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My first solar image


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StarTravel 80, some solar paper, a webcam and thirty minutes during my lunchbreak. My first solar image :-)

Any tips for obtaining focus with the rather rough ST80 R&P focuser on a sunspot would be appreciated. I was using my camera tripod (Hama Star 63) - a fairly flimsy thing and it was quite difficult to get the scope pointed and the solar image stable.

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The best way to focus that I have found is to simply take your time over the process. As the image comes and goes into and out focus you just have to be patient and try to get it "just right" during one of those fleeting moments of good seeing. I don't consider well over five minutes as time wasted when focussing - and then I often tweak the focus after a couple of .avi's as I always think that I can get it "just that little bit better".

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Thanks chaps,

I have the motor drive, I may install it but I didn't expect that it would do much good on the rack and pinion focuser. As for focusing in and out - it doesn't make much difference at all. In or out of focus the disk is still a disk so I have to go off the sunspots. The sunspots go from out of focus to mildly in focus to out of focus again. But getting any fine focus? Not happening...

All the best,

Mike

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You can use the edge of the disk as a guide though Mike - once that is sharp you're nearly there.

Helen

Thanks Helen,

I'm struggling to get much contrast out of the edge of the disk and by extension, the sunspots themselves. I might try focusing on the sunspots while using a bigger OTA.

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Hi Mike. I found an Electric Focusser worth it's weight in gold. The reasonable-budget Skywatcher 'frac one worked well with my ST102. Nothing worse than trying to twiddle a focusser, with a Laptop in one(!) hand and a manky old bathroom towel over the head (LOL) - Only a matter of time until something gets dropped? ;)

Now you have the "Quattro", might be worth an experiment or two? I'm sure far better things can be achieved, than with "Yesterday's" GSO [teasing] - Again, with an electronic focusser though. :rolleyes:

Edited by Macavity
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Using a hartmann mask and focusing on the edge can be a huge help, especially with the 'blank' disk which had been the norm over recent months. Sunspots would be the ideal target to focus on but lacking those, the edge is always handy.

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Thanks Sheri and Macavity,

The hartmann mask has to be the way to go with the ST80. I'm having a lot of trouble with the focuser being so stiff (it's a cheap rack and pinion) so I might lubricate it a little too and see if that helps.

I do have an electric focuser but I haven't attached it to the Quattro yet ;) I'm too scared to tackle this focuser and take it apart :rolleyes:

All the best,

Mike

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Shooting at lunch can be tough. A good hood or cloak to cover your focus area might help. Make sure its light colored on the top or it will heat up. Also, I've found it easier to tell when the image is out of focus. I'll usually rock back and forth between focus and out on both sides of focus and then find the mid spot. What type of filter material are you using? You might try some Baader film and a Green #58 filter. When taking the image put your camera in B&W mode. This will null out any odd green coloration and only show the contrasts.

Best of Luck ;)

Edited by armicheal
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Thanks for the tip, armicheal - I'll see if I can put the camera into B&W mode.

Also I forgot to mention that the solar filter was very kindly provided by KevG - thanks for the paper, Kev! :-)

Clear skies to all,

Mike

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