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)