Pinpoint failing to solve in SGP Pro


#1

I seem to have solved my previous plate solving issues - except one!!

The image at the Dropbox link:-

is a PinPoint test image and is a good example. It solves OK in SGP Pro using astrometry.net, ANSVR and PlateSolve 2 all giving the same result. In addition it will solve using PinPoint via the Visual PinPoint interface with both the GSC and UCAC4 catalogues.
However trying to solve using PinPoint from SGP Pro fails with the message:

“Failed to plate solve image (Solve failed!. No matching stars found.
Check your estimated centre point RA/DEC, and your image scaling
and quality.)!”

Since I’m giving Visual PinPoint and SGP Pro / PinPoint the same image with the same hints I expected similar results. Is there any difference between using PinPoint via SGP Pro and the Visual interface? Any other ideas on what’s causing the problem. I would really like to use PinPoint from SGP Pro.


#2

I have no solution for the problem, but I can confirm the behaviour using SGPro 2.5.2.6.

I also checked the Image Solver of PixInsight. I have tried the UCAC3 and PPMXL catalog. Here I get the messeage “0 star pair matches found”


#3

Thanks, I tried the Image Solver in PixInsight using both the catalogues you suggest - for the default limit magnitude (12) - and I got the same results. When I increased the limit magnitude to 16 then the image solves OK.

I suspect this might give a clue as to why PinPoint fails when launched via SGP Pro since Visual PinPoint does find a solution on this image at a limiting magnitude of 14!! I guess this may be a question for DC-3 Dreams perhaps - is there a difference in the way star limiting magnitude is treated in the astrometric engine when accessed via the API and the Visual PinPoint interface?


#4

@Pronto

When I solve your image with Astrometry, I get:

Does that look right?

Not to my knowledge… should be the same property in both (we use it to set the PinPoint property programatically).


#5

It isn’t what I get, mine looks like this:

The image is one of three test images that come with PinPoint and RA/DEC and scale are close to the values in the accompanying readme.


#6

From my point it seems, that the assumption of Pronto, that it has to do with the maximum magnitude is correct.

A year ago I played around to write a own software for plate solving using PinPoint. I had a look in the code and made some tests again.

It turned out, that the image from Pronto is solved, if the “CatalogMaximumMagnitude” property is left on its default value (20).
But on setting this property to a value less than 15 the solve fails:

The same applies by solving the image with Visual PinPoint and changing the “Max Magnitude” setting.

So I assume the property is changed within SGPro prior solving with PinPoint.

If you consider to bubble the property “CatalogMaximumMagnitude”, to make it a user setting, I would like ask you also to reconsider an old (but rejected) change request from me: Configurable PinPoint time out limit.

If the latter is not possible - no big issue. Then I will stay with local astrometry.net as my default plate solver (I only had the feeling I should use PinPoint as it was not cheap :slight_smile: )

Best regards

Reinhard


#7

This is true.


#8

When I plate solve the image using Visual PinPoint I use the default settings like this:

this solves with the result:

I get similar results using the GSC11 catalogue and varying the object Detection parameters.

Since SGP Pro and Visual PinPoint are using the same engine for plate solving, I surmise that the difference must be in the parameters passed to the engine. Is this correct? And if so would it be possible for SGP Pro to have more flexibility in the setting of these values through an extended interface please?


#9

This might be true.

Probably… the trick is identifying what is different.

For anyone that has experience with PinPoint, this is what SGPro sets prior to asking PinPoint to solve:

plate.ArcsecPerPixelHoriz
plate.ArcsecPerPixelVert
plate.RightAscension
plate.Declination
plate.Catalog
plate.CatalogPath
plate.CatalogMaximumMagnitude

There are at least another 100 properties that can be set… The ones we set are pretty basic.


#10

I would suggest (in order of decreasing effects):

  • Max Nr Of Stars. This selects the brightest N stars to be used for the solve. The default is 500 but this is too much. Something like 100 to 150 works much faster. This is also recommended in the help file of the Visual Pinpoint and is very helpful.

  • Expansion. This extends the length and width of the search area as compared to the image dimensions (in arcsec) to help if the coordinate hints are off. The default is 30% on each side. Increasing this slows down the solve.

  • Timeout. The default seems to be 30sec and is only a nice to have.

Regards,
Horia


#11

Thanks Ken, I had hoped that as I’m in a minority (of one!) who seem to be having this issue then the problem would be something simple and quite specific to my setup etc. It’s clearly considerably more difficult than that unfortunately. I had hoped to use PinPoint because a) it’s fast and accurate and b) I’d paid for it!

I guess I’ll stick with PlateSolve and astrometry.net. Thanks anyway

Mike


www.mainsequencesoftware.com