What Can You Do With SALTICAM

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• What Can You Do With SALTICAM?
• (aimed at grad students)

Darragh ODonoghue SAAO SALTICAM Principal Invest
igator
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Optical Layout at the Top of the Telescope
PFIS Slit Plane
SALTICAM
SALTICAM fold mirror
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SALT Layout atTop of Telescope
RSS/PFIS
Salticam
Salticam
Salticamfold mirror
Spherical aberration corrector
Light fromprimary mirror
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SALTICAM (in here)
SAC
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SALTICAM Major Components
Optics
Cryostat detector
Filter jukebox
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• Available filter sets
• UBVRI
• Sloan
• Stromgren

Up to 8 filters at a time
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• THE 2 SALTICAM CCDs (at installation)
• 180 k of silicon

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The need for optics mapping the field of view
onto affordable silicon










ScienceFoV(8 arcmin)
CCD1 CCD2
GuideStarFoV (outer 1arcmin)



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Architecture of a single CCD

IMAGE AREA Frame Transfer
boundary STORE AREA
vertical clocking
vertical clocking
Split readout register
Readout Amp 1
Readout Amp 2
50 pix
50 pix
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Typical SALTICAM Data Frame
Vignettingbycryostatwindow
Badcolumn
Amp2
Amp3
Amp4
Amp1
Bias/overscan strip foramps 2 3 physical
gap
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Typical Applications
Colour-Magnitude Diagrams
GlobularclusterM5
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Variability Studies SNe etc.
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• Science Applications
• Supportive of programs on RSS/PFIS and other
  facilities
• Queue-schedule advantage variability
• High-time resolution

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• What are the major considerations?
• Efficiency max shutter-open time andloss of
  light in the instrument
• Image quality for maximum contrast against the
  background sky

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Throughput
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Throughput
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• Technical Specifications/Details
• http//www.salt.ac.za/telescope/instrumentation/sa
  lticam/

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• Signal To Noise Calculations
• Signal
• Photons From Target
• Noise
• Photons From Sky underneath the target
• minimize by going for dark time
• minimize by best image quality (seeing)
• CCD detector readout noise
• minimize by using least number of pixels (by
  prebinning)
• S/N Target photons
• ___________________________________
  _

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• Signal To Noise Calculations for U B V R
  I 20

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• Gain and Readout Speed Considerations
• Gain
• Faint for the faintest targets
• Bright for brighter targets
• Readout Speed
• Slow less readout noise
• usual mode
• Fast more readout noise
• if you need the time resolution

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For High Time Resolution (seconds)Frame
Transfer Operation Is Needed
At the end of each exposure, rapidly transfer the
image from the image section to behind the
mask section and read out during the next
exposure
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• CCD Performance

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Highest time Resolution astronomy 100
millisecond resolution studies of eclipses,
QPOs and other short timescale phenomena.
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• Frame Transfer Mask in Slot Modefor 0.1 sec
  sampling

Image/store area Split

Serial Readout Registers
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• Frame Transfer Mask Slot Mode

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Slot Mode Control
(a)
(b)
(c)
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• Total cycle timewill be 0.10 or 0.25 sec.

Slot Mode Mask
Slot Mode Vignetting
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RSS/PFIS highest time resolution slot similar to
SALTICAM
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PFIS Fast Spectroscopy

• PFIS Slot mode
• Slot in telescope focal plane
• placed just above frame transfer
• boundary
• Do 2 x slot width row transfers
• (discard smeared rows)
• This example has 204 px slot
• (27 arcsec), each shifted 408
• rows at a time.
• Expect to run at gt76 msec integrations with 6
  msec deadtime (row transfers)
• fast spectroscopy
• fast spectropolarimetry

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Driftscanning
Vertical clocking of rows at same rate star
drifts down chip

• 100 per cent shutter open time
• Tracker stationary
• Maximum primary mirror area

Horizontal clocking after each individual
vertical transfer
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• Salticam Upgrade
• Minor fixes of mechanical issues
• Software upgrade
• Installation of autoguider
• Delayed due to the instrument being needed for
  image quality investigation