Canon 20D modded for Ha ?

[gurney]

Hi there,

I have a basic understanding of the modded DSLR camera situation. I know that the unmodded cameras have daylight filters in them which can remove wavelengths necessary for astronomical imaging.

But I've seen a very attractive looking second hand Canon 20D which has been modded for Ha. That bit I'm not sure about.

Does it mean it's very much a one trick pony, only suitable for imaging in the Ha region? Or would it be more generally useful for astro imaging?

[themos]

Someone with experience will hopefully answer but my understanding of modded for Ha means just that the red response has been improved a bit which means you need to do your own colour balance. I expect it to be useful for astro imaging and daytime imaging too. I am looking forward to learning from someone with experience, though.

[steppenwolf]

This camera will be excellent for imaging many Deep Sky Objects, not just those with an Ha content but has the advantage of having had its standard IR filter removed. This IR filter will have filtered out light from the red end of the spectrum including that of Hydrogen Alpha which means that a lot of the valuable light from emission nebulae would have been lost. With the filter removed this light will pass through to the sensor and be captured.

Without an IR filter, standard daylight images will take on a 'pink' appearance!

[Ant]

Didn't Canon do a 20Da - especially manufactured for astronomers? Cost a damn fortune if I remember correctly.

I think the Pete Lawrence hadone.

Ant

[gurney]

The one I've seen is going for £300. No lens, but for astro that doesn't matter of course.

[Kaptain Klevtsov]

There are two ways of doing the modification, one is to remove the IR filter and replace it with a different filter which lets more red light through, the second way is to just remove the filter. The disadvantage with the second method is that the camera's autofocus system no longer functions.

Both would, as pointed out above, be good for astro stuff, but the second option would be no good for normal use.

With the first option, it might be possible to add a clip filter as sold by Bern at Modern Astronomy to replace the IR filter for terrestrial use.

Kaptain Klevtsov