For This Session You Will Need: A recent version of the - - PowerPoint PPT Presentation

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For This Session You Will Need: A recent version of the - - PowerPoint PPT Presentation

Feb 21, 2024 222 likes •521 views

For This Session You Will Need: A recent version of the Astronomers Proposal Tool (APT): Google Search JWST APT or go to http://www.stsci.edu/hst/proposing/apt The Coronagraph Visibility Tool (CVT): Google Search JWST

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SLIDE 1

For This Session You Will Need:

  • A recent version of the Astronomer’s Proposal Tool

(APT): Google Search “JWST APT”

  • r go to http://www.stsci.edu/hst/proposing/apt
  • The Coronagraph Visibility Tool (CVT):

Google Search “JWST CVT”

  • r go to https://jwst-

docs.stsci.edu/display/JPP/JWST+Coronagraphic+Visibi lity+Tool+Help

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SLIDE 2

Implementing Coronagraphic Observations in APT

Chris Stark

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SLIDE 3

3 Tools You Will Want for Coronagraphic Observation Planning

JWST Exposure Time Calculator (ETC) JWST Coronagraph Visibility Tool (CVT) Astronomer’s Proposal Tool (APT)

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SLIDE 4

3 Tools You Will Want for Coronagraphic Observation Planning

Recommended Sequence:

  • 1. JWST Coronagraph Visibility Tool

(CVT)

  • 2. JWST Exposure Time Calculator

(ETC)

  • 3. Astronomer’s Proposal Tool (APT)
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SLIDE 5

Step 1: JWST Corongraph Visibility Tool (CVT)

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SLIDE 6

Allowable JWST Orientations

Solar elongations from 85° – 135°

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SLIDE 7

Rotating about Sun axis forms stripe on ecliptic sphere

Creating a PA Visibility Tool

Allowable JWST Orientations

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SLIDE 8

Visibility Depends on Ecliptic Latitude 2 Semi-Annual Viewing Blocks 1 Annual Viewing Block Continuous Viewing Zone

Creating a PA Visibility Tool

V3 PA varies over the course of a viewing block

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SLIDE 9

Allowable JWST Orientations

Solar elongations from 85° – 135°, V1 roll angles range from ±3.5° to ±7°

±7° ±3.5°

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SLIDE 10

Example of 1 Annual Viewing Block

HD 10647 Wide range of possible PAs

Observable Window Solar Elongation Allowed PAs

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SLIDE 11

Example of 2 Semi-annual Viewing Blocks

HD 141569

~14° ~7°

Limited range of PAs, larger roll dither allowed at elongation ~ 135°

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SLIDE 12

Let’s Use the CVT!

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SLIDE 13

Step 2: JWST Exposure Time Calculator (ETC)

(Discussed yesterday)

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SLIDE 14

Step 3: Astronomer’s Proposal Tool (APT)

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SLIDE 15

Guidelines to Follow:

  • 1. Thou shalt observe your science target at 2 roll

angles, differing by at least one degree (a “roll dither”)

  • 2. Thou shalt observe a reference star to measure the

PSF (for PSF subtraction by the pipeline)

  • 3. Thou shalt make these a non-interruptible sequence.

Figure credit: M. Perrin

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SLIDE 16
  • 1. Thou shalt observe your science target at 2 roll

angles, differing by at least one degree (a “roll dither”) Mitigates bad pixels in science image Rotates speckles wrt astrophysical scene

Guidelines to Follow:

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SLIDE 17

Guidelines to Follow:

  • Increases contrast by subtracting reference PSF from science

image

  • Reference PSF star should be uncontaminated
  • Reference PSF should be close in spectral type (see supporting

docs)

  • Reference PSF should be bright (shorter exposure time)

Rf PSF hld b l t th i tt ( h t

  • 2. Thou shalt observe a reference star to measure the

PSF (for PSF subtraction by the pipeline)

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SLIDE 18

Guidelines to Follow:

PSF spectral type selection guidelines: a future JDOX page Currently at http://www.starkspace.com/JWST_PSF_references.pdf

Jarron Leisenring

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SLIDE 19

Guidelines to Follow:

  • Reduces PSF changes between science and reference
  • bservations; higher contrast
  • Science target & reference must be simultaneously visible
  • 3. Thou shalt make these a non-interruptible sequence.
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SLIDE 20

The Basic Coronagraphic Sequence

Obs # Target Roll Inst Mask Filter 1 Science θ0 2 Science θ0 + ∆θ 3 Reference N/A

Non-interruptible

Figure credit: M. Perrin

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SLIDE 21

A Multi-Filter Coronagraphic Sequence

Obs # Target Roll Inst Mask Filter 1 Science θ0 NIRCam 210R F182M, F210M 2 Science θ0 + ∆θ NIRCam 210R F182M, F210M 3 Reference N/A NIRCam 210R F182M, F210M

Non-interruptible

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SLIDE 22

A Multi-Instrument Coronagraphic Sequence

Obs # Target Roll Inst Mask Filter 1 Science θ0 NIRCam 210R F182M 2 Science θ1 MIRI LYOT F2300C 3 Science θ0 + ∆θ NIRCam 210R F182M 4 Science θ1 + ∆θ MIRI LYOT F2300C 5 Reference N/A NIRCam 210R F182M 6 Reference N/A MIRI LYOT F2300C

Non-interruptible

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SLIDE 23

A Multi-Epoch Coronagraphic Sequence

Obs # Target Roll Inst Mask Filter 1 Science θ0 NIRCam SWB F210M 2 Science θ0 + ∆θ NIRCam SWB F210M 3 Reference N/A NIRCam SWB F210M 4 Science θ1 NIRCam SWB F210M 5 Science θ1 + ∆θ NIRCam SWB F210M 6 Reference N/A NIRCam SWB F210M Non-interruptible Non-interruptible

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SLIDE 24

Let’s Use APT! Walk-through #1:

Create a basic coronagraph sequence for GJ 758 using MIRI Lyot mask

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SLIDE 25

Let’s Use APT! Walk-through #1:

Create a basic coronagraph sequence for GJ 758 using MIRI Lyot mask

Independent Task:

Add observations using MIRI 4QPM/1065 mask

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SLIDE 26

Let’s Use APT! Walk-through #2:

Create a basic coronagraph sequence for Beta Pic disk using NIRCam 210R mask + F210M filter

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SLIDE 27

Let’s Use APT! Walk-through #2:

Create a basic coronagraph sequence for Beta Pic disk using NIRCam 210R mask + F210M filter

Independent Task:

Add observations using SWB mask + F210M filter

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SLIDE 28

Let’s Use APT! Walk-through #3:

Make a multi-epoch NIRCam SWB

  • bservation of Beta Pic
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SLIDE 29

Overheads & Efficient Observing

  • Visit-level overheads can be seen in the Form Editor view by

clicking on a single visit (expand observation folder, then expand the observation)

  • Detailed overheads can be seen by exporting a .times file