric interference from temperature changes, convection currents, and other funny stuff going on in the air above your telescope. I did get to test out the Pentax 200mm f/4 lens with the Atik 414EX monochrome CCD, and an Ha longpass filter. These clusters are fairly small, so this isn't a very good setup for shooting them, but here you go anyway. Top left: the 300,000 stars that make up Messier 13 (NGC 6205), a globular cluster in the constellation Hercules. Messier 5 in the constellation Serpens. The M3 globular cluster the constellation Canes Venatici. Messier 92 (NGC 6341) is another cluster in the constellation Hercules.

 

April 5, 2018
As the days become longer, as we swing around our sun, headed for aphelion in July (greatest distance from the sun), and our planet's 23.5 degree tilt is angled toward its rays, we'll be seeing less of the constellation Orion--in normal viewing hours. I took this 30 second exposure last night around 9PM, and Orion is already moving below the trees to the southwest. That's the Pleiades (M45) at the far right. I also happened to capture the headlights and brakelights of Alice's car as she's driving past to our driveway, almost home after picking up Christopher from work.

 

March 16, 2018
This was the first chance I've had to put the ZWO ASI071MC through some serious long exposure tests on four very different targets, the region around Alnitak in Orion, the Rosette Nebula, Markarian's Chain, and M101. I ran most of these frames with unity gain (90 Gain, 20 Offset), and I built up a nice library of dark calibration frames in the afternoon, for 600, 300, and 120 second exposure times.

Rosette Nebular Region - Caldwell 49 (13 x 300 sec frames, 24 dark calibration frames) in the constellation Monoceros, about 5000 lightyears from earth. William Optics GT81 APO refractor, ZWO ASI071MC-C camera, iOptron CEM25P EQ mount.



A whole string of galaxies millions of lightyears from earth. Markarian's Chain in the Virgo Cluster, including M84, M86, the Eyes Galaxies (NGC 4435 and NGC 4438) and a few more galaxies and galaxy pairs. The Eyes are 52 million lightyears away! 30 x 120 sec frames, 20 dark frames, stacked in DSS. William Optics GT81 APO refractor, ZWO ASI071MC-C camera, iOptron CEM25P EQ mount.



Pinwheel Galaxy, M101, a spiral galaxy about 21 million lightyears from earth in the constellation Ursa Major (Big Dipper). (Light frames: 10 x 120 secs, 4 x 600 secs, 12 x 300 secs). William Optics GT81 APO refractor, ZWO ASI071MC-C camera, iOptron CEM25P EQ mount, INDI/KStars/Ekos.





Part of the Orion Molecular Cloud Complex that surrounds the blue supergiant Alnitak (large star in the center), including the Flame Nebula (NGC 2024), IC 434, Horsehead Nebula (Barnard 33), NGC 2023, IC 431, and more. About 1500 lightyears from earth. (22 x 300 sec frames, 24 dark frames). William Optics GT81 APO refractor, ZWO ASI071MC-C camera, iOptron CEM25P EQ mount. In case you're wondering, I'm pretty damned excited about this camera (ZWO ASI071MC), just going off what it can capture in faint nebulosity, and what I can bring out without much effort by stretching 22 stacked frames. I can't wait to see what I can capture in the summer when the big galaxies like Andromeda and Triangulum swing through.



Here's my setup for last night's astro session, with the William Optics GT81 APO refractor, ZWO ASI071MC-C primary camera, iOptron CEM25P EQ mount.





