using a Newtonian for Astrophotography

[DJDD]

Hi all,

What should one look for in a newtonian for Astrophotography?
I realise a fast (but not too fast) telescope, e.g f/5 or f/6.
But what about optics? Anything special or will the GSO/Bintel telescopes be ok?

To compare, for the refractors it is preferable to use ED glass for truer representation of colours and less CA.

cheers,
DJDD

[iceman (Mike)]

Hey DJDD. What type of astrophotography do you want to do with it?
And what typeof camera/imaging device are you going to use?

[DJDD]

thanks for the reply, iceman.

ok:
objects- DSO
camera - Nikon D80

I have been playing around with the D80 (nothing I want to show here) and so have not taken the plunge to spend $2000+ on equipment.

I am still interested in the ED80 but was thinking about a longer focal length telescope (as well as or instead of) as i really like photos of galaxies even more than nebulae. The ED80 probably will not cut it for that. of course, my terrible, light polluted location may make galaxies unattainable. i am not sure...

cheers,
DJDD

[iceman (Mike)]

Well the longer the focal length, the better everything needs to be. EQ6 as a minimum, and an 8" or 10" newt with a guidescope would be ok on it.

Nothing wrong with an f/4 or f/5 newt for astrophotography - you'll just need a Baader MPCC for coma, and probably to move the mirror up the tube so your DSLR can come to focus.

Just check out the work of Eric (EzyStyles) with his 10" newt on EQ6, or Alchemy with his 12" newt on G-11. Paul Mayo also uses a 12" newt on a G-11. Scott Alder (tornado33) uses a 10" newt on a Samson mount.

Paul and Alchemy (and myself) all have GSO 12" newts. You don't need to spend a fortune on custom optics.

Their work speaks for itself.

[Chief Wiggum (Warrick)]

Mike, I'm just a beginner with AP, and have 10" SN. If I can get focus with my DSI Pro, will I get focus with a DSLR if I buy one or will I need to move the mirror up (which sounds a bit scary!).

Thanks
Warrick

[skwinty (Steve)]

Originally Posted by smallgirl

Mike, I'm just a beginner with AP, and have 10" SN. If I can get focus with my DSI Pro, will I get focus with a DSLR if I buy one or will I need to move the mirror up (which sounds a bit scary!).

Thanks
Warrick

Hi Warrick
I have just modded my 12" Newtonian by cutting 5cm off and moving the mirror up the tube.
Not as scary as you may believe. I think you will get a deep sense of satisfaction when all is done and your DSLR gets focus.
Read the article by Alchemy in the article section first and apply the measuring up procedure to see how much needs to cut off.
Good Luck and be strong especially when wielding the angle grinder.
Regards
Steve

[iceman (Mike)]

Hi Warrick,

Unfortunately the DSI coming to focus does not mean a DSLR will come to focus. You just won't know until you try it.

The Schmidt-Newt design may be slightly different than the standard newtonian in terms of in-focus so you may be right. Give it a go.

[DJDD]

Originally Posted by iceman

Well the longer the focal length, the better everything needs to be. EQ6 as a minimum, and an 8" or 10" newt with a guidescope would be ok on it.

Nothing wrong with an f/4 or f/5 newt for astrophotography - you'll just need a Baader MPCC for coma, and probably to move the mirror up the tube so your DSLR can come to focus.

thanks for the follow-up.
I was looking at the EQ6 as it will be a once in a lifetime purchase (hah! ) and I cannot spring for something meatier. I would only go as far as the 8" or 10", anyway so the EQ6 would be enough.

I forgot the coma corrector and the mirror move... hmmm...

Just check out the work of Eric (EzyStyles) with his 10" newt on EQ6, or Alchemy with his 12" newt on G-11. Paul Mayo also uses a 12" newt on a G-11. Scott Alder (tornado33) uses a 10" newt on a Samson mount.

Paul and Alchemy (and myself) all have GSO 12" newts. You don't need to spend a fortune on custom optics.

Their work speaks for itself.

well, i am impressed by all the great photos from those you mention, plus yourself (so modest... ).

[DJDD]

Originally Posted by skwinty

Hi Warrick
I have just modded my 12" Newtonian by cutting 5cm off and moving the mirror up the tube.
Not as scary as you may believe. I think you will get a deep sense of satisfaction when all is done and your DSLR gets focus.
Read the article by Alchemy in the article section first and apply the measuring up procedure to see how much needs to cut off.
Good Luck and be strong especially when wielding the angle grinder.
Regards
Steve

hmmm...this bit worries me.
my home handyman skills are definitely lacking so would probably cut along the tube and not across it.

you should see my attemptes at mortise & tennen joints!

what a dilemma- galaxies or widefield...

cheers,
DJDD