APT NIRCam Imaging JWST GTO CANUCS Dan Coe ESA/AURA Astronomer II - - PowerPoint PPT Presentation

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APT NIRCam Imaging JWST GTO CANUCS Dan Coe ESA/AURA Astronomer II - - PowerPoint PPT Presentation

Jul 08, 2023 437 likes •823 views

APT NIRCam Imaging JWST GTO CANUCS Dan Coe ESA/AURA Astronomer II NIRCam Instrument Scientist Help Desk Lead JDox Deputy Lead Dan Coe STScI 1 NIRCam Imaging Observations Pointing Exposure Times Overheads in detail for

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Dan Coe – STScI

APT NIRCam Imaging JWST GTO CANUCS

Dan Coe

ESA/AURA Astronomer II NIRCam Instrument Scientist Help Desk Lead JDox Deputy Lead

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Dan Coe – STScI

NIRCam Imaging Observations

  • Pointing
  • Exposure Times
  • Overheads

– in detail for every exposure

  • Dithering

– including proposed more efficient patterns

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Dan Coe – STScI

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Abell 370

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Dan Coe – STScI

Default NIRCam

  • bservation

centers target in gap between modules

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Special Requirement Offset (87”, 0”) to center target within module

(We will request an “Aperture” feature for offsets as in HST APT.)

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Dan Coe – STScI

Offset 87” to center target within module

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Dan Coe – STScI

Offset 87” to center target within module

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JDox: “NIRCam Apertures”

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Dan Coe – STScI

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Prime: NIRCam Imaging Parallel: NIRISS WFSS

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Dan Coe – STScI

ETC Results

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Exposure times could be adjusted to match depths

Filters paired for simultaneous

  • bservations in short and long

wavelengths

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Dan Coe – STScI

Filter Pairs

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ETC Pandeia Python engine Abell 370 2019-08-30

CANUCS APT pairing of filters: F150W – F277W F200W – F356W F115W – F444W F090W – F410M

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Dan Coe – STScI

Dither to fill NIRCam gaps

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short wavelength (0.6 – 2.3 µm) 0.0317” pixels long wavelength (2.4 – 5.0 µm) 0.0648” pixels

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Dan Coe – STScI

Fill short wavelength gaps only

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gap between modules no subpixel dithering

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Covering module gap is inefficient

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two 58” dithers (then 117” to return to beginning) I am designing a more efficient pattern…

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Dan Coe – STScI

Slew Time vs. Distance

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Extragalactic Gap between modules

new reduced times improve efficiency especially below 20” Abell 370

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Dan Coe – STScI

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Path 1

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Path 2 1

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Path 3 2 1

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Path 3 2 1 4

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Path 3 2 1 5 4

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Path 3 6 2 1 5 4 CANUCS shorter exposures with NIRISS direct images in parallel

see JDox and .pointings file

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Dan Coe – STScI

NIRCam Imaging Overheads

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Initial

16% surcharge

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Dan Coe – STScI

NIRCam Imaging Overheads

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File – Export… – times file [.times]… Initial

16% surcharge

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Dan Coe – STScI

NIRCam Imaging Overheads

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File – Export… – times file [.times]… Initial

16% surcharge

Instrument Overheads primarily slews, exposures, filter “changes”

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CANUCS NIRCam Imaging Overheads in detail

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…

11.4 total charged

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No graphical timeline yet as for HST…

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HST APT

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Dan Coe – STScI

Proposed New Dither Patterns

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  • 1. INTRAMODULEX

More compact INTRAMODULE

6” per step per axis all dithers < 20” reducing overheads

Shorter Paths 1 8 26 73 5 4

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Dan Coe – STScI

Proposed New Dither Patterns

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  • 2. BOX

Cover short wavelength gaps with 4 dithers each move 6” or so

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Dan Coe – STScI

Proposed New Dither Patterns

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  • 3. SUBPIXEL FSM

Subpixel dithering < 0.06” using the Fine Steering Mirror (without slewing)

Large enough to mitigate bad pixels in short wavelength channel

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Dan Coe – STScI

Proposed New Dither Patterns

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  • 4. BOXWIDE

Cover module gap with 4 dithers 6” and 49” moves

(49” won’t split visits for Galactic latitude > 45°)

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Dan Coe – STScI

Proposed New Dither Patterns

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5? BOXXL 62” dithers to maximize area: 6.1´ × 3.2´ useful for NIRSpec? variable size dithers?

  • ther suggestions?
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Exposure times defined by readout patterns

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Detector completes exposure 1 frame later

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Dan Coe – STScI

Consistent Exposure Times in APT 25.1 and ETC

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Example: 2 integrations, 3 groups, SHALLOW4 2 × (2 × 5 + 4 + 1) = 2 × 15 = 30 frame times = 322.1028 seconds (full detector) single frame time = 10.73676 s (ETC currently assumes 10.74 s → 322.2 total)

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Dan Coe – STScI

9 NIRCam Readout Modes

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  • M. Robberto
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Dan Coe – STScI

NIRCam Readout Modes are Familiar

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WFC3/IR Readout Mode first group (s) subsequent groups (s) SPARS5

2.932

5 SPARS10

2.932

10 SPARS25

2.932

25 SPARS50

2.932

50 SPARS100

2.932

100 SPARS200

2.932

200 NIRCam Readout Mode first group (s) (approx.) subsequent groups (s) (approx.) RAPID

10.7

10.7 BRIGHT

10.7 or 21.4

21.5 SHALLOW

21.5 or 42.9

53.7 MEDIUM

21.5 or 85.9

107.4 DEEP

21.5 or 85.9

214.7

Times for full detectors (not subarrays)