 

March 11, 2018
First test shots of M42, the Orion Nebula, M43 De Mairan’s Nebula, Sh2-279 Running Man with the ZWO ASI071MC cooled CMOS camera. No calibration frames, just 17 stacked 300 second light frames, with the sensor cooled to -10C. Last night was not very clear, scattered clouds, fairly poor seeing. I can't wait to test things out with some really clear and dark skies. I definitely need cal frames, because things ended up pretty noisy after processing. I will say, so far, with only a few hours of use, I'm impressed with this ZWO color camera. That doesn't surprise me. ZWO makes a solid camera--I've been using an ASI120MM-S for several years, as my guide camera. It's fast--USB 3, with a small but very sensitive monochrome sensor, and it just always works under any OS on a variety of hardware--Windows, Linux, MacOS. That's what I meant--it shouldn't surprise me that the ASI071MC (quite a bit more expensive and a far more capable camera) just works well. What did surprise me is how much this camera can pick up, bringing out some very faint nebulous areas. I know it has a very wide/high dynamic range. That's one of the things I was looking for in an OSC camera. For this M42 test I used a Gain of 0 and Offset of 8, the minimum recommended by ZWO for long exposure times and HDR (high dynamic range). We'll see how things go on the next clear night. I'd like to test out unity gain settings, and LRN (Lowest read noise) setting, which is high gain, high offset, used for short exposures. (William Optics GT-81 + 0.8x Field Flattener/Reducer f/4.7, ZWO ASI071MC cooled CMOS camera, iOptron CEM25P EQ mount, 30mm mini guide scope with ZWO ASI120MM-S guide cam, INDI/KStars/Ekos observatory control. Location: Stratham, New Hampshire, US. Bortle ~4). Astrobin

 

February 27, 2018
Our moon is looking especially beautiful tonight, even if it's making it difficult to do some deep space imaging. This is a single frame with the William Optics GT81 refractor and Atik 414EX CCD camera and a Celestron UHC/LPR filter that's been sitting in its box for a couple years--so I thought I'd give it a try. I also added a subtle RGB color layer from a few months back.

 

February 16, 2018
I took the Nikon D750 out tonight and got a nice 30 second exposure of the constellation Orion (upper right of the first image), with some of the PSNH transmission lines in the foreground. That's Sirius almost center in the shot, with Procyon on the upper left. Centered in the image about a quarter of the way from the top, there's a reddish blur between the star Procyon and the star Betelgeuse in Orion--that's the Rosette Nebula--see my December 26 post. (Nikon D750, 24mm, Hoya LiPo filter, f/4.5, 30 sec. exp. ISO 800). The second shot is M44, the Beehive Cluster in the constellation Cancer--plus a few more stars. (Nikon D750, 24mm, Hoya LiPo filter, f/4.5, 1 x 300 second exposure, ISO 800). These are both single exposures, and I shot both on the iOptron CEM25P mount, and what amazed me was that, with pretty good polar alignment, just using the polar scope (no drift or polemaster), I was able to get 3 and 4 minute exposures unguided. The M44 shot is 300 seconds (5 minutes) with some slight star elongation, but still not a bad shot.


Hertzsprung-Russell diagram - source: ESO

The color of stars is interesting to look for--take a closer look at the Beehive Cluster (M44) image and it's easy to see that the star-field is full of color. I think there's this notion that stars are white pin-points of light in the night sky, but every star has a color, most of them ranging from red to deep blue, depending on many factors including where in its life-cycle it is, the materials it's made from, size, and more. See the Hertzsprung-Russell diagram, listing some of the more familiar stars in our galaxy by surface temperature and luminosity. Our star, the Sun, is pretty close to the middle of the Main Sequence line, between cooler, redder stars and the hotter blue stars. What's interesting is that the shot of the constellation Orion I took the other night--included here--contains several of these stars from the diagram. If you start at the Sun and follow the Main Sequence line up toward the blue end, you will quickly find Procyon, which is the bright star in the top left corner of my image. Sirius--in the diagram--is a couple up from there, but it's almost in the center of my shot. Keep going into the blue, and there's Bellatrix, the blue star which makes up Orion's right shoulder. Now head right from there, out of the Main Sequence line and into the Supergiants, and find the blue supergiant Rigel, which makes up Orion's right foot. And finally, keep going right to the massive red supergiant, Betelgeuse ("Beetle-juice"), which is the left shoulder of Orion. (Hertzsprung-Russell diagram source: ESO - European Southern Observatory, ). How's that for taking one picture of the night sky with some nice examples of stars of varying size, color, and lifespan?




