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Old 10-08-2014, 08:25 PM
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skysurfer
Dark sky rules !

skysurfer is offline
 
Join Date: Dec 2011
Location: 52N 6E (EU)
Posts: 1,152
Halpha filter for Canon EOS 6 ?

For deep sky astrophotography I use an unmodded EOS 6. Modding is too much hassle, limited use for regular photography as the white balance is disrupted because all photos are too pink.
And the display of red nebulas is not too bad.
Obviously after (un)installing the filter I have to refocus.

I am thinking about buying an Halpha filter which I will use for a series of frames which I'll stack together with unfiltered (or IDAP LPv2 filtered in light polluted areas) frames. Or make a stack of the filtered and unfiltered separately and then overlay both stacked images (the red and the 'light' one) and with Photoshop/GIMP. I have to experiment yet but am sure one option will work.
The trick is that exposure times of 'light' frames are limited in light polluted areas, so I can expose the red frames at least 4 times as long as the 'light' ones due to the narrow bandwidth. This will compensate the only 25% passthrough of Halpha in an unmodded camera.

How I have two choices:
* 12nm Astronomik clip-in for $279
This can be used with *any* lens or telescope as the filter is mounted direct over the sensor. But (un)installing in a dark (and usually moist) environment, even with a red headlight on, must be a tedious and very careful job. Also because I have to keep the camera pointed at exactly the same field with or without filter.


* 7nm Baader for $195
This can be screwed on the same lenses as the IDAS LPv2 2" screw filter or in the T2=>2" tube mounted on the camera which I put into the Genesis. Moreover, I can use it visually on the Genesis and on the 50 or 85mm lenses when used as a wide field mini scope. And no risk damaging the sensor / mirrorbox of my 6d and a lower price.

What are your opinions ?
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