Outer Limits and a Challenge

I continue to have nice imaging weather with no Moon, so I've been trying to take advantage. Our forecast is for things to turn rainy this afternoon, so imaging will likely be on hiatus for a while.

The night before last I decided to revisit the "Outer Limits" Galaxy, NGC 891, so called because it was featured in the introduction to the 60's TV show. I had imaged it a couple of years ago and got what were at the time excellent results, so I wasn't sure I could improve on that. I had some wind gusts that made me doubt even more, but set up the session, focused as well as I could, and went to bed. After stacking and processing the subframes, I was quite happy with the result. I think it's a clear improvement on what I did two years ago. I masked out the fuzzy edges of the galaxy when I deconvoluted, and that prevented them from getting grainy while I was able to process the dust lane aggressively. Here's the old image, then this year's for comparison. The newer image is sharper, better resolved, has tighter stars, and has better color. It's at a slightly smaller scale because I've stopped using my coma corrector (because it doesn't make any visible difference with the tiny imaging chip I'm using:

Maybe I was lucky, but this was a pretty easy find because after my first try with the Telrad I recognized a 3-star asterism and a 2-star asterism that were in the AT8IN field of view chart in AstroPlanner.  So it was a simple matter to move over and find the galaxy.  Since I knew what I was looking for, it was easy to see in 5 s in the imaging scope.  I can also see it in the guide scope at 1.5 s, again because I know where to look.  I'm still guiding at the 4x setting, and I've also loosened up the worm side-to-side adjustment a bit, reasoning that I don't really care about backlash in RA.  So we'll see how this turns out.  Chiller at 7 V, T=5 °C.  Medium RA dither, settling at 0.5.

Date: 7 Nov 2012

Subject: NGC 891 (Outer Limits Galaxy)

Scope: AT8IN+High Point Scientific coma corrector spaced properly

Filter: None

Mount: CG-5 (Synta motors)

Guiding: Orion ST80 + DSI Ic + PHD 1.13.7

Camera: DSI IIc (1.8 A, 7.0 V  T = 5 °C)

Acquisition: Nebulosity 3.1.2, medium RA dither, settling at 0.5

Exposure: 40/44 x 300 s

Stacking: Neb 3, bad pixel map & flats, bias included, normalize first, trans+rot align, 1.5 SD stack

Processing: Neb 3 crop and autocolor balance.  StarTools 1.3 develop, sharpen, color wipe, color saturation, life, magic (star shrink).  CS6 star color enhance, star shrink, curves.

I was a little hesitant to try NGC 891 because I already have a pretty good image of it from 2 years ago, but I decided to see if I could do better. Intermittent wind gusts, but very clear. Synched on γ1 Andromedae and the PicGoto put NGC 891 in my imaging field of view easily. Chiller at 2.5 A, falling from 18 to 11 °C through the night. I must have timed things just right because I went to bed and my imaging session ended just before the mount bumped, while I got a good night's sleep! I tried a bit more sophisticated deconvolution on this image than usual; I masked so I aggressively deconvoluted the dust lane but didn't touch the outer fringes of the galaxy. I probably should have masked the stars a bit more because I got some ringing, so maybe I'll redo the processing.  

Date: 24 Sep 2014

Subject: NGC 891, Outer Limits Galaxy

Scope: AT8IN

Filter: Baader Fringe Killer

Mount: CG-5 (Synta motors, PicGoto Simplificado)

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.1 (Win 7 ASCOM)

Camera: DSI IIc chiller at 2.50 A, 18-11 °C

Acquisition: Nebulosity 3.2.1, no dither

Exposure: 62x300 s

Stacking: Neb 3, bad pixel map, bias included, no flats, normalize first, trans+rot align, 1.5 SD stack.

Processing: StarTools 1.3.5.289 Crop; Wipe:Color & brightness 75%; AutoDev with ROI; HDR:Optimize; Color:Scientific, 250%; Deconvolute auto mask+block outer parts of galaxy 3.5 pix; Life:Less is more; Track Grain size 5.9 pix; Magic:Shrink 1 pix. Photoshop CC 2014 + Carboni Astronomy Tools Healing brush; Increase star color; Astro Frame.