 

February 11, 2018
It's been a cloudy week, and the seven days ahead don't look much better. So I'm digging through some wide-field frames from last summer--to stack and process, and I particularly love this small section of our galaxy, the Milky Way. We are about 26,000 lightyears from the center of our galaxy, all of us on our little blue planet orbiting a G-type main-sequence star. And if you're looking inward, toward the galactic center from our world, you'll see something like the image here (this is a crop of a much wider field of view, so you'll actually see much more, that well-known and aptly-named long pale band across the sky). We are right in the thick of things with our galaxy, which is well over a 100,000 lightyears across and contains as many as 400 billion stars. To put the size of our galaxy in perspective (and keep in mind that 100,000 lightyears is the low side of the approximate diameter, calculated to be between 100,000 and 180,000 lightyears across), we are talking about 587,863,000,000,000,000 miles. So, we'll round up a bit and say our galaxy is at least 588 quadrillion miles across. And to put the size our galaxy in perspective, one of our neighboring galaxies, M31, Andromeda, may be twice the size of the Milky Way, with as many as a trillion stars (It seems like there's always a debate on the size of M31). And if that doesn't make you think about our place in the universe, take a look at this Hubble image and understand that almost everything in the frame, every point and spiral and smear of light is itself an entire galaxy: https://www.nasa.gov/feature/goddard/hubble-spies-big-bang-frontiers. How's that for something to contemplate on a nice Sunday afternoon? You're welcome.

The above shot covers a 30 × 20° FOV of the Milky Way from a little below M17 (Swan Nebula) in the constellation Sagittarius to a little past Delta Aquilae, the bright white star at the bottom left, in the constellation Aquila. Below, is my original shot cropped from M17 on the right to just past Eta Cygni, a variable double star in the constellation Cygnus--about twice the width of the one above. The brightest star in the frame, low center, is Altair.

 

January 14, 2018
Astrophotography - Leveling Up
Something strange and wonderful happened over the summer, and at the time I was wondering if it was a unique couple days. Well, it has continued, and looks like it’s here to stay. I seem to have made it to the next level. How do I know? Not only am I taking 5, 10, 20-minute subs with narrowband filters, they look good. Really good. Okay, so I’m not in the same set with the astrophotographers posting some of the really impressive dark nebulae, integrated flux nebulae (Yes, the mysterious IFN), and other deep sky objects out there on Astrobin and elsewhere, but I’m very happy with the images I’m getting out of my equipment.

There’s a process we go through when we set out on this whole astronomy and astro imaging path--from beginner to wherever you are now. A process when we learn how to use new equipment, when we set up an equatorial mount, work through the intricacies of guiding, alignment, processing images, automating our gear with ASCOM or INDI—and whatever software you’re using on top of these protocols for observatory control.

We learn in different ways, but there’s one part of the process all of us have or will experience--I’ve experienced this four or five times over the last few years: one day you set up your EQ mount and OTA, you start everything up, your alignment process goes smoothly, you slew to your first target, focusing just works, plate solving and tracking have pinned your view down to the exact few arcseconds or degrees in the sky where you want to shoot, and suddenly you’re leaning back during 20-minute subs, thinking about things that—as someone who’s obsessed with astronomy—you should be thinking about on a night out under the stars, like: isn’t it amazing that the light allowed through the really narrow bandpass of the Ha filter to touch the CCD sensor on my camera has travelled 23 million lightyears through 2.176 x 10^20 kilometers of interstellar space, through the earth’s atmosphere to get here--to get to the telescope and camera I just set up in my backyard. Or maybe you’re thinking, hey, the neighborhood around Cassiopeia and Cepheus really is a kick-ass part of the sky when it comes to interesting nebulae. It’ll be something like that.

