Recent issues

[RodgerDodger008]

I have been a sharpcap user for a little over 2 years and really enjoying the software for livestacking EAA.

In the past I have always kept up to date and even used 4.1 in beta but since the introduction of the unstack feature I have found some issues requiring me to rollback to 4.1.12311.0.

I then decided to wait till the later version become availble through auto download for increased stability and this past Friday I updated to 4.1.12529.

After about an hour I again uninstalled and reverted to 4.1.12311.0.

Unfortunately I don't have logs and since this earlier version works well it is really difficult to invest time in the later version but soon I will. So really just want to share two main issues I am seeing.

Using a ASI2600MC with 8 second exposures.
1) the frame comes in and unstack flashes less than a second, it is really impossible to use unstack because there is litterally less than a second, maybe even 500ms available to click it, surely this is not normal even though I am only using short exposures.

2) after a while the FWHM rejection filter stops working, the frames could be over the limit but they still get stacked.

These two issues I found also back in July when the unstack feature was introduced.

I know this may not be helpfull without logs but will post more when I try and test again. In principle the unstack feature sounds wonderful. I do use sigma clipping not sure of that combo with unstack is the culprit.

One other comment is I noticed that in the later version the option to reduce fan speed and the brightness of the LED on the ASI2600MC was no longer there, seems strange as this is still available on 4.1.12311.0

Thanks again Robin for all your great work with Sharpcap, for EAA this is definately the best out there in my opinion.

[admin]

Hi,

sorry to hear that you have been having some problems since unstack was introduced

The unstack button only being on part of the time is how it is supposed to work... How long you get depends on how quickly frames are coming from the camera and how long your PC takes to add a new frame to the stack.

Let's say frame 10 arrives from the camera and starts being added to the stack. Maybe the star detection, FWHM checking, alignment, stacking and processing the image to view takes 5 seconds. Once that 5 seconds is finished you see the updated stack and the 'Unstack' button becomes enabled. But, while that stacking is happening, the camera is taking frame 11 (8s exposure) - so, 3s after the unstack button got enabled, frame 11 arrives and live stacking starts working on that. Once that frame starts being processed to add it to the stack, the 'Unstack' button has to be disabled again (as trying to subtract frame 10 while adding frame 11 - or after adding frame 11 - will give a mess).

So, you end up seeing the 'Unstack' button for a variable amount of time depending on the exposure and the time taken to stack a frame. It's not really something I can do much about I'm afraid - once the next frame is started, unstacking the old one just can't work any more.

The FWHM filter issue is something I haven't noticed or heard of before - if you notice anything that perhaps has to happen before this error occurs or that it maybe occurs after a certain number of frames, that would be a help tracking it down. The main SharpCap log is unlikely to be useful to understand this issue, but there is a separate live stacking log (check the Log tab) which records things like the FWHM of each frame and whether it is being skipped due to filtering on FWHM or brightness - that might show something.

cheers,

Robin

[RodgerDodger008]

Thanks Robin, could unstack maybe be turned on or off in settings in the future? Seems like with shorter exposures that I am running it may not be possible for me to use. I could just ignore it I suppose. Thanks again

[Xio1996]

Hi Robin,

I do see the FWHM filter being ignored, now and again, but only at the beginning of the stack. I'm not sure if this is what RodgerDodger008 experiences?

The first screenshot is from the 18/08/24, v4.1.12489 as you can see in the screenshot the FWHM filter is enabled and set to 4.08 but the first two frames of FWHM 4.24 and 5.03 were stacked. The third frame of 4.84 was filtered.

18-08-24.jpg

The second screenshot is from the 18/09/24, v4.1.12551. The FWHM filter is set to 5.78 but the first frame with a FWHM of 6.19 is still stacked. I can't remember(or didn't notice) it not honouring the FWHM filter setting for more than 2 subs, after that it appeared to reject the subs correctly.

Have fun.

Pete

18-09-24.jpg

[MarMax]

I do not have a screen shot but have also experienced the early frame stacking over the FWHM filter setpoint. This is typically the first frame and occasionally the second frame, but not after the second frame. I just chalked it up to SharpCap needing some reference frames to get rolling. And if they bother me I just reset the stack.

[admin]

Hi,

yes, you are correct that the FWHM filter is ignored for the first one or two frames to get the stack started. The alternative could be frustrating if you have left an FWHM filter from a previous session and nothing stacks at all until you work out why. Beyond those first couple of frames, the FWHM limit should be enforced fully.

As noted by MarMax - it's easy just to reset if the first frame gets stacked in spite of being of low quality, so there is no real loss in the way that there is later in a stack when the bad frame messes up good existing data.

cheers,

Robin

[RodgerDodger008]

Hi Robin

Had time to test the latest version available for download and can confirm that with default stacking, 8s sub exposure, usb speed maxxed out and high speed on unstack works as I would expect. After each 8s sub there is around 4s to hit unstack, which is reasonable for such short exposures.

If I use sigma clipping the behaviour is very different. Unstack either does not flash up or it flashes and disappears almost instantly.

If I had to make an assumption based on your earlier reply this probably is normal as there would be more going on during a sigma clipped frame. So no issues just wanted to report back.

Overall happy, many of the new features like the new drift graph is very useful. The first few frames do stack regardless of fwhm as explained above, never noticed that before but makes sense.

Thanks for your great work and updates to the software.

[admin]

Hi,

thanks for the report - sigma clipping certainly introduces a fair bit of extra calculation over the default stacking, so will be slower. You should see though that if you move to a 16s exposure, you should see 'Unstack' available for a sensible amount of time even with sigma clipping.

cheers,

Robin

[RodgerDodger008]

Thanks Robin

Appreciate the reply and feedback. This makes complete sense. Must say sigma clipping works amazingly well for me, using sigma clipping with fwhm and brightness filter essentially removes the need to unstack in my use case.

Lets say there is a strong gust of wind, geneally either the brightness filter or fwhm rejection would catch that.

If I get a satelite streak early in the stack (after the first 5 frames) by the end of the stack it is almost invisble.

Thanks again for all your hard work on the EAA components of Sharpcap, I know many (including me) in the community regard Sharpcap as having no equal in terms of EAA capture software.