Pointings Search

What is a pointings search?

The MAST "pointings" interface allows a user to search for ACS, WFPC2, STIS, FOC and NICMOS images in a powerful way. For each of these instruments we have assembled a searchable data table that allows users to look for sky regions (or pointings) which have been observed N times or more, observed with 2 or more filters, or have been observed more than twice with a time separation of more than (or less than) N days. An exposure is defined to be the file created after the shutter closes. The total number of exposures for each of the defined bands within a defined pointing were tallied.

The definition of a pointing is different for each instrument. See the Search Help page for a more complete description of the methodology used to define a pointing.

Example of a WFPC2 Pointings search

An example of the type of query these tables will allow is: How many high galactic latitude observations taken with WFPC2 exist [for RA between 9 - 18 hours in the northern hemisphere (dec > -20) observable from the northern hemisphere in the early spring] where there have been at least two observations, and where at least one of those observerations was in the I-band, and at least one of those observations was in any other filter?

Choose the following options:

Galactic Latitude Above & below plane +/- > 20.0 degrees
Exposures in Band I >0
Number of Unique Bands >1
Total Number of Exposures >1
RA 09..18
Dec >-20.0

How are the pointings and bands defined for each instrument?

ACS Definitions

WFPC2 Definitions

All exposures within a 40 arcsecond radius are considered a pointing. Some exposures may fall within more than one pointing.

NICMOS Definitions

STIS Definitions

FOC Definitions