That’s the day things just work, and from that day forward (apparently) they continue to work--for the most part. Things click effortlessly together, and you’re not thinking about problems with focusing, or why the guide camera keeps losing the guide star, or any of the thousand other pieces of the astro-imaging process that can ruin that night out under the stars. It’s as if you’ve leveled up. All the accumulated knowledge, failures, weirdness in the system you’ve experienced--all the troubleshooting you’ve done over the last few years has seeped into your brain to become automatized behavior. And stuff that was difficult a month ago is now second nature. It’s like that happy moment in a good D&D game when you add up the points and you’re suddenly a level 8 Paladin Astrophotographer. It’s a damn good night.

And don’t worry if it this hasn’t happened yet--or recently. That only means if you stick with this astro stuff you’ll level up soon. Even if you’d like to, you won’t forget the frustrations of last night--as time-consuming and apparently wasteful they may have appeared. You’re learning from them. You’re picking up details you may not even be aware of, and you’re packing them away for the next clear night.

Here’s to clear skies. Go find them!

 

January 13, 2018
It's winter and that's when Orion is arguably the main attraction in northern hemisphere skies. HaRGB of the Horsehead Nebula (Barnard 33) along with the reflection nebula NGC 2023 (below and left), part of a whole neighborhood of nebulosity around the leftmost star in Orion's Belt, the blue supergiant Alnitak. (I kept Alnitak out of frame, but it would off to the left with a wider field of view). The Horsehead is an absorption (or dark) nebula about 1500 lightyears from Earth, and shows up so prominently because it's blocking most of the starlight behind it. (10 x 600 second Ha frames, 10 x 240 second RGB frames, 24 dark cal frames taken with an Atik414Ex mono CCD, William Optics GT-81 + 0.8x Field Flattener/Reducer f/4.7, iOptron CEM25P EQ mount, Astronomik 12nm Ha filter, Baader RGB filters, WO 50mm guide scope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control. Location: Stratham, New Hampshire, US. ~Bortle 4)


The full FOV for this shot:

 

January 10, 2018
The temps are nice--downright warm compared to what we've been hit with over the last couple weeks. The clouds are the problem. They gave me two hours of clear skies, and I spent them taking a batch of five minute exposures of M42, the Orion Nebula. (Atik414Ex mono CCD, William Optics GT-81 + 0.8x Field Flattener/Reducer f/4.7, iOptron CEM25P EQ mount, Astronomik 12nm Ha filter, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control)

 

December 27, 2017
California Nebula NGC 1499, an emission nebula in the constellation Perseus. Named after the Golden State because of the similarity in shape--and this is just the lower portion, basically Santa Barbara on down, although depending on how you match up coastline similarities you might be able to squeeze in everything up to Pismo Beach. I attempted to do some Ha + RGB color process stuff with this set, and I think it worked out. I overloaded the red channel to bring out some contrasting shades, and the GB didn't contribute much. NGC 1499 is mostly ionized hydrogen, and it's massive, almost 2.5°. I'd have to take two or three combined shots to get the whole nebula in one image with the camera+telescope FOV of my setup: Atik414Ex mono CCD, William Optics GT-81 + 0.8x Field Flattener/Reducer f/4.7, CEM25P EQ mount, Baader and Astronomik filters, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control.

 

December 26, 2017
A couple test Ha frames of Lower's Nebula (SH 2-261) in the constellation Orion. I only took two exposures of Lower's Nebula while waiting for the Rosette Nebula to rise, and it reminded me of a scene in the movie Roxanne with Steve Martin (CD Bales) and Daryl Hannah (Roxanne):

C.D. Bales: You must know about M31.
Roxanne: Yeah.
C.D. Bales: Now, see, I like it when they give astronomical objects names, you know, like "Andromeda" and "Saturn" and "Sea of Tranquility." This whole numbering thing is just too boring for us civilians.
Roxanne: Do you know how many objects are up there?
C.D. Bales: Well, I know it's over fifty.

