SharpCap Forums

Good Day - With the Big Club Star Party this weekend I made a post on Cloudy Nights last night in attempt learn about the issue without bothering you. So Far the only reply at CN shares my issue.

https://www.cloudynights.com/topic/9308 ... -sharpcap/

I took a short Video with my Digital Hand Camera.
The First 2 images are harvested by Photographing my PC Screen playing that short video - taken when Paused at the Band Flashes with digital hand camera.
The Zebra Look patterns are NOT in the Video.

The Third Photo is the Save as Seen from the M17 Live Stack. I see no effect from the flashes in the image. Its just a bright quick Flash thats pretty distracting out in the dark - and around others.

I am attaching my Log File from the session. The Data from the M17 Live Stack starts at Time 23:30. These instances happened when adjusting the Histogram Sliders. Happens with other adjustment features as well. This happens on all other sessions as well. Its been happening for a while.

--------------- Requested Details ---------------
Happening with all recent versions of Sharpcap. I keep up to date weekly.
Players One Uranus C . Celestron 6SE - 6.3 Reducer - Starsense Alignment thru CPWI.
Windows 10.
---------------------

Let me know if you need any other information.
Thanks so much for what you do !!
MIKE in OREGON

Hi Mike,

thanks for posting - I wasn't aware of this issue, but it seems to be affecting a fair few people from the replies over on CN.

There's not much that I can tell from the log - there are no errors/warnings related to displaying images or anything like that. In fact, it seems that it isn't so much that it is failing to display, just displaying the wrong thing.

I'm going to list some questions - hopefully the answers to them will help me understand the potential causes and narrow down the possibilities somewhat...

1) Can you make it happen 'on demand' - for example by using the folder monitor camera to reprocess previously captured frames through live stacking and then adjusting the histogram? Being able to reproduce a bug on demand is important as then you can change things and find out if the bug stays or goes away...

2) Does the problem always clear straight away when you stop adjusting the histogram, or does it stay until the next frame updates the image? Does it ever happen when the adjustments are not being made?

3) Try using the Save button in the mini histogram on the right - repeatedly! That should save exactly as shown on screen - if the problem occurs in the saved files at all then the issue is somewhere within SharpCap. If it's occuring on screen, but never in the saved files then the ideas about graphics drivers or similar might be relevant.

4) Does it go away if you go back to SharpCap 4.1.12196 or earlier? In 4.1.12221 I made a big update to the underlying framework that SharpCap runs on - version 7 to version 8. Maybe that update is the cause?

5) Can you post the capture settings file saved alongside a live stack saved image? That shows all the live stack processing options that are enabled - maybe some of them are relevant to the problem.

6) Are the coloured stripes always Red/green and blue? Are they 1/3 of the height of the image each? If you zoom/scroll the image, do the stripes move around as if they were part of the image, or do they seem to behave as if they are a layer on top of the image that is not responding to zoom/scroll?

7) What graphics card are you using and are you using remote connection software or directly using the computer keyboard/monitor? I can see Mike's video card from the log, so this really applies to anyone else answering.

thanks,

Robin

1. Yes - repeatable

2. The Flash in the snapshots I attached only last a portion of a second, My Exposures for that item were just 4 seconds. The two are in one slow slide of the Midrange Histogram Bar. and were harvested from a short ( poor quality ) video . I needed a third and 4th hand.to take more stable but short ( to keep the MB size low ) video. 2 hands for the laptop and 2 for the little camera. If you keep moving the sliders it keeps doing it. It does not happen when the adjustments are not being made.

Here are One Drive Links to the two short videos I took showing the action.

https://1drv.ms/v/c/2600125e174cbc98/Ef ... g?e=ha7AP2

https://1drv.ms/v/c/2600125e174cbc98/EX ... A?e=3UvXlj

One is the one that the two images are pulled from and the other also for same capture of M17 just moments from the first.
Sorry for the Wobbley look. Camera Not designed to run one handed and the set up of my gear also makes it the Left Hand.

3 Will attempt and report.

4. I Wont be able to try that myself till after the Weekend - Its the weekend for the Yearly Eugene Astronomical Society Star Party.

5. Yes - Will attach
6. My laptop is not a giant. I can only see the top 55 - 60 % of the image I am working with. Histogram covers the bottom 40 - 45% even when pulled down to minimum size. However it always appears in that same height band. Colors are bolder / Brighter at times ( maybe in relation to the positions of the Sliders ?? ) . Sometimes one of the bands is Yellow.

7. X

I'm rather low tech on Attachments - One Drive - Google Drive etc - I don't use them much SO.... if it doesn't work let me know and I will try again.

THANKS

Hi,

thanks for the answers above - I've been lucky enough to have some clear sky this evening and had a play and I can see the issue too. It looks like the issue is related the image on screen being updated at the same time that the new frame is being added to the stack. I did have code to prevent that from happening, but it looks like it has ended up getting broken (probably by changes for the unstack feature that removes the last frame).

You will see it more if you have

* short exposures (a new frame is added more often)
* high resolution (adding a new frame takes more time)
* slow PC (also increases time taken to add a frame)

I don't see it in my development testing as I usually use relatively small (1 megapixel or so) images and have a very fast PC. My observatory PC is a few years older so that helps make it happen.

I think I have a decent handle on this now, so should have a fix by the next update on Monday.

cheers,

Robin

Hi,

one more thing... As a workaround, switch from 'Default' to 'Sigma Clipped' stacking - that mode is unaffected by the issue.

cheers,

Robin

Thanks Robin.

Here is my test on a stack from Seestar S50 of Pelican Nebula: https://mega.nz/folder/1ek2zJJL#6YnJ_KwfN7G5IxaE4iScKQ

The issue appears when moving the histogram sliders.

Switched to "Sigma Clipping" and it disappears.

Looking forward to Monday's update.

Sweet -

Loading gear for the Star Party now .
Any recommendation for a starting setting number for the Sigma Clipping ?
Expecting a pretty good crowd since the biggest Star Party in Oregon has been cancelled for Wildfire and Smoke. Always hate to be fiddling to learn and experiment with a group of onlookers .

Celestron 6se -- 6.3 Reducer - Player One Uranus C Camera

Thanks So Much
MIKE

Hi Mike,

a sigma threshold of 3 to 4 sigma should be good, and set the initial frame count to about 8 to 10 (no sigma clipping occurs in those first frames - SharpCap is just accumulating statistics at that point, so if you have a satellite come through, use 'unstack' to get rid of it in the early frames). You should be able to leave the sigma low limit alone.

cheers,

Robin

Hi,

just to say - new version 4.1.12452 now available to download that should resolve this issue.

thanks,

Robin

Thanks Robin, it works without flashes.