MODS1 Commissioning Run 7: UTC 2011 April 16

Observer(s): R. Pogge, R. Stoll (OSU), E. Skillman (UMinn), M. Fumana (INAF), M. Wagner, O. Kuhn, J. Hill (OSU/LBTO), M. Trueblood (NOAO/TSIP)
Telescope Operator: G. Bechetti (LBTO)
AO Support: Remote from Tucson as needed
Telescope Support: J. Urban (LBTO)
Instrument Support: D. Officer (LBTO)


Worked all night, gorgeous seeing: 0.5-0.8 arcsec, typically around 0.7. Clear skies after a band of cirrus at sunset, but increasingly bright moonlight. System worked beautifully, no telescope or instrument downtime.

Demonstrated operation of MODS1 to Mark Trueblood from NOAO/TSIP (one of the major grant sponsors of MODS2) and he went away impressed.

Heavily exercised slit and MOS acquisition, and pushed into more tricky acquisition scripts, including doing blind offsets after presets to nearby "reference" stars.

Overall a highly successful night!


No special preparations tonight. Some small bug fixes/enhancements in the scripting engines.

Mark Trueblood from NOAO (TSIP program) is here for the first part of the night to see MODS1 in action on the sky.


All times are UTC unless otherwise noted.

0140 - Some thin bands of cirrus at sunset, but otherwise calm winds and clear above the cirrus bands. Warmer than yesterday, so it looks like the high-pressure system is starting to settle in for the weekend.

After sunset ran a series of twilight sky flat fields in imaging mode to get the internal flat field illumination gradient corrector frames. Also shot a twilight sky spectrum in the 1.2-arcsec segmented long slit (LS5x60x1.2)

0236 - Pointing star

Collimation star: BS9134. 0.7 arcsec seeing and 200nm rms WFE, nice convergence.

0255 - Stone F multi-object mask acquisition. Used to demo the alignment procedure for Mark Trueblood.

0310 - SN1999as - faint long-slit target, seeing 0.6 arcsec (hooray!), alignment with fuzz-ball as the host, 3x600s dual grating spectrum. Clear detection of emission lines in single 600s snap

0358 - SN1999bd host - another faint fuzzy long-skit acquisition test target. Shot separate red-only and blue-only spectra (split mode observing script test).

0418 - M51 CM10 HII region long-slit spectrum - crowded field diffuse target acquisition. Seeing 0.6-0.7arcsec. 3x600s dual grating mode with the 1.2 arcsec slit.

0543 - Abell 1869 AD test - Olga did the mask alignment. After alignment in the SDSS r band, took a sequence of images through the mask in ugriz filters as an atmospheric dispersion effect demonstration/measurement.

0620 - Doug Miller logged in to test the next iteration of the reconstructor, this time in good (0.6-0.8arcsec) seeing. The new reconstructor does OK on-axis but diverges quickly off-axis. He gathered data and headed back to the drawing board.

0645 - PTF10u host. A faint and very challenging target acquisition in bright moonlight conditions. Acquired the source and ran a sequence of dual grating mode spectra to verify we got this nearly blind emission-line dominated target into the slit. Emission lines detected as expected with little or no continuum.

0810 - PTF09bce, a brighter host galaxy, this superimposed in the foreground of a background early-type disk galaxy. A challenging "diffuse source" target acquisition. 3x600s sequence. Seein got as good as 0.5-arcsec, but 0.6-arcsec typical.

0900 - Hz44 - 6-mode photometric standard star sequence in the LS60x5, part of the growing standard star library. Seeing 0.6 arcsec

0930 - Hz43 - similar sequence to Hz44. Seeing 0.6-0.7 arcsec

1000 - G138-31 - similar sequence, but a fainter redder star than the other two thus far. Seeing 0.7 arcsec

1100 - PTF09cnd host galaxy - a very faint host, so much so it is not on SDSS. Used as a test of blind offsetting in target acquisition by presetting to an easily acquired star, aligning it on the slit, then doing a blind RA/Dec offset to the faint target. In lieu of the slit we used a reference image as a stand-in. The test was done at PA=0 and PA=30°

Verified the signs of the dRA/dDec offsets (we had Dec off, RA OK). Multiple repeat presets showed a high degree of repeatabilty. Took the opportunity to take deep images (150s) in g, r, and i of the field to see if we could detect the host. It was ambiguous, perhaps our coords weren't so hot.

Seeing was 0.5 arcsec through much of the sequence.

We will continue this theme tomorrow night, and develop proven acquisition script templates.

1151 - PTF09atu host. This was a last blast as twilight was encroaching. Took a series of images to try to find a very faint host galaxy. Found nothing at the target coords or published finders even in 3min of imaging at i, r, and g. Interesting, but not a good candidate for future blind-offset tests, this is too blind.

1230 - Wrapped up, running imaging flats and long-slit calibration lamps in the dark enclosures after closing up

-- RichardPogge - 16 Apr 2011
Topic revision: r2 - 16 Apr 2011, RichardPogge
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