Planetary filters v's CCD filters

[aerobrake (Michael)]

I'm about to put an order in for the new Orion Telescopes (in the US) filter wheel which comes with planetary filters but I've read a couple of posts on Cloudy Nights that say there is a difference between planetary (visual) filters and ones for shooting RGB.

What am I supposed to buy to use my mono DMK CCd camera to get colour shots? I figured as long as you have red/green/blue filters you can use em to make a colour image!! I already have a set of R/G/B filters and dont want to double up.

Cheers
Mike

[[1ponders] (Paul)]

You can use the planetary filters to create an RGB colour image but the post processing to get the colour balance right can be a real pita. Even using less expensive CCD colour filters is challenging (I have the Baader ones and I'm still not happy with them). I believe the most common rgb filters used for planetary imaging with a mono camera are the Astronomik and the Custom Scientific.

[jase (Jason)]

Typically, visual filters are not IR blocking (a requirement for CCD imaging due to the chip's sensitivity across a broad spectral band). As Paul indicates, you can use them, but you'll struggle to get the right colour balance due to IR leaks poisoning the signal. You can play around and perform G2V star tests to get close, but for what its worth I personally wouldn't bother. If you've got a good RGB set with a high transmission rating - stick with those.

[aerobrake (Michael)]

Thanks for the reply chaps. I'll look at getting the Astronomik Filter set.

Cheers
Mike

[netwolf]

How about the True Technology Filters? Are they any good for Planetry and DSO?

Regards

[jase (Jason)]

Originally Posted by netwolf

How about the True Technology Filters? Are they any good for Planetry and DSO?
Regards

Yes, but only the True Technology type 2 filters. The type 1 RGB filters do not incorporate IR blocking. The RGB set comes with a separate clear IR blocking filter which is next to useless unless you intend to couple the individual RGB filters with the clear IR blocking filters - very unlikely. The type 2 filter set incorporates IR blocking across the RGB set.

The type 2 filters appear to have a high transmission rating and an exceptionally high blue/green colour cross-over of ~85% centered on 500nm wavelength. This would allow you to acquire the OIII band very well.

[rumples riot]

Astronomiks are the filter for taking planetary images. You can use these for LRGB DSO imaging too.