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Old 30-12-2008, 12:18 AM
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RobF (Rob)
Mostly harmless...

RobF is offline
Join Date: Jul 2008
Location: Brisbane, Australia
Posts: 5,624
Hi Matt.

You might be interested in these 2 pics of HH neb area I took last week when playing with effect of different ISOs, filters, exposure times. Both 180sec single frames, ISO 800, no flats, ICNR turned on (with unmodded 450D, 8" F5 newt, MPCC)

I get a lot of sky glow here. The first shot is typical of the orange cast to pics without filtering. 2nd one shows overall blue cast IDAS LPS lends to pics, but I think you'd agree a cleaner pic with greater potential.

I scooped Jerry Lodriguss' CD book on DSLR astrophotography for XMAS, and he talks about IDAS LPS filters giving the potential for 2 - 3x greater exposure times. I really haven't had time yet to do a lot of imaging with my setup, but seems to me up to 2x longer exposure times seems reasonable before pollution fogging, albeit with loss of some light. That is, a 10min frame in city with LPS will never be as good as 10min from a dark sky site.

Ezystyles and other gurus here have mentioned before that the IDAS LPS seems to be easier to colour correct where necessary than harsher filters (eg. UHC-S)

I'm happy with mine!
Attached Thumbnails
Click for full-size image (HH neb 180 iso800 no filter.JPG)
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Click for full-size image (HH neb 180 iso800 IDAS LPS.JPG)
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