Create imaging system for Vespera Pro

[orionbelt]

Hello,

I am trying to create an imaging system on SkyTools Imaging for my new smart telescope Vespera Pro to get an idea of the SN ratios for exposures but I am getting very off results. The system is a 50mm f/5 quadruplet with a Sony IMX676 Color CMOS chip. The usual subexposure is 10 sec but can change up to 30 sec but is not recommended because causes tracking problems, the systems basically stacks subexposures and tracks on the fly, and the usual gain 20 even you can manually change it up to 27. I am trying to estimate the ADU for the gain and I think that is what I am doing wrong. I look for information on the chip online and I estimate a 2.3 e/ADU, reading noise of 4 and full well of 74000.

I will appreciate some help figuring out the sensor parameters or if someone else had success creating a imaging system for this or similar telescope let me know that they did.

Clear skies,

Carles

[theskyhound]

Hello,

I am trying to create an imaging system on SkyTools Imaging for my new smart telescope Vespera Pro to get an idea of the SN ratios for exposures but I am getting very off results. The system is a 50mm f/5 quadruplet with a Sony IMX676 Color CMOS chip. The usual subexposure is 10 sec but can change up to 30 sec but is not recommended because causes tracking problems, the systems basically stacks subexposures and tracks on the fly, and the usual gain 20 even you can manually change it up to 27. I am trying to estimate the ADU for the gain and I think that is what I am doing wrong. I look for information on the chip online and I estimate a 2.3 e/ADU, reading noise of 4 and full well of 74000.

I will appreciate some help figuring out the sensor parameters or if someone else had success creating a imaging system for this or similar telescope let me know that they did.

Clear skies,

Carles

Hello Carles,

CMOS cameras have different stats for each gain setting (.e.g. 20 or 27) so its critical to individually set up each of the gain settings you actually use with the correct readout noise, internal gain value, and full well. I did some digging and was unable to find anything on this camera that was useful. We need the standard CMOS gain vs. read noise, etc. graphs. Perhaps someone on Cloudynights has the data? 

Also, its not a simple matter to estimate read noise. Better to compare signal. The best sources to use for signal comparisons are stars (if you can measure the total signal in a circular aperture) or the cores of galaxies. 

We are going to have to figure this out before I release the EAA version of SkyTools, which I am working on right now. Its that version that will be designed specifically for these smart cameras. SkyTools imaging is designed for planning long term for traditional long exposure imaging. Its not optimized for using a camera on the fly. Because the workflow is similar, the EAA support is being added to SkyTools Visual Pro, which will become SkyTools Pro (for Visual & EAA). 

I urge you to join the beta test when the time finally comes. Its been a larger challenge than I had hoped it would be.

[orionbelt]

Hello,

I am trying to create an imaging system on SkyTools Imaging for my new smart telescope Vespera Pro to get an idea of the SN ratios for exposures but I am getting very off results. The system is a 50mm f/5 quadruplet with a Sony IMX676 Color CMOS chip. The usual subexposure is 10 sec but can change up to 30 sec but is not recommended because causes tracking problems, the systems basically stacks subexposures and tracks on the fly, and the usual gain 20 even you can manually change it up to 27. I am trying to estimate the ADU for the gain and I think that is what I am doing wrong. I look for information on the chip online and I estimate a 2.3 e/ADU, reading noise of 4 and full well of 74000.

I will appreciate some help figuring out the sensor parameters or if someone else had success creating a imaging system for this or similar telescope let me know that they did.

Clear skies,

Carles

Hello Carles,

CMOS cameras have different stats for each gain setting (.e.g. 20 or 27) so its critical to individually set up each of the gain settings you actually use with the correct readout noise, internal gain value, and full well. I did some digging and was unable to find anything on this camera that was useful. We need the standard CMOS gain vs. read noise, etc. graphs. Perhaps someone on Cloudynights has the data? 

Also, its not a simple matter to estimate read noise. Better to compare signal. The best sources to use for signal comparisons are stars (if you can measure the total signal in a circular aperture) or the cores of galaxies. 

We are going to have to figure this out before I release the EAA version of SkyTools, which I am working on right now. Its that version that will be designed specifically for these smart cameras. SkyTools imaging is designed for planning long term for traditional long exposure imaging. Its not optimized for using a camera on the fly. Because the workflow is similar, the EAA support is being added to SkyTools Visual Pro, which will become SkyTools Pro (for Visual & EAA). 

I urge you to join the beta test when the time finally comes. Its been a larger challenge than I had hoped it would be.

Hello again Greg,

Sure I will work with you with the beta testing, did you got my email? I just not wat to post my contact on open internet, my email is enough crowded at it is.

I will go looking on Cloudy Nights for is someone has the data.

Yes SkyTools Imaging is not designed for this. But for now I can use as an approximation to figure out the results that I will get and if some targets are achievable, if I can get the sensor data figure out.

If I am going to figure out this by myself (supposing no one did it yet) what type of stars you suggest magnitude and spectra? So that we can get data on the sensor SN ratio and other characteristics . Can star clusters be a good option so we have a good range of measurements?

The Vespera Pro has different modes, an on expert mode you can control the exposure and the gain up to 27. I just used to take some pictures of 3I/Atlas with only 5 seconds exposure to freeze the movement as much as possible, the telescope doesn't have the capacity to track the comet, at least not yet.

The usual astrophotography setting is 10 seconds exposures with gain 20.

Clear skies,

Carles

[theskyhound]

Hello Carles,

I do not believe that I have received an email from you. Try using the contact form on my web site.

Let the equipment tell you which magnitude stars are good. Look for stars that have a strong signal, but not so strong as to be saturated. Sort of the middle brightness stars on you image. You can compare them directly to the SkyTools model via the Advanced Exposure calculator. Use the interactive atlas to determine what star it is that you have captured and then enter that as the target in the advanced exposure calculator. It is important that the settings be exactly the same as that for the image, including the date and time. For now just compare the signal calculated o the signal you measure on the image. As a starting test it just needs to be in the ballpark.