RGB Moon imaging ?

[kirkster501]

Hello folks,

Do you use an IR filter in conjunction with the RGB filters?  i.e. the IR is in front of the RGB glass?

Which RGB filters do you use?

Do you stack the same number of frames per filter or do you make adjustments in PS?

Thanks!

[CraigT82]

Are you talking about an IR pass or IR block? Assuming IR pass?? you wont need RGB filters as you'll wont be getting any RGB light, just IR.

 

[vlaiv]

Depends on the scope and RGB filters.

If RGB filters are good, meaning only pass wanted wavelengths of light, then you don't need additional IR/UV cut filter.

If one of filters is leaking some wavelengths outside visible range and you are using refractive optics, you'll need IR/UV filter.

Here is example of Baader RGB filters with marked "leaks":

These are however too small to have any significant impact on contrast, so in this particular case I would not use additional IR/UV cut filter with those.

On the other hand, if you plan to do LRGB Moon imaging and as CraigT82 assumed, you want to maybe use a IR pass as luminance layer, then you certainly don't want to combine them, but shoot each channel separately. In this case, you won't need additional IR/UV filter for color even if your RGB filters pass some of the out of band light as sharpness will be defined by Luminance.

You can also use other filters for luminance on Moon besides IR pass filter - like Ha/SII filter if you have one, or maybe Solar Continuum filter, even OIII is going to be good. Any filter that is narrower band and shifted towards red part of spectrum will be a good L filter for the Moon. Such filters will negate some of the effect of the seeing, and since Moon is broad band target with "uniform color", you won't miss any features if you use such filter.

[wouterdhoye]

Hi,

if using proper CCD RGB filters usually no additional UV/IR cut filter is required. eg, Baader/ astrodon,... Make sure to check the bandpass graphs for the respective filters.

I personally do IR - RGB using high res IR images as luminance together with lower res RGB data. For RGB I use a colour camera however. In this case a UV/IR cut filter is required as the bayer matrix does pass beyond the visible spectrum.

Check my astrobin for some examples. 

Wouter.