That's the problem when you're a constellation like Orion, with a nebula so massive and bright you can see it clearly without a telescope (M42), or you possess dark nebular structures famously shaped like animals (Horsehead nebula, Barnard 33). You get overlooked if you're not a superstar or supernova remnant or "The Great" Orion Nebula. Yeah, that's Lower's Nebula (SH 2-261), which I'm sorry to say, I had never heard of before last night. Unfortunately that's probably because Lower's Nebula isn't the buckle on Orion's Belt. It isn't even hanging off of Orion's famous belt. It is literally out on a distant arm of the constellation--yes, Orion has one arm raised, far away from the Belt, and the famous stars like Betelgeuse, Bellatrix, and Rigel, and that's where you'll find this obscure cloud of hydrogen that doesn't even have a wikipedia page (In English. I found an Italian page for SH2-261. Nicely done, Italy.)

(Subframe info: one 600-second exposure and one 1200-second exposure stacked in DSS, no calibration frames, Atik414Ex mono CCD running at -10C, Astronomik 12nm Ha filter, William Optics GT-81, CEM25P EQ mount, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control)

 

December 26, 2017
I took several hours of hydrogen-alpha, oxygen 3, sulfur 2, and RGB images last night. Here's the color version of the Rosette Nebula (nebular region) with OIII and SII frames added to a bunch of Ha frames I shot at the beginning of the month.

Okay, this new astro setup worked well (see yesterday's post). I just bolted on the mount, did a quick polar alignment, and I was taking beautiful twenty-minute exposures of NGC 1499 (California Nebula). I shot some hydrogen-alpha of the California while waiting for the Rosette Nebular region to come into view.

I have been on this automated portable astrophotography path for a while; it's been a slow but continuous process of remote controlling my entire astro imaging rig from anywhere. I set it up, and as long as there's power and wifi, I'm good to go. This latest iteration, making the whole rig portable, is going to make things easier on those nights when I know I'll only have two hours of clear skies. Before now I wouldn't even think about setting up because that could eat up an hour alone. (Atik414Ex mono CCD, William Optics GT-81, CEM25P EQ mount, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control)


Four stacked 1200-second frames of NGC 1499 with the 12nm Astronomik Ha filter:

 

December 25, 2017
My Winter Astro Setup, essentially the same William Optics GT-81 - iOptron CEM25 combo, with the addition of the iOptron Tri-Pier Adapter, some 6x8 aluminum plates off eBay, and one treated 4x4 post from Home Depot.

The good side of winter and astrophotography is it’s usually dry on clear nights--and “clear” really means clear in terms of astronomical seeing, atmospheric turbulence and all that. Downside is that it’s freakin’ cold. Tonight it’s supposed to get down to about -8°C (about 20°F), pretty cold to be out for a long time, but not painfully cold.

Here are a couple shots of my setup for tonight--and possibly the rest of the winter. (William Optics GT-81, CEM25P EQ mount, Atik414Ex mono CCD, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control). What’s cool is that I can unbolt the mount with the pier adapter and aluminum base plate (they’re all bolted together) from the 4x4 post and top plate, and carry in the entire setup--mount, scope, cameras, etc. What I especially like about this is the ease with which I can setup and tear down each night. The whole thing remains balanced and ready to go, with polar alignment reduced to very fine adjustment to zero in on the NCP.

