Catalog matching Between Sextractor Sources and Querying APASS

[thomastu]

We want to take ALPHA_J2000 (RA) and DELTA_J2000 (RA and DEC) in decimal degrees and match to APASS catalog.

[thomastu]

There appears to be an implicit API on the APASS site --

https://www.aavso.org/cgi-bin/apass_download.pl?ra=10&dec=10&radius=1&outtype=1

Ultimately we want to be able to call

>>> print(apass(ra, dec, radius))
Some rectangular format that can be hashed by header names (e.g. pd.DataFrame or astropy table)

[thomastu]

Matching can be done via astropy.coordinates -- read "Matching catalogs/finidng nearest coordinates"

[thomastu]

APASS query thing is done, but some discussion on how we want the data is probably a good idea.

Currently, the output table is based off a pandas dataframe which is a little prohibitive. Great framework, but potentially steep learning curve.

Otherwise, querying APASS currently works as follows

in bash:

git fetch && git checkout apass

in python:

from flipp.libs.apass import Client as APASS

df = APASS.query(10., 10., 1.)
print(df.head())

[thomastu]

this has been merged to master. Second part of this is in zeropoint.py, might be good to rewrite later.

[thomastu]

We want to consider the ability to run catalog matching against other surveys as well. This issue will remain open to address that this should eventually be generalized.