Search found 456 matches

by oopfan
Wed Apr 03, 2019 7:05 pm
Forum: Gallery
Topic: unguided galaxies
Replies: 7
Views: 450

Re: unguided galaxies

Nice!

There is a lot of nebulosity that we are not seeing because you have the black level set too high -- that is why outer space is black. Can you reprocess it so that we can see space as a shade of gray?

Thanks,
Brian

PS: What's worse: the sky glow from San Antonio or Austin?
by oopfan
Wed Apr 03, 2019 4:49 pm
Forum: Altair Cameras
Topic: Altair 290M sensor analysis has dramatically changed
Replies: 1
Views: 317

Altair 290M sensor analysis has dramatically changed

Robin, When SharpCap 3.1 Beta was released October 2017 I jumped on the bandwagon. I kept up with each minor revision and on January 9, 2018 I ran sensor analysis on my new Altair 290M (see attachment entitled "Altair GP290M Sensor Analysis MONO12 2018-01-09.png".) Afterwards I used The Brain a few ...
by oopfan
Tue Apr 02, 2019 4:04 pm
Forum: General Discussions
Topic: White-balancing Optolong LRGB filters with Altair 290M
Replies: 5
Views: 562

Re: White-balancing Optolong LRGB filters with Altair 290M

I decided to try out the empirical approach to find white balance as described here: http://kellysky.net/White%20Balancing%20RGB%20Filters.pdf Last night I took 100x 2s frames with each RGB filter of a magnitude 8.23 G2V star in Ursa Major: HIP 60268. I chose the best 10 frames for each filter, cali...
by oopfan
Sun Mar 31, 2019 9:19 pm
Forum: Gallery
Topic: M101 in LRGB
Replies: 26
Views: 855

Re: M101 in LRGB

Hi Andy, Thanks for the FITS file. Here is what I discovered: 1. The maximum pixel value of 55920 as reported by FITS Liberator are hot pixels, not stars. 2. The brightest star in the frame that I could match against C2A planetarium software is magnitude 11.015 at maximum pixel value of 22800 ADU. I...
by oopfan
Sun Mar 31, 2019 2:11 pm
Forum: Gallery
Topic: M101 in LRGB
Replies: 26
Views: 855

Re: M101 in LRGB

Andy, One more thing: In the image screenshot you posted, FITS Liberator set the initial white level at 1800.01 but notice that there are lots of pixels brighter than that in the histogram. One thing you can do is check the box labeled "White clipping (green)" middle right-hand side of the app. Zoom...
by oopfan
Sun Mar 31, 2019 12:58 pm
Forum: Gallery
Topic: M101 in LRGB
Replies: 26
Views: 855

Re: M101 in LRGB

Hi Andy,

When you are sampling the peak ADU of a star, are you zooming in to make sure that you are picking the right one?

Thanks,
Brian
by oopfan
Sun Mar 31, 2019 10:12 am
Forum: Gallery
Topic: M101 in LRGB
Replies: 26
Views: 855

Re: M101 in LRGB

Thanks, Andy. I am trying to measure the effects of the lower QE of CCD vs CMOS but there are too many variables. CCD has lower quantum efficiency than CMOS but I've read that it roughly makes up for it in larger pixel size. I'll just have to wait for my camera to arrive. I want to take advantage of...
by oopfan
Sun Mar 31, 2019 12:57 am
Forum: Gallery
Topic: M101 in LRGB
Replies: 26
Views: 855

Re: M101 in LRGB

Andy, Wow! That's 200 minutes total integration time in one night, right? I can't wait for my Atik! Did you save the light frames as FITS? If you did can you do me a favor? Can you bring up one of the light frames in FITS Liberator, take a screenshot, choose a few of the brightest stars and tell me ...
by oopfan
Sat Mar 30, 2019 1:08 pm
Forum: Gallery
Topic: M101 in LRGB
Replies: 26
Views: 855

Re: M101 in LRGB

Hi Andy,

I am at Bortle 5 consistently but some nights push Bortle 4. No street lights or anything but I am in a valley.

Brian
by oopfan
Sat Mar 30, 2019 12:53 pm
Forum: Gallery
Topic: M101 in LRGB
Replies: 26
Views: 855

Re: M101 in LRGB

I reworked the image after having discovered that the blue stack was not contributing enough to the final image due to low signal-to-noise. Next time around I will double the exposure on all channels. Difference between this image and the original on page one: 1. Boosted blue channel by 15%. 2. Boos...