The Morehead Saga
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Transcript of The Morehead Saga
The Morehead Saga
(Frustrating) Tests of Integral Field Hexabundles for SOAR
Speeding up 4m telescope for $300K or $10K or …
$75K ResearchCorp. (1st phase)
Hexabundles
Fusing will trigger FRD
Deployable IFU
• Four 4.5” diam. IFUs rove 10’x5’ >50” apart– Each fused bundle -> single fibers (U. Sydney collab.)– Each 61 fibers 0.45”– Measured 75% filling, 95% soon
Prototype issues to fix• Non-telecentricity & FRD
(f/16.5 -> f/10) 0.”3 to 0.”45/pix
• Scattered light & cross-talk
• Positioner servo accuracy ok?– 0.3x0.9 arcsec2 error ellipse– Test jig ready to measure
• Fiber routing/handling (presently just break fibers )
$45 5-mm diam.achromat
bundle
Probe near centre vs edgeof 10x5’ fov
Layout
Lucky ImagingEMCCD acquisition/skymonitoring camera
Gantry for Goodman
Mounting fiber slit blocks• Interleave spectra from 4 blocks, total 61• 3 broken fibers, a dozen diminished throughput
Goodman “slit” now 100 microns wide -> higher spectral R
Fibers
Back illuminating
Mangling a spectrograph• Remove cal lamp, slit,
decker, off-slit viewer• Add fiber bundle feed
through top, attach bundle to Morehead f/13.5 Cass.
• Apogee 1530x1024 CCD covers 21“ diam @ 2.4”
Long slit mode
Fibers: dispersed daylight
= sunlight (+ O3 + … )
Test on stars, Pne, mosaic to 1x1’ on Orion … But spectrograph very slow (collimator unreflective)