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Hoges
19-12-2014, 07:36 AM
Geez, didn't even know this was in the sky till yesterday....oops. This is 7 x 90 second unguided exposures at 200mm f 4.5 (sigma 70-300mm) Pentax K50 riding on top of my 4" scope/HEQ5.

Just saw Bruce's excellent photo where he's stacked on the comet, so I'll try that too.
PeterEde
19-12-2014, 08:07 AM
Top shot
cometcatcher
19-12-2014, 02:38 PM
Nice one John! :thumbsup:
BruceG
20-12-2014, 05:24 PM
John that's great!
I had another go at processing from the same night and tonight I'm hoping to try a faster scope (albeit one that I cannot guide - this will be a test of my PA).
I really like the compromise between focal length and total exposure time. You have manged it well and got good definition on both.
Cheers,
Bruce.
Hoges
20-12-2014, 05:42 PM
Many thanks, guys! I tried stacking on the comet, but the end result looked a bit weird as I was using the in-camera noise reduction thereby putting a 2 minute gap between the stars. The comet nucleus was certainly more defined but the tail didn't stand out overly. Might try again tonight at 300mm. Did some shots last night through the ED80 but couldn't find much to guide on nearby (manual guiding atm) so they were unguided 2min shots.
Hoges
20-12-2014, 05:45 PM
See what I mean about it looking weird with the 2min gap?
cometcatcher
21-12-2014, 12:58 AM
Yeah pauses in shooting will do that. A cloud every now and then and it will look like morse code.
Hoges
21-12-2014, 08:49 AM
Couple more attempts - this time 8 x 2min and 2 dark frames with camera NR settings turned off. Unfortunately, I took them through my 100mm f5 acro, so there's some lovely blue fringing. Next time I'll go back to the ED80 and try more shorter exposures to improve the tracking.

One stacked on stars, one on the comet.

Speaking of stacking - does 20 x 30 second exposures give the same result (after stretching) as 10 x 1min or 5 x 2min ?
cometcatcher
21-12-2014, 10:35 AM
Roughly yes. (With an uncooled DSLR)
glend
21-12-2014, 12:21 PM
That's pretty much the real colour. I imaged it last night with my 10" newt and it was coloured green like a christmas ornament. Speaking to Allan_L who was at the Pony Club last night looking through a 28" dob, he also mentjoned how green it was. Your fringing of course, as shown in the star the comet is passing in front of, is due to the achro glass but the comet colour is not bad.