The Mikulski Archive for Space Telescopes (MAST) contains infrastructure to overlay the locations
and shapes of instrument apertures on images, and to perform spatial footprint queries on catalog databases. This has enabled the creation
of a webservice which can be executed remotely to visualize the WFIRST Field of View (FOV), and to return catalog objects (e.g., GSC2,
2MASS, WISE) within specified detectors.
The user interface to this service is available at
The interface allows one to specify a target name and lookup coordinates from SIMBAD/NED or to input a position directly. Once a
telescope/instrument/aperture combination has been selected, then one can retrieve or display the footprint (Figure 1 below) as well as
retrieve or display extractions from one of the catalogs (e.g., Figure 2 below). The portal defaults to displaying the DSS as the background
sky image, however, SDSS and GALEX imagery are also available.
Known limitations of the prototype tool:
- For the "Display Footprint" and "Display Catalog Data" functionalities
to work, it may be necessary (e.g., in Safari or Chrome) to set your
browser preferences to allow pop-up windows. This is not required in
all browsers though.
The display for the "Display Footprint" function defaults to a size
of 0.2 degrees at the center of the telescope's focal plane, rather
than at the location of the aperture. The WFIRST Wide Field Imager
detectors have a significant offset from the center of the field of
the telescope's focal plane (Figure 3 below), so the initial display
will typically not show the aperture. Please zoom out and you will
see the aperture at the offset location. If needed, you can drag the
display location over to that point and zoom in again. The display
for the "Display Catalog Data" function defaults to center on the
first object in the retrieved catalog list. Here too, zooming out
may be necessary so as to see all the catalog objects. Planned
portal improvements will eventually allow specification of both the
location and the size of sky display.
We cannot currently overlay both the aperture and the
catalog on the same display because we can only instantiate the
portal with one remote query at a time. Planned improvements to the
portal API will eventually eliminate this restriction.
Additional footprint-service help is available on-line or via email to
the STScI Archive Helpdesk .