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Old 05-10-2020, 10:20 PM
Hemi
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Planetary Capture 101

Im using a C925, 2xBarlow and a ASI 294 MC Pro OSC camera. SharpCap Pro
I’m trying to capture Jupiter at a high frame rate.
When i reduce the region of interest to something very small, the planet disappears. It doesn’t appear on the sensor anywhere, as i move the ROI systematically to find it.

It reappears when i bin 2x. Is that what’s meant to happen? It makes the final stacked image quite blocky.

It happens at a certain point of ROI. Before that point i can find the planet by coursing around the sensor, after that point, it’s nowhere to be found until i bin.

An explanation/solution would be really appreciated.

Cheers

Hemi
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Old 06-10-2020, 03:41 AM
sunslayr (David)
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Maybe it's too dim? Try increasing your exposure a bit. What software are you using? Maybe I can be a little more specific. Check whether you can see it with the full sensor, position it in the middle by slewing (the crosshair may help) then try going smaller rois in sharpcap.

Last edited by sunslayr; 06-10-2020 at 03:51 AM. Reason: Actually used my eyes to read
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Old 06-10-2020, 07:17 AM
Hemi
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Thanks David,

Yes the planet is visible at Max resolution, and still visible as i progressively reduce the ROI and recentre. Until I get to about 640x480 (or slightly bigger I canít recall) and then it disappears. Iíve increased the exposure (time and gain) and systematically scanned the entire sensor by moving the ROI window.

The planet reappears (is able to be found) only when i bin at these ROI.

Thanks

Hemi
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Old 06-10-2020, 07:51 AM
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multiweb (Marc)
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Maybe your software recenters the ROI when you change its size. You can pan the ROI to find the planet again in the surface covered by the sensor.
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Old 06-10-2020, 07:58 AM
Hemi
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Thanks Mark, that’s what I was trying to explain in my posts (badly ��)
I’m panning the ROI systematically across the entire sensor, but can’t find it, until I bin.


Edit.....ok it seems from both of your experienced posts, that this shouldnt happen and the planet will be there, I will retry again tonight and pan the ROI again as carefully and painstakingly as I can.


Thanks again

Hemi
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Old 06-10-2020, 08:17 AM
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multiweb (Marc)
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I use Sharpcap as well. If you put the planet in the top left corner let's say of your full sensor resolution and then select 640x480 the ROI will be centered again so you'll have to pan to the top left corner to see the planet. You can do this by just dragging the ROI box in the preview window on the right menu column. If you bin again you change the number of pixels in the ROI so same thing. Just takes a little getting used to. Best to try to keep the planet centered in the sensor.
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Old 09-10-2020, 07:57 AM
Hemi
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So I tried again, the planet is definitely disappearing from the sensor.

So I played around a bit and this is what is happening....
Initially use full sensor and continue to reduce ROI and recentre plant on the ROI.
All going well until I get to 640x480.
Then if the capture rate is between 10ms and 50ms the planet goes away. Below 10ms and the planet pops up, but gain needs to be cranked up and becomes noisy but good FPS. At 50+ ms the gain and noise better but FPS takes a massive hit.

What’s happening between 10ms and 50ms? Why is the plant disappearing? Occasionally I will get white flashes or a white screen at just over 10ms...strange.

Cheers

Hemi
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Old 09-10-2020, 10:33 AM
Saturnine (Jeff)
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Hi Hemi

As a user of Sharpcap and a 290mc camera, I haven't experienced any of the problems you are having, it certainly is a weird one. The only thing I could suggest is to delete then reload the software to the latest version and re-connect the camera and see what happens.
Certainly sounds more like a software issue than hardware. As recommended, start with a large ROI, centre the planet on the sensor then reduce the ROI , re-centre and repeat the steps until you get to the desired ROI.
With mine, when I am reducing the ROI the planet briefly disappears from the screen but re-appears after a few seconds. Hope this is of some help.
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