Cygnus Wall in SHO
Narrowband North America Nebula (NGC 7000) in the Constellation Cygnus, with the "Cygnus Wall" across the lower third of the image. You're looking at about 130 trillion miles of dense clouds of ionized hydrogen, with a bit of oxygen thrown in. NGC 7000 is around 1600 lightyears aways, and the "Cygnus Wall" is about 20 light years long. Imaging notes: William Optics GT81 Apochromatic refractor, Astronomik 6-nanometer hydrogen-alpha (Ha), Oxygen 3 (OIII), sulfur 2 (SII) filters, ZWO ASI1600MM-Pro monochrome camera, QHY 5iii178 guide camera, Sky-Watcher EQ6-R Pro Mount.
Posted October 4, 2021
Testing the Narrowband Rig with the New OTA
First narrowband test with the new Apertura Newtonian scope, although it was barely a test—31 sub-exposures in Ha before the clouds started rolling in, and with a very bright full moon in the sky. IC 1396 is a large (3 degrees in diameter) emission nebula and star-forming region in the constellation Cepheus, about 2400 lightyears away. Within IC 1396 is the Elephant's Trunk Nebula catalogued as IC 1396A, pictured here in hydrogen-alpha (narrowband). This structure is well over a hundred trillion miles long (roughly 20 lightyears), so if you want to get from the top to the bottom you'd better have a pretty fast vehicle.
Notes: 31 x 240 second subs in Ha. Apertura 8" Newtonian 880mm FL at f/4.4, ZWO ASI1600MM-Pro monochrome camera, Astronomik 6nm Hydrogen-alpha filter, SkyWatcher EQ6-R Pro mount, controller: INDI/Ekos/KStars. I managed to capture 31 subs of IC1396A, but no calibration frames—that's only half the subs I would normally want for this one in Hydrogen-alpha. I was not dithering here either, which is something I normally have on, and the result is some "walking noise" which is pattern noise in one direction--top-right to bottom left, in this case, introduced either by polar alignment drift or differential flexure between the guide scope and the OTA (this is the most likely suspect here, but not absolutely sure). Guiding total RMS averaged around 1 arcsecond the whole time, not the best, but I attributed it to the full moon, lack of contrast, but who knows. I didn't see any walking noise with the color rig, but even so, I'm going to go with off-axis guiding next time th eskies clear and see what happens!
Clouds swept in around midnight, and then it rained through the night, so I took what I could get and did some mild processing. There's serious coma around the edges. I have the stars pretty well dialed in with the color train, but not here. I have some measuring and caliper work to do!
The area around the constellation Cepheus is an astrophotography buffet, and because the constellation is circumpolar, it's in the night sky for at least half the year—if you're anywhere near the north. Both the Iris Nebula and the Fireworks Galaxy, two amazing deep sky objects I captured last week, are here, along with the Elephant's Trunk nebula, Cave and Wizard nebulas—and a lot more! Some of these targets span the border with Cassiopeia at the bottom.
BiColor version of the central region of the Elephant's Trunk Nebula--Hydrogen-alpha and Oxygen 3:
Posted June 25, 2021
Our moon
There's a beautiful moon out there tonight! Nikon D750, AstroTech AT6RC 1350mm f/9, 1/2500 sec exposure.
Posted June 23, 2021
Second night out with the Apertura 8" Newt
I selected IC 5146, the Cocoon Nebula as a nice broadband color target for my second clear night with the Newt, and at 800mm focal length, the Cocoon should fit nicely in the frame, with room for the long trail of dust flowing away from it--if I can manage it.
Mechanics: the stars only look slightly better tonight, still wacky around the edges. They were a coma-induced mess last night, but I rearranged some of the imaging train and...it looks, well, not much better. But I'll get there. I am not the type to spend all night twiddling with spacers and digital calipers to calculate the correct back-distance and eliminate every last trace of coma. I'd rather image, and make small corrections along the way, even if it means the stars look like crap before I get things properly dialed in.
So, I was also looking for a nice target to shoot while the Cocoon climbed a bit higher in the sky, more than 30°, and I went for NGC 6946, Caldwell 12, the Fireworks Galaxy in Cepheus. I don't normally go for galaxies, unless they're relatively close by, but there are a few like M101 (Pinwheel Galaxy) and M81 (Bode's Galaxy) which are great targets if you're running with less than a 1000mm--other than the obvious ones like M31, M33, LMC, etc.
