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

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.

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.