MDM Observatory 2.4m Telescope Observing Report for 2019 Jul 02

Observer(s): John Thorstensen
Institution(s): Dartmouth College

Instrument: OSMOS/B

Worked for 9 hours (all night)
Conditions were Photometric most of the night.
No equipment or software problems were encountered.

Seeing and Weather:
   Beg: Seeing 2 arcsec, Clear, Winds Moderate
   Mid: Seeing 2 arcsec, Clear, Winds Light & Variable
   End: Seeing 2 arcsec, Clear, Winds Calm

Observing Summary:

Nearly photometric, completely moonless since there was a total
eclipse of the sun just yesterday.  Seeing could have been a 
little better, I think, but very productive. No problems.

I've discovered that the dispersion of OSMOS seems to change, 
so that shifting a single calibration using the 5577 line
can lead to velocity errors of over 100 km/s in lines far from the
5577 line.  It will be interesting to see if this correlates
with bench temperature, or what.  

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Submitted on 2019 Jul 3 [5:24:31]