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Hello,

I have a question about filterwheels; SBIG filter wheels specifically. As far as I know they are the only ones that really use the 8 position filter wheels. So I have it loaded with L, R, G, B, Ha, OIII, and SII. So that is seven filters, what goes in the 8th slot???

Thank you for your insight,
Christopher

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There is a C filter, which is like the L but with (without?) the IR block (can't remember which way round they are).

Some people also have a special IR-pass filters for imaging the moon and planets. And some use a set of UBVIR filters for photometry.

There are also other less usual filters. I have a CH4 filter for (particularly) Jupiter & Saturn. I also have an NE3 filter for (particularly) planetary nebulae.

So that's another nine options ...  where can I get a 16-position filter wheel :biggrin:?

  • Haha 1

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I could use an 8 position wheel for my Trius camera, for LRGB, [SII]. [NII], HII, [OIII]. Baader LRGB, plus a full set of 3nm Astrodons. As it is, I either have to lose the L filter, or else one of the NB, usually the [SI].

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Just curious, having just started imaging with a DSLR, and having a long way to go before I'm ready for mono cameras and filters.

Would you need all 8 filters in one session, or do you just keep all your filters loaded and control which ones to use in a given session ?

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No, the most you'd need is R, G, B if you were going to cycle through them during the course of a session, any L data would be added separately The reason for loading up the wheel is to have all your filters in one place, and hopefully not gathering dust, something they can do with alarming ease.

A narrow band session would likely use only one filter at a time, to gather as much signal as possible.

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Keep them loaded and use what you need.  Although it is not uncommon to use LRGB in rotation (LLLRGB LLLRGB,  etc).

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A dark filter would be handy if you are using the gear remotely and need a new set of darks.. :)

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Just to mention (though it only applies to thinned CCD chips), I always use an  IR blocking filter to get rid of those pesky diffraction patterns on my images caused by atmospheric moisture.

Diff.jpg

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On 24/06/2019 at 02:51, stardude07 said:

Hello,

I have a question about filterwheels; SBIG filter wheels specifically. As far as I know they are the only ones that really use the 8 position filter wheels. So I have it loaded with L, R, G, B, Ha, OIII, and SII. So that is seven filters, what goes in the 8th slot???

Thank you for your insight,
Christopher

There is such a thing as aNitrogen 2 (NII) filter if you have a 3nm Ha filter then you can split it out. Some people will use a LP filter as Luminance in a mono camera.

Edited by Adam J

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On 25/06/2019 at 19:46, jjosefsen said:

A dark filter would be handy if you are using the gear remotely and need a new set of darks.. :)

That kinda implies that your leaving the scope permanently without a cap on it. Would not want to do that to a scope of mine.

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