Sensor Analysis Readings: Hypercam 183C Pro TEC.

Discussion of features and issues relating to Altair Astro Cameras
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jaq1967
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Sensor Analysis Readings: Hypercam 183C Pro TEC.

Post by jaq1967 » Thu Mar 05, 2020 12:26 pm

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Hello...

I've attached 2 sensor analysis readings from Sharpcap for my Hypercam 183C Pro TEC. Taken one after the other; same condition; same lighting.

Two different results. Any ideas?

Regards

Jaq

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admin
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Re: Sensor Analysis Readings: Hypercam 183C Pro TEC.

Post by admin » Thu Mar 05, 2020 9:44 pm

Hi,

It looks like both sets of readings are being affected probably by the illumination brightness varying during the last set of measurements when the relative gains are being evaluated (the stage after you uncover the sensor). This problem will affect all the columns in the table, but is most obvious if you look at the 'relative gain' column. For Altair cameras, the relative gain should be pretty close to the gain value divided by 100, but in both sets of data there are some pretty significant deviations from this.

Here's a data set from running the analysis on my 183M Pro -
Capture.PNG
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You can see here that the relative gain is pretty close to the gain value divided by 100 in all rows. I was just using the camera with a CS mount lens and pointing it at a cupboard when running the analysis,

Hope this helps, Robin

PS - sensor analysis for this camera is already part of the SharpCap install - there should be no need to run your own except as an experiment. The analyses that are installed with SharpCap are quality checked for this sort of problem.

jaq1967
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Re: Sensor Analysis Readings: Hypercam 183C Pro TEC.

Post by jaq1967 » Fri Mar 06, 2020 10:41 am

Light source had not changed. I used example to run Sensor Analysis as demonstrated on YouTube:

https://www.youtube.com/watch?v=AidhxeAJJ3s

Was I incorrect to follow this example?

astrostace
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Re: Sensor Analysis Readings: Hypercam 183C Pro TEC.

Post by astrostace » Fri Mar 06, 2020 1:04 pm

Hi

Just wanted to point out that this is the method that has worked for me for a while :) but without seeing the equipment you’re using (your tablet or light source etc) and how it is being carried out then I can’t really comment on what is changing :)

Hopefully Robin should be able to give you some answers though :)

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Re: Sensor Analysis Readings: Hypercam 183C Pro TEC.

Post by admin » Fri Mar 06, 2020 6:45 pm

Hi,

Some phones and tablets will automatically adjust the brightness of the screen as the light level around the device changes – this could easily throw off the calibration badly if for instance you happen to move around while the calibration is running in your shadow covers the device or the light level in the room changes for some other reason. If you are going to use a phone or tablet for your illumination, I would strongly suggest finding and disabling this feature in the device settings.

My preferred approach is to use a comma piece of furniture or some other object that is illuminated by ordinary household lighting – the only thing to beware of then is to select a tall and thin area when measuring so that if you get any horizontal banding due to the 50 Hz flicker in the lighting the selection area contains a number of bands and the effect will therefore be small. Natural light on either a fully clear or fully overcast day is good too, but avoid using natural light on days where there are scattered clouds.

Cheers, Robin

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