Camera lens filters for CCD??

[ollypenrice]

Hi,

I have just seen the Geoptic camera lens to CCD adapter at Altair Astro and think it looks great. I've always wanted to try this.

However, there is only 8mm backfocus going spare between adapter and camera so no filterwheel.

I have a One Shot Colour CCD so it might be worth a try but on widefield it is going to be really undersampled. Will it work with lots of dither, do you think?

But the main question concerns UV/IR blocking. You can get UV 'haze' filters and IR filters for the front of camera lenses but would I need both? Or just one? And if one, which one?? I know nothing about all this stuff.

Olly

[Merlin66]

Olly,

What about using a 2" (48mm) UV-IR up front on the lens.... you can get stepper rings to suit most lenses.

Ken

[steve51450]

olly what about a filter drawer system, i think Steve L uses one

[SteveL]

Like this?

[Merlin66]

Looking at Gerd's current pricelist:

Filter drawer body (10.501.002) 99 euro

1.25" filter slide (10.502.125) 29.95 euro

2" filter silde (10.502.200) 29.95 euro

Plus shipping etc

Ken

[brianb]

I think that filter drawer is going to be too thick - though it does depend on which camera you're using, there's no standard flange to sensor distance for astro CCD cameras & they do seem to vary quite a lot.

You can get T threaded filters, these are about the right thickness to use up the backfocus with e.g. the Atik 314L.

The more expensive Canon telephoto lenses (the ones that cost more than a Tak OTA) use a "drop in" 52mm filter, a stepping ring would take that down to 48mm (astro 2" filter fit) without too much vignetting though you'd need to be careful about the thickness of the assembly.