Changes in APT 2020.2 release

APT version 2020.1.1, was released in January 2020, and a patch release, APT 2020.1.2 was released in February in support of preliminary work toward the JWST cycle 1 call for proposals. However, a number of updates have been made for APT 2020.2, which was released to the community on March 10, 2020, and is the official APT version for Cycle 1.  This article lists the changes of most interest to the user community.

APT version 2020.2 must be used to submit all proposals for JWST Cycle 1 (the deadline is May 1, 2020). This is because APT 2020.2 includes additional timing model changes, and will be the official accounting tool for Cycle 1.  In the event of the need for any patch release (2020.2.n) between the APT 2020.2 release and the proposal deadline, an announcement detailing the changes will be made to the community.

Changes of significant interest to proposers in APT 2020.2 compared to earlier releases are listed below:

  • Overhead/Timing Changes: Additional work has occurred to improve the fidelity of overheads. APT 2020.2 may now report less "Charged Time" than in previous versions due to improved estimates of Small Angle Maneuvers (SAMs).  For example, the overhead for a 20" SAM will decrease from ~86 seconds to ~60 seconds to reflect two efficiency enhancements that will be implemented before Cycle 1 observing begins.  Observations that include many dithers or other small motions thus may see a significant decrease in charged time.

  • Changes to names of Visit Planner constraints: If you need to examine the individual constraints reported in the APT Visit Planner you will find that the constraint names and order have changed to be more readily understandable and consistent with special requirement nomenclature.  For more details, see the related Knowledge article in the JWST Help Desk.

  • Minor Changes in Graphical Timeline: Close examination of the APT Graphical Timeline compared with the previous version may show small changes in the way overheads are reported even if the total amount has not changed.

  • A New NIRCam WFSS Dither: A 2-point subpixel dither pattern has been added to the NIRCam WFSS template.

  • New NIRISS WFSS Dithers: 

    • Filter-dependent dithers have been implemented for the NIRISS WFSS template when GRISM=BOTH.

    • Optional 3-point “Direct Imaging” dithers have been implemented for the NIRISS WFSS template.

  • New Keywords: Debris Disks and Circumstellar Disks have been added to appropriate Science Keyword lists.



Latest updates

    Article updated with the release of APT 2020.2 to reflect actual changes that were implemented.

    Significant new timing reduction for SAMs added.

  • APT 2020.2 release date updated to current expectation.

    Small correction to text of 2nd bullet.