The Fireworks Galaxy is 22 million lightyears away. To put that distance in perspective, one lightyear is almost 6 trillion miles. I'll leave the multiplying by 22 million up to you. Fireworks is a medium-sized galaxy, about half the size of the Milky Way at about 40,000 lightyears across. It's a spiral galaxy, and it has the advantage, from our perspective, of being face-on, or is that top-down? Notes: 31 x 120 second subs, no filters.
NGC 6946, Caldwell 12, the Fireworks Galaxy in Cepheus:
The Cocoon Nebula (IC 5146, Caldwell 19, Sh 2-125) is a roiling mix of new stars, ionized gases emitting light, mostly in wavelengths out at the hydrogen end of the spectrum, with additional layers of clouds of dust and gas lit up by those same stars. Actually, most of the ionizing weight appears to be carried by the central pre-main-sequence B type star, BD+46°3474. The whole circular structure labeled IC 5146 is a reflection nebula and an H ii region that forms a "cocoon" around BD+46°3474 (that bright star in the center), which is probably less than a 1 million years old and is probably closer to 100,000 years old (compare that to our star, the Sun, at 4.6 billion years old). This central star's intense radiation and stellar winds have hollowed out the dense molecular clouds, and the radiation flowing off it is ionizing the material and lighting it up. There's a long dark band of gas trailing off frame at the bottom of this image that leads to a separately identified dark nebula, Barnard 168 (B168). The Cocoon is around 2500 lightyears away in the constellation Cygnus. Imaging Notes: There's so much going on here across the visual spectrum right on out to hydrogen-alpha and near-infrared. Most color astro cameras, DSLRs, and mirrorless cameras will be able to pick it all up. If you can, light pollution allowing, try to catch the Cocoon Nebula without any extra filters. My imaging run: 67 x 240 second subs, no filters. Apertura 8 inch f/4 800m FL Imaging Newtonian, ZWO ASI071MC color camera, GSO Coma Corrector, SkyWatcher EQ6-R Pro mount, Stellarmate/Raspberry Pi 4 running INDI/Ekos/KStars.
IC 5146, the Cocoon Nebula in Cygnus:
Posted June 18, 2021
NGC 6820
NGC 6820 (Sh2-86) in hydrogen-alpha narrowband. This emission nebula in the constellation Vulpecula is made up of one vast pillar and several not-so-vast pillars of dark molecular dust and gases that have been eroded by the driving stellar winds and intense radiation of the star cluster NGC 6823 (above NGC 6820 in this rotation). Did someone say, "Bok globules"? Yeah, we got those, small dense chunks of dust and gas (hydrogen, carbon, helium, silicates, etc.) that lead to star formation. Of course, small is relative in this case. You can probably take a dozen copies of our entire solar system, including the Kuiper Belt and Oort Cloud and easily fit them all inside most. I gave this monochrome image a hint of vintage tint, a bit or warmth, to counter the core temperatures of Bok globules, which are thought to be some of the coldest objects in the universe. It also makes the image appear a bit brighter.
Posted June 11, 2021
Night Sky, June 10, 2021
It's a beautiful night out, even if our eyes can't see in 30+ second exposures. Our galaxy, the Milky Way, is swinging up from the East. The "Summer Triangle" is right there in the center, with Altair just above the tree line, Vega is the bright star in the center, Deneb below and to the left. Nikon D750 and Irix 15mm f/3.2
Posted June 10, 2021
NGC 1499 (California Nebula) Reprocess
While the clouds and rain hang about, I'm reprocessing some data from late last year. False color imaging is fascinating, and I'm retrying the bi-color, Hydrogen-alpha and Sulfur 2 made up of Red and Blue with equal parts Green. The dark clouds of interstellar dust and pockets of hydrogen stand out more this time. NGC1499 is an emission nebula in the constellation Perseus, about 1000 lightyears away from us. This is the central region of the California Nebula, so that means the interstellar version of Fresno is somewhere in there. 
Posted May 23, 2021
Messier 13
Hercules Globular Cluster (M13, NGC 6205) with the ZWOASI071 and SpaceCat 51. This is cropped quite a bit, but still not bad.
