Big Ian 65
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Status Updates posted by Big Ian 65
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Hi Pete, I hope you are well, just thought I’d drop you a quick message to let you know that I had a good session last night with my setup, configured as you kindly advised.
I managed to get all the component software to work, and even had a go at plate solving. Whilst I had some reasonable success with some smaller DSO objects, I am finding the images a bit noisier than I would like, and I think it’s time to change my setup to include the Antares F6.3 focal reducer - however I am now entering the world of “back focus” I currently have a 2” quartz dielectric diagonal with a direct SCT connection, And will install the reducer directly between the scope back and the diagonal. Could you advise how you went about setting the correct distance between the reducer and the camera sensor? How do you estimate the light path through the diagonal?
cheers,
Ian
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Hi Ian,
Sorry, for the late reply. I didn't see your message.
The excepted distance for the Celestron Focal Reducer to achieve F6.3 is 105mm. I would have thought the Antares would be the same. However, the distance depends on what reduction you are after and what distortions you come across with your setup. As an example a user on Cloudy Nights has a CPC-800 and runs his scope at F7 (less spacing) and know star diagonal. Another user on Cloudy Nights double stacks two F6.3 reducers on 8 inch SCT to achieve around F4 (EQ mount). It is all down to personal choice. I use the Baader T2 star diagonal as that is smaller than a 2-inch prism and hence has a reduced light-path while still maintaining a 37mm clear aperture (more than enough for my Altair Astro 294C).
I messed around for ages changing the distance in and out and finally settled for very close to F6.3. Not because it was the optimum position but because I was losing too much observing time 😀 Try with the 2 inch diagonal and try with the spacing closer without a diagonal (F7 is better than F10 😀) My camera's USB port is on the rear of the camera so I have no option but to use a diagonal.
Have fun
Pete
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