Space Telescope Science Institute
Cycle 21 Phase II Proposal Instructions
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Chapter 3: Fixed and Generic Targets > 3.1 Target Identification

3.1 Target Identification
The following information is required to identify and classify each target.
3.1.1 Target Number [Target_Number]
Each target in your program will be assigned its own unique number (which can be changed by the user) by APT (they are base 10 and go from 1 to 999). A different target must be defined whenever different coordinates or a different target description are required. Separate targets should be defined and listed if you plan to take observations at several points within an extended object. For example, if you were to take spectra at three different locations in the Crab Nebula, each point must have its own target number, name, and coordinates, such as CRAB1, CRAB2, and CRAB3.
If you are using the Text Proposal File, all target numbers and names within a proposal must be unique.
3.1.2 Target Name [Target_Name and Alternate_Names]
Target names provide unique designations for the targets that will be used throughout the proposal. These names will also be used to designate targets in the HST data archive. Prospective proposers and archival researchers use these names to determine whether HST has observed a particular object. This facility will be most useful if consistent naming conventions are used.
The following conventions must be followed in naming targets:
No blanks are permitted in target names. Blanks between a letter and a numeral must be suppressed (e.g., HD140283, NGC4378), but a hyphen (and not an underscore) must replace blanks between two letters or two numerals (e.g., ALPHA-CEN, NGC224-0040+4058). Also, a hyphen should be used where required for clarity (e.g., NGC4486-POS1).
Only letters, numerals, hyphens, periods (.), and + or are allowed in target names; other punctuation is not permitted (e.g., BARNARDS-STAR is valid, but BARNARD’S-STAR is not). Greek letters must be spelled out (e.g., ALPHA-ORI). Letters may be upper-case or lower-case, but will always be treated as if they are upper case (e.g. Alpha-Cen will be treated as if written ALPHA-CEN).
Degree signs must be represented by an upper-case “D” (e.g., CD-4214462 becomes CD-42D14462).
If desired, you may give one or two “common names” for your target, which will be entered in the Alternate_Names. For example, HD124897 could have Alternate_Names of ALPHA-BOO and ARCTURUS.
Only Target_Name is used when the target name is repeated in the Visit and Exposure Specifications. Cataloged Targets
If your target is in a well-known catalog (e.g. SDSS, NGC, PG), then use that catalog designation for the target name. This is the name your object will have in the Archive, so please try and select the most common name for the target to make it easier for archive researchers to find your target. Uncataloged Targets
Objects that have not been cataloged or named must be assigned one of the following designations:
Isolated objects must be designated by a code name (the allowed codes are STAR, NEB, GAL, STAR-CLUS, GAL-CLUS, QSO, SKY, FIELD, and OBJ), followed by a hyphen and the object’s J2000 equatorial coordinates, if possible, rounded to seconds of time and seconds of arc (e.g., for a star at J2000 coordinates RA: 1H 34M 28S, DEC: –15D 31' 38", the designation would be STAR-013428-153138).
Uncataloged objects within star clusters, nebulae, or galaxies must be designated by the name of the parent body followed by a hyphen and the rounded J2000 coordinates, if possible, of the object (e.g., for a target within NGC 224 with J2000 coordinates RA: 0H 40M 12S, DEC: +40D 58' 48", the designation would be NGC224-004012+405848).
3. Alternate Names
In addition to the catalog name, a target could be assigned at most two alternate “common names,” or aliases, if they exist. Examples of common names are the following: BARNARDS-STAR, OMEGA-CEN and M31. Special Targets
The names of certain types of targets must be designated by appending a code to the target name. For example, -CALIB should be appended to the name of a target that is being observed only as a calibration standard for other observations. These designations will assist in planning of the observing schedule. The possible codes are listed in Table 3.1.
Table 3.1: Designations of Special Targets
An astronomical target used for calibration (e.g., BD+28D4211-CALIB). Internal calibration sources (e.g., WAVE) and calibrations using the Earth must not be included in the Target List.
Two separate exposures must be defined on the Visit and Exposure Specifications; an acquisition of the -OFFSET target, and a science exposure of the (target of interest) program target. The location of the latter target may be specified either by equatorial coordinates or by an offset (see Section 3.2.2 on page 34).
For example: to observe the JET in 3C273, first acquire “stellar-like” source 3C273-OFFSET, then offset to program target 3C273-JET.
3.1.3 Target Category and Target Description [Description]
A target description must be selected for each target. The Target Description will be one of the key fields used by archival researchers in searching through the HST data archive; thus it is extremely important that the information be filled out completely and accurately for each target.
Each target must be assigned a single primary category from Table 3.2, and at least one descriptive keyword, chosen from the appropriate Table 3.3 through Table 3.9 (see Table 3.2 for which table is appropriate for each category). The discrete features and descriptors in Table 3.10 may be used as descriptive keywords for any category. A maximum of five descriptive keywords may be selected.
The categories in Table 3.2, and some of the descriptive keywords in Table 3.3 through Table 3.10, are followed by explanatory text in parentheses. This text is provided only for explanatory purposes and is not part of the category or keyword itself.
Text Proposal File
If you are using the Text Proposal File, target description items must be separated by commas.
SOLAR SYSTEM (Solar System Object)
STAR (Galactic Stellar Object)
EXT-STAR (Star in an External Galaxy)
STELLAR CLUSTER (Galactic Star Cluster, Group, or Association)
EXT-CLUSTER (Star Cluster in an External Galaxy)
GALAXY (Galaxy or AGN)
CLUSTER OF GALAXIES (Galaxy Groupings, Clusters, Large-scale Structure)
ISM (Interstellar Medium of the Galaxy)
EXT-MEDIUM (Interstellar Medium of an External Galaxy)
UNIDENTIFIED (Unidentified Objects)
CALIBRATION (Calibration Observations)
Table 3.3: Descriptive Keywords for STAR and EXT-STAR 
LMXB (Low Mass X-ray Binary)
MXB (Massive X-ray Binary)
Polar (AM Her Star)
Intermediate Polar (DQ Her Star)
Table 3.4: Descriptive Keywords for STELLAR CLUSTER and EXT-CLUSTER
Table 3.5: Descriptive Keywords for GALAXY
Spiral (Spiral Galaxy)
Quasar (Radio Loud)
Lenticular (Lenticular Galaxy)
Elliptical (Elliptical Galaxy; Not A Dwarf Elliptical)
BL Lac (BL Lac or BLAZAR)
Dwarf Compact (Dwarf Compact/HII Galaxy)
BCM (Brightest Cluster Member)
BGM (Brightest Group Member)
LSB (Low Surface Brightness/HI Rich Galaxy)
QSO (Radio Quiet)
Table 3.6: Descriptive Keywords for CLUSTER OF GALAXIES
BCM (Brightest Cluster Member)
BGM (Brightest Group Member)
Table 3.7: Descriptive Keywords for ISM and EXT-MEDIUM 
SNR (Supernova Remnant)
Damped Lyman Alpha Cloud (Extragalactic)
Coronal Gas (105–106 K)
Hot Gas (107–108 K)
PDR (Photon Dominated Region)
Table 3.8: Descriptive Keywords for UNIDENTIFIED
Table 3.9: Descriptive Keywords for CALIBRATION 
BLR (Broad Line Region)
NLR (Narrow Line Region)

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