Search found 8 matches

by vichman
Sat Aug 10, 2019 6:51 am
Forum: Tips and Tricks
Topic: Why do we need dark frames?
Replies: 6
Views: 208

Re: Why do we need dark frames?

Hi Dave, you could also add a sentence about dark frame scaling . This is very powerful, as one needs only one master dark (with an exposure time longer than that of any lights), and - of course - a master bias, to compensate the dark current in pretty much any light frame (of any exposure time or t...
by vichman
Thu May 23, 2019 4:08 pm
Forum: Deep Sky Imaging
Topic: Understanding Dark Noise and Shot Noise
Replies: 7
Views: 414

Re: Understanding Dark Noise and Shot Noise

Hi Robin, I took the liberty to use the extensive description of yours in https://forums.sharpcap.co.uk/viewtopic.php?f=35&t=456, and to modify the math, assuming this time that one cannot neglect thermal noise in comparison to sky noise (Part 6): ... We have assumed that we have measured the read n...
by vichman
Tue May 21, 2019 7:33 am
Forum: Deep Sky Imaging
Topic: Understanding Dark Noise and Shot Noise
Replies: 7
Views: 414

Re: Understanding Dark Noise and Shot Noise

Hi Robin, thanks for your reply. You are right, generally the light pollution dominates the dark current from the camera electronics. But when using an uncooled camera such as a DSLR under very dark skies (e.g. Bortle 1 or 2), then the impact from both light pollution and dark current should be in t...
by vichman
Sun May 19, 2019 4:08 pm
Forum: How do I?
Topic: Bias Frames
Replies: 7
Views: 360

Re: Bias Frames

Ah, missed that, thanks!
But there is no option to shoot Flat Darks, right?.
With my CMOS OSC camera I need to do that, as Bias frames are not recommended by the manufacturer.

CS
Stefan
by vichman
Sun May 19, 2019 3:02 pm
Forum: How do I?
Topic: Bias Frames
Replies: 7
Views: 360

Re: Bias Frames

Hello cuivenion, yes, that is exactly what I do when I user other imaging SW. I am only wondering why Sharpcap does not apply Bias frames or Flat Dark frames to Flats when shooting Flat frames inside of Sharpcap (and applying them automatically while doing live stacking). Or does Sharpcarp apply the...
by vichman
Sat May 18, 2019 8:56 am
Forum: Deep Sky Imaging
Topic: Understanding Dark Noise and Shot Noise
Replies: 7
Views: 414

Understanding Dark Noise and Shot Noise

Hello Robin, with high interest I watched the video of your recent speech at PAS (https://www.youtube.com/watch?v=3RH93UvP358) and read your tutorial on "Picking the correct exposure for Deep Sky" here in the forum (https://forums.sharpcap.co.uk/viewtopic.php?f=35&t=456). There is one thing though t...
by vichman
Sat May 18, 2019 4:39 am
Forum: How do I?
Topic: Bias Frames
Replies: 7
Views: 360

Re: Bias Frames

Hi Robin, I have the same understanding concerning subtracting bias frames from the lights: Typically you do not need bias frames as they are already included in the dark frames. But: Don't you need them (or flat darks) to calibrate your flats? IMHO they are needed there, otherwise your flat correct...
by vichman
Sun Nov 04, 2018 12:45 pm
Forum: General Discussions
Topic: Capturing Flats
Replies: 10
Views: 1747

Re: Capturing Flats

Hi Robin, thank you for the advices here, they also help me a great deal! I am also using "Capture Flat" from the "Capture" menu for my ZWO color camera (ASI071). But in my case the automatic white balance kicks in and moves all three colors on top of each other, so I can move one nice peak into the...