Photometric CC using APASS Catalogue

Software Siril
1

Hello,

I’m trying to run a Photometric Color Calibration using the APASS catalogue but it throws me always the same error:
“Plate Solving failed. The image could not be aligned with the reference stars.”

Using the NOMAD catalogue it runs every time without problems, but not with APASS. I tried using the APASS after using the NOMAD catalogue so the information like coordinates, focal lenght, etc… it’s the more acurate possible, but even so throws the same error.

It’s something wrong with this catalogue ?
Thanks

2

I assume you’re talking about siril?

3

Yes

4

@lock042 any idea?

5

Yep. Answers is probably in the tooltip:

  • NOMAD is a simple merge of data from the Hipparcos, Tycho-2, UCAC2, Yellow-Blue 6, and USNO-B catalogs for astrometry and optical photometry, supplemented by 2MASS near-infrared. The almost 100 GB dataset contains astrometric and photometric data for about 1.1 billion stars.
  • APASS, the AAVSO Photometric All Sky Survey, is performing an all-sky photometric survey. This survey is conducted in eight filters: Johnson B and V, plus Sloan u’, g′, r′, i′, z_s and Z. It is valid from about 7th magnitude to about 17th magnitude for over 37 million stars.

NOMAD has much more stars.

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6

I know that NOMAD catalog have more stars, but i think that the APASS catalog it’s much more accurate than NOMAD.

I’ve tried the same procedure with Pixinsight using the APASS catalog without any problems using exactly the same images that i’m trying to use in SIRIL.

7

Of course it is.

Yes, but PixInsight only uses APASS for photometry.
In our algorithm, same catalogue is used for astrometry and photometry.

8

It’s working :slight_smile:

The only way i get it working was by opening the Dynamic PSF Window, click on the “Detect Stars in the current loaded image…” and change Star Detection mode in Photometric Color Calibration window to “Manual Detection”.

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