3.2 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:

•	A new target name must be defined for each (celestial) target. For example, for several pointings within a galaxy, one might define target names such as NGC4486-NUC, NGC4486-JET, NGC4486-POS1, and NGC4486-POS2.

•	The length of a target name must be anywhere from 2 to 31 characters.

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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).

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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-42°14462 becomes CD-42D14462).

•	Some special target names are reserved for calibrations and other purposes and may not be used for names of external pointings; see Table 3.1: Designations of Special Targets.

Whenever possible, two types of designations should be provided for each target. The first will be a “catalog name” (for example, HD124897), and the second will be at most two “common names” (e.g., ALPHA-BOO, ARCTURUS). The “catalog name” is entered in Name and the “common names” are entered in Alternate_Names.

Only Target_Name is used when the target name is repeated in the Visit and Exposure Specifications. If the target is in the STScI Guide Star Catalog (GSC), the GSC name should be included as one of the common names (e.g., GSC5637-12345).

3.2.1 Catalog Name

The preferred order for catalogs to be used for the designation of various classes of objects is provided below. It is arranged in order of decreasing preference.

If a target is not contained in these catalogs, other catalog designations may be used (e.g., 4U X-ray catalog designation, Villanova white-dwarf catalog number, etc.). The use of positional catalogs (SAO, Boss, GC, AGK3, FK4, etc.) is discouraged.

For uncataloged targets, see Section 3.2.2 on page 29.

Stars

1.	Henry Draper Catalog number (e.g., HD140283)is preferred. HDE numbers are discouraged, except in the Magellanic Clouds.

2.	Durchmusterung number (BD, CD, or CPD). In the southern hemisphere, adopt the convention of using CD north of –52 degrees and CPD south of there (e.g., BD+30D3639, CD-42D14462, CPD-65D7691).

3.	General Catalog of Variable Stars designation, if one exists (e.g., RR-LYR, SS-CYG).

4.	AFGL designation.

5.	IRC designation.

6.	IRAS designation.

Star Clusters and Nebulae

1.	New General Catalog (NGC) number (e.g., NGC6397, NGC7027).

2.	Index Catalog (IC) number (e.g., IC418).

3.	For planetary nebulae for which you do not have an NGC or IC designation, the Perek-Kohoutek designation (e.g., PK208+33D1) may be used.

4.	For H II regions for which you do not have an NGC or IC designation, the Sharpless catalog number (e.g., S106) may be used.

5.	For IR nebulae, AFGL designation.

Galaxies and Clusters of Galaxies

1.	NGC number (e.g., NGC4536).

2.	IRAS designation.

3.	IC number (e.g., IC724).

4.	Uppsala Catalog number, only if an NGC or IC number is not available (e.g., UGC11810).

5.	For clusters of galaxies, the Abell catalog number, but only if an NGC or IC number is not available (e.g., ABELL2029).

Quasars and Active Galaxies

1.	The name defined in the compilation by Veron-Cetty and Veron (ESO Report No. 7, 1989) must be used (e.g., 3C273).

3.2.2 Uncataloged Targets

Objects that have not been cataloged or named must be assigned one of the following designations:

1.

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).

2.

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.

Positions within nebulae or galaxies may also be designated by the name of the parent object followed by a hyphen and a qualifier. The qualifier should be brief, but informative (e.g., the jet in NGC 4486 could be designated NGC4486-JET). Other examples are: NGC5139-ROA24, LMC-R136A, ABELL30-CENTRAL-STAR, NGC205-NUC.

3.2.3 Common Names

In addition to the catalog name, a target should be assigned at most two “common names,” or aliases, if they exist. Examples of common names are the following:

1.	Stars: The Bayer (Greek-letter) designation or Flamsteed number with standard three-letter constellation abbreviation (e.g., ZETA-CAP, 22VUL, OMICRON2-ERI-B); the Bright Star Catalog number (e.g., HR5270); other names, if they exist (e.g., CYG-X1, BARNARDS-STAR, PROXIMA-CEN).

2.	Star clusters, nebulae, galaxies, and clusters of galaxies: Commonly used names (e.g., HYADES, OMEGA-CEN, CRAB-NEBULA, ABELL63, COMA-CLUSTER); Messier numbers (e.g., M13, M31, M67).

3.2.4 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

Target Type	Code	Description
External calibration target	-CALIB	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.
Offset acquisition target	-OFFSET	A target that will be used for an offset acquisition; it is the object that will be acquired first, from which an offset will be applied to move to the target of interest (e.g., 3C273-OFFSET). 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 3.4 on page 36). For example: to observe the JET in 3C273, first acquire “stellar-like” source 3C273-OFFSET, then offset to program target 3C273-JET.
Special designations		These are reserved designations and may not be used as the names of external pointing in a target list: ANTI-SUN, ANY, BIAS, CCDFLAT, DARK, EARTH-CALIB, DARK-EARTH-CALIB, INTFLAT, KSPOTS, NONE, ORBIT-POLE, ORBIT-POLE-NORTH, ORBIT-POLE-SOUTH, UVFLAT, VISFLAT, WAVE