Note on my other mount: I probably won’t use my Orion Atlas EQ-G mount until spring when things start to warm up, and that’s based on the weight of the Atlas and the low temperatures--with ice adding some difficulty to the setup process. (Yeah, I don’t want to lug around this monster with any probability of slipping, landing on my back, and having to catch fifty or sixty pounds of metal out of the air before it kills someone). The average winter low in New Hampshire is around -12°C, and the average winter high temp is still below 0°C (around 30°F). It’s not unusual for things to get down to -20 to -30°C (-10 to -20°F). We’re still in December, so early in the season, but we’re already getting repeated snow storms interspersed with temps above 0°C (32°F). We typically get a few days of warmer weather here and there, snow and ice melting weather, but there haven’t been enough of them to make a dent in the accumulating snow and ice we have in the yard, driveway, or back deck. We just ended yesterday (the 25th) with another 6 inches or so. When there’s ice, lighter is better.


 

December 1, 2017
We were very close to a full moon last night, so my astro imaging options were limited to narrowband. I spent most of the night with Hydrogen-alpha, an inexpensive 12nm Astronomik filter, but as you can see, able to bring out some fantastic contrast, depth, and details throughout this region of interstellar ionized hydrogen. (This is the filter I currently have in the 1.25" wheel. My Baader 6nm Ha is in the 2" filter wheel)

The "Rosette Nebula" is a cluster of nebulosity that includes NGC 2237, NGC 2238, NGC 2244, NGC 2239, NGC 2246 and more. The Rosette is a bright mag 9 area of the sky about 1.3° across in the constellation Monoceros. (subframe info: 28 600 second exposures in hydrogen-alpha, no calibration frames, Atik414Ex mono CCD running at -10C, Astronomik 12nm Ha filter, William Optics GT-81, CEM25P EQ mount, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control). https://www.astrobin.com/324406/



One of many reasons I love the Atik 414EX is how clean (free of noise) the light frames are when you cool the sensor down to -10C or below. I didn't shoot dark frames, or any other calibration frames last night, and didn't use any from my library when stacking.

My last target of the night: center portion of IC 2177, the "Seagull Nebula" in the constellation Monoceros. There's noise that showed up during stretching, but this one of IC 2177 is just 4 stacked Ha frames, each 600 seconds.



Here's a screenshot of Ekos and KStars, in the process of capturing 600 seconds of photons landing in my backyard from the Rosette Nebula. This is pretty much what I see--the tools I work with--when remotely controlling the mount, telescope, cameras, targeting, focusing, plate solving, and more. And that's what a single 600-second frame looks like. With stacking I'm obviously getting a lot more signal to noise.

 

November 10, 2017
M33 Triangulum Galaxy, about 3 million lightyears away, so... not that far. M33 is a relatively small spiral galaxy with only 40 billion stars. I'm having some trouble with my guide camera (ZWO ASI120MM), so this is all unguided. I took 80 LRGB exposures--120 seconds each, 10 Ha frames at 120 secs, 20 dark calibration frames, stacked in DSS).

 

November 10, 2017
Constellation Orion (and that's Sirius in the lower left). I was out in the cold last night, with the Nikon D750 (24mm, 30 sec. exposure, ISO 800). Love that Hampton sky glow.

 

October 18, 2017
The three central and brightest (low magnitude) stars in the open star cluster M45, called The Pleiades or The Seven Sisters: Alcyone (upper middle), Maia (right), and Merope (left). The light of the stars in the Pleiades pass through and illuminate a cloud of dust in the interstellar medium. (8 x 5 minute exposures, 18 dark frames - William Optics GT-81 478mm FL, Atik 414EX Monochrome CCD, Baader luminance filter, CEM25P EQ mount).

 

October 17, 2017
Color version of M81 (Bode's Galaxy) in the constellation Ursa Major (Big Dipper). From another set of subs I shot at 4am--this time with the color QHY CMOS camera, QHY5III178. Info: 21 x 300 sec. with 20 dark frames, QHY5III178 color CMOS, William Optics GT-81, CEM25P EQ mount, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control.

