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Old 29-02-2016, 11:37 AM
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MattT
Reflecting on Refracting

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Join Date: Jul 2011
Posts: 1,217
Quote:
Originally Posted by Allan View Post
There are numerous reports of seeing it in good quality 4" refractors. I think the 3" size might be stretching the friendship, but it is up to us Southern Hemisphere observers to try.
I'm going to add:

#12. Use a long focal length Achro.

I tried again on Saturday night and got the Pup in the 10" no problems. The E+F stars in the Trap were visible too.

So onto the 70mm f13 Achro. Yep this 70mm is well in the Conrady scale for CA at about 4.5. Sirius was a white star, shown as an Airy disc with a couple of diffraction rings, dimmer and a lot less scatter than the 10".
I got a result that was surprising to me but more on that later as I need to try it again on another night.

In the meantime read this article by Neil English...love him or otherwise

http://www.cloudynights.com/page/art...-fiction-r2452

This is turning into an epic thread.
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