HPOL Search Output Columns

This document defines the catalog entries describing the HPOL Data Archive as delivered to STScI by NSSDC. The documentation below was obtained from Marilyn Meade from the HPOL project at the University of Wisconsin.,

Archive Background:

HPOL data is archived at MAST as a set of complementary data for the ASTRO/WUPPE mission. The HPOL spectropolarimeter is a modified Boller and Chivens small telescope spectrograph. The system provides simultaneous spectrophotometry and spectropolarimetry over the range of 3200Å to 10500Å (prior to 1995, the spectral range was 3200Å to 7750Å), with a spectral resolution of 10Å (25Å prior to 1995). The halfwave plate is a super-achromatic half-wave retarder. The wave plate is rotated by a stepper motor and rack and pinion drive, with stops every 11.25 degrees. A Wollaston prism produces two orthogonally polarized beams (ordinary and extraordinary) separated perpendicular to the dispersion. The ultraviolet achromatic camera is specifically designed for this instrument. The camera is all-refractive, which eliminates vignetting and thus enhances the polarimetric stability. The image is focused on a 400 X 1200 pixel CCD. The instrument is installed on one of two telescopes. Primarily, it is installed as a dedicated intrument to the 36" telescope at the University of Wisconsin-Madison Pine Bluff Observatory (PBO). HPOL can also be mounted on the 3.5 m WIYN telescope at Kitt Peak National Observatory for limited observational runs once a year or so.

General Results Options

Most mission search results pages have the following general features/options. (Note that the sorting, paging and VOPlot options all require javascript to be turned on.):

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. Note that a bug currently exists whereby exponents are ignored in numbers using exponential notation (e.g., 6.3E-3 is sorted as if it were 6.3). Since most tables don't include exponential numbers this is not felt to be a major problem.
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 50 entries per page, with links to additional pages if more than 50 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. (Note that when the total number of returned rows is a multiple of 50, an extra page is displayed with no entries.)
One numerical column can be plotted versus another using VOPlot.
For some missions, thumbnail images of the reurned 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.

Column Information

Mark

Clicking on this box will mark the entry for retrieval.

To Retrieve:
The selected datasets will be downloaded in a single file. You may select the file type: .tar, .tar.gz, .tar.Z, and .zip. After selecting the file type, click on the "Download selected files" button and the selected files will be downloaded to your disk.

To Coplot:
After selecting up to 15 observations to be plotted, click on the "Plot marked spectra" button to coplot the selected observations.

The spectra that you selected will be automatically scaled to the full range of wavelengths and nearly the full range of fluxes (i.e., y axis plot scale runs from 0 (or .25 * the minimum flux for spectra with negative fluxes) to the 10th highest flux). Each spectrum is automatically assigned a color, up to a maximum of 15. The spectra are labelled by their dataset names, with a summary of the datasets plotted given below the plot. After inspecting the plot, you may wish to change the selection of datasets which are displayed. Use your browser "Back" button to do this.

Plot range
Adjust the minimum and maximum wavelengths (in \305ngstroms) and minimum and maximum fluxes (in erg /cm2/sec/\305) to select the spectral region of interest and to exclude noisy data.

Plot dimensions
Adjust the X size and Y size in pixels to create the size of plot desired. The maximum dimensions ar e 850 by 640 pixels.

Redraw plot
Use this button to replot the spectra when you have changed the plot range or plot dimensions.

Target Name

The name of the astronomical object (e.g., Omi2-Cyg, SAO32635)

Alternate Target Name

The alternative name of the astronomical object (the HD catalog where it exists).

RA (J2000)

Object's Right Ascension in J2000 coordinates specified in hours, minutes, and seconds. (Note the original coordinates provided by the project were B1950.) For moving targets, the coordinates refer to the position of the target in the sky at the start of the observation.

Dec (J2000)

Object's declination in J2000 coordinates specified in degrees, minutes, and seconds. (Note the original coordinates provided by the project were B1950.) For moving targets, the coordinates refer to the position of the target in the sky at the start of the observation.

Galactic Longitude

Object's galactic longitude in decimal degrees derived from the original B1950 RA and DEC.

Galactic Latitude

Object's galactic latitude in decimal degrees derived from the original B1950 RA and DEC.

Observatory Position Angle

Obs. Start Time

This is the GMT time of the start of the observation (Note, although stored in the database to the nearest second, the default print format truncates the date to the minute.)

Exposure Time

The total useable exposure times in seconds. Note these times were corrected to compensate for pointing problems. In many cases, the target did not stay centered in the aperture.

WUPPE/ASTRO object identification ID

The ASTRO Mission assigned each target planned for obeservation a distinct identification number. For those objects observed with with both WUPPE and HPOL, the identification number is included. For a more complete description of the ASTRO id see WUPPE Category or science class.

Object Type

Publication Reference

Aperture Slit

Aperture Decker

Spectral Type

Spectral type, luminosity class, and/or object class.

Visual Magnitude

Apparent visual magnitude.

Data ID

The HPOL data id uniquely defines each HPOL observation. The name is of the form objectid_yyyymmdd where

objectid = object name (e.g., alf-her or hd204827), identical to the entries under "Target Name" but in lower case,
yyymmdd = year month day of observation.