queryusno.pro

basic median filter simulation

function Queryusno, target, dis,magrange = magrange, HOURS = hours
;+
; NAME: 
;   QUERYUSNO
;
; PURPOSE: 
;   Query the USNO-A2.0 Catalog at the ESO/ST-ECF Archive by position
; 
; EXPLANATION:
;   Uses the IDL SOCKET command to query the USNO-A2.0 database over the Web.    
;   Requires IDL V5.4 or later.
; 
;   With the introduction of QUERYVIZIER this routine became mostly obsolete
;   as the newer USNO-B1 catalog can be accessed from QUERYVIZIER.
;
;   USNO-A2.0 contains entries for over a half billion stars (526,230,881, to 
;   be exact!) which were detected in the digitized images of three photographic
;   sky surveys. For the entire northern sky and the southern sky down to 
;   declinations of -30