< Back to All Articles

Preparing Observations for HST and JWST: Getting to know the Observation Planning Branch

D. Taylor (dctaylor[at]stsci.edu)

The primary task for the Observation Planning Branch (OPB) is to implement and assist in the planning of observing programs for HST and JWST. Each of the members of OPB are assigned to this task for either or both missions, in their role as Program Coordinators (PCs). PCs serve as the primary point of contact between investigators and STScI, assisting investigators in creating their observations through the Astronomer's Proposal Tool (APT) while ensuring that the specified observations are technically feasible to execute onboard the observatories.

The proposal pathway

Figure 1: The Life Cycle of a Hubble/Webb proposal. OPB focuses on proposal implementation and assisting SMSB with the Long Range Plan and Short Term Scheduling.​​​​

Programs for HST include General Observer programs, SNAPshots, calibrations, Director's Discretionary programs and Target of Opportunity programs. For JWST, PCs are currently working on Guaranteed Time Observer programs, Commissioning programs, Early Release Science programs, and programs used in rehearsals and testing; General Observer programs for JWST will be chosen in 2020 and will be assigned to the PCs at that time. The PCs implement all of these programs, verifying that each program contains only the targets, instrument configurations, scheduling constraints, and total observing times that were approved by the appropriate committee, usually the Time Allocation Committee for each observatory. PCs resolve any scheduling issues with observations that may exist at the time of submittal, typically due to timing constraints; however, for HST programs, guide star availability is also a factor that investigators cannot determine, so PCs must work alongside them to rectify any problems. Additionally, PCs work with the Long Range Planners (LRP) and Short Term Schedulers (calendar builders) to resolve scheduling conflicts between programs, conferring with investigators when program changes are needed.

Program Coordinators have developed a wide range of skills and specialties while working on observing programs and in developing tools to make their work more efficient and less error-prone.

Elizabeth Nance handles some of the HST observations that must be coordinated with other observatories for execution times. Coordinated observations can be approved by Hubble to grant another observatory’s (Chandra, XMM, ALMA, etc.) time or vice versa, and Hubble usually drives the scheduling for both (or more) observatories involved because its scheduling parameters are highly constrained. This scheduling involves input from the other observatories, the Principal Investigator (PI), the LRP, the HST calendar builders and even the HST mission office in some cases; this may result in some much needed compromise from all parties, but the end objective is to achieve the PI's science goals as close to the originally accepted program as possible. Elizabeth, in cycle 26, was responsible for the communication between ALMA, XMM, and Chandra for one single simultaneous observation program! In addition to the work of getting the HST program ready to be observed, she had to make sure the other three observatories were all on the same page for timing constraints. Coordinated observation programs require most of the work to be done as soon as possible by both the PI and PC to make sure that the time on the requested observatories is available and no reprioritizations by the mission office are required before it is scheduled to fly.

Bill Januszewski certainly knows about coordinating HST observations, too. Over the last four cycles, Bill has implemented and planned seven programs totaling 319 orbits that have been coordinated with the Juno spacecraft now in orbit around Jupiter. These observations started in cycle 23 with HST observations timed to occur as Juno passed through Jupiter's intense magnetosphere, and a few weeks later after it entered orbit. In cycles 24, 25, and 26, additional proposals were approved to continue the unique science enabled by having a spacecraft provide up-close details about Jupiter and its environment, while HST provides the "big picture" to put the Juno data into context. In September 2019, the last of these coordinated observations took place near closest approach of Juno's 22nd orbit.

Alison Vick also implements observations of Solar System bodies. Alison specializes in preparing observations of close-approach, fast-moving targets. Moving targets closer than 0.25‑AU from Earth need special attention to decide if their motion requires any special handling, such as special guiding considerations; and targets closer than 0.05 AU must use HST-centric parallax instead of the default Earth-centric parallax. When HST-centric parallax is necessary, Alison must use special processing overrides, as well as generating customized HST orbit-crafting to match the apparent motion of the fast-moving body.

Due to HST's positioning outside of Earth's atmosphere, it is capable of taking extremely accurate measurements of planets orbiting far-off stars. As such, HST is highly sought after for its ability to image transiting exoplanets in addition to Solar System planets. Exoplanets offer some unique challenges to the implementation, planning and scheduling teams, as Wes Eck well knows. An exoplanet's orbit around its host star must be carefully aligned with Hubble's own orbit in order to fully capture the transit of the planet. Should the observation be mis-timed by even a few minutes, the observations may fail and another opportunity may not be available for years. Wes has worked intensely on these observations, collaborating with the LRP group to determine the perfect windows for observing, and running test schedules to verify the timing of the observations for the Principal Investigators.

But HST observes more than planets! Every cycle brings observations of fascinating objects, including objects that can cause health and safety issues with some of the onboard instruments, when a too-bright source could permanently damage a detector. Amber Armstrong worked with the Cosmic Origins Spectrograph (COS) instrument group to develop and specialize in the COS Safe Target Offset Procedure. This procedure is used whenever a PI proposes to observe targets subject to infrequent or unpredictable outbursts that would exceed the brightness limits of the instrument, should they occur during the observation. The observation is set up so that the telescope can be pointed to a safe part of the sky until the PI provides information that the intended target is not too bright to observe. Amber collaborates with a COS instrument scientist to determine that safe position, and incorporates it into the observing program. The intended target must be determined to be safe for COS within 24 hours of the scheduled observation. The telescope will be able to be commanded to the target at that time. Otherwise, HST remains pointed at the safe part of the sky for the duration of the observation, ensuring no harm comes to the COS detectors.

