Gemini Nebula (NGC 2371) using an Off Axis Guider on a C-11 SCT

Peter Nerbun
Location of photo
Perry Hall, Maryland USA
Date/Time of photo
May 9 2015 at 0225 UT
C11 SCT, Atik 460EX Monochrome camera, Celestron Off-Axis Guider, Lodestar X2 autoguider camera, Orion EQ-G mount, F/6.3 focal reducer, 3nm H-Alpha and O-III narrowband filters, Aurora Flatfield panel, Orion Nautilus motorized filter wheel
This image shows the Gemini Nebula (NGC 2371); measuring only 1 arc minute wide with a visual magnitude of 11.19 this nebula is a rather small object making it ideal for the relatively high resolution capability of my Schmidt Cassegrain telescope. I recorded 15 minute subframes with an ATIK 460EX camera coupled to 3nm H-Alpha and O-III narrowband filters. I used an Off-Axis guider and Lodestar X-2 guide camera for autoguiding to eliminate differential flexure and neutralize the effect of mirror flop in my SCT. Finding a guide star with an OAG can be rather difficult since the prism of the OAG picks off a very small ring shaped field of view (FOV) surrounding the main camera FOV however the Lodestar X2 autoguider camera's high quantum efficiency ameliorated this situation to a large extent.
All comments must follow the Sky & Telescope Terms of Use and will be moderated prior to posting. Please be civil in your comments. Sky & Telescope reserves the right to use the comments we receive, in whole or in part, and to use the commenter’s username, in any medium. See also the Terms of Use and Privacy Policy.


This site uses Akismet to reduce spam. Learn how your comment data is processed.