This is a replacement image for M4 because was not satisfied with my original 5-minute image I captured two years ago when I was just starting out. I was not planning on imaging this, it was a last minute decision. I would like to come back to it and really put in some time as there is a lot more nebulosity than the 'hints' that appear in my new image. I tried to keep more of it but I was not on it long enough to make it look good. I was under a time constraint in order to get other Messier objects which are also not visible from my house. M4 is very easy to find being so close to Antares and you can see it with a small telescope pretty well.
Antares is an enormous supergiant star with a radius 883 times that of the Sun. If it were in the center of the Solar System, its outer surface would lie between the orbits of Mars and Jupiter. Antares is approximately 550 light-years from the Sun (source: wikipedia). I would have liked to get rid of orange secondary halo around Antares (or not have it show up at all - limitation of equipment) but everything I tried really did not work. I am sure there is some Astrobin superuser that could probably get rid of it but I couldn't. Feel free to comment if you know how.
I believe the red halo is due to the modified camera picking up more Ha light. Knowing this I tinkered with the image RGB balance in PS and subtracted it out.
M4 and Antares
M4 and Antares (halo subtracted out)
Location: St. John's Cemetery, Monroe, CT
Camera: Canon EOS Rebel T3i(a), Backyard EOS
Telescope: Orion ED80 80mm f/7.5 Apochromatic Refractor Telescope
Focal Length: 600mm
Focal Reducer: Orion 0.8x Focal Reducer for Refractor Telescopes
Mount: Orion Atlas Pro EQ/AZ Mount
Filter: Astrodon UV/IR
Autoguiding: QHY-5L-II-M attached to an Agena 50mm Guide Scope with Helical Focuser
Exposure: 21 x 60s
Temp: 22 C
Post Processing: Deep Sky Stacker, Photoshop, Lightroom, Gradient Exterminator, Astronomy Tools, StarTools.