Search found 526 matches

by oopfan
Fri Apr 03, 2020 3:57 pm
Forum: Gallery
Topic: NGC 4449
Replies: 7
Views: 64

Re: NGC 4449

I plugged in the info for your telescope, camera, and site. At your B6 site, 6.9 hours got you to SNR 14.1 At a B5 site, you could get to SNR 19.2 At a B4 site, you could get to SNR 30.6 For you to get to SNR 19.2, you would need a total time of 12.8 hours. To get to SNR 30.6, you'd need 32.7 hours....
by oopfan
Thu Apr 02, 2020 6:06 pm
Forum: Gallery
Topic: NGC 4449
Replies: 7
Views: 64

Re: NGC 4449

Ah, I see. Thanks for the great follow up. Much appreciated. I've looked at a few images on AstroBin. The outer extent of the galaxy is a faint glow which I would probably have difficulty picking up with my B5 skies. Re: LP filters, they take a large chunk out of red-green wavelengths which gives a ...
by oopfan
Thu Apr 02, 2020 4:50 pm
Forum: Gallery
Topic: NGC 4449
Replies: 7
Views: 64

Re: NGC 4449

Hi, what's the total integration time?

I ran the numbers. It's surface brightness is similar to M81. I could get a good LRGB in 10 hours.

I've drawn the dimensions of the galaxy atop a screenshot of your photo:
NGC 4449 Dimensions.jpg
NGC 4449 Dimensions.jpg (39.64 KiB) Viewed 56 times
Thanks.
by oopfan
Tue Mar 31, 2020 9:09 pm
Forum: Deep Sky Imaging
Topic: ASCOM and Offset -- a call for expertise
Replies: 7
Views: 339

Re: ASCOM and Offset -- a call for expertise

Robin said: When cameras have no adjustable gain control, it's easy for the manufacturer to pick a single value for the offset that is just high enough to ensure that the histogram remains unclipped without wasting a significant amount of ADU value between zero and the mean level for a bias frame (w...
by oopfan
Mon Mar 30, 2020 2:49 pm
Forum: Gallery
Topic: Endymion, Mercurius, Messala: #21 orange filter
Replies: 8
Views: 76

Re: Endymion, Mercurius, Messala: #21 orange filter

You da Moon Man, Dave.
Great work!
by oopfan
Sat Mar 28, 2020 12:37 pm
Forum: Gallery
Topic: M101 Galaxy
Replies: 8
Views: 86

Re: M101 Galaxy

Hi Nick, Since you have a low-noise, CMOS camera the image quality won't improve dramatically from 20s to 60s but you will consume one-third the disk space, plus APP will complete faster. Another thing you might want to try is selecting a ROI centered on M101 since it takes up so little real estate....
by oopfan
Fri Mar 27, 2020 1:35 pm
Forum: Polar Alignment
Topic: Off by 2 arc minutes? Help?
Replies: 6
Views: 156

Re: Off by 2 arc minutes? Help?

Jeffrey, There is another weak point in their design: the single shoe that mates to the main scope. To test, grab the stem and give it a firm twist to see if you feel any movement. If you do then loosen the thumbscrew and slide the scope out of the shoe. Take a screwdriver or Allen Wrench and make s...
by oopfan
Fri Mar 27, 2020 4:35 am
Forum: Polar Alignment
Topic: Off by 2 arc minutes? Help?
Replies: 6
Views: 156

Re: Off by 2 arc minutes? Help?

Hi Jeffrey, Do you have something like this: https://www.telescope.com/Orion-Mini-50mm-Guide-Scope/p/99607.uts Me too. It's got three spring-loaded adjustment screws that unfortunately shift a bit as the scope tracks a target. I've witnessed 2 arc-minutes of offset during the course of a 3-hour sess...
by oopfan
Tue Mar 24, 2020 12:50 pm
Forum: Gallery
Topic: M51 & M13, Vixen 81s+Atik314E, LRGB
Replies: 7
Views: 373

Re: M51 & M13, Vixen 81s+Atik314E, LRGB

Excellent, Dave!

I really like M13 with NGC 6207, the spiral galaxy in the corner.
It's a challenge working with the light pollution filters.

Brian
by oopfan
Tue Mar 17, 2020 12:52 am
Forum: Tutorials
Topic: Picking the correct exposure for Deep Sky
Replies: 16
Views: 8410

Re: Picking the correct exposure for Deep Sky

Mark, You can check out my site here: https://snrcalc.now.sh/ The code is open source and available at GitHub (scroll down to the footer for a link). You can create a spreadsheet if you want from the formulae in calculation.service in the core/services folder. It takes minutes to read the general in...