We're getting to the point in the year when the Andromeda Galaxy (M31) is above the Indiana haze at around 11:30pm - so it's the earliest in the season to attempt a decent Andromeda stack. My previous attempt was
back in January when I was first learning how to use Deep Sky Stacker - and while I haven't had too much practice since then, I figured I could do a little better.
For comparison, my
previous attempt was during a gibbous moon with 318 light frames. This time around, I had a new moon and 667 light frames (but I chose to keep the best 80%, so an effective 534 total subs). Total exposure time is around 11 minutes. Images were taken with Canon Rebel XT (350D) on a fixed tripod.
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Stack of 534 subs, 94 darks, 104 bias, f/5.6, 300mm, ISO 1600, 1.3 sec each
Layered with my previous image at 30% transparency |
It's definitely more recognizable than just a fuzzy blob! Granted, it's got plenty of fuzz and blob to go around. I try to remind myself that this is with a relatively slow lens and 8 megapixel camera (Canon Rebel XT) so it's not going to be Hubble quality. It's a baby step, and my best Andromeda to date! Still, after two nights of shooting, 4 hours of image stacking, and 2 hours of image processing, I had high expectations!
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| Dust trails are visible on M31 as darker lines on the top ridge. M110 and M32 are featureless but visible nonetheless. |
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| Baby steps, improvement over my first Andromeda attempt |
Update: Planning my shot...
Jason in the comments asked for an unprocessed light frame, but I can do one better. Here is some more info on how I planned out the shot.
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| First I find the right general area by star-hopping from Mirach to the left |
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| Then I scan the area at ISO 1600 with 8 second exposures until I get Andromeda framed correctly. In this case, in the bottom 1/3 of the frame. This is because the sky will appear to move upward, so Andromeda will be centered as long as possible. |
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| After getting Andromeda in the right spot in my field of view, I switch to 1.3 sec exposures to avoid star trails following the 600 rule (600 ÷ 1.6 (my image sensor crop factor) ÷ 300 (focal length) = 1.25 sec |
Could you post one of your light frames unprocessed please? I tried photographing M31 with my new cameraa couple of nights ago but I couldn't even locate it with binoculars! I took a few photos of the general Cassiopeia area and I've pinpointed where it should be, but there's nothing in the picture. I think there may be too much light pollution where I am and o just want to see a comparison photo before I spend a lot of time taking shots for a stack!
ReplyDeleteThanks
Hi Jason, I added some more content to the bottom of the post. I hope this helps! Instead of binoculars I'd try locating it with an 8 sec exposure and looking for a fuzzy blob.
ReplyDeleteThanks! I've got clear skies forecast tonight so I'll give it another shot
ReplyDelete