Last night I got the itch to try a new object. From Kier's 100 Best Astrophotography Targets, NGC 925 was in the right part of the sky. I'd never attempted it before because Kier says it is dim and that "LRGB methods are almost essential", and that even the luminance data might need to be 2x2 binned. That scared me off in the past with my lowly one-shot color camera, but this year I decided I'd give it a try. Kier is right that this galaxy has very low surface brightness. I initially tried 450 sec subframes, and decided that wasn't long enough, so I went to 600 sec, which is the longest I've ever attempted (and I probably couldn't go much longer with my mount). I also tried adjusting my focuser, thinking that it might be the source of the differential flexure I experience near the meridian (it didn't seem to make any difference though). Finally, I used my UHC-S filter, hoping to knock down the background sky glow. In retrospect, perhaps I should have just gone with the UV-IR cut filter. Anyway, I did get something:

This is one of those "don't image from the suburbs, LRGB methods are essential" type objects that I'm crazy enough to try anyway. I do like going after something new every once in a while, and this is a new object for me. Consider it a “challenge” object. Synched from β Tri and found on the first attempt. Some wind gusts & some scattered clouds, but conditions overall were very good. NGC 925 is quite dim, especially the spiral arms (the core is reasonably bright so not terrible to find at 5 s exposures or so). Chose the UHC-S filter, hoping to improve contrast between the galaxy and background sky glow. Used 600 s exposures for the imaging session. Got fairly good data all the way up to the meridian, and finally the mount bumped about 4 AM, ending the session.

Date: 25 Sep 2014
Subject: NGC 925
Scope: AT8IN
Filter: Baader UHC-S
Mount: CG-5 (Synta motors, PicGoto Simplificado)
Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.1 (Win 7 ASCOM)
Camera: DSI IIc chiller at 2.50 A, 18-11 °C
Acquisition: Nebulosity 3.2.1, no dither
Exposure: 40x600 s
Stacking: Neb 3, bad pixel map, bias included, no flats, OSC neb filter extract, normalize, trans+rot align, 1.5 SD stack.
Processing: StarTools 1.3.5.289 Crop; Wipe:Color & brightness 75%; Develop 87.49%; HDR:Optimize; Color:Scientific, 250%; Life:Moderate; Deconvolute auto mask 2.9 pix; Track Grain size 9.1 pix, Scl 1 100%, Scl 2 100%, Scl 3 96%; Magic:Shrink 1 pix (twice). Photoshop CC 2014 + Carboni Astronomy Tools Healing brush; Deep space noise reduction; Levels (darken); Increase star color; Astro Frame.

Hunting the Phantom Galaxy

As I saw the forecast for last night was for clear skies, I began thinking about an astrophotography target. My first criterion is almost always favorable placement of the object in my sky, which generally means it should be in the east or southeast. I have light pollution to my north and west, so I avoid those parts of the sky. I usually want something I can image all night if possible. So to choose targets I use my Astroplanner observing list (which began as the list of objects from Ruben Kier's The 100 Best Targets for Astrophotography (Springer: New York, 2009)) but which has expanded from there as I've added objects I've seen others image (mostly on Astrobin.com). I sort the list by time of meridian transit, then look for things I haven't yet imaged or prior targets I think I can improve on. I then use Astroplanner to check the field of view with the combination of telescope, optical aids, and imaging chip at my disposal, with the goal of making sure I can frame things properly.

Via this process, last night I decided to image M74, the "Phantom Galaxy." M74 is in the dim constellation of Pisces, but is not far from some brighter, easily recognized stars in Aries. This galaxy has fairly low surface brightness, which probably accounts for its mysterious-sounding nickname; it is relatively difficult to find, see, or image. It is also a beautiful, perhaps prototypical example of a "grand design" spiral galaxy, with two spiral arms emerging from a nucleus with two bright concentrations of stars. I've imaged M74 before (the last time 2 years ago), but the results were fairly noisy so I thought I could probably improve on them. Also, M74 is the right size to frame pretty nicely at 800 mm focal length with my AT8IN scope.

