DSLR for Narrowband Imaging

[Aeseir]

Quick question (may be silly).

Does having a full spectrum modified DSLR (UV and IR blockers removed) or is IR Mod camera (IR blockers removed) same for imaging?

All narrowbands that i have seen have been in IR spectrum thus making me believe UV spectrum is useless when it comes to imaging.

Is this true or is there light we capture on UV level as well?

[Astroboffin]

Hi,

If you have the full spectrum mod and remove both filters, then you will need and IR block filter fitted before imaging, most people get an LP filter that has IR block built into it, like the AStronomik EOS clip in CCD version.

If you just have the one filter removed, which I would class as the normal or usual astro mod, then you would not need an IR cut filter as the one left in the camera does this very well indeed, that is why it is left in place.

You may still need a LP filter, but you would not need one with IR block built in, so in the case of the AStronomik ones then it would work out a lot cheaper.

I am not sure whether the filter that is removed is a UV filter, the way I understood it, is that the filter that is left in place in the normal astro mod, For the IR cut function, also cuts the UV, most IR filters that you buy are UV filters also, but I might be mistaken about that, I know my 1.25" AStronomik IR filter is a UV filter too, I use that on my planetary camera for imaging

Hope that helps

AB

[redmoo]

Just a quick note, you don't need a UV blocking filter if you are not using a refractor. 

As a general rule, UV is no use to AP photos, and with refractors, the UV focus is all out of whack (which gives you star bloat). With reflectors, it isnt so much of a problem. Don't think it does anything for the pictures, but no big deal.

I am only relaying information that I have read on here and little bits that I came across when I modded my camera.

[Thalestris24]

Quick question (may be silly).

Does having a full spectrum modified DSLR (UV and IR blockers removed) or is IR Mod camera (IR blockers removed) same for imaging?

All narrowbands that i have seen have been in IR spectrum thus making me believe UV spectrum is useless when it comes to imaging.

Is this true or is there light we capture on UV level as well?

Hi

As far as I know, all narrowband imaging takes place in the visible part of the spectrum i.e. excluding IR and UV. The benefit of a full-spectrum mod is an increase in sensitivity but you don't normally want to pass UV or IR so you need a UV/IR cut filter for normal colour imaging or a narrowband filter that also cuts UV/IR e.g. a Baader 7nm H-alpha ccd filter. However, I believe planetary imaging can benefit from UV/IR though I've no experience of it.

Louise

[Aeseir]

Thanks for responses guys.

[Merlin66]

Hmmm.

The "normal" DSLR mod removes the colour compensating filter and retains the UV/IR blocker. This enhances the red response.

The "full" FULL DSLR mod removes all the original built-in filters and allows the CCD to "see" from 360nm (in the UV) to the NIR (beyond the Ha)

For "normal" AP work a UV/IR filter needs to be fitted to the FULL mod- this has NO effect on the red response.

I use a FULL modded Canon for spectroscopy, because I want to record the spectrum from 360nm through to the NIR.

[Aeseir]

Thanks Merlin, clarified a few things for me there.