Using the sharpCap smart histogram?

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bluesilver
Posts: 80
Joined: Mon Oct 05, 2020 12:51 am

Using the sharpCap smart histogram?

#1

Post by bluesilver »

Hi, I just have a bit of a question in regards to the SharpCap Smart Histogram.
So i have SharpCap Pro, also the Latest version of SharpCap installed
Camera is asi2600mc ( colour camera )
Scope is Skywatcher Esprit 150
Mount is iOptron CEM120

So last time i had clear skies, i thought i would give this Smart Histogram a go and see what the results come back as for exposure time and gain.
Now from what i have read, this shouldn't take very long to complete.
I was planning on imaging a spiral galaxy, NGC 6744, so i set PHD2 going so that the mount was tracking a star nice and stable, imaging camera in focus.
I click on the measure button to get a reading for the sky darkness, ( i am Bortle 2-3 area )
Now for some reason after 1/2 hour latter it was still running through changing exposer times,
I figured this can't be right and ended up closing down the program.
I think the last thing i seen it saying was something about measuring 600 second exposures ( so 10 minute exposures )

So for the settings that i set, they were:
Min. Exposure 30s Max. Exposure 5m
Read noise ( i think i left it at the default setting )
Stacking time 60m ( i think i read it doesn't matter if you change this up to 300m, it still works it out as 60m ) but may have miss understood that.
Aim for: ( i honestly can't remember now if i went with Max Dynamic Range or Unity Gain ) Not really sure which one i should be going for with this camera?

But dose 1/2 hour seam a tad long for this to run, or dose it take quiet a while to go through?
So i am guessing i have something set incorrect here?

I have read that i don't need to run a sensor analysis for this camera, but have done, just for the experiment of these options.
I even tried to find that file that it lists in the instructions but couldn't find that anywhere,
Followed this instruction C:\Users\<your user name>\AppData\Roaming\SharpCap
But there is no AppData\Roaming\SharpCap folder in there at all.
What happened instead was i go a sensor analysis file on my home screen for some weird reason.
I am wondering if i should go back into Settings and untick the box labelled 'Automatically restore the last used camera settings when opening a camera?
Or if the sensor analysis has somehow messed up the settings, if so is there a way to restore all of ShapCap Pro settings back to default and start over from scratch?

Lots of questions, sorry about this.
Any advice on this would be greatly appreciated,
Cheers.
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admin
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Re: Using the sharpCap smart histogram?

#2

Post by admin »

Hi,

first advice would be to make sure your version of SharpCap is up-to-date, as this is something I have improved in the last few months to try to stop it from taking an extremely long time.

There is no need to worry about the sensor analysis - if SharpCap let you try to measure the background then it means it had sensor data for your camera (probably pre-installed), which is fine.

If you are up-to-date then you need to watch what happens during the measurement to see what is causing the excessive time. For instance

1) You have vignetting at the corners of your image, which means they are significantly darker than the rest - SharpCap tries to find the darkest part of the frame and will select the corners and then try to increase the exposure to get a good corner brightness measurement. Solution : tick the 'avoid edges/corners box'.

2) You are using a filter of some sort which cuts down the light getting to the camera. Particularly if you are using a tri-band/quad band filter these can cut the light levels significantly and hence mean longer exposures are needed. Particularly watch out if you have chosen to measure either 'blue' or 'darkest' channels as these can be nearly non-existant with some filters. Solution : choose to measure green/red/luminance - a channel with some light getting through the filter.

3) You have really dark skies - this means long exposures are needed to measure the sky brightness. Could go up to a few minutes, but shouldn't really take longer than that. Keep an eye on what the exposure gets set to in this case.

4) There is an underlying issue with frames being dropped from the camera that is either causing the problem on its own or is mixing with one of the above (or something else) - SharpCap is trying to measure the background but isn't getting the frames it needs, but keeps on trying. Keep an eye on the frame count/dropped count bottom left.

Hope this helps,

Robin
bluesilver
Posts: 80
Joined: Mon Oct 05, 2020 12:51 am

Re: Using the sharpCap smart histogram?

#3

Post by bluesilver »

Thanks for the reply and advice with this, it is appreciated.
Yes, we have good dark skies here, only issue is we get a lot of cloud coverage this time of year.

Sounds all good to what i have been doing.
Not sure if i did tick the 'avoid edges/corners box, but i will do that next time to see if that helps.
No filters are being used at all.
The version of SharpCap Pro that i am running is V4.0.813

I decided to to an uninstall of SharpCap and do a fresh install to see if that makes any difference,
I went with the 64 bit version as that is what my Laptop is running, not sure if i were running the 64 or 32 bit before, but will see how this goes.
The surprising this was that when i did the fresh install, i went to put my license back in and found that it was already there, so that bit was a tad odd, that shouldn't of happened.

Next time we get clear skies here, I will try it out again and see how things go.
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Re: Using the sharpCap smart histogram?

#4

Post by admin »

Hi,

the retention of the license key is expected. An uninstall of SharpCap does not clear any settings that SharpCap has saved, since in many cases people do want to reinstall and don't want to set things up from scratch again.

good luck with some clear skies!

cheers,

Robin
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