So I hauled all my gear out and got set up. At first I had a hard time even seeing Polaris in my polar scope; my 20-month-old grandson loves to twiddle any knobs he can reach, including the elevation knobs on my CG-5 telescope mount, so he had "adjusted" things a bit for me at the start. After getting polar aligned once via the polar scope, I had to stop and move the mount and redo the alignment once I realized M74 would be behind a tree an inordinate amount of time from the place I had set up the mount initially. (It turned out that even after moving the mount I still got M74 behind the tree--oh well!) I synched my scope using the PicGoto on β Ari and did the goto, only to see...nothing! Checking the position of the scope I discovered the aforementioned occultation by the tree. So I waited until M74 got high enough to clear the leaves, and to my delight it was right in the center of my field of view so I started the imaging session. After about an hour and a half, something went wrong (I suspect a USB cable came loose) and Windows 7 crashed, but I got it restarted and continued imaging. M74 reached my local meridian last night about 3:30 AM (more useful information from Astroplanner), and I expected the telescope mount to bump shortly after that time, but decided I'd go to bed and just let that happen. Happily, when I got up to shut everything down this morning I discovered the end of the scope had cleared the tripod, so there was no bump and imaging continued until dawn.

The stacked image is not as sharp as I would like, but considering that I was battling wind gusts and all my usual cheap gear issues, it turned out OK and certainly a lot better than the 2-years-ago image.

Some gusty wind early (probably canyon breeze). Had to wait for Brown's tree to get out of the way before I could start. USB connections dropped and Windows crashed after the first hour and a half, but restarted and went to bed, expecting the mount to bump around 3:30 AM. However, it missed and imaging continued all the way until dawn. I still got quite a lot of differential flexure in this set of subs. This object must get the name “Phantom Galaxy” because its surface brightness is so low, but it was easy to find with the PicGoto from β Ari; the goto was dead center.

Date: 23 Sep 2014

Subject: M74, “Phantom Galaxy”

Scope: AT8IN

Filter: Baader Fringe Killer

Mount: CG-5 (Synta motors, PicGoto Simplificado)

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.1 (Win 7 ASCOM)

Camera: DSI IIc chiller at 2.50 A, 15-9 °C

Acquisition: Nebulosity 3.2.1, no dither

Exposure: 69x300 s

Stacking: Neb 3, bad pixel map, bias included, no flats, normalize first, trans+rot align, 1.5 SD stack.

Processing: StarTools 1.3.5.289 Crop; Wipe:Color & brightness 75%; AutoDev with ROI; HDR:Optimize; Color:Scientific, 300%; Life:Moderate; Deconvolute auto mask 2.3 pix; Track Grain size 5.2 pix; Magic:Shrink 1 pix. Photoshop CC 2014 + Carboni Astronomy Tools Healing brush; Deep space noise reduction; Space noise reduction; Layer masked levels; Increase star color; Astro Frame.

Two Fall Galaxies

With the Moon waning and a few nights of clear skies, I've tried to take advantage by switching back to straight RGB imaging. (I did take the cheap Meade IR cut filter off my camera and am using a Baader Fringe Killer UV-IR cut filter instead. I'm doing this because it will be easier to switch between RGB and Hα this way, particularly if I'm using a focal reducer. The Meade filter goes between the camera and its nosepiece, so it slightly alters the distance between the focal plane and any focal reducer mounted on the nosepiece, slightly altering the image scale. With the Baader Fringe Killer, which mounts on the front of the focal reducer, that won't happen.)

Last Tuesday night was clear, so as I thought about what I might image I realized the Deer Lick Galaxy Group was pretty high in the sky. I didn't want to miss it this year so that was my target. If you want to see lots of faint fuzzies all in one frame, the Deer Lick Group does not disappoint. I guess my title is wrong; you can see a lot more than 2 galaxies in this picture. Conditions were not great because there were a lot of random wind gusts; not good if you want to image at full focal length. This image is probably a bit greener than it should be.

