Buying 8 in. F3.9 Astrograph from Orion with Atlas Mount

[TangoCharlie]

Greetings!

I appreciate the work seen on this site!  I am entering the next stage from Binoculars to First Scope.  But I am also 5-7 years from retirement so want to buy a scope that will service observation as well as doing AP.  I am looking at an Orion 8 inch f3.9 Astrograph with either a CG5 or Orion Atlas Go To Mount.    A few questions:

1. Are there Back Focus Issues with this scope?

2. Would I need a coma corrector or parracor?

3. Is collimation of this scope a bear to do each time?

4. Any other issues?

Thanks!

 

TC

[Louis D]

18 minutes ago, TangoCharlie said:

Greetings!

I appreciate the work seen on this site!  I am entering the next stage from Binoculars to First Scope.  But I am also 5-7 years from retirement so want to buy a scope that will service observation as well as doing AP.  I am looking at an Orion 8 inch f3.9 Astrograph with either a CG5 or Orion Atlas Go To Mount.    A few questions:

1. Are there Back Focus Issues with this scope?

It claims to have 69mm of backfocus which should be enough for photography.

2. Would I need a coma corrector or parracor?

The description recommends it and I would have to agree.  You could go with the GSO 2" Photo-Visual Coma Corrector for much less than a Parcorr and get excellent results.

3. Is collimation of this scope a bear to do each time?

With the primary mirror locking bolts, it shouldn't shift.  Initial collimation might be trying.

4. Any other issues?

a. That's a mighty expensive mass produced 8" Newtonian.

b. That's a huge (35%) secondary obstruction to achieve low light falloff.  Visual usage will be compromised.

c. Reviews indicate modest optical quality.

Thanks!

 

TC

Responses in teal.

[gnomus]

Welcome TC.  This is a great site for the sort of advice you are looking for.  I've already responded on your Astrobin thread, so won't repeat what I've said here.