 

October 13, 2017
IC 405--"Flaming Star Nebula" in the constellation Auriga, centered on the mag. +6 star AE Aurigae. It's relatively close to us, at about 1,500 light-years. This set of subframes covers the center of the fairly large nebula, which measures 37 x 19 arcminutes. (6 x 1200 second subs in Ha, O3, S2, taken with my current main setup: Atik414Ex mono CCD, William Optics GT-81, CEM25P EQ mount, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control).

 

October 12, 2017
M81 (Bode's Galaxy) and M82 (Cigar Galaxy) in the constellation Ursa Major (Big Dipper). I was up at 4am, and there's the big dipper swinging around and climbing into the sky. Bode's and the cigar galaxy were just waiting to be captured. Info: 15 x 120 sec. with 10 dark frames, Atik414Ex mono CCD, William Optics GT-81, CEM25P EQ mount, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control.

 

October 12, 2017
NGC 281 (IC 11, Sh2-184) "Pacman Nebula" in the constellation Cassiopeia. More narrowband imaging, although the moon is waning, and didn't even make into the sky until the early morning hours. I completed the subs for NGC 281 by 1am, and scheduled some narrowband exposures of IC 405, Flaming Star Nebula. (subframe info: 6 x 1200 second exposures in Ha, 5 x 1200 sec OIII & SII with 16 dark frames, Atik414Ex mono CCD, Astronomik 6nm Ha, OIII, SII, William Optics GT-81, CEM25P EQ mount, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control).

 

October 5, 2017
I finally made some time to process one of the image sets I shot on October 2, and here's one result: narrowband of the central region of the emission nebula IC 1805, the Heart Nebula, which is only 7500 lightyears away in the constellation Cassiopeia. (It's almost in our backyard!) I used the "Hubble Palette", mapping the separate hydrogen alpha, oxygen, and sulfur image channels to RGB channels (SII = Red, Ha = Green, OIII = Blue) in the final. (subframe info: 4 x 1200 second Ha, 4 x 600 sec OIII & SII with 2x2 binning, Atik414Ex mono CCD, William Optics GT-81). I'm not entirely happy with this one, but good enough to post.


 

October 5, 2017
NGC 6888 - Crescent Nebula in Ha (4 x 1200 second subs + 15 dark frames stacked in DSS). I continued my hydrogen alpha campaign tonight, with a couple more targets, including the Crescent. My goal over the next month or two is to continue capturing these nebulae in O3 and S2, and use those results with these Ha shots to produce color images. I may also test out some Ha+RGB image processing on a couple of the brighter ones like IC 1369a, the Elephant Trunk Nebula.


 

October 4, 2017
Astrophotography with a full moon! I switched to narrowband imaging a few days ago, which has the advantage of limiting the light to a very narrow range, and not really being affected by the light of the sun reflected off the big smiling face of our moon. The requirements are far stricter than color or LRGB imaging in terms of exposure times (10 - 30 minute exposures are typical), which in turn require far tighter alignment for the mount and guiding system. I have three narrowband filters--Ha (hydrogen alpha) OIII (oxygen) and SII (sulfur), all with 6nm bandpass. For these images below I'm only imaging with the Ha filter and the Atik 414EX monochrome CCD camera. Image info: top-left: IC 1848 Soul Nebula (the center portion), bottom-left: IC 1369a Elephant Trunk Nebula, right: NGC 281 Pacman Nebula. 4 x 20 minute (1200 second) subs stacked in DSS.


 

October 2, 2017
I love this early autumn weather! Here's a 20 minute hydrogen alpha exposure/sub of IC 1805, the Heart Nebula, a diffuse nebula in Cassiopeia. FoV: 1.05 × 0.79° (William Optics GT-81, Atik 414Ex CCD, ZWO ASI120MM guide camera with WO 50mm guide scope, Astronomik Ha 6nm filter).

