...interpret sensor analysis results

[GoFraRo]

Hi everyone,
now, with some more or less experience, a new mount that allows longer exposures and guiding, I did another sensor analysis for my Neptune-C and ASI120MC-s.
I'm struggling with interpreting the results, especially for the Player One Neptune-C (IMX178c).
It would be great, if someone could take a look on the results and give my some guidance.

I'm familiar with gain, exp, offset settings, noise ratio etc. etc. as well as the use of calibration frames.

Thx in advance
Gottfried

ASI120MC-s

Sensor_Analysis_Results_ASI120MCs.jpg (96.04 KiB) Viewed 1243 times

Neptune-C

Sensor_Analysis_Results_Neptune_C.jpg (92.5 KiB) Viewed 1243 times

[admin]

Hi,

there look to be a couple of glitches, potentially the value of read noise for gain 20 on the ZWO and the rise in read noise at the far right on the Neptune-C, but those do not really affect the key features of the analysis.

The key things to take away are

* The NeptuneC is a 14 bit sensor compared to 12 bit for the 120MC
* The full well depth of both sensors is roughly the same - that is they will both saturate with roughly the same number of electrons captured
* The read noise of the NeptuneC is about 1/3 of the 120MC - this is important as it means that if you want to use the camera for deep sky, the Nepture needs exposures that are 9 times shorter than the 120MC

Overall, the improvements in the Neptune are really just the result of about a decade of sensor improvements, since the 120MC uses the Aptina AR0130 sensor that is well over 10 years old now.

cheers,

Robin

[GoFraRo]

Thanks a lot for your help Robin,

I've tried different values for the Neptune-C and could achieve some (at least for me) good results.
Yesterday, I worked with Exp 120s, Gain 180 and Offset 250 with my TS Photoline 60/360.
47 selected frames stacked with DSS and processed with SIRIL and Astrosurface.

Testobject: NGC 3938, very faint and far far away (at least for this setup)

Bortle 4, FWHM around 4 and unfortunately interrupted by clouds.

NGC3938_reduced.jpg (171.9 KiB) Viewed 1202 times

Another one, the Monkeyhead nebula NGC2174, with the same settings. This one, the 16bit Fits summary of the Liveaddition, processed with SIRIL and Astrosurface. 57 frames.

NGC2174_Affenkopfnebel_LS_Summary.jpg (558.45 KiB) Viewed 1202 times

Btw. it was the first time, I used Dither. Is there a way to prevent the short exposure frames to get stored ?

Gottfried

[admin]

Hi Gottfried,

excellent images - glad that things are starting to work well for you

In Live Stacking, there is an option to set which raw frames are saved which lets you choose to ignore the short frames during dithering. For saving raw frames you can choose to save

* None
* All
* Those added to the stack or
* All except when paused/dithering

See https://docs.sharpcap.co.uk/4.0/#Controls%20Group for more info.

cheers,

Robin