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HUT Search Columns

This document defines the catalog entries describing the HUT Data Archive as delivered to STScI by NSSDC. Most of the documentation below was obtained from the the HUT project web site at Johns Hopkins Univ. and the online documentation available from the ADF at Goddard Space Flight Center.

Archive Background:

The Hopkins Ultraviolet Telescope (HUT) was one of three instruments which comprised the ASTRO observatory. ASTRO-1 was flown on the space shuttle Columbia in December, 1990, and ASTRO-2 was flown in March, 1995 on the space shuttle Endeavor.

Clicking on this box will mark the entry for retrieval.

Data ID
The HUT data ID uniquely defines each set of HUT observations. The name is of the form HUTxyyyzz where
  • x = 1 or 2 for Astro-1 or Astro-2 mission
  • yyy = a zero padded integer designating a sequence number,
  • zz = a zero padded integer designating a exposure number.
As an example, data ID HUT128901 designates a HUT-1 observation.

Note that for each observation, several data sets may be produced representing different stages of processing.

Clicking on an "Data ID" entry on the HUT search results page will display the HUT preview file. This page contains a plot of calibrated flux vs. wavelength as well as links to display the FITS header, download a tar file of gzipped FITS files, download an ASCII file of fluxes and wavelengths, and display online ADS papers referencing the specific data ID.

Target Name
The name of the astronomical object.

RA (J2000)
Object's Right Ascension in J2000 coordinates specified in hours, minutes, and seconds.

Dec (J2000)
Object's declination in J2000 coordinates specified in degrees, minutes, and seconds.

RA (J1950)
Object's Right Ascension in J1950 coordinates specified in hours, minutes, and seconds.

Dec (J1950)
Object's declination in J1950 coordinates specified in degrees, minutes, and seconds.

Specifies the number of currently known papers referencing the listed HUT data ID. A blank indicates there are currently no known papers referencing the listed data ID (although the database may not yet be complete). Clicking on a "Ref" entry (other than a "-") will display the list of known papers with links to the online ADS papers.

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.)

Obs End Time
This is the GMT time of the end 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 exposure times in seconds. Note the times do not reflect pointing problems. In many cases, the target was not in the aperture.

Day Exposure Time
Exposure time in seconds during spacecraft day.

Night Exposure Time
Exposure time in seconds during spacecraft night.

Object Category
These are broad categories assigned by the HUT project using a classification system adopted by the ASTRO mission. The entire list of ASTRO science classes (as obtained from the Astrophysics Data Facility at Goddard Space Flight Center) is listed below. Note that the HUT search page lists only those categories for which HUT observations were obtained.

  • Astro Science Classes:
            0       Calibration
            0.0             HUT Camera Sensitivity Targets
            0.1             HUT Spectrometer Focus Targets
            0.2             HUT
            0.3             UIT Flat Field Sources
            0.4             UIT
            0.5             WUPPE Aperture Position Calibrators
            0.6             WUPPE Unpolarized & Polarized Standards
            0.7             BBXRT Calibration Sources
            0.8             BBXRT
            0.9             Joint Focus and Alignment Targets
            1       Solar System Objects
            1.1             Comets
            1.2             Planets
            1.3             Asteroids, etc.
            2       Individual Stars
            2.1             Supergiants
            2.2             Oe/Be Stars
            2.3             Wolf-Rayet Stars
            2.4             Rapid Rotators
            2.5             Normal White Dwarfs
            2.6             Magnetic/Pulsating W.D.'s
            2.7             Planetary Nebula Nuclei
            2.8             Normal Stars A0 & Later
            3       Variable and Binary Stars
            3.1             Pre-Main Sequence Stars
            3.2             Cataclysmic Variables
            3.3             Interacting Binaries
            3.4             Symbiotic Stars
            3.5             Active Chromospheres
            3.6             Pulsating Variables
            3.7             Low Mass X-Ray Binaries
            3.8             High Mass X-Ray Binaries
            3.9             X-Ray Transients
            4       ISM & Nebulae
            4.1             Planetary Nebulae
            4.2             Reflection Nebulae
            4.3             H II Regions
            4.4             Super Nova Remnants
            4.5             I.S. Polarization Probes
            4.6             I.S. Absorption Probes (Nearby & Hot)
            4.7             Herbig-Haro Objects
            4.8             Dark Clouds
            4.9             Diffuse Galactic X-Ray Emission Regions
            5       Star Clusters
            5.1             Metal Poor Globulars
            5.2             Metal Rich Globulars
            5.3             Open (Galactic) Clusters
            5.4             O/B Associations
            6       Normal Galaxies
            6.1             Nearby Galaxies
            6.2             Spirals
            6.3             Ellipticals
            6.4             Irregulars
            6.5             Dwarfs
            6.6             Edge On Systems
            7       Abnormal Galaxies
            7.1             Interacting Galaxies
            7.2             Amorphous Galaxies
            7.3             Rapid Star Formation
            7.4             W/Circumgalactic Matter
            7.5             E/S0 with I.S. Matter
            7       X-Ray Miscellany
            7.6             X-Ray Background
            7.7             Unidentified X-Ray Sources
            8       Active Extragalactic
            8.1             Seyfert I Galaxies
            8.2             Seyfert II Galaxies
            8.3             Radio Galaxies
            8.4             Radio Loud Quasistellar Objects
            8.5             Radio Quiet Quasistellar Objects
            8.6             BL Lacertae Objects
            8.7             LINERs
            8.8             Optically Violent Variable (OVV) Quasars
            9       Clusters of Galaxies
            9.1             Spiral Poor Clusters
            9.2             Spiral Rich Clusters
            9.3             X-Ray Selected Clusters
            9.4             Deep Survey Fields
            9.5             Cooling Flow Clusters
            9       Spacecraft Specific
            9.7             TAPS Tests
            9.8             Gyros/IMC/IPS
            9.9             Waterdumps/Handovers

