The Wizard and the Soul

August 2, 2019 - Reading time: 3 minutes

I captured almost 5.5 hours of OIII and SII data on NGC 7380 (Sh2-142) the Wizard Nebula and star cluster in Cepheus, along with a full set of narrowband frames for IC 1848 the Soul Nebula in Cassiopeia.  I timed things well enough that I captured 20 subs each of Ha, OIII, and SII for the Soul before the earth rotated into early morning. Not a ton of data, but enough to process and see how it looks--not bad, in my opinion. My camera rotation is almost 90º off, almost vertical against the long side of the sensor, but I cropped the nebula to a square so you don't have to see how silly that looks. 

I captured the Ha data for the Wizard Nebula early in July, and now I have enough to process in SHO (Hubble Palette) that's where we map the three bandpasses, sulfur (SII), hydrogen (Ha), and oxygen (OIII) to RGB, Red, Green, Blue to make up a color image. 

Here's NGC 7380, Sharpless 2-142, Wizard Nebula:

IC 1848, the Soul Nebula:

I don't know if I succeeded but I was trying to get more hydrogen green back into the arrangement. Most of the nebula is hydrogen--just going off the signal in the Ha frames compared with the OIII and SII data. The rims of both regions of IC 1848 are thick with sulfur--red and green gets us that golden brown, but I think the processes, filters, actions typical for astro imaging go too far in reducing green in the images, bending it more toward blue. This does have the benefit of bringing out oxygen, which is nowhere near as plentiful as the blues I see in most SHO/Hubble Palette images. That's just what everyone's come to expect from a "Hubble" image. On the other hand this is one of the coolest aspects of the hobby, the ability to go back and re-processes your data, because you have new or improved processing tools or skills, a new set of data, or simply because you want to experiment with color allocation.

I woke up around 3:30 am and went out to check on the night's imaging run. I was in the middle of the sulfur2 frames when I took this shot with the Nikon: the William Optics GT81 APO refractor pointed at Cassiopeia (top left), actually just below it, which is where you will find IC 1848, the Soul Nebula. Just so you are aware, this is all automated--slewing, plate solving, focusing, filter rotation, and image capture. Once I plot and schedule an imaging run, the last place I want to be is near the telescope where the slightest motion in the ground can ruin a good 5-minute exposure. I was just out there to look at the beautiful sky, and take some crappy blurry photos of my astro gear against the starry background.


Pelican Nebula ( IC 5070 and IC 5067)

July 25, 2019 - Reading time: ~1 minute

Another one from my June 8th narrowband imaging run through the constellation Cygnus. The Pelican Nebula ( IC 5070 and IC 5067) in sulfur 2, hydrogen-alpha, oxygen 3, mapped to RGB.

My narrowband imaging rig: William Optics GT81 (81mm aperture, focal length 392mm, f/4.7), Moonlite Focuser, Pegasus Astro Power, and ZWO monochrome cameras and EFW. 


Short nights, narrow bands, works in progress

July 9, 2019 - Reading time: 2 minutes

We probably have less than four hours of seriously dark night this time of year--at my location, coastal New Hampshire. And you have to make do with that. So, last night I spent every minute on hydrogen-alpha frames for three targets, Sh 2-54 (with the star cluster NGC 6604 in the center), NGC 7830 Wizard Nebula, and NGC 281 Pacman Nebula. I went through each of these and shot 30 x 180 second exposures, starting around 10:30 pm, which is still a bit within astronomical twilight.

The nebula Sh2-54 is about 5000 lightyears away in the constellation Serpens. It's part of a long band of nebulosity that extends almost ten degrees through the Eagle Nebula (M16) and Swan/Omega Nebula (M17) below that. NGC 6604 is the cluster of stars above and to the right of the brightest knot of the nebula. Imaging notes: 30 x 180 sec Ha sub stacked in DSS and processed in Photoshop CC. 

NGC 7830 is the star cluster surrounded by the Wizard Nebula, an HII region about 7200 lightyears away in the constellation Cepheus. This is 30 stacked 3 minute exposures, no calibration frames. 

NGC 281, called the Pacman Nebula for obvious reasons is an HII region in Cassiopeia. Pacman has some amazing features including a batch of really distinct Bok Globules, those small dark nebulae full of cosmic dust that may be playpens for newborn stars. William Optics GT81, ZWO ASI1600MM-Pro, Astronomik Ha 6nm filter, 30 stacked 3 minute exposures, no calibration frames. 

NGC 281 Pacman nebula in Ha:

NGC 7380 star cluster surrounded by the "Wizard Nebula" in Ha:

Sh2-54 Nebula and NGC 6604 open star cluster in Ha:


Wide Field, Narrow Band

July 5, 2019 - Reading time: ~1 minute

Going to run some manual focus tests on my wide-field narrowband setup, if I can see the stars tonight. I just want to see if I have the backfocus correct for the Nikon f/2.8 180mm lens. I'm using a 2" Optolong 7nm Ha filter with the Atik 414EX mono CCD camera. No guiding with this tonight, but normally I would have the 130mm guide-scope and ZWOASI120MM-S on top of the aluminum camera/lens ring (ZWO 78mm Holder Ring for ASI Cooled Cameras). My hydrogen-alpha filter is in the AstroShop 2" Filter Drawer System with the tripod foot, which just adds more stability to this setup. You may also notice--if you're familiar with the iOptron CEM25P--that I'm using the short counterweight bar with a single weight. I can carry this whole rig around without taking anything apart.


