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
