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Old 01-06-2016, 03:37 PM
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Regulus (Trevor)
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Light Frame Lens Cap

I wonder if these would be any good for doing light (white) frames?

http://www.aliexpress.com/item/58mm-...d-9057fffd4dd7

Trev
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  #2  
Old 01-06-2016, 07:46 PM
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billdan (Bill)
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Hi Trev,

I think you really need to see the freq response curves to make a judgement ( it could cutoff all the Ha content).

Bill

EDIT: I just saw the price at $2.35, its not a risk taker.
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Old 01-06-2016, 08:03 PM
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RB (Andrew)
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I think Trevor's talking about doing flat frames.
They're normally used for white balance, as stated, but you can try them.

You may risk introducing vignetting, in your flats, at either end of the focal range of the lens.
Plus you'd need different sizes for different lenses.

You'd be better off just shooting a white/grey PC screen for flats, just for doing widefields.

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Old 01-06-2016, 08:50 PM
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Stonius (Markus)
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Does that work? PC screens are typically very blue (depending on settings)...
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Old 01-06-2016, 09:01 PM
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RB (Andrew)
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Quote:
Originally Posted by Stonius View Post
Does that work? PC screens are typically very blue (depending on settings)...
It's not my preferred option but yes you can, depending on the size of your scope.
It's not the colour that's critical, close to white or light grey works.
What you're trying to achieve is an even illumination of the chip, with your Histogram having a sharp spike at approx. 1/3 to 1/2 way across.
That's why I don't use these methods.

I use an EL Panel that I made up.
See here:

RB
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