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rwg

SharpCap - free Astro Webcam Capture Software

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5 minutes ago, rwg said:

Sadly no, the field of view will be much too small with 2+ meters of focal length and a guide cam size sensor.

cheers,

Robin

OK, thought so. Thanks anyway

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Robin - I have an issue which I hope that you can solve for me.

I like using Sharpcap with my ASI224MC but the frame rate that I get is very low sometimes (single figures). If I open up Firecapture I get a huge increase in frame rate - up to 100fps.

I would prefer to use Sharpcap and have played around with the settings but cannot find any way to improve on the frame rate - any ideas please? The ZWO drivers are installed and the camera comes at the top of the list in "cameras". I just tried a test using the camera on the desk and FC was showing over 100fps - Sharpcap shows 19.

Peter

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Hi Peter,

the usual cause of getting about 20fps is that the camera exposure is set to 50ms and you haven't turned it down. If you've already turned the exposure down to less than 10ms (to be able to get 100fps) then have a look at the 'Turbo USB' control and try turning up.

cheers,

Robin

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I know that the 'Feature Tracking' tool is experimental but are there any instructions on it's use.

I tried it out the other night on Jupiter but seeing was pretty poor, I did notice that it seemed to be doing something when there was a very bright image on the screen.

No idea what buttons I am supposed to press or in which order, I assumed 'Calibrate' first, which placed a load of coloured circles on the screen but when does the 'Guide' button become available etc..?

Thanks

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Ah, glad someone is at least trying it out - I got so little feedback on this during the beta period (ie none) that I couldn't progress the feature in the way I would for other features.

The theory is that you press 'Monitor' which adds markers to the image showing the features that are being tracked. Then you press 'Calibrate' which starts moving the mount to let SharpCap work out which way RA/Dec movements move the image (or Alt/Az movements for an Alt/Az mount). This can take a while and you may need to adjust the mount movement speed and initial step size to make this work nicely.  You will see some graphs of the amount of movement during calibration.

Calibration can fail if things happen like

* The image doesn't seem to move when the mount is moved (possibly if you have lots of backlash)

* The image doesn't move in opposite directions for RA+ vs RA- or Dec+ vs Dec-

* The image moves at different rates for RA+ vs RA- or Dec+ vs Dec-

* The movement directions for RA and Dec aren't at roughly right angles to each other

Once the calibration completes you can then press the guide button, which should keep the target roughly in the same place - note that this is not designed to keep the target absolutely stilll, but to stop it drifting slowly off center.

cheers,

Robin

 

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8 minutes ago, rwg said:

Ah, glad someone is at least trying it out - I got so little feedback on this during the beta period (ie none) that I couldn't progress the feature in the way I would for other features.

The theory is that you press 'Monitor' which adds markers to the image showing the features that are being tracked. Then you press 'Calibrate' which starts moving the mount to let SharpCap work out which way RA/Dec movements move the image (or Alt/Az movements for an Alt/Az mount). This can take a while and you may need to adjust the mount movement speed and initial step size to make this work nicely.  You will see some graphs of the amount of movement during calibration.

Calibration can fail if things happen like

* The image doesn't seem to move when the mount is moved (possibly if you have lots of backlash)

* The image doesn't move in opposite directions for RA+ vs RA- or Dec+ vs Dec-

* The image moves at different rates for RA+ vs RA- or Dec+ vs Dec-

* The movement directions for RA and Dec aren't at roughly right angles to each other

Once the calibration completes you can then press the guide button, which should keep the target roughly in the same place - note that this is not designed to keep the target absolutely stilll, but to stop it drifting slowly off center.

cheers,

Robin

 

Brilliant, thanks Robin. 

I’ll give it another try with better seeing. 

I suppose the size of the target in relation to the ROI plays s big part i.e. I had a large Jupiter in quite a contained ROI. 

Would it be better having a little more black space around the target to aid calibration?

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The alignment points will probably only appear on the disk of the planet (or the edge of the disk), so the space around it will not be used. That said, a bit of space around the edge is good as it gives the guiding some room to play with - if the guiding isn't perfect you still shouldn't have the disk going out of frame.

 

cheers,

Robin

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28 minutes ago, rwg said:

The alignment points will probably only appear on the disk of the planet (or the edge of the disk), so the space around it will not be used. That said, a bit of space around the edge is good as it gives the guiding some room to play with - if the guiding isn't perfect you still shouldn't have the disk going out of frame.

 

cheers,

Robin

OK, thank you. 

