The All-Sky Portable (ASP) optical catalog  (2017, PASA 34, 25) 

The ASP (All-Sky Portable) catalog presents 1,163,237,190 optical objects in 100 files of 9GB total download size.  Fields are RA and Dec J2000 to tenth-of-arcsecond precision, red-blue photometry which yield magnitudes to a hundredth-of-magnitude precision, PSFs and variability indicator, and flags for proper motion, survey epoch, photometry source survey & catalog, and astrometry source survey & catalog.  Full details are in the paper and ReadMe.  ASP was published as 2017, PASA 34, 25. 

Here is the pre-print paper for the catalog.   

Here is the ReadMe , essential for its field descriptions and sample computer code (in BASIC and Python) to process the fields.   

The catalog can be downloaded from the PASA datastore at  http://dx.doi.org/10.4225/50/5807fbc12595f .  Web address is: https://data-portal.hpc.swin.edu.au/dataset/the-all-sky-portable-asp-optical-catalog If the PASA datastore is down, files can be downloaded below, at the bottom of this page.

ADS page for ASP is http://adsabs.harvard.edu/abs/2017PASA...34...25F .   ArXiv page is https://arxiv.org/abs/1705.05434 .  DOI (publisher's page) is https://doi.org/10.1017/pasa.2017.18 .



Use ASP to get the "O" band for Pan-STARRS ! 

Those who use Pan-STARRS data might bemoan the lack of a "u" band.  There is a quick fix, of sorts -- the POSS-I O band which is centered on 4050A.  While not exactly u, it is blueward of Pan-STARRS grizy, and overlaps the g band only about 33%.  The POSS-I survey was done in the 1950's and it covers all sky down to declination -33, which means it contains the entire Pan-STARRS sky which is down to declination -30.  ASP carries the complete digitized POSS-I survey, and individual objects can be matched from ASP to Pan-STARRS using a matching radius of 1 arcsecond.  For each object, even variable ones, POSS-I O can be calibrated to Pan-STARRS via the POSS-I E band (which is just Cousins R), as follows.  

Lupton 2005 gives the following transform for Pan-STARRS r & i  to Cousins R:   R = r - 0.2936( r - i ) - 0.1439   -- it was actually for SDSS r & i, but the SDSS & Pan-STARRS r & i are just the same, so works fine for this too.  So use the Lupton equation to get Pan-STARRS RPS , use with POSS-I E to calculate the (RPS - E) offset, add that offset to POSS-I O, and boom, you've got Pan-STARRS "o" to add to their "grizy" bands -- the individual-level calibration cancels out any variability across the epochs.  This is for the brighter objects, as POSS-I is about 2 magnitudes less deep than Pan-STARRS; it has 375M sources.

For this to work, the POSS-I O and POSS-I E bands must also be correctly calibrated to each other, and ASP does provide that.  A predecessor catalog, the USNO-B, had inconsistent offsets there.  The history is that USNO first released the USNO-A1.0 which digitized the entire POSS-I survey and was photometrically well-calibrated.  But shortly thereafter they released USNO-A2.0 for the purpose of better astrometry, but scattered photometric O-E offsets got introduced in the process, which were sadly passed onwards to the USNO-B catalog. 

However, ASP to the rescue: the ASP catalog presents the whole POSS-I data calibrated correctly to the USNO-A1.0 standard and also to the APM (which covered POSS-I away from the Galaxy) standard.  The calibrations are shown on the web pages:
 
http://quasars.org/APM-USNOB-plate-calibration.txt for USNO-B, and 
http://quasars.org/APM-USNOA-plate-calibration.txt for USNO-A1.0

The ASP catalog gives the full POSS-I data, 375 million sources, with POSS-I O calibrated correctly to POSS-I E.  ASP always presents POSS-I photometry as the top priority, so the whole POSS-I is ready to be accessed simply by reading the red & blue magnitudes for every ASP record flagged as having POSS-I photometry. 
So that data can be mined for "Pan-STARRS o", using the above technique.  


     Get the ASP data  (and be sure to get the ReadMe)    

Here is the ReadMe , essential for its field descriptions and sample computer code (in BASIC and Python) to process the fields.   

The PASA datastore at  http://dx.doi.org/10.4225/50/5807fbc12595f  has infinite bandwidth to download the ASP files, but you can also get them here.

Files to download (zipped files, 5+ ASP files in each):

 


Eric W. Flesch, this page last edited 6 April 2021