Do I need a filter to go with a full spectrum mod.

[Crushellon]

Hey guys,

So after doing astrophotography for a little while with my dob and camera lenses, I now have gotten some gear that's actually meant for photography... An Neq6, 8" f5 reflector, 80mm short scope and a ProStar - LP-GUIDE for guiding. So I figure now that I won't be using camera lenses for imaging, I should do a full spectrum mod on my 500D. Just wondering if I will need a filter for this to work or if it will be fine without anything. I will be getting one eventually to help with light pollution seeing as I will be doing almost all of my imaging for my backyard in suburbia, but as it stands at this point I think my wife is under the impression that I have spent enough money for now :D

Thanks

[Crushellon]

http://www.iceinspace.com.au/forum/showthread.php?t=146968 ??

maybe I will have to convince the boss to let me spend more cash...

[luka]

You won't need a filter with a reflector. Refractors suffer from star bloating and require IR/UV cut filter.

[bobbyf]

If you plan on ever doing widefield imaging with normal lenses, you'll need a piece of glass to correct the refractive index (or something like that) so that you can focus at infinity.
Might as well go with an IR/UV cut filter and then you can use it with anything.
Some say that the CLS clip in corrects well enough to use lenses without a filter, but i'm not sure.
I'd fit the filter anyway, in case you're ever under a dark sky and don't need the CLS.
If you decide to mod it, DO NOT use JJCamera in Sydney for the service though.
The filters they use do not correct enough, and they blame your equipment for it. (mine was a Nikon D7000)
Worst service I've ever used, for anything...ever.
They have a service on eBay too, but by a different name.
I would do it yourself or send it somewhere more reputable.
Cheers
Bob

[bojan]

I am using Rocolax UV-IR CUT filter with modified (by myself) 450d when imaging with Canon 400mm F2.8
Ebay prices (http://www.ebay.com.au/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC 0.H0.Xrocolax+uv-ir+cut+filter.TRS0&_nkw=rocolax+uv-ir+cut+filter&_sacat=0) for those filters are not prohibitive at all.
Hoya filters are probably a bit better, but much more expensive.

[Anth10]

Snap that Bojan, I too use a UV/IR cut filter with my modded 60D. This brings the image almost back to the camera's original state and use it for images other than nebula where the mod most useful. Globulars, planets and galaxies don't really require full spectrum mod so the filter goes on for these.