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Hey Robin! I am in need of some help. I just lost a whole night of imaging. When I do a capture and set SharpCap to capture (let's say) 10 frames at 180 seconds, it captures 1 image at the specified exposure settings, but that is all. Just one image and the whole rest of the capture sequence is not there. I messed with the filename templates. I messed them up, but I'm not sure if that is the problem. Other than that I cannot think of anything else I would have changed that would prevent the files from saving in the designated spot. I tried changing the folders that the images should save to, but that didn't change anything. Please help :(

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Hi,

sorry to hear that you have lost imaging data. If you have been tinkering with the filename templates then maybe you ended up taking the '{Index}' tag out of the sequence template - if you did that then every file in the sequence would get given the same name, which would lead to the outcome you experienced. The sequence template needs to have either '{Index}' or '{FrameTime}' in it to avoid this problem.

The quickest way to get the templates back to something sensible is to untick the 'Edit Filename Templates Manually' option then make some change or other to the filename options above, which will reset the templates for you. I will look into setting up a warning in a future version if the sequence template does not have '{Index}' specified to help others avoid this issue.

cheers,

Robin

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Question!

The ZWO ASI120MC and Touptec Mono both use the same sensor.

I seem to be able to get a MUCH faster connection with the ZWO, 27 fps -  compared to about 15fps for the touptek.

The 'tuning' options are very different for the two scopes - is this a given or is it possible to get a more advanced interface for the Touptek?

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On 29/05/2018 at 11:19, rwg said:

Hi,

sorry to hear that you have lost imaging data. If you have been tinkering with the filename templates then maybe you ended up taking the '{Index}' tag out of the sequence template - if you did that then every file in the sequence would get given the same name, which would lead to the outcome you experienced. The sequence template needs to have either '{Index}' or '{FrameTime}' in it to avoid this problem.

The quickest way to get the templates back to something sensible is to untick the 'Edit Filename Templates Manually' option then make some change or other to the filename options above, which will reset the templates for you. I will look into setting up a warning in a future version if the sequence template does not have '{Index}' specified to help others avoid this issue.

cheers,

Robin

I imaged last night and all of the light frames were there. However, the darks are missing. SharpCap created a file called "darks", but the folder is empty. Could this still be due to the filename issue?

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How did you capture your darks? If you use the 'Capture Dark' button then SharpCap captures the individual frames as temporary files and then makes a single master dark from them - the individual frames get deleted. The master dark gets files in a subfolder of the 'Darks' folder - the subfolder name is based on camera, resolution, bit depth, exposure, gain and temperature - the idea being that a 'dark library' slowly builds up of darks taken with different settings and that sometimes settings will be close enough to re-use old darks.

cheers,

Robin

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@Stub Mandrel ToupTek cameras are only supported via the ASCOM or DirectShow drivers. There may be options inside the configuration for those that allow you to tweak the frame rate (USB speed), but I've not used those drivers so can't say for sure.

What I do know is that ZWO have worked hard to make their cameras run as fast as possible. The downside of that is that with certain settings on some computers the cameras freeze up (turn up your Turbo USB too high on some USB chipsets...). That can obviously be an issue as to some new users it will look like a faulty camera. Other companies may take a more conservative approach of making sure the device always works, even if that means never hitting quite the same performance - maybe it allows them to get away with less after sales support that way?

cheers,

Robin

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There is an API option to control "speed" for the Touptek cameras, but I'm really not sure what it does or which cameras support it.  To claim that the documentation is "poor" would be being altogether far too kind in my opinion.

James

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10 hours ago, rwg said:

@Stub Mandrel ToupTek cameras are only supported via the ASCOM or DirectShow drivers. There may be options inside the configuration for those that allow you to tweak the frame rate (USB speed), but I've not used those drivers so can't say for sure.

What I do know is that ZWO have worked hard to make their cameras run as fast as possible. The downside of that is that with certain settings on some computers the cameras freeze up (turn up your Turbo USB too high on some USB chipsets...). That can obviously be an issue as to some new users it will look like a faulty camera. Other companies may take a more conservative approach of making sure the device always works, even if that means never hitting quite the same performance - maybe it allows them to get away with less after sales support that way?

cheers,

Robin

Hi Robin,

Thanks, I hadn't realised just how different they could be.

I am a bit bewildered by what option I get for the Touptek GCMOS01200KPA:

 

The Touptek comes out with Altair GPCAMAR0130M top of the list, so that's what I have used... On MONO12 it manages less than 3fps(!), MONO8 is abut 17 fps, both with USB speed set at 4.

Direct show only lets me use RGB24 (its a mono), but also gives about 17 fps.

