DLSR astro-modification confusion

[choochoo_baloo]

I had my DLSR "astromodified" a few years ago whilst very new to the hobby and not really understanding in great deal why it should be done.

Now that I've revisited a lot of the theory, I'm wondering whether I do in fact have the optimum equipment. Please bear with me:

1. The DSLR modifier sent back the (blue-ish) rear colour correcting filter. Great; increased red visible specturm repsonse.
2. I'm now wondering whether the front (red-ish) Antialising IR&UV filter was also removed? How can I hold the mirror up to check for this red-ish filter is in place?
3. Assuming 2. is true, does that mean the standard Astronomik CLS light filter fitted is suitable? Is the additional IR blocking feature of the pricier Astronomik CCD filter range only required for full spectrum modded (ie bot filter removed) DLSRs?

Thanks in advance.

 

[michael8554]

To examine the sensor

Set the shutter to Bulb and hold the shutter down

Or go into the menus and perform a manual sensor clean.

Not sure you'll be able to tell anything !ooking though.

Michael 

[Thalestris24]

Hi

I think you'd have to check back with who did the mod to be certain as I'm not personally familiar with the 450d. If they followed Gary Honis' instructions then they probably left the anti-aliasing filter in as it's part of the piezo cleaner. I think you only need an extra UV/IR filter if you have the anti-alias/ir cut filter removed (that would then be a full-spectrum mod). See also Gary's video from  7:20 onwards. I had an 1100d full-spectrum mod and it's pretty sensitive to IR now i.e. to wavelengths outside of the range of human vision, rather than just to Ha wavelengths. Occasionally I'll do some IR astrophotography with the aid of an IR-pass filter. It's good for beating LP but is purely monochrome, of course.

Hth

Louise

edited: made a correction!

ps see Astronomiser's mod - I think it was he who did my 1100d a few years ago

[Merlin66]

Definitely sounds like the "standard" astro-mod, where the colour balance filter (filter#2 below) only is removed. This gives an enhanced red response, and the remaining dust shaker/anti-alias filter (filter#1 below) provides some UV/IR correction.