Step-by-Step APT Guide for NIRISS AMI Observations of Extrasolar Planets Around a Host Star
Instructions are provided for filling out the AMI observing template in the Astronomer's Proposal Tool (APT) for the JWST NIRISS AMI Example Science Program.
The Astronomer's Proposal Tool (APT) is used for submitting JWST proposals. There are multiple components to an APT submission: generic proposal information, target information, and exposure specifications for the proposed program. This guide discusses how to fill out the APT observing template for the "NIRISS AMI Observations of Extrasolar Planets Around a Host Star" Example Science Program.
A filled out APT file can be downloaded here for reference. The APT file was created with version 27.1. There may be inconsistencies or additional warnings or errors with other versions of APT.
Fill out Proposal Information
Main article: JWST Astronomers Proposal Tool Overview
After opening APT, we selected "New JWST Proposal" under the "New Document" pull-down menu. On the Proposal Information page, we entered Title, Abstract, and Category of proposal and kept Cycle number at its default value. We updated Scientific Category to Planets and Planet Formation and added the following Science Keywords: Exoplanet Host Stars,Extrasolar Planets, and Giant Planets.
Note that APT issues errors in the Proposal Information page since Category is set to GTO (which is reserved for GTO proposers whose programs should already be marked as approved in the proposal database) and a PDF science justification is not uploaded. For the purposes of this tutorial, it is fine to ignore these warnings. However, for proposals submitted in response to the Call for Proposals, ensure the Category field is correctly set and that you upload a PDF of your science justification prior to submission.
Enter Proposed Targets
Target information is entered by selecting Targets in the Tree Editor, which provides options in the Active GUI window. If a target has significant proper motion (> 10 mas /yr), we recommend fetching the coordinates and proper motion from the Gaia DR2 archive and inputting this information manually into APT. Note that the coordinate epoch from Gaia is 2015.5, so this needs to be added into the Epochbox.
We chose the New Fixed Target button so that we could add in the Gaia coordinates (J200 CoordinatesRA = 23 07 28.8327; Dec = +21 08 2.53) and proper motion (Proper Motion RA = 108.30 mas/yr; Dec = -49.48 mas/yr). We updated the Category to Star and inserted Exoplanet Systemand F starsinto the Descriptionbox.
We created a New Fixed Targetfor the PSF reference star (HD 218172) and entered the Gaia coordinates (J200 CoordinatesRA = 23 05 35.3371; Dec = +20 14 27.69) and proper motion (Proper Motion RA = 7.81 mas/yr; Dec = 20.86 mas/yr). We updated Categoryto Calibrationand added Point spread function to Description.
We note that by clicking on Target Confirmationin the Top Tool Bar, you can create target confirmation charts to verify that the target coordinates are correct and the telescope will be positioned in the expected place. The observations can be visualized onto various sky location using the Aladin visualization tool.
Main article: APT Observations
Selecting Observations in the Tree editor, we clicked on the New Observation Folder, and in the Label field, we entered Exoplanets in HD 218396 with NIRISS AMI.
Create Observation for Source (HD-218396)
We next clicked Observation 1 in the Tree editor to open the observation template in the Active GUI window. In the Instrument pull-down menu, we selected NIRISS, and then selected the NIRISS Aperture Masking Interferometry template in the Template pull-down menu. Note that only parameters of interest to NIRISS AMI are shown in the GUI. In the Target pull-down menu, we selected HD-218396 which we defined above. We added HD-218396 into the Label field.
Create Observation for PSF Reference Star (HD-218172)
We returned to the observation template and clicked Addto create an observation template for the PSF reference star. Similar to the steps above, we selected NIRISSfrom the Instrumentpull-down menu and selected the NIRISS Aperture Masking Interferometrytemplate. In the Target pull-down menu, we selected HD-218172. We added HD-218172 into the Label field.
Complete APT Observation Template for NIRISS AMI
Fill out APT Template for PSF Reference Star (HD-218172)
For this science program, we perform the TA on the target, so in the NIRISS AMI APT Observation Template we kept the acquisition target in the Target ACQ pull-down menu at its default value of SAME TARGET AS OBSERVATION. Using the results from the ETC calculations, we selected AMIBRIGHT for Acq Mode, NISRAPID for Acq Readout Pattern, and 5Acq Groups/Int. For your own tracking purposes, it is recommended you include the ETC workbook and calculation ID number in the Acq ETC Wkbk Calc ID field so the TA SNR calculations can be verified by Instrument Scientists during technical reviews after the proposal is accepted. In this example, we do not include an ETC workbook ID number in the provided APT file since a unique ID number is generated when an example workbook is added to a user's list of workbooks.
We selected NONE for both Primary Dithers and Subpixel Positions, and selected the SUB80 Subarray. We selected the F480M Filter and updated Groups/Int to 40 and Integrations/Exp to 2849,based on our ETC calculations; the only available Readout Pattern is NISRAPID since we chose a subarray.
We selected Falsefor Direct Image since we are not taking a direct image with this program. In the PSF Reference Observationsbox, we click the checkbox next to This is aPSF Reference Observation.
Fill out APT Template for Source (HD-218396)
Similar to the PSF reference star, we perform target acquisition on the source, so we choose SAME TARGET AS OBSERVATION in the Target ACQ pull-down menu. We selected AMIBRIGHT for Acq Mode, NISRAPID for Acq Readout Pattern, and 3Acq Groups/Int,based on results from the ETC calculation.
We selected NONE for both Primary Dithers and Subpixel Positions, and selected the SUB80 Subarray. We selected the F480M Filter and, based on our ETC calculations, updated Groups/Int to 23 and Integrations/Exp to 2934; the only available Readout Pattern is NISRAPID since we chose a subarray.
We selected Falsefor Direct Image. In the PSF Reference Observations box, we selected the checkbox next to HD-217783 to associate the target with the PSF reference star so that the JWST pipeline will calibrate HD-218396 with HD-218172.
Define Special Requirements
Main article: APT Special Requirements
Run Visit Planner
Main article: APT Visit Planner
The APT Visit Planner checks the schedulability of an observation and whether guide stars can be found to support the observation. To check the schedulability of these linked observations, we made sure one of the observations was selected in the Tree editor, we clicked on the Visit Planner icon in the Top Tool Bar, and then clicked on Update Displayin the Active GUI. The Visit Planner returned with a confirmation that the set of observations is schedulable (green check next to both observations).
Run Smart Accounting
Main article: APT Smart Accounting
To minimize excessive overheads, we ran Smart Accounting from the Visit Planner page by selecting the Run Smart Accounting option. The charged time for the observing program, including exposure time and overheads, is now accurately calculated.