Wind is tossing the scope to and fro. Chiller running at 2.5 A, but I'm still seeing 19 °C, which suggests something is wrong. Probably should have chosen a target which would have used a focal reducer tonight. Did meridian flip and continued; things seemed to settle down some.

Date: 16 Sep 2014
Subject: NGC 7331, Deer Lick Galaxy Group
Scope: AT8IN
Filter: Baader Fringe Killer
Mount: CG-5 (Synta motors, PicGoto Simplificado)
Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.1 (Win 7 ASCOM)
Camera: DSI IIc chiller at 2.50 A, 15 °C
Acquisition: Nebulosity 3.2.1, no dither
Exposure: 61x300 s
Stacking: Neb 3, bad pixel map, bias included, no flats, normalize first, trans+rot align, 1.5 SD stack.
Processing: StarTools 1.3.5.279 Crop; Wipe:Color & brightness 75%; Develop 89.78%; HDR:Reveal Core; Deconvolute auto mask 3.1 pix; Life:Moderate; Color:Scientific, 275%; Track RNC 32.11%; Magic:Shrink 2 pix. Photoshop CC 2014 Astronomy Tools Increase star color; Deep space noise reduction; Make stars smaller (2x); Levels; Astro Frame.

Clear Friday nights, when I can image and not have to get up to go to work the next morning, are not to be missed. I like imaging the Triangulum Pinwheel Galaxy because it is large in my field of view without exceeding it. (That's one of the big problems with Andromeda: it is huge so even at the shortest focal lengths available to me I have trouble fitting it in one frame. Maybe I'll have to try a panorama again.) Friday's conditions were as good as they ever get at my site: good seeing, almost no wind, and no clouds. I was able to image pretty much from the time the galaxy rose until morning twilight. I got things started, set an alarm for 3:15 AM, and slept until the alarm woke me to do a meridian flip, which was easily accomplished with the ever-capable PicGoto; it is so nice to use even when I'm putting my body through contortions to sight through the Telrad near the meridian. Unfortunately, when I stopped for the meridian flip I discovered the focus had softened a bit, so I could have had a sharper image than I got. I like how the hydrogen emission regions in M33 (the red, Hα-colored areas) show up in this picture.

Conditions don't get any better than this: clear, no wind to speak of, and comfortably cool. Dec guiding excellent, RA pretty good. Chiller at 2.5 A, 14.5 °C (I don't think it is working very well). Still imaging with Neb 3 (Mac) and controlling everything else with Windows versions. Initial synch was on α Trianguli. Set an alarm and got up at 3:15 AM to do meridian flip. Found the focus was a little soft and fixed it. Went back to bed and let the scope continue imaging until dawn.

Date: 19 Sep 2014
Subject: M33, Triangulum Pinwheel Galaxy
Scope: AT8IN+Antares 0.5x focal reducer
Filter: Baader Fringe Killer
Mount: CG-5 (Synta motors, PicGoto Simplificado)
Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.1 (Win 7 ASCOM)
Camera: DSI IIc chiller at 2.50 A, 15-10 °C
Acquisition: Nebulosity 3.2.1, no dither
Exposure: 74x300 s
Stacking: Neb 3, bad pixel map, bias included, no flats, normalize first, trans+rot align, 1.5 SD stack.
Processing: StarTools 1.3.5.289 Crop; Wipe:Color & brightness 80%; Develop 74.99%; HDR:Optimize; Color:Scientific, 500%; Life:Moderate; Deconvolute 2.7 pix; Track: 1.7 pix, RNC 13.97%. Photoshop CC 2014 Astronomy Tools Increase star color; Deep space noise reduction; Smudge tool to fix some badly oblong stars; Astro Frame.

Off to See the Wizard

Now that my new computer is here, I'm back to imaging on clear nights (when the Boss allows it; she didn't last night, for example). Earlier this summer, I got good RGB data for NGC 7380, the Flying Horse or Wizard Nebula, so I decided to try it in Hα. Once again, the Hα filter added amazing detail to the nebulosity that I just couldn't get using the UHC-S filter before. I can easily see a "flying horse" in this image; the horse is upside-down, with its head at bottom center. I have more trouble seeing a wizard. If the images below are rotated 90° clockwise, I see what looks like the full body of a wizard standing up, with outstretched arms and a flowing cape. I had trouble seeing him because I was expecting a face wearing a wizard hat. Here's the Hα image (false colored). I got less data than intended, because acquisition froze about 40 minutes after I went to bed, but it still came out OK I think.

