‘Alopeke

evolution of an instrument line and new capabilities

Nic Scott

NASA ARC

SEG 2018

Labeyrie

1970

Text

 long exposure

speckles blur

produce Airy pattern

true images are impossible, only centrosymmetric objects can be reconstructed

speckle pattern is the Fourier transform of telescope pupil

Fourier autocorrelation of speckles

modulus

(time-averaged intensity)

Weigelt & Lohmann

1977-1983

double star simulation

bispectrum modulus

triple correlation

record PSF of object

produce synthetic reference star by shifting the speckle pattern

phase is preserved

Speckle masking/triple correlation theory/bispectral analysis, a 3rd order correlation

deconvolve

  true images

1s

40s

20min

Publications

Text

blue bars are refereed citations to refereed papers

green bars are non-refereed citations to refereed papers

SAO/NASA ADS “Bumblebee” search: ‘‘speckle’’ - ‘‘speckle noise’’

  • limited to astronomy and refereed
  • removed AO speckle noise references
  • excluded AO and spectroscopic techniques
  • constrained to 1970+ sorted by citation count

This search returned 1,139 papers with 24,181 total citations

rise of EMCCDs  & start of large speckle survey programs (& Kepler)?

Title Text

Text

DSSI/NESSI/`Alopeke/Zorro

mag limit ~17

0.011'' @u

0.026'' @832nm

0.025'' @u

0.060'' @832nm

6.7''

60''

19''

56''

672.9

11

15

17

22

26

mas

  • Quad 6 -channel
  • Wave-front sensing
  • 2 near-IR channels
  • DSSI heritage at the DCT+NPOI
  • novel construction

QWSSI ?

van Belle

Science Programs

40 total proposals

110.04 total nights

(NOAO 2016A to 2018B)

NEAs

  • sizes
    • radar typically quotes 40% uncertainties
    • albedo/radar size mismatch
  • shapes
    • adapt stellar surface modeling tools
    • light curve inversion/illumination model 

a~2.8AU

d~270km x 80km

(neck~50-65km)

model: Franck Marchis

Phaethon

Dec 2017 ~ 0.07AU

d~6km

Point source PS

Phaethon power spectrum (resolved)

Pluto opposition

SOFIA occultation target duplicity

WF and speckle optics

Conv and EMCCD imaging

466/832 and g/i filters

New Horizons (not us.....yet)

TNO Varda ⌀~700km, d~50au

multiplicity is the single largest source of error to occultation path prediction

Open to the community

  • NOAO proposal process
  • NESSI - WIYN@KPNO
  • `Alopeke - Gemini-N
  • DSSI -> Zorro - Gemini-S
  • Transitioning from visitor to ''Resident'' instrument

backup slides

  • Constrain NEA diameters. Image SS objects
  • Determine multiplicity of nearby K and M-dwarfs, does it vary across spectral type?
  • Imaging of brown dwarfs and distant large planets, particularly around M dwarfs
  • Investigate differences in planetary system architectures between multiple vs not (known) multiple host stars
  • Examine long-term RV trends/determine binarity of RV planet hosts.  
  • K2, TESS follow-up
  • Provide an unbiased sample for TESS, so statistical determinations of planet occurrence rates can be made
  • Occultations, transit photometry, pulsar time scales, observe pulsating WDs at high cadence

Some proposals so far:

Seeing-limited

Reconstructed

42''

Two-color wide-field speckle reconstruction

from NESSI

  • 0.25'' resolution from 500 frames (20s)
  • compromise b/t angres and contrast
  • Seeing ~ 0.85''

Urban telescope WF speckle

 Wide-field speckle techniques for small, urban telescopes, Nicole M. Granucci, Elliott P. Horch, Southern Connecticut State Univ. (USA)  talk Tues (coming up next actually)[10701-20]

Knox & Thompson

cross-spectrum, a 2nd order correlation

1974

non-symmetric input

long exposure avg

Labeyrie technique

Knox & Thompson method

mean square of the image transform

modulus of the object transform

autocorrelation of the image transform

phase of the object transform

diffraction-limited image of the object

+

An aside on Lucky Imaging

  • reaches higher resolution than typical seeing
  • does not utilize Fourier analysis
  • not capable of reaching the diffraction limit
  • requires a very large number of  images

http://inspirehep.net/record/823349/plots

Fried

1978

record a large series of images

discard instances of poor resolution

combine the remainder through shift-and-add techniques

Can reach high angular resolution and is often confused with speckle imaging.

‘Alopeke - evolution of an instrument line and capabilities

By Nic Scott

‘Alopeke - evolution of an instrument line and capabilities

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