On Sat, 21 Oct 2017 22:06:23 -0400, Davoud wrote:

Old Geezerr:
The Canon that I have is a Rebel T5...
The Celestron would be a 1250mm lens as the camera mounts right to
the telescope rear face via a T- ring.

That's OK for Solar System photography. If you want to do deep-sky
you're going to need a focal reducer. 1250mm is too great a focal
length for most extended objects. I made the photos on this page
http://www.primordial-light.com/deepsky9.html with a refractor of
focal length 387mm. (530mm Ÿ5 with a .73x reducer = 387mm Ÿ3.65.) Such
a telescope is called an "astrograph" or "fast astrograph." It is not
suited for visual use with an eyepiece.

The Rosette image on that page was made at the native FL, 530mm Ÿ5.
Divide it out and you find that this is a 106mm refractor.
http://www.primordial-light.com/technique.html.


Thanks for the information. I'll have to discuss that with the people
at the telescope store when I go to see them. They are the only
dedicated telescope store in Tucson, Arizona.

That is some snazzy equipment that you have there.

Dave:

There goes the happy moron.
He doesn't give a damn.
Gee I wish I was a moron.
My God, maybe I am