There are also special, very large, observing programs that are occasionally awarded time by the STScI Director. These have included the Multi-Cycle Treasury programs, the Frontier Fields program, and the upcoming ULLYSES program. These are the favorites of Tricia Royle. Her specialty is large, multi-cycle programs that usually require intricate scheduling over several epochs, often with complicated links or timing constraints requiring some creativity in finding solutions and new scheduling methodologies. Tricia’s years of experience have taught her how to manipulate programs and the HST ground system software to safely and successfully implement these programs. She enjoys the challenge these programs present with complex observing strategies, the familiarity with observers the program allows over multiple cycles of working together, and the long-term focus these programs require to maximize science and scheduling, epoch after epoch, on a changing telescope.

Along with a variety of primary observations on HST, parallel observations can also be performed using separate instruments from the primary. Parallel observations can be included in the same program as the primary observations as Coordinated Parallels. Parallel observations can also be submitted as separate programs to be matched to existing primary observations as Pure Parallels with specifications given for the desired locations, durations, and instrument configurations to be obtained. Shelly Meyett specializes in these pure parallel observations. The Pure Parallel observing process is designed to take advantage of the full complement of instruments currently operating on HST. These observations are designed to use ACS/WFC and/or WFC3 on an area of the sky, then matched, structured and scheduled simultaneously with COS and STIS prime observations that fit the requested parameters. Shelly works with the PIs of the pure parallel programs to determine the matching opportunities each cycle and prepares each parallel observation for execution.

Denise Taylor, as OPB Branch Head and the team’s Technical Lead for HST, provides administrative assistance as well as program implementation. She serves on the HST Telescope Time Review Board (TTRB), reviewing and commenting on program change requests, requests for repeat observations, and requests for observation duplication reviews. Denise also records the TTRB decisions in the proposal tracking database for use by the PCs. She provides advice on policy and procedures, assigns programs to each PC, creates the program IDs for approved programs, and provides program reports to INS and Grants when requested.

OPB members spend as much time working on the JWST mission as they do on the HST mission. Tony Roman, Deputy Branch Head of OPB, serves as the JWST Technical Lead for the team. Tony leads OPB's efforts to implement JWST observing programs for science, commissioning, and calibration. He assigns programs to the PCs as well as advises them on policy and procedures for JWST program implementation. Tony determines the schedule of PCs to support the numerous operational rehearsals that will be executed before the launch of JWST in 2021. He reports monthly to the JWST Mission Office on the progress and status of tasks assigned to OPB. Tony has also organized OPB members to provide training with APT for future JWST observers at the American Astronomical Society meetings and the Division of Planetary Sciences (DPS) meetings, as well as for the JWST Master Class training held at STScI and ESAC. Tony's years spent implementing Solar System observations for HST led to his interest and participation in the DPS, where he now serves on the Leadership Committee.

While Tony may be the JWST Technical Lead, Beth Perriello leads the JWST commissioning efforts for the OPB branch, overseeing the creation and processing of over 180 programs that will be used during the commissioning of JWST. In addition, she, along with the Institute JWST commissioning lead, Scott Friedman, runs the Program Implementation Team (PIT) meetings. PIT meetings are held to review each program and verify that the programs will complete the goals outlined in the commissioning activity requests. Beth also informs the PCs of the programs that are needed for each rehearsal, and advises on the proper implementation for them, ensuring the software and environments are ready for the programs when needed.

The PC team as a whole participates in JWST commissioning rehearsals occurring in the JWST Mission Operations Center. Blair Porterfield often finds herself working different shifts to staff the Science Operations Center while supporting these rehearsals. She makes changes to programs in real time during the rehearsals, conferring with instrument scientists and schedulers to determine their immediate observing needs. She then processes the changes and generates the products needed for the rehearsal to continue. Blair and other PCs will continue this shift work up to and during the actual commissioning of JWST in 2021.

Outside of explicit program implementation, members of OPB also use their programming skills on tools for the team and tools provided to observers. Crystal Mannfolk maintains a number of web interfaces that help observers keep track of their programs. One of these is a web tool that allows observers to make major change requests, report observation problems, and to report observation duplications directly to the TTRB. This tool uses a web form that can be filled out and submitted by observers to a CGI-based python script that uses the JIRA python module. The script then creates the request in JIRA as a new issue, which can be reviewed by the TTRB. The JIRA python module is extremely useful for interfacing with JIRA; it is used to track releases and changes to the HST and JWST Operations databases. Crystal is also one of the primary people who maintains and updates tools used by the PCs to carry out their implementation and planning tasks.

Alison Vick assists the LRP group every year by generating a long-range plan based on the HST Phase Ⅰ proposal submissions. This plan is used by the STScI Director to determine if any of the TAC-approved programs will have any obvious conflicts or scheduling difficulties, especially the Large programs consisting of more than 75 orbits of HST observing time. If any issues are found, the assigned PCs can begin working with PIs and the HST Mission Office immediately after notification to resolve any problems.

Michael Leveille has provided his talents to the WASABI team to develop automated tests for their web applications (e.g., STGMS, ProPer) using Robot Framework. These tests are designed to simulate a user interacting with a web app, and can be run either locally with a GUI browser or in a GitLab runner environment using a headless browser. They have developed tests for actions such as editing and submitting a budget and submitting interim financial reports (IFRs).

The OPB work is mainly centered around JWST and HST; however, the PC team is just beginning to support the WFIRST mission. Crystal Mannfolk leads this effort with the development of the proposal planning and scheduling database for that mission. Program implementation for WFIRST will be one of the future tasks for OPB.