Generic Targets

The Generic Targets form is used to specify generic targets in some JWST observations. The Astronomer’s Proposal Tool (APT) is used to enter the targets into the proposal.


Purple text indicates the parameter is Limited Access.

Boldface italics type indicates the name of an APT parameter or a value for a parameter.

(warning)Red text indicates restrictions on a parameter.

(red star) Black text indicates an important note.

Brown text indicates notes for the developers.

Green text indicates the name of the parameter used by Commanding.

Items in brackets - <value> - are required values.

Items in square brackets - [<value>] - are optional.

Generic targets are those that can only be described in terms of astronomical characteristics or a general location in the sky, and may be used when the target will be specified at a later date (for example, Targets of Opportunity or Solar System Targets).

Observations using Generic Targets must have either an ON HOLD or a TARGET OF OPPORTUNITY special requirement. In this case the generic target should be replaced by a fully specified target when the ON HOLD is removed.

(warning)The following timing special requirements – AFTER (<date> only), BEFORE , BETWEEN, and PHASE/PERIOD/ZERO-PHASE – are not allowed for generic target observations. The APERTURE PA special requirement is also not allowed for generic target observations. Timing and Position Angle links are not allowed between generic target observations and non-generic target observations.


Each target in your proposal will be assigned its own unique number (which can be changed by the user) by APT (they go from 1 to 999).

Name in the Proposal 

NAME IN THE PROPOSAL provides a unique designation for a target for use throughout the proposal, and should be a descriptive name of the object; use a short text description either of the target location (e.g., RANDOM-FIELD) or of the target itself (e.g., NEXT-SUPERNOVA, NEW-JOVIAN-MOON). If a name cannot be specified in advance, a provisional name should be supplied. When the actual target is determined, a new fixed or solar system target will be added to the proposal.

(warning) The following restrictions should be noted for the target name in the proposal:

  • The length of a target name can be anywhere from 2 to 31 characters.
  • Only upper and lower-case letters, numerals, '.', '+', '_' and '-' are allowed.  Spaces are not allowed.
  • Two targets may not have the same name with different cases.

Target Description 

Depending on the type of target you are using, follow either the Fixed  or Solar System target instructions.


The Criteria field is where you describe your Generic Target. Examples are “Next SN in M31”, “Next bright, galactic nova”, or “GRB at z>5”.


This (optional) field should include in words what you are trying to define by coordinates.

Change log


    1. PROPINSTJWST-91578 Updated Introduction section to include TARGET OF OPPORTUNITY requirement.

February 28, 2023

  1. PROPINSTJWST-91555 Updated text entry constraints in the NAME IN THE PROPOSAL section.

Version 3 (April 16, 2019)

  1. Editorial change (moved change log to main article)

Version 2 (October 6, 2016)

  1. PR 85913 - removed strikethrough on text for the target description

Version 1 (June 16, 2016)

This is the converted Word File from Chapter 3.