Zodiaclight Home Page


Gallery Equipment Astronomy Astrophotography

Refractor Rig

Imaging Telescope Orion ED 80mm f/7.5 apochromat
600mm focal length
Weight 5 lbs 11 oz. (2.58 kg)
Guide Scope Orion ST80 80mm f/5
400mm focal length
Video finder Scope Mintron 13V1C 50mm f/2 Pentax lens
Mount Meade LXD-75

The Orion 80 ED refractor (5 lbs 11 oz.) is a good quality apochromat well suited to the Canon 350D camera.  It has very noticeable coma (i.e. field curvature) around the edge of field, however when cropping a 1280 pixel-wide image from the centre of a picture the coma is hardly noticeable.   Images show minor color (blue) fringing, but usually this is hardly noticeable.

I use a William Optics x0.8 field flattener/reducer which greatly reduces the coma at the edge of field, at the cost of some very minor distortion in the centre.  The reducer speeds up the scope to f/6 and reduces its focal length to about 480mm.  It also increases the field of view.

Canon 350 D Fields of View ( 22.2 x 14.8 mm chip)

Focal Length Horizontal Vertical Sampling/pixel
600 mm natural 2.12 deg 1.41 deg 2.207 arcsec/pixel
480 mm (x0.8) 2.65 deg 1.77 deg 2.759 arcsec/pixel

The Orion 80ED has a 2" Crayford focuser which is sturdy and nice to use.  It doesn't have a 10:1 micro-focuser, but I found it easy to focus.

The Orion 80ED is being replaced by the new kid on the block - the Orion 80 f/6 EON telescope which from all accounts is  a much better scope for imaging.  It's got less coma, shorter focal length and a microfocuser.  I want one for Xmas.

The Author's Imaging Rig September 2008

The Orion Short Tube (ST) 80mm is a nice little scope for the money (very cheap).  As a guidescope it is okay, however the focuser tube is only 1.25" and has a little bit of yield/wobble in it.  I wouldn't recommend it for imaging with, but as a guidescope it is good.  As a scope for kids it would beat most similarly priced department store scopes.


Email: bill *at* zodiaclight: com

All images and content of this website are copyright (c)2005-2008 Bill Christie.  All rights reserved.