Ouput Field Help

This page describes the fields that may be returned by one of the HST Archive Search forms.

The row number in the results. We put this in so you won't get lost in the middle of scrolling through a long page (happens to me all the time).

Mark

Mark this dataset for retrieval by pressing this checkbox. After you have marked for retrieval all the datasets that you're interested in, hit the Retrieve Marked Datasets for Retrieval button to initiate the retrieval.

Proprietary datasets will have a @ character next to their mark buttons (and in some browsers will show up with a yellow background). Proprietary datasets can be marked and retrieved by appropriately authorized users. If you are a principal investigator and would like to retrieve your data (or would like to authorize one of your co-investigators to retrieve your data), contact us at archive@stsci.edu.

Users running Javascript-enabled browsers will see some buttons at the top and bottom of the search results labelled Mark all, Unmark all, etc. These buttons may be used to mark or unmark all of the datasets in the search results; mark or unmark only the proprietary datasets; or mark or unmark only the public datasets.

Targname

The name of the target of the observation, as given by the proposer. If the target name is hyperlinked, then a preview image or spectrum is available for that observation. Clicking on the target name in that case will bring up the preview form (which lets you select the format of the preview).

Occasionally, you will see target names like PAR, UNKNOWN-TARGET, and so on; these are (most likely) parallel observations, which are observations done by one instrument while another is making the primary observing of the telescope's visit.

RA

The equatorial right ascension of the instrument aperture, in equinox J2000. (The output equinox selector on the search form doesn't work yet.)

(For the WFPC2, the aperture right ascension coincides with the V1 right ascension, which is the middle of the field of view.)

Dec

The equatorial declination of the instrument aperture, in equinox J2000. (The output equinox selector on the search form doesn't work yet.)

(For the WFPC2, the aperture declination coincides with the V1 declination, which is the middle of the field of view.)

V3 Position Angle

The V3 position angle (PA_V3) is the direction in degrees east from north that the tip of the L shape formed by the 3 WF chips would point, if the L shape is imagined to form the tip of an arrow. (see WFPC2 Position & Orientation). The V3 position angle is 180 degrees different (exactly opposite in direction) rom the U3 position angle, which is specified by the observer during the Phase 2 proposal process as the "ORIENT".

Angular Separation

The angular separation in arcminutes between the observation and the search center (the coordinates you're searching on). This is calculated during the search, and the search results are sorted in order of increasing angular separation. It has the nice effect of sending parallels to the bottom of the list. (If you're interested in the parallels, you can sort the list in descending order of angular separation.)

It also means that you can give a search radius like, say, 2 .. 8 to find all observations between 2 and 8 arcminutes from some position. This could be used, for example, to exclude observations of the nucleus of a galaxy, or the central star in a planetary nebula.

Instrument

The HST instrument that performed the observation.

Operating Mode

The operating mode of the instrument that performed the observation.

Cent Wave

The central wavelength, in Ångstroms, of the observation. For images, this is the central wavelength of the filter used, while for spectra, it is midpoint of the wavelength range of the spectrum.

Exp Time

The exposure time of the observation, in seconds.

Reference

The number of known literature references associated with the listed proposal ID. Clicking on an entry in this field (other than a "-") will display a list of references with links to the online ADS papers. Note that because the literature references are based on proposal id, the specific data set(s) listed may not be cited in the references. Please also note that matching HST proposal ID's to published papers is an ongoing project and never completely up to date.

PEP ID

The ID number of the observing program. Clicking on an entry in this field will display the HST proposal search page containing the proposal title, PI's name, abstract, ads links to published papers, and a table of all known observations.

Start Time

The starting time of the observation (GMT).

Release date

The release date for the dataset, in GMT. HST data has a nominal proprietary period of one year (though in special cases, this may be shortened or extended). The Release Date field gives the end of the dataset's proprietary period. After this date, no special priveleges are required to retrieve the data.

Dataset Name

The unique identifier for an HST observation.

This value is hyperlinked. By clicking on it, you can bring up detailed information about the observation.)

Archive Class

Classes of data files in the HST Archive. See archive handbook for additional information.

Program ID

THe SOGS Program ID for the proposal that requested the data.

Observation Set

The observation set within the program. This is usually the same as the visit number, though in a small number of cases it will be different. The obset ID is used as the fourth and fifth letters of a dataset name. You can enter a comma separated list here. If necessary, obset IDs will be padded with leading zeroes to two characters.

Obsnum

The Observation number from the SOGS header.

ASN ID

Unique identifier assigned to association.

Target Description

A short description of the target, supplied by the observer. Like target names, these may not always be reliable- one observer's CLUSTER OF GALAXIES may be another's ELLIPTICAL- but they are generally better than nothing (especially where solar system objects are concerned; planet, asteroid, and comet names are more likely to be spelled out in the target description than in the target name).

Broad Category