    HUT-1 data includes a comment which usually refers to the quality of the signal-to-noise ratio. (Not available for HUT-2 data.)

    When searching on the comments field, you may want to use wild card such as *S/N* . Use all caps when entering comments as a search criteria. Remember that only data acquired during the first ASTRO mission includes comments.

    Shutter Door State
    To observe brighter stars, the HUT telescope aperture could be reduced by closing one or two semi-circular shutter doors (full aperture size was 5120 cm2), and by opening either of two small apertures (although the 1 cm2 aperture was not employed during either mission). Changes made in HUT-2 software allowed 2 additional modes in which the shutter doors were partially closed. All the possible values are shown below:

    Value HUT-1 HUT-2
    1 1 cm2 small aperture 1 cm2 small aperture
    2 50 cm2 small aperture 50 cm2 small aperture
    3 half aperture half aperture
    4 half aperture half aperture
    5 full aperture full aperture
    6 - partial aperture 3.9% of full aperture
    7 - partial aperture 14.6% of full aperture

    Note that door 4 was never used.
    Valid search qualifications are 1,2,3,5,6,7

    Mission Number
    The ASTRO mission number, either 1 for HUT-1 or 2 for HUT-2.

    Slit Positions
    Used to describe one of 8 aperture sizes and/or filters combinations as shown in the table below . The Al filter was used to reject first order FUV light and provide a pure EUV bandpass (i.e., 415-700 Å), while the CaF2 filter excluded Lyman-alpha and all wavelengths below 1250 Å. Note the aperture selection was revised for HUT-2, so the values in the database table have different meanings depending on which mission is referenced.

    Value HUT-1 HUT-2
    0 closed closed
    1 30" diameter 12" diameter
    2 9"x116" 32" diameter
    3 30" Al filter 32" diameter Al filter
    4 calibration hole calibration hole
    5 18"x116" CaF2 filter 19"x197"
    6 18"x116" 10"x56"
    7 18" diameter 20" diameter
    the qualification 2*,3* and all objects classeNote that slit options 3 and 4 were not used. Valid search qualification values are 0,1,2,5,6,7

    Point ID
    ID code assigned by the ASTRO missions that identifies each shuttle pointing includes the jotfid which identifies each target

    The Point Id is a character field. The first two characters in the field are codes for the category of the target. The last two characters identify the specific target. Where know, the number of the pointing follows a -. The first four characters are also known at the JOT ID.

    The first character is a broad category (e.g. 2 is the broad category for Individual Stars and 3 is the broad category for Variable and Binary Stars). The second character is a more specific category (e.g. 21 would be Supergiants). See the category help to see how they are broken down.

    With this knowledge you can use this field for a more general search on category. For instance if you are interested in all stars you could enter 2*,3* and all objects classified as stars by the ASTRO project would be found. See the category to see

    JOT ID
    ID assigned to each astronomical target name by ASTRO missions.

    The JOT ID is a numeric field. It is the numeric version of the first four characters of the point ID column. Like the Point ID field, you could use it it to find all of one category. To find all the stars you could enter 2000..4000 and all objects classified as stars by the ASTRO project would be found. For more information see information on the Point ID and Category.

    Ecliptic Latitude
    Ecliptic Latitude for the observation.

    Ecliptic Longitude
    Ecliptic Longitude for the observation

    Galactic Latitude
    Galactic Latitude for the observation.

    Galactic Longitude
    Galactic Longitude for the observation.