Comet C103p/Hartley in Perseus Oct 13, 2010
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More time on the green comet, 20 minutes of comet combined with 80 minutes of background. The tail is becoming easier to see, rather image,
but it takes at least a few four minte exposures to bring it out. I had planned 100 of the comet, but, if you look closely in the larger image,
you can see a star right next to the nucleus... bad news for the guider which I had left unattended... Obediently, the guider
took off after the star.. and did quite well actually, giving me 80 minutes .. LOL

Processing on these subs was tricky. I first did a standard deviation stack of the comet nucleus, and then a standard deviation stack of the
background aligning on the stars. I cleaned up the star trails in the comet stack, and combined that with the star stack using "lighten" in
photoshop. I used curves to stretch the comet a bit, and the spotting brush to clean up residual star junk...
Carboni's tools made the stars a bit more colorful and a final density adjustment was applied on the end stack with Photoshop...

simple, no?
 Telescope Explore Scientific David H. Levy Comet Hunter Maksutov-Newtonian 152mm f/4.8 mounted piggyback on Meade LX 200 Classic 12 inch
Camera Canon XT/350d modified with Baader type 1 filter by Hap Griffin
Exposure  twenty 4-minute sub-exposures guiding on the stars, and five 4-minute sub exposures guiding on the comet, all at iso 800
 Guiding PHD Guide from Stark labs with Meade DSI pro I on Meade 12-inch LX 200 Classic at f/3.3
 Software  Images acquired, calibrated, stacked and color corrected with Nebulosity 2.3.3 from Stark Labs. Further processing in Photoshop CS 3.
on-line links to more information    for more information try a google search for the comet.