I was able to get set up last night and capture a decent image of the Leo Triplet. The seeing was fair with some moisture and freezing temperatures so I had some frost to chase away. Guiding was not the best possibly aggravated from the location in the southern sky. Different areas of the sky have inherent atmospherics often discernible from the tell tale twinkling stars. They may look pretty, but they indicate thermal instability that make things appear to move around. This drives guiding crazy and is referred to as ‘chasing seeing’. This was stacked from 22 frames of 220 seconds each or about 1hr 20 min total. Using dithering again with no dark frames. I need to try some comparisons with some dark frames I guess but this works surprisingly well.

The Leo Triplet (also known as the M66 Group) is a small group of galaxies about 35 million light-years away[5] in the constellation Leo. This galaxy group consists of the spiral galaxies M65, M66, and NGC 3628.


Three local galaxies in the constellation Leo

     My first run of the night ended unexpectedly. Not sure what happened but it seems my computer decided it was a good time to restart or update or something. So on to another target in the neighborhood. The Pinwheel Galaxy or M101 is front and center. Low to the right is NGC 5474.

Per Wikipedia:

NGC 5474 is a peculiar dwarf galaxy  in the  constellation Ursa Major . It is one of several companion galaxies of the Pinwheel Galaxy (M101 , a grand-design spiral galaxy . Among the Pinwheel Galaxy’s companions, this galaxy is the closest to the Pinwheel Galaxy itself. The gravitational interaction between NGC 5474 and the Pinwheel Galaxy has strongly distorted the former. As a result, the disk  is offset relative to the  nucleus ] The star formation in this galaxy (as traced by  hydrogen  spectral line  emission) is also offset from the nucleus.  NGC 5474 shows some signs of a spiral structure. As a result, this galaxy is often classified as a dwarf spiral galaxy , a relatively rare group of dwarf galaxies.

I was also running dithering for the first time on an actual imaging run. This is a concept where the scope moves a bit between each sub, or individual photo. Some people swear by this as a great way to improve results, and as I did this time, avoid taking dark shots. “Darks” take the same time as “Lights” and are super boring time hogs looking at the black interior of the telescope cover. The idea of darks is to subtract the noise. The idea of dithering is to randomize the noise and thus it keeps reducing the more individual subs are compiled together, or “Stacked”. Stacking is fundamental to modern astrophotography and the whole digital revolutionary leap that makes all this amateur stuff so much fun!

In this photo:

• NGC 5486
• NGC 5485
• NGC 5477
• NGC 5474
• NGC 5473
• M 101
• NGC 5457

M101, Pinwheel Galaxy
Annotated Pinwheel Galaxy courtesy astrometry.net

Yeah, I finally have a coma corrector for the Orion 6″ f/4. These are necessary for any Newtonian telescope with “FAST” optics.  Parabolic mirrors have no chromatic aberration nor spherical aberration, but they do have focal plane curvature. Actually, any curved lens or mirror produces a curved focal plane. Optical designers have to come up with corrective lenses to overcome this issue since optical sensors are flat. Hmm, maybe they should make the sensors curved……?? No, not going to happen but it would be in theory the better solution. Just need it custom curved to each optical system!

This is the Whirlpool Galaxy in the center, but a casual close look will find another galaxy on the left edge and two more over on the right side. A quick check on astrometry.net confirms this and a few more objects seen at this focal length. I included the annotated version. Check it out full screen!

In this image:

• NGC 5229
• NGC 5198
• NGC 5195
• Whirlpool galaxy
• M 51
• NGC 5194
• IC 4263
• NGC 5169

Whirlpool Galaxy and friends
Annotated version curtisy of astrometry.net

The Whale Galaxy and the Crowbar Galaxy are close neighbors from this perspective. Some wiki info:

NGC 4631 (also known as the Whale Galaxy or Caldwell 32) is a barred spiral galaxy in the constellation Canes Venatici. This galaxy’s slightly distorted wedge shape gives it the appearance of a herring or a whale, hence its nickname.[3] Because this nearby galaxy is seen edge-on from Earth, professional astronomers observe this galaxy to better understand the gas and stars located outside the plane of the galaxy.

NGC 4656/57 is a highly warped barred spiral galaxy located in the constellation Canes Venatici and is sometimes informally called the Hockey Stick Galaxies or the Crowbar Galaxy. The galaxy is a member of the NGC 4631 Group. A Luminous Blue Variable in “super-outburst” was discovered in NGC 4656/57 on March 21, 2005.

Imaged last night with a bit less than an hour of integration time. 180 second subs at 800ISO. Good dark area of the eastern sky for my location, but rather late in the night before they get up enough for a good look.

Whale and Crowbar Galaxies

Around 6 degrees Fahrenheit last night while catching some images. This from Wikipedia:

NGC 2403 is an intermediate spiral galaxy in the constellation Camelopardalis. NGC 2403 is an outlying member of the M81 Group, and is approximately 8 million light-years distant.

Just north of straight up around 10:30 last night, I took 21 light frames of 180 seconds each at ISO800 plus darks, flats, and bias frames processed in Deep Sky Stacker and Photoshop CS2. Tracking was rather good for my setup on this high target with end of run RMS error just over 0.8 arc seconds. This is a cropped photo, since I still do not even have a Coma Corrector for this setup. Basically the edges of the picture are very distorted without the corrective lens. That is just the way optics work in a “fast” Newtonian telescope.

The Canon camera at this telescopes focal length of 610mm covers about 1.6 arc seconds per pixel, so if I believe the numbers, most of the time the imaging will stay within one pixel during exposure. Kinda mind boggling actually.