DSLR vs CCD for beginner on DSO

[jetstream]

I have decided to buy a Gem &CCD-but in the mean time my photographer buddy has offered to lend me his Canon 40A.Can I take a half decent series of subs of M31 with my alt az?I will go to a dark site under good conditions to try this.....depending on the responses here.Any one have a photo of M31 taken like this I can see?My book should be here at the end of the week & I have contacted Atik for some advice on things as well.Thanks people

[poogle]

Great choice! Sure you'll be able to image M31 with your alt az mount and your friends dslr while waiting for your new gear It's not the optimal gear, but I think you will be quite pleased with the image, and I'm sure you'll learn something from it. The field rotation will be there, but try 20-30 sec exposures and don't forget taking dark and flat frames:)

/Patrik

[Demonperformer]

Agreed.

20 sec subs, one every 30sec to allow a little cool-down between them, in two hours that's 240x or 80 mins worth. There will be significant field rotation, but DSS (the stacking program) will be able to cope with that. You will be able to crop the centre of the image to get rid of the effects.

As regards darks on a dslr - maybe I'm just a little obsessive, but I used to do 10 at the start, then another 10 every half hour. Then batch each set of 30 mins of lights with the 10 before and 10 after when stacking them in DSS [D1,+L1+D2; D2+L2+D3; etc]. This can help alleviate changes in temperature throughout the session. As I say, that could be a little OTT and just my OCD talking!

Good hunting!

[poogle]

On a side note though, you might want to try to image something else than M31. The Andromeda galaxy will fill your entire FOV and is quite difficult to process, and you won't be able to crop the image without loosing parts of the galaxy. I would try for example the Dumbbell nebula (M27).

/Patrik

[AndrewG]

DSO astrophotography is a none starter without an equatorial mount or SCT/wedge combination. The latter is complex and time consuming to set up and take down unless left in a permanent observatory. GEM is the way to go.

I for one can agree with Kirkster501!! Unfortunately when I started out Astro-imaging was not even on my agenda so I went down the alt-az route and given I had spent quite a bit on a CPC925 XLT I stuck with it and bought a wedge (Orbit Type £1K!), the rig then was really heavy to move and one night late in deep winter I nearly killed myself as I struggled to stop the dam thing falling over (a bit like jumping in front of a runaway car to stop it getting damaged... ). So I ordered a Pulsar observatory (£4.5k ish) and then all the other costs associated, concrete base, power......

The moral of my story is that I should have probably cut my losses originally and bought a really good mount for imaging with a small refractor and kept the CPC for visual use; the only good side to it all is it is great to have an obs especially as I can go and hide in it away from the wife!!!

[melsky]

I only have limited experience with my 314L+ mono but because I travel and setup every time I do find DSLR's much easier and faster to operate than CCD's. I use Canon 600D's and the flipable screen is a godsend when operating near the zenith, I can usually find a star in the live view mode to focus on and a quick shot at 6400 iso to finalise the position of the target is almost instant. Another benefit was highlighted to me last week, a friend with his DSLR was struggling taking shots and moving the scope to try and position M31 nicely in the frame and asked for help, I simply said why don't you look through the camera's viewfinder instead, it was easily visible, so no need to swap back and forth with eyepieces either.

Mel

[jetstream]

Thanks for all the great advice,after reading the book I should have a better understanding of the process,one of my main concerns is the programs "getting" along together,I may run a PC dedicated to Astrophoto,we'll see.In the meantime,I am gonna try taking a picture Alt/AZ of something...!M31 just sits there glowing,so thats the one I thought of,but M27 is sitting there too,so maybe I"ll try both!For the processing end,a friend is willing to help me to get started-he suggested giving the DSLR a try in the meantime.I need the field flattener anyway & the camera adapter isn't much,so I'm going to give it a try