Added details to HST data pulling

utils/pull_hubble_csv.py

@@ -3,6 +3,36 @@ from astroquery.mast.missions import MastMissions
 """
 Used to pull the list of observations that fit our filter criteria from 
 online Hubble archives. See all filter details in the function call below.
+
+    sci_spec_1234='F606W,F606W;*,*;F606W,*;F606W;*'
+
+        We are only pulling observations which have used the F606W filter, which is one of the most commonly used ACS filters.
+        We need the regex strings because observations that used multiple filters will include all filters in a list.
+        Documented at https://etc.stsci.edu/etcstatic/users_guide/appendix_b_acs.html
+    
+    sci_aec='S'
+
+        This value denotes that we are searching only for science observations, not observations that were done in order to 
+        calibrate various parts of the instrument or imaging process.
+        
+    sci_instrume='acs'
+    sci_instrument_config='ACS/WFC'
+
+        Here, we define that we want data from the ACS/WFC instrument.
+    
+    sci_expflag='NORMAL'
+
+        This is a quality flag, ensuring that no quality issues were flagged for this observation.
+        
+    sci_actual_duration='>300'
+
+        We require the minimum total observation duration to be at least 300 seconds, to remove any faulty observations 
+        that may have ended after a short period of time and to further narrow the distribution of data away from edge cases.
+    
+    sci_aper_1234='WFC,WFC1,WFC2,WFCENTER'
+
+        We require that the aperture be one of the standard apertures, documented at
+        https://hst-docs.stsci.edu/acsihb/chapter-7-observing-techniques/7-7-acs-apertures
 """
 
 missions = MastMissions(mission='hst')