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Astrophotography by Bob Franke

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All Plate Solves Are Not Equal

 

 

Plate Solve Software

RA

Dec

PA

Star Count

Astrometry.net

19:59:51.3

22:44:06.4

0.047

 408

Astrometry.net
w/ SExtractor

19:59:51.4

22:44:05.3

0.082

1232

TheSkyX

19:59:51.4

22:44:05.0

0.083

1208

PinPoint V5.0.14

19:59:51.2

22:44:05.3

0.172

 178

PixInsight

19:59:51.4

22:44:05.2

0.087

 535

 

 

 

 

 

The results, in the above table, are for a single field-of-view and do not suggest that one software package is better than another. Additional FOVs showed that the results vary greatly.

The Star Count column indicates the number of identified useful stars by eXcalibrator for color balancing. The data show that the major factor in star count is the accuracy of the Position Angle.

With the above data, eXcalibrator calculated identical color balance ratios in all five cases.

The table also shows that using the Astrometry.net default settings can produce inferior results. The declination is off by one arc-second with a significant error in the PA. Additional tests show that it is better to select the Source Extractor option on the Astrometry.net upload page. The results can be significantly improved but never reduced.