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HPOL Search Help
Use the HPOL Search form to search the HPOL Catalog by object name, position,
observation date, etc., and to specify the output format.
You can then view preview data and mark data for
retrieval using this interface.
The name of the astronomical object you want to search for.
This column must be used in coordination with the resolver menu.
Choose SIMBAD or NED if you wish to get coordinates for your
target from these services.
If you wish to search on the object name alone, choose the Do not resolve
option. Then the search will be of the target name.
Examples of valid names include GAM-GEM, NGC1068, JUPITER, and HD45677.
(Note no spaces are used in HPOL target names.)
When you search on the object name in the database, case will be ignored.
The object name will not be wildcarded at the front and back
(that's so if you innocently enter IO, you don't match things
like ORION). You can wildcard the object name using *,
however (for example, *1987*). You can also enter a comma-separated
list; for example, *JUP*,*SAT* would match object names containing
either JUP or SAT.
The name resolver allows you to select either SIMBAD or NED
to resolve an object name into its coordinates.
This is useful particularly for searching for objects that may be known by different names.
If you wish to search the object name field of the database with a string search
choose the Do not resolve option.
The SIMBAD and NED object name resolvers can resolve only fixed objects;
they cannot compute the positions of moving objects (planets, comets, etc.).
To find moving objects, try selecting the appropriate object class, entering
an object name that could match what you're looking for, and selecting
Don't resolve for the name resolver. NED is an extragalactic
database, and generally won't resolve object names
within the Milky Way galaxy.
To resolve an object name, enter the object name in
the Object Name field,
select either SIMBAD or NED
for the resolver, and hit the Search button.
is the Nasa Extragalactic Database at Caltech in Pasadena, California, and
is the Set of Identifications, Measurements, and Bibliography for Astronomical
Data at the Centre de Données astronomiques in Strasbourg, France.)
The object name will be sent to SIMBAD, which will send back the coordinates.
(If the object name is not recognized by the resolver,
or there is some other problem with the SIMBAD service, then the search
form will be redrawn with an error message at the top.) These coordinates
will then be used to search the HPOL database, along with whatever
other query qualifications you have given.
You can also hit the Resolve button instead of the Search
button. In that case, the search form will
be redrawn with the object's right ascension and declination entered as
defaults in the RA and Dec fields. Resolving an object name
will not change any other choices
made in the form, except for the equinox, which will be reset to J2000
(since the SIMBAD resolver returns J2000 coordinates).
We recommend that you use object name resolution to find observations
of specific objects in the database.
This is the most reliable way to look up observations, because the
observer could have given any object name
at all (for example, NGC1976 instead of M42).
However, if you do know the object name that the observer used, you
can select Don't resolve,
in which case the object name will not be resolved into coordinates,
but will be used as a search qualification in the database.
(This will happen only when you press the Search button.)
The Right Ascension and Declination around which you want to search.
These fields give the J2000 equatorial
coordinates for the center of the image.
A number of formats are accepted for the RA and Dec. Here are some examples:
Hours, minutes and Seconds
12 22 31.98 29 53 45.55
12h 22m 31.98s 29d 53m 45.55s
12h 22' 31.98" 29d 53' 45.55"
12h 22' 31.98" -29d 53' 45.55"
12h 22' 31".98 -29d 53' 45".55
Hours/Degrees and Minutes (no seconds)
12 22 29 53
12h 22m 29d 53m
12h 22' 29d 53'
12h 22' -29d 53'
The RA may be given in decimal degrees by
indicating a D or d after the degrees:
12d 22m 29d 53m
Spacing is not important, as long as the value is unambiguous, and that
you delimit the hours/degrees, minutes, and (optional) seconds with
letters, colons, spaces, or any character that's not a digit or a
Note also that seconds of the form 31".98 or 31s.98 are accepted. This
should make it easy to cut and paste values into these fields from
This is a broad target category also known as the
ASTRO Science Classes. The categories were choosen by the project and
used for all the ASTRO instruments (i.e., HUT, UIT, and HPOL).
Categories for which no data is available have been removed from
the selection. One or more categories may be selected for the search.