Conditions excellent again. Chose this target because I already have RGB data from this season at the same scale, so I intend to do HαRGB combination. Had a terrible time getting CdC+PicGoto to work correctly. Tried synching both from Delta and Zeta Cephei, and from both the synch seemed to work but as soon as I hit goto the telescope reticle in CdC would jump way off (in RA). Finally tried from Beta Cas, going the opposite direction in RA, and everything worked. After doing a meridian flip, the synch from Delta Cephei worked fine. Once again my session hung about 40 min. after I went to bed. I've searched both Windows and VMWare logs and so far haven't figured out what is going wrong. I suspect a bad VMWare setting.  I do get a Windows error about being unable to find a sound device each time this happens.

Date: 12 Sep 2014

Subject: NGC 7380, Flying Horse/Wizard Nebula

Scope: AT8IN

Filter: Baader Planetarium 7 nm H-α

Mount: CG-5 (Synta motors, PicGoto Simplificado)

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.1 (Win 7 ASCOM)

Camera: DSI IIc chiller at 2.50 A, 6.5 °C

Acquisition: Nebulosity 3.2.1, no dither

Exposure: 18x600 s

Stacking: Neb 3, bad pixel map, bias included, extract R, normalize, square, trans+rot align, 1.5 SD stack, resize 2x (Catmull-Rom).

Processing: StarTools 1.3.5.279 Crop; Develop 75.00%; HDR:Optimize; Deconvolute 4.2 pix; Life:Moderate; Track:RNC 0.01%; CC 2014 Photoshop AstronomyTools B&W to Hα; Astro Frame.

I combined the Hα data with RGB (taken through a UHC-S filter) from 18 Jun this year to get the following in full color. I like this one.

This is an HαRRGB composite, combining my 12 Sep 2014 Hα data with 18 Jun 2014 RGB. I used Starizona Method 1, with the R (actually HαR) channel boosted 200% with the channel mixer. I can see the flying horse (he’s upside down, with his head at the center bottom in this image). The wizard is harder for me to picture. He's lying on his back, with his pointed cap to the left and arms outstretched. Maybe others see this differently than I do.

Back in Business...Sort of

My brand-spanking new, souped-up MacBook Pro finally arrived, which makes it possible for me to image again. The Moon is still pretty bright, so I decided to do more Hα imaging. In choosing targets, I look for objects that have a lot of emission nebulosity. So the night before last I imaged the Pacman Nebula, and last night I did the Cave Nebula. Both are about the right size to use a focal reducer, which makes my optics quite fast.

To enable imaging control, I copied my Windows 7 VMWare image from my old laptop, and started experiencing some quirky things. VMWare attempts to use the full resolution of my display, which is very high on my new retina-display MacBook. As a result, I've got lots of screen real estate on the new machine under VMWare, but most of the fonts are now quite small.  There must be some setting to fix that, but I haven't found it yet, and actually I like having more screen space for my space photography. The other quirk is more serious. Both sessions with the new laptop have ended early with the imaging hanging up (last night, only a half hour after I went to bed after doing a meridian flip). This looks like perhaps more of the same stuff that shut me down with the older, loaner machines. My new MacBook definitely doesn't have performance bottlenecks that I thought caused this, so probably something in VMWare is not right. I'm thinking about getting a clean VMWare Windows 7 image and rebuilding from scratch. Another option would be to control the imaging session from the Mac side and only run the finding/guiding from Windows 7. That would be easy to try but not particularly convenient to run.

Aside from the bright Moon (which makes no difference to Hα imaging), conditions have been quite nice the last couple of nights. Both targets were very easily found with the PicGoto (and the PicGoto is the reason I don't try to solve the hanging problem described above by going Mac-native. I'm addicted to using it because it makes finding and aligning so much easier, and I also like using ASCOM. Unfortunately, I have to use Windows to use the PicGoto, which means VMWare on my system).