Lobster Claw Nebula in Ha + OIII

July 3, 2019 - Reading time: ~1 minute

The "Lobster Claw Nebula" (Sh 2-157), an emission nebula in Cassiopeia, and Sh 2-157a a ring nebula around the Wolf-Rayet star WR 157. I finally captured hydrogen-alpha and oxygen-3 frames for one of my favorite Sharpless catalogue objects. I will come back later in the year to get better OIII frames and an SII set. I didn't get to the underside of Cepheus--or the borderlands between Cepheus and Cassiopeia until 1:30 am, and by then I only had an hour and a half of astronomical night left. This time of year the sky begins brightening at 3:30am, which makes it tough to get to some of these later objects. 


Elephant Trunk Nebula

July 3, 2019 - Reading time: ~1 minute

I hung around Cepheus and shot several hours of sub-exposures last night, mostly focused on IC 1396, the "Elephant Trunk Nebula", which is easy to make out near the center of the frame. This giant ionized gas region in Cepheus has some amazing dark bands of dust and other interstellar debris, blocking the light of more distant stars. Like there's that little guy on the right I want to call the "Harry Potter casts an Imperio" nebula. Imaging notes: bi-color made up of 48 stacked subs in Ha and OIII, William Optics GT81 APO refractor, ZWO ASI1600MM-Pro mono camera, Astronomik filters, iOptron CEM25P mount.

I also shot RGB subs. Here's the HaRBG:

 


More from Cygnus: Crescent and Tulip Nebulae

June 12, 2019 - Reading time: 2 minutes

The Crescent Nebula, NGC 6888 (top right) is an emission nebula in the constellation Cygnus, about 5000 light-years away. Like most of this region around Cygnus, you can't do anything in hydrogen-alpha or sulfur2 without wading through clouds of the stuff—billowing, eddying, and general nebulousing. It's beautiful. There's a Wolf-Rayet star, WR 136, at the lower left edge of the Crescent Nebula (from this angle), and it's stirring up violent stellar winds and blazing quickly through its life; it's expected to go supernova in a couple hundred thousand years, and it's only a four or five million years old. WR stars are unusual: they're very bright--thousands of times brighter than our sun, and they burn much hotter, thousands of times hotter than almost all other stars. And they have very short lifespans.

Notes: 31 x 240 sec Ha, 33 x 240 sec OIII, 29 x 240 sec SII,  Astronomik Ha, OIII, and SII filters, William Optics GT81 at f/4.7 with WO 0.8x Flat6A II, Moonlite focuser, ZWO ASI120MM OAG, Imaging camera: ZWO ASI1600MM Pro cooled mono on an iOptron CEM25P mount.

Sharpless 2-101, the Tulip Nebula (top left) is an emission nebula in Cygnus, about 6,000 light-years away. The microquasar Cygnus X-1 is the bright star just above the top point of the Tulip in this image. Cygnus X-1 is famous for being one of the first suspected blackholes, as well as a famous bet between physicists Stephen Hawking and Kip Thorne over that possibility. Hawking conceded to Thorne in 1990 as evidence for a blackhole mounted. Although the Tulip (Sh 2-101) stands out brightly with oxygen in blue, the whole region around the constellation Cygnus is cloudy with interstellar dust and gas. Notes: Astronomik Ha, OIII, and SII filters, William Optics GT81 at f/4.7, ZWO ASI1600MM Pro cooled mono camera, on an iOptron CEM25P mount.

 


Eagle Nebula - wide-field view with a side-order of infrared

May 25, 2019 - Reading time: 2 minutes

Here's another one from last night's run, a wide-field view of the Eagle Nebula (M16, NGC6611) in IR-OIII-Ha with Ha luminance. From our perspective Messier 16--Eagle Nebula--sits just north of the Milky Way's dense core of stars, bands of clouds, dust, hydrogen, and other galactic detritus. I wasn't very hopeful with the IR subs, but the Ha subs were beautiful. The OIII frames were about what I expected--not too much but enough to include them. To brighten things up I went back and added the processed Ha stack as a luminance layer. Yes, this may be a spectacularly weird color arrangement, but we're working in false color imaging already, and this doesn't seem that far off from our galaxy's actual core colors--at least in terms of the bands of dust and ionized gases.

Here's the Ha stack:

For comparison (with NGC 6611 above), here's the processed version of the Eagle Nebula (M16) I took last year with a slightly different setup--same William Optics scope + Atik414EX mono CCD camera. This is a bi-color hydrogen-alpha and oxygen3. With this one I think I had my OIII frames mapped to G and B channels, and Ha mapped to the Red channel.