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Old 01-09-2008, 11:00 PM
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bmitchell82 (Brendan)
Newtonian power! Love it!

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slowly getting there but focus???

heres my latest attempt... weather conditions where less than favorable. dammn wind

question. I have used the hartmann mask to get bright stars perfectly set, but how do i get things like this in perfect focus?

Picture of 47 Tuc, at 13 second exposures and stacked in registax with 60 subs
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Last edited by bmitchell82; 01-09-2008 at 11:02 PM. Reason: whats the picture of :D
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  #2  
Old 02-09-2008, 12:49 AM
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Merlin66 (Ken)
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Practise!!
Another idea is to use a Ronchi grating on a flip mirror. Set the CCD to your "best" Hartmann focus and then put a Ronchi grating on the guide port of the flip mirror, adjust until you get the gray null image of a star and lock in place. If the focus is spot on, all you need to do the next time is set a bright star to null with the Ronchi, flip to the CCD and away you go!
If you find the focus is still "soft" adjust it slightly and note the view in the Ronchi ie three wide bands etc. When it's 100% then re-adjust the Ronchi screen ( without moving the focusser) back to a null. Then you have a great reference for the future....
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Old 03-09-2008, 09:26 PM
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jjjnettie (Jeanette)
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With my Gstar I use "point and zoom" to achieve focus.
Put the mouse on a star to magnify it, and then adjust focus.
I get live view from my camera to the puter screen, I don't know if you can do that with your camera though.
There's a couple of different versions for free download here
http://www.hsinlin.com/software/mouse.html
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Old 04-09-2008, 05:06 AM
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montewilson (Monte)
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I find I get good final focus by picking a star that is just on the verge of being too faint to see on the screen and getting it to come in and out of view. When in focus the star appears and when out , it simply dissapears. Its quite accurate.
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Old 04-09-2008, 10:12 AM
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bmitchell82 (Brendan)
Newtonian power! Love it!

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that sounds like a good one, for me at the moment. untill we get some better gear.!
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