SPCC Error

Matthew Humphrey

I am very new to PixInsight and AP, and just finished the FastTrak videos.  I am now trying to go through the process using my own data.  Basically, I am following the same steps as outlined in the FastTrak videos.  

The data I am working with is of M101 in a Bortle 7 sky.  I took 150 x 60s sub (it was windy that evening, so opted for shorter exposures).  It was taken with an ASIAir 2600 through a Celestron C11 with a .7x Flattener/Reducer.

Up until the SPCC step, everything went as outlined in the videos. 

When I get to this step, I place a "Preview" on the image and use it for the RoI, select "Sony IMX411/455/461/533/571" for the QE Curve, and "Sony Color Sensor X-UVIRcut" for each of the R/G/B Filters.  All other settings are left at default.

After clicking apply, I get the following output:

* Output binary file generated: C:/Users/mthum/AppData/Local/Temp/Gaia_SP_256WFITV5U97.bin

Extracting catalog star spectrum data: done

212 catalog sources found.

Saturation threshold: 0.4435

* Extracting PSF signal samples

Fitting 229 stars: done

Fitting 252 stars: done

Fitting 211 stars: done

* Integrating spectrum data

Robust linear regression (R/G): 0%

*** Error: Insufficient data: only 1 sample(s) are available; at least 5 are required.

Reading swap files...

2018.908 MiB/s

<* failed *>

I found another thread on here that suggested that the stars are too fuzzy.  I can definitely see where that might be the case with my images.  In that thread, it was suggested to set the Minimum detection SNR to 0.  I tried this, as well as choosing different areas of the image for the RoI, but this did not resolve the error. 

Perhaps the image is too fuzzy for SPCC to work?

Thanks,

-M

BlockHead

Post a screenshot of some registered data?

I have two videos on this:

https://www.adamblockstudios.com/articles/spcc-not-enough-samples-error

and

https://www.adamblockstudios.com/articles/spcc-not-enough-samples-error-another-example

If you search for "samples" on my site you will come up with these two videos.

-the Blockhead

Matthew Humphrey

Here is a screenshot of the SPCC step.  

By registered data... did you mean something else? 

Also, I have not yet purchased the "Fundamentals" program - only FastTrak.  I figured I'd make sure i'm not too far over my head...

BlockHead

Well.. I was going to look at the data before the integration.. but the integrated image is fine as well.

Can you make this image available to me for download?

Upload to a cloud server (any)... make the file permission available to anyone to download.

Post the link.

The image looks fine and SPCC should do its thing.

-the Blockhead

Matthew Humphrey

I saved as a TIF at the state it was in in the screenshot I shared, and uploaded to OneDrive:

https://1drv.ms/f/s!Arcl9TtTrZIxh_Ze1g0-j0qQ4a_xlw

The M101_Integration.tif file should be in that folder.

Thank you for taking a look at this.  

Matthew Humphrey

Some other details about the data that I didn't mention in my original post:

1) Given the focal length (2066mm) and the pixel size of the 2600, I used 2x2 binning during acquisition

2) I used an Optolong L-Pro light pollution filter during acquistion.

Not sure if any of that matters, but just in case...

BlockHead

You need to always provide the original integrated XISF file. 

By saving the file- you can potentially mess things up... maybe.

For example, the TIF file does not have an astronomical header. It will not have the astrometric solution. 

Could you please make the real data file available?

-the Blockhead

Matthew Humphrey

Sorry about that...  

XISF file is uploaded (file - save as... - XISF, left everything default) to the same OneDrive folder

https://1drv.ms/f/s!Arcl9TtTrZIxh_Ze1g0-j0qQ4a_xlw

Thanks again,

-Matt

BlockHead

Matthew,

I discovered the issue. I got the same answer you did. 

However, somewhere along the way I suspect you made an error. 

I had to assume the very thing that *could not be wrong* was wrong. 

The astrometric solution that is in your file is not correct. I am not certain how you did this. 

I believe you likely did not copy or find the correct solution. 

When you have a problem like this, it is a good idea to not assume anything at all. I too messed around with the parameters in SPCC...but that was not the issue. Please open your integrated image and run ImageSolver on it. Then run SPCC without adjusting any S/N or noise parameters. You will find it works just fine.  See my attached screen capture. 

-the Blockhead

Matthew Humphrey

Yep.  That indeed did the trick. Sorry to send you on a wild goose chase.

The original data already had the coordinate information in the FITS header.  After integration, I did a "Copy Coordinates" script instead of re-computing the astrometry.  Looking back, I'm not sure why I made that decision.  Lesson learned...

Thank you for taking to the time to look into this and finding an answer.