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Configuring during the day


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Is there a way that works to enable one to test out the spacing between flattener and chip sensor during the day which translates well to actual results when used at night? I am currently fiddling with some spacers on my T-ring between a flattener and a DSLR, but its awkward to do at night and I wondered how, if at all, people fine tune during the day?

Thanks

Matt

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Interesting point but im not sure if the distortions would show up i know some of my camera lenses look fine if shooting something like a brick wall but show bad coma on a star field, it has to be worth a try if you can get the right type of target.

Alan

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Is there a way that works to enable one to test out the spacing between flattener and chip sensor during the day which translates well to actual results when used at night? I am currently fiddling with some spacers on my T-ring between a flattener and a DSLR, but its awkward to do at night and I wondered how, if at all, people fine tune during the day?

Thanks

Matt

Hi Matt.

In a word no and for different reasos. The biggest problem is emulating a star, a pin point of light, at true infinity focus during the day. I think out of an optical lab with computers simulating the night conditions this is a very diffcult task. Depending on the length of the spacing required you might be able to use the Baader variable extension tubes to make the task less painful.

A.G

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Thanks - I had a sinking feeling that it was not going to be easy. My DSLR chip is not that far off, but even a small way off the required distance results in some pretty distorted edges on the big chip. I am using Baader Delrin T2 spacers to get the last few mm right, but they are fiddly little things and seriously hard to get on/off and at night just makes it more difficult. I know that once done, its done, but with limited clear sky time it is a right old test of patience.

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It is allways a faff it took me ages to get mine spot on and fractions of a mm do make a difference in the end i found a solution that  worked but was not that stable so i measured it and found that an M42 adaptor with a 15mm T spacer screwed in was close enough.

Alan

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Thanks Louise. Those adjustable extension tubes look a lot easier than the spacers I am using, although I don't think I need more than a few mm from the adaptors I already have. I'll try tonight, given the forecast is promising and if I need more space than the thread allows, then a cheeky purchase is in order.

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Thanks Louise. Those adjustable extension tubes look a lot easier than the spacers I am using, although I don't think I need more than a few mm from the adaptors I already have. I'll try tonight, given the forecast is promising and if I need more space than the thread allows, then a cheeky purchase is in order.

With my ED or Apos and a medium size CCD, I have found that 0.5 mm of tolerance is workable. The biggest head ache to date that I have had have been with a Hotech FF for the EDs and the Baader MPCC III for the Quattro 8s if  I am using a QHY8 or a DSLR as so far I have not had any joy. The best out of my selection for universal application have been the Televue TRF 2008 which seems to be infallible but pricy and the SW FF which at £60.00 is a real bargain.

A.G

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