The Nightwatchman

Edition 1

Spring 2001

Hilo, March 1

[Regular readers of this newsletter will note that this is the first 
appearance of an article in the JCMT Newsletter by a Telescope System 
Specialist.  I hope that you find this column to be some combination of 
enlightenment and entertainment, at least as far as the TSS perspective 
goes, and I welcome comments, questions, compliments, and criticisms. -JK]

TSS Support

The JCMT TSS corps has undergone several changes since the last newsletter 
and I thought I'd devote much of this inaugural edition to elaborating on 
some of those changes and the ramifications that they will have upon 
observer use of and interaction with the JCMT facility.

As of the last newsletter, Jim Hoge and I had just joined JCMT and begun 
our training.  Since then, we have each become substantially more familiar 
with the JCMT and its operations an we would each like to thank observers 
and JCMT staff alike for their patience during our familiarization 
periods.  And, we'd also like to thank current TSSs Ed Lundin and Thomas 
Lowe, as well as recently-departed but long-serving TSSs Rusty Luthe and 
Jeff Cox, for their time and patience during the training periods.  
(Aside:  Rusty and Jeff each report that they are enjoying the new 
challenges they are facing at CFHT and Gemini-South, respectively.  For 
those wishing to keep in touch with them, they can be reached at 
luthe@cfht.hawaii.edu and jcox@gemini.edu.)

Support scientists Robin Phillips and Nick Jessop have begun a program of 
taking a few nights each month at the telescope, becoming more familiar 
with the facility and its nighttime operational mode, and Scott Mikkelson 
has left the TSS group.  The presence of Robin and Nick has also helped 
augment the support model for nighttime operation, as outlined below.

The JCMT Board considered the TSS staffing issues at their November 
meeting and it was decided that no additional TSSs would be hired so that 
funds could be transferred to development, most notably including the 
support of future instrumentation.  Based on this decision, a plan was 
developed for the covering of the approximately 8% of normal 16-hour 
operation that was lost due to this staff shortage.  This involved the 
development of a remote-observing plan, to