I got a lot of data for the Pacman Nebula. I've found I can deconvolute a bit more aggressively with these Hα images than I'm used to, and I'm very happy with the results. I think this is the best Pacman I've ever gotten, and I tried really hard on it a couple of years ago. My skills have improved, I guess.

The air was mostly quite still. Interestingly, my RA guiding was great but the DEC was only so-so, the opposite of what I usually see. This was first light for my 2014 MacBook Pro. T = 9-15 °C with chiller at 2.50 A. By far my best Pacman to date. Hα helps a lot on this one.

Date: 10 Sep 2014
Subject: NGC 281, Pacman Nebula
Scope: AT8IN+0.5x Antares telereducer
Filter: Baader Planetarium 7 nm H-α
Mount: CG-5 (Synta motors, PicGoto Simplificado)
Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.0 (Win 7 ASCOM)
Camera: DSI IIc chiller at 2.50 A, 9-15 °C
Acquisition: Nebulosity 3.2.1, no dither
Exposure: 36x600 s
Stacking: Neb 3, bad pixel map, bias included, extract R, normalize, square, trans+rot align, 1.5 SD stack, resize 2x.
Processing: StarTools 1.3.5.279 Crop; Develop 74.99%; HDR:Optimize; Deconvolute 3.7 pix; Track; CC 2014 AstronomyTools B&W to Hα; Astro Frame.

The Cave Nebula is fairly dim, and the last time I tried to image it 2 years ago my notes start out with "perhaps this is a target one should not try to image from the suburbs with a low-end one-shot color camera." However, a low-end one-shot color camera with a Hα filter does pretty well, I think.  Here's the evidence:

Extremely good conditions. Lots of moonlight, but who cares when using the Hα filter! Chiller at 6.5 °C, 2.5 A. Found easily with the PicGoto from Iota Cephei. Got about 70 min of data, did a meridian flip, and continued. Unfortunately, the imaging run hung up about half an hour after I went to bed, so I got a lot less data than I had planned for. This is two runs in a row with this problem so I need to get it sorted. The image turned out much better than I expected. Woo-hoo to the Hα filter!

Date: 12 Sep 2014
Subject: Sh2-155, Cave Nebula
Scope: AT8IN+0.5x Antares telereducer
Filter: Baader Planetarium 7 nm H-α
Mount: CG-5 (Synta motors, PicGoto Simplificado)
Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.0 (Win 7 ASCOM)
Camera: DSI IIc chiller at 2.50 A, 6.5 °C
Acquisition: Nebulosity 3.2.1, no dither
Exposure: 11x600 s
Stacking: Neb 3, bad pixel map, bias included, extract R, normalize, square, trans+rot align, 1.5 SD stack, resize 2x (Catmull-Rom).
Processing: StarTools 1.3.5.279 Crop; Develop 75.00%; HDR:Equalize; Deconvolute 3.7 pix; Life:Moderate; Track:RNC 0.01%; CC 2014 Photoshop AstronomyTools B&W to Hα; Healing brush to remove a hot spot trail; Astro Frame.

Kaput Computer Woes

I've been out for a couple of attempted sessions recently, but without any success. I think I mentioned in my last post that my laptop bit the dust. Somehow, I was able to get an old Core 2 Duo laptop running VMWare/Windows 7 to run the session that led to images of Comet Jacques and the Helix Nebula, but I have not been able to repeat that feat despite a lot of trying with two different computers and even using both of them simultaneously (one to run my imaging camera and the other to run the mount and guiding). Both these computers share two problems: each has "only" 4 Gb of RAM (and VMWare is a big-time RAM hog) and both have relatively slow USB (it says "high speed USB", which probably means USB 2.0). I suspect the RAM is the real issue, because I can run my cameras fine if I use the Mac version of Nebulosity. Unfortunately, I have to have Windows to run my PicGoto mount control, and despite numerous reboots with different combinations of settings I have not been able to run the PicGoto and the guider reliably at the same time. So I'm waiting for my new replacement laptop to get here. Hurry up, Apple!