From: Alan Friedman <alan@greatarrow.com>

Date: October 31, 2007 9:49:36 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Comet Holmes Oct 30 from Toronto

Hi Jim -

That's a great image of the comet. I'd be interested to hear a little more about how you captured and processed this shot. Did you sum the exposures rather than average them?

I was looking at the specs for the PGR dragonfly cameras the other day - it appears they use the Firewire 800 bus for data transfer. Does the Flea as well?

best wishes,

Alan

On Oct 31, 2007, at 10:48 AM, jimchung2338 wrote:

I thought I'd experiment with longer exposure imaging with the PGR Flea using that most
convenient of recent target - Comet Holmes. Subs were taken at 5s with automatic dark
frame subtraction via AstroIIDC.

http://tech.groups.yahoo.com/group/Astro_IIDC/files/Planetary/Holmes_FleaRGB.jpg

I think the colors are faithful and there is siginificantly less green in the outer cloud as
compared to a shot I took 2 days earlier with my Starlight Express CCD.

Milton, are you planning to change the algorithm used in sum stacking images. Using
AstroIIDC I can really only stack about 10-12 5s subs before I reach the maximum white
levels values in the comet nucleus. I had to resort to exporting the movies as individual
TIFFs and stacking them in another program. There wasa real benefit in stacking the full 5
minute exposures in terms of noise reduction.

.