I will post my actual setup for this one soon--mainly because I want to lock down my portable gear for reference when setting up in the field. What amazed me tonight was the ability to get pretty clean 20-minute subframes with the new iOptron CEM25P mount, leveled, pointed toward the NCP, and a quick polar align. And all of this on the back deck, which isn't the most stable platform around. (There is some star elongation at the top right and bottom left corners, which I'm attributing to the image train and focuser sag. It's slight, but it's there. My next large-ish purchase for the GT-81 is a Moonlite focuser, which will significantly improve the rigidity of the system).

I have to say I am really impressed by the CEM25P mount (the latest iteration of the ZEQ25 from iOptron), and I was expecting quite a bit of precision given that the company pretty much guarantees a low periodic error (< ± 10 arc seconds). But to have this come through without even trying...well, that makes me happy.


 

September 23, 2017
What the backyard looked like last night. Sort of an astronomy campout under the stars. It was a pretty clear night. I hope you had clear skies wherever you were last night! (Nikon D3100, 18mm, 13 sec. exp. ISO 1600 - I used my son's camera for these shots because mine was hooked up with the AstroTech scope)


Here's one from last night's astro shoot: M42 - Orion Nebula (Yes, my favorite diffuse nebula). This time of year Orion doesn't start appearing over the horizon until the early morning hours. My Exposures started around 2am and ended around 5am. (Nikon D750, AstroTech AT6RC, William Optics field flattener/ 0.8x reducer; 162 light frames stacked in DSS, 140 dark frames).



And another shot from last Saturday night--of the Orion Nebula (M42) and De Mairan's Nebula (M43). This was the view from my other scope, William Optics GT-81 with the Atik 414EX monochrome CCD camera--which is just going to pick up a lot more of that good old ionized interstellar hydrogen.


 

August 21, 2017
My contribution to the 2017 Solar Eclipse craziness. I shot nearly 200GBs of video and still images with a QHY5III178 CCD camera, Nikon 300mm lens, Seymour Solar filters.



I did manage to pick up some decent sun spots on all the filtered images:



Solar eclipse and moon composite shot:



Here's the simple setup I used for these solar shots: QHY5III178 CCD camera, Geoptik Adaptor for Nikon lenses, Nikon 70-300mm lens, Seymour Solar filter. I used SharpCap under Windows 10 to capture frames. And before you ask I'll say, yes, I am using dew heater strips to hold on the solar filter, which is sized for 4.1" diameter scopes (like the William Optics GT-81). And yes, that isn't very safe if I was looking directly through the lens, but since I was doing all of this from the shady comfort of my garage...well, that's okay then, right? Sometimes you just have to rig something up to take some pictures.


 

July 24, 2017
I'm down with the LMC--let me hear you say Large Magellanic Cloud. I took some wide field images of a small portion of the LMC, centered on the Dragon's Head Nebula (NGC2035), that colorful stretch of star-forming cloudiness in the middle of the pic. Astro specs: 8 stacked 300 sec exposures, Takahashi SKY90 APO, SBIG ST2000 XMC camera, Paramount PME.

Now, before you go thinking that I've teleported to the southern hemisphere, which is where you have to be to see our nebulous galactic neighbor, the Large Magellanic Cloud, I assure you I haven't. I have merely bought a tiny slice of observatory time on some fantastic hardware that happens to be located at the Siding Spring Observatory, New South Wales, Australia.

I will also tell you that I can fly from here to Australia seven or eight times--first class--for what that equipment setup costs. It's so much easier pretending to be there under the stars near Coonabarabran, using some totally badass astronomical gear. And it's easy, and inexpensive. Besides, it's pouring rain here, and I miss seeing the sky. Wait, I don't have to justify my imaginary stargazing trip to Australia to you! Go check it out yourself: https://www.itelescope.net (The observatory in Spain is lovely as well).

A portion of the Large Magellanic Cloud

 
 

ASTRO LINKS
DSO Browser - One of the best sources for selecting astro targets.
Cloudy Nights
The Astro Imaging Channel - AIC Youtube Channel
Starry Sky Project - Japan


 

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Saltwater Witch copyright © 2017 Chris Howard