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Camera modding advise

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Guys can i get some help!!!

I am just being stupid but i can't get my head around it :( :(

I am looking at modding my camera which i know is a good thing, as i will only be using it for astro imaging i believe the mod i require is the filter removal... Here is what i can't get my head around...

As i have the filters removed to allow more Hydrogen Alpha in to get more red Nebulosity .. i have then been recommended to get the CLS-CDD clip filter as this has a IR filter in it wouldn't that cancel out what the modification was for??

Like i said i am probably just being stupid :(

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Ha nebulosity is at 656nm (deep red). The inbuilt camera IR filter blocks most 656nm and the longer IR wavelengths.

The add-on astronomy IR filters allows the 656nm through but blocks longer IR wavelengths.


NB- If you used a Newtonian scope then a replacement IR filter is not required- they are just for fracs that can only cope with a limited spectral range before going all blurry!

Edited by laser_jock99
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First of all no, IR and Ha signal are different, an IR filter will just cut that particular wavelength and not the Ha.

When doing the mod you only really need to remove one of the two filters in front of the camera sensor, this is the normal mod to remove the one closest to the sensor and leave the other one in as it gives the needed IR cut for digital imaging.

The one you will remove is the one that cuts a huge chunk of the Ha signal hence that is what it is removed, the one that you leave in the camera, only cuts IR and NOT the Ha signal, so best left in place then you don't need an external IR filter, as you have been told to purchase.

If you remove both filters this is called the "full spectrum mod" and is not quite as common, if you go down this route then yes you would need to buy an IR filter to put on the camera before imaging, so you have two options.

1. You buy just an IR filter, which does as it says on the tin, cuts IR....

2. You buy the Astronomik CLS CCD clip in filter as this has the IR cut but also is an excellent light pollution filter, which you may also need so you get the two in one filter.

If you do,the normal mod and just remove the one filter then you can still get the Astronomik CLS filter for LP, but you would only need the cheaper version without the IR cut as you will still have an IR cut filter in the camera.

So in a nutshell two filters in the DSLR camera, one cuts both Ha and IR signal so is removed, the other just cuts IR to a very good acceptable level so is left in place.

Hope that helps explain a bit



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