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What's best for Whitelight?


MattGoo
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Just after a bit of advice on which is the best option for some solar imaging with my Canon 1000D. I have some Baader solar film ND5 and could make a filter for either:

1) Full aperture Skywatcher Explorer 200P. [200mm F5]

2) Masked aperture Skywatcher Explorer 200P. i.e. 3" circle offset / though the spider vanes gap.

3) Full aperture Skywatcher StarTravel 80 (ST80). [80mm F5]

Any thoughts on which would give the best image? I could probably do both 2) and 3) from the same A4 sheet?

All will be mounted on a EQ5 with dual motors.

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2 and 3 would be my choice. 3-4" is large enough to let in plenty of light for any telescope. There might still be enough left to make some filters for the binos too. :)

The refractor should produce the best images of all. Certainly does in my case with a 70mm vs a 130mm Newt.

Baz.

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Option (1) for me, more aperture == more resolution.

Especially since you are using visual solar film instead of imaging solar film, the more light you capture the shorter the exposure you can use.

Chris

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I'd probably go for a 4" to 5" mask on the 200P. I think once you get beyond about 120mm you can't resolve much more in white light anyhow. If there's any left you could make one for the ST80, but I'm not sure how it would fare with colour aberration.

James

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I got these images with a skywatcher 200PDS, Baader film with a 90mm off axis aperture, using a Nikon D50 DSLR camera for the full disc, and a webcam and barlow for the close up. I think 90mm is as big as you can get with the 200 while avoiding the side and secondary mirror.

sun61.jpg

sun58_1734_1732.jpg

Edited by ArmyAirForce
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I use an ST120 stopped to 100mm , I experimented with a full aperture on the 200PDS and to be honest it made little discernable difference.

The main limiting factor is the atmosphere , and unfortunately the seeing on a warm sunny day is rarely good enough to warrant the bigger aperture.

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I use a 120mm refractor stopped to 100mm, reasons as above. Given your choice I would go firstly with the off axis mask on the 200P or secondly the ST80 (but this would be better with a 2x Barlow to get the Solar image to fill more of the camera sensor).

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