Help with deep sky imaging please!

[Ashdown]

I'm ready to make the purchase, I plan to buy an EQ6 Pro with SynScan and an 80mm Skywatcher Equinox APO for astrophotography, my friend has an unmodded Nikon D80 that I can borrow, can anyone help me with the technical details, eg how much of the CCD chip will be covered by this scope, how will the D80 respond to nebulae in the deep red, do I need a seperate guide scope or will the EQ6 follow accurately enough for 30min exposures, and will the focusser support this weight or do I need to upgrade the visual back? So rry if this is asking alot, eventually I will learn this stuff myself and get myself a more suitable setup... I'm asking this now because it's my girlfriends birthday in a couple of months and one of my ideas was to get her a picture of the heart nebula that I took myself (she's getting interested in astronomy because of me and I think she'd love it), how well will this be framed in the shot? do I need to produce a mosaic or not? I'm completely new to this, thank you for any help, it's going to save my life!

[Siguy]

Alright, first of all, the EQ-6 pro is certainly enough for an 80mm Equinox, I would say it's overkill. You should probably step down to the HEQ-5.

As long as you have a good 2'' camera adapter, then you will cover the full chip. The focuser will certainly support the weight, but you should keep it tight and lock it when in focus. I think the new ones have better, dual speed, crayford focusers.

Since your borrowing your friend's D80, I don't think he'd be very happy with you removing the hot mirror to reduce emission nebula exposure times, but it will still pick up adequate reds for emission nebulae.

Few mounts have the accuracy to do 30min unguided exposures. But don't worry, nobody uses 30min exposures in DSLR imaging. You take multiple 10 second to five minute exposures, then stack them in a program like DeepSkyStacker. (http://deepskystacker.free.fr/english/index.html)

The heart nebula is rather big. But your field of view with the 600mm FL of the Equinox will be 2 1/4 degrees by 1 1/2 degrees, so I think you'll be able to capture its extent. Keep in mind that it will only be up early in the morning for the next few months.

[Ashdown]

excellent you answered everything! I have to decide on mount now, I do need it to carry a 10" newtonian but not for imaging so I guess an HEQ-5 should be find for visual work :) thanks for your help, I recognize you from helping other people out, youre a good member!

edit: before i forget... can you fit 2" filters to either the t-ring or the camera or anywhere when using a DSLR the same way you can using a 1.25" CCD camera? So I can work in H-A, OIII etc?

[Siguy]

Actually, if you are going to be carrying a 10'' Newt, then you should probably get the EQ6. A HEQ5 can handle a 10'', but not as stable as an EQ6. Then you could possibly even use the 10'' for photography, and guide with the 80mm.

A T-ring is 42mm, so 2'' filters won't thread directly in one. But if you get a 2'' to T ring adapter, chances are it will be threaded for filters.

Also, thank you for your compliment. :) I try to help out.

[matthewota]

NO NO! When you do astrophotography, the answer is to get an oversized mount compared to the OTA you are using. Read Michael Covington's book.

If you reduce the load on the mount's drive gears and motors, it will run smoother. Maxing out the OTA will result in less accurate tracking.