Using the Ascom driver only gives me about 1.7 fps with RGB and slower (flickers from 0.8-1.7) with RAW.

Neither the ASCOM or DirectShow allow me to tweak the USB speed.

 

In contrast, with the ZWO ASI120MC I get truckloads of options and it can run at 30fps full frame. I have noticed that 'Auto' on the Turbo USB setting is faster than flat-out for the ZWO, letting me get about 30 fps.

 

It's frustrating as the slow frame rates seem to negate the befits of RGB vs OSC for planetary, at least ?

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The Altair GPCAMAR0130M was just a rebadged Touptek camera as far as I'm aware, so that's probably why it gets listed as one.  With oacapture on my Linux desktop I get about 22.2 fps in 8-bit raw colour and I'd expect the same from the mono camera in 8-bit mode.  Going to 12-bit should at least halve the expected frame rate I think.  As far as I'm aware the 12-bit data is not transferred over the wire in a packed form, but as 16bpp rather than 8bpp.

Oddly the original USB2 ASI120MC that I just happen to have sitting on my desk at the moment manages 17.3fps in raw colour mode.

Neither of these tests are particularly reliable as the camera isn't the only USB device plugged in on that bus.

I'm not sure I see how you get 30fps with your ASI120MC though.  My understanding is that USB2 tops out at around 35MB/s.  30fps at 1280x960 is just over 35MB/s by my calculations and that doesn't allow for any of the overheads.  Or perhaps I've just done my maths wrong.

James

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Raw quoted throughput on USB2 is 480 megabits/s or 60 megabytes/s. As you say there are overheads to account for - normally these would stop you from getting to the rate required for 30fps, but I believe that there is a trick with using larger than normal data packets that reduces the overheads enough to get 30fps through.

cheers,

Robin

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Ah, yes, there is one that I'm aware of where the camera advertises larger (and out-of-spec) bulk transfer packet sizes.  I think, though I am not certain, that was one of the issues with using the original ASI120 cameras on MacOS, which I think is more strict in its implementation.

James

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1 hour ago, JamesF said:

The Altair GPCAMAR0130M was just a rebadged Touptek camera

Oddly (as you might guess from the name) it claims to have the 130 sensor instead of the 120 in the Touptek..

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3 minutes ago, Stub Mandrel said:

Oddly (as you might guess from the name) it claims to have the 130 sensor instead of the 120 in the Touptek..

It is strange, but the two share the same USB vendor ID (Touptek's) and product ID (which is why they show up as each other), unlike some of the later cameras.  The Mallincam Skyraider guide camera is the same, I believe.

James

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2 hours ago, JamesF said:

I'm not sure I see how you get 30fps with your ASI120MC though.

I've only got the 'pipped' versions now, but they claim to be 30 fps. Just plugged into my desktop and it's reporting 27.5 fps. I use a USB3 socket on my laptop, but I doubt that makes a difference (or just a psychological one)?

My modified Microft Lifecam at 1280 x720 (so about 75% of the frame size) manages 30 fps in YUY2, not sure that means much but it gave me the best results of all webcam solutions.

[ZWO ASI120MC]
Debayer Preview=On
Pan=0
Tilt=0
Output Format=AVI files (*.avi)
Binning=1
Capture Area=1280x960
Colour Space=RAW8
Temperature=21.5
Discard Split Frames=On
High Speed Mode=On
Turbo USB=80(Auto)
Flip=None
Frame Rate Limit=Maximum
Gain=50
Exposure=0.012488
Timestamp Frames=Off
White Bal (B)=95
White Bal (R)=52
Brightness=17
Gamma=82
Auto Exp Max Gain=50
Auto Exp Max Exp=30
Auto Exp Max Brightness=132
Mono Bin=Off
Subtract Dark=None
Display Brightness=1
Display Contrast=1
Display Gamma=1

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39 minutes ago, Stub Mandrel said:

My modified Microft Lifecam at 1280 x720 (so about 75% of the frame size) manages 30 fps in YUY2, not sure that means much but it gave me the best results of all webcam solutions.

YUY2 is a lossy compressed format.  Half the chrominance data for the image is thrown away if I recall correctly.  You can therefore achieve a higher frame rate at the expense of colour resolution.

James

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7 minutes ago, JamesF said:

YUY2 is a lossy compressed format.  Half the chrominance data for the image is thrown away if I recall correctly.  You can therefore achieve a higher frame rate at the expense of colour resolution.

James

I had an idea that was the case, still it worked well until I saw how the ZWO was even better!

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