Clicking "reset to defaults" or "clear form" (described
below) will erase previous selections.
This is the GMT time, to the nearest second, of the
start of the observation.
(Note the HPOL1 observations were all obtained during December 2-10, 1990
and HPOL2 observations were obtained during March 2-18, 1995.)
When specifying this date, you need to include at least a date; a time is optional.
The date can have any of the following formats
(the month name can be spelled out or abbreviated to three letters; case is not significant):
Dec 15 1990
Dec 1990 15
15 Dec 1990
1990 Dec 15
1990 15 Dec
If the day is omitted, the first day of the month is assumed. This means
that a specification
like "Dec 1990" will look for observations done on Dec 1 1990 00:00:00,
not for observations done during Decy 1990. Note also that when
entering a date with the month in
numerical format, the American ordering is used; i.e., the first number
is the month.
If a time is omitted, then any time for that day will match.
Otherwise, you can specify a time in any of these formats:
To search for observations before a given date, use <, and for
observations after a given date, use >. For example,
> Dec 10 1990
< Dec 10 1990
You can use the .. operator to search on a range of dates:
Mar 2 1995 .. Mar 5 1995
This operator is inclusive on the first date and exclusive on the second.
Finally, you can search on a list of dates or date ranges. For example,
Mar 10 1995 .. Mar 11 1995,
Mar 15 1995 .. Mar 16 1995
will search for observations done within either one of these date ranges.
You may now search on any column in the mission database. Select the field
you wish to search on and type in the qualification. You may find the valid
range of values by clicking on the field name. NOTE that if you choose a
field in BOTH the form and in the User Option field, then you may not get
results or the result you expect.
Your choice of what columns you want to see in the output.
A set of columns that are commonly requested has been chosen as a default.
The default set of columns is:
Mean % Polarization
Mean Error in % Polarization
Polarizarion Position Angle
Obs. Start Time
Angular Separation (')
NOTE: If the % Polarization, % Error, and Pos Angle are all set to
0.000, the dataset does not include any polarization data, only the
You remove output columns by highlighting the column to be removed and then clicking on
the remove button to the right of the list of chosen output columns.
You may determine the order of column placement by highlighting a column and then clicking
on the up or down buttons to the right of the list of chosen output columns.
You may add a column to the list of chosen columns. Select the desired column on the pull down
menu beneath the list of chosen output columns. Then click on the add button. The column will
be added to the bottom of the output column list.
Choose how you want the output rows sorted. You can select
up to three fields to sort on. The rows will be sorted in the order of
the first sort field; if two rows have the same sort field, they will be
sorted in order of the second sort field, and so on.
For each field, you can select that the rows be sorted in reverse
order on that field by selecting the reverse checkbox. For example,
you can sort the rows with the most recent observations first by selecting
Observation Date for the first sort field and selecting
the reverse checkbox next to it.
Select this checkbox if you want to have a set of distinct rows displayed. This is
useful if you would like to see a distinct list of objects with certain criteria e.g. all
the objects within an object class. To make this function useful, you should not select column name
such as Data Id, Mark or Observation Date in as output columns as all output is considered when maki
ng rows distinct.
Note that columns such as RA, Dec and Magnitude were defined by the IUE GO and often have different
values for the same target name. If columns such as these are chosen as output columns, there will
often be more than one row listed per object name.
Some queries will be capable of returning hundreds of rows or more.
Such large search results tend to use up memory on both the client
and server sides, and aren't usually useful. By default, we limit
the number of rows displayed to 100 rows, but you can increase (or
decrease) this limit as needed.
Select this checkbox if you want to see the SQL query
that the HPOL Search engine constructs from your query qualifications.
The query will be shown at the end of the search results.
SQL (Standard Query Language, pronounced either "ess cue ell" or "sequel")
is a language used
by most relational database systems for retrieving information from database tables.
The HPOL Search Page takes your search specifications and converts them
to an SQL query to run on our database. Viewing the generated query is often useful for
debugging, and may also be useful for SQL-literate users who want to see what logic was used
in the query. (In fact, this may be useful for most people, since SQL is pretty easy to understand.)