Canon EOS 50D, Hooded Canon EF 85mm ƒ/1.8 USM prime @ ƒ/1.8, 4 sec. exposure, ISO 12800, tripod, 2 sec shutter holdoff x 10 frames. Stacking and processing in WinImages.
Focus was manual using live view @ 10x mag on a star; focus until star has minimum diameter *and* CA disappears. This is not quite critical focus; but then again, you don’t end up with all purple stars, either.
*NO* tracking mount
*NO* long exposures
You can do it too. Go on, try. 🙂
Highly recommended: "Stellarium" — this is a free planetarium program for your computer; it’ll tell you where the interesting things are. Try for…
o The Orion nebula
o Andromeda galaxy
o The Pleades star cluster and nebula
o Triangulum galaxy (difficult)
o Dumbbell nebula (extremely difficult)
o Low humidity (humidity was horrible for this shot ~50% !!! – midwinter is best)
o Low dust (dust was bad here too, we had 15-20 mph winds all day)
o Clear skies – *no* clouds
o As little light from towns and cities as you can manage
o To shoot when the object you’re after is as high in the sky as possible
o A lens hood (really helps keep ambient light out of the shot)
I highly recommend the 85mm ƒ/1.8 lens. At 100mm, things get more difficult, and at ƒ/2.8 it becomes impossible to use live view to manually focus on a star. Below 85mm, objects get quite small, and your crops won’t have much detail.
I’ve used the 85mm ƒ/1.2 lens, and that puppy can gather some light, all right… but the cost is high and frankly, it isn’t much use for anything else, the DOF is too thin (and if you’re not going to be shooting at ƒ/1.2, why spend all that money?) Plus it has terrible chromatic aberration… yech.
This winter, around the beginning of January, I intend go after Andromeda again, because humidity and dust should be optimal – near zero. I intend to use this lens again; it does a good job. I may shoot and stack as many as a hundred images in order to try and resolve the fine details in the spirals.
Tagged: , andromeda , astronomy