This page describes the fields that may be returned by
one of the HST Archive Search forms.
General Results Options
Most mission search results pages have the following general
features/options. (Note that the sorting, paging and VOPlot
and the interactive plotting option uses HTML5 which is not
supported in Internet Explorer before version 9.)
Clicking on the column headings at the TOP of the
results table will sort the returned results based on the selected
field. Clicking the column heading a second time will sort the
results in descending order. As of August, 2014 sorting is now
possible with RA and Dec coordinates in sexigesimal notation,
and the previous bugs
whereby exponents are ignored in numbers using exponential notation
(e.g., 6.3E-3 is sorted as if it were 6.3), and signs were
ignored in floating point numbers have both been corrected.
that the sort functions (like many interactive features)
Alternatively, selecting the sort options in the initial query
and will sort the entire search result, not just the displayed
Clicking one of the column headings
at the END of the results table (or clicking the
"columns help" link at the top of the page) will display
help information about the search results page and the displayed
columns (i.e., this page).
By default, results are shown with 500 entries per page, with links
to additional pages if more than 500 entries were returned. The number of
rows per page can be modified using the "Records per Page" form element
on the search form. The total number
of entries returned is set by the "Maximum Records" value from the search page.
One numerical column can be plotted versus another using VOPlot
although see the Help page regarding issues
with the latest version of Java.
For some missions, thumbnail images of the returned entries
can be displayed by clicking the link listed just below the VOPlot link.
The mark column, as described below, can be used to plot spectra
and download files. Plots are now interactive with added features.
You can press this checkbox to either mark a dataset for retrieval
or to coplot selected spectra. Both functions are described below.
Retrieve Data -
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
Plot Spectra -
If you want to coplot multiple spectra from the seach results page
(i.e., up to 15), click the checkboxes next to the datasets you are
interested in, then hit the Plot marked spectra button to
initiate the plotting process. The requested spectra will be displayed on
a page with options to rescale the plot or rescale individual spectra.
Note however that the listed datasets
on the search results page may be a mixture of images, spectra without preview
data, and spectra for which preview data is available. Only datasets in the
last category can be plotted and all other selections will be ignored.
One indication that preview data exists is to
see if the entry in the "target name" field is linked. If the entry is not linked,
no preview data exists. Also, NICMOS, FOC, and some STIS spectral data are not
in a form that can be plotted, so these files will be ignored as well.
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.
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.
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)
from the U3 position angle, which is specified by the observer
during the Phase 2 proposal process as the "ORIENT".
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.
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.
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.
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.
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.
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).
observation mode, either staring (nominal) or spatial scan
(target is trailed through the field of view). Values include \null -
not a scan i.e. observation was taken in nominal staring mode,
C - observation taken in continuous scan mode,
D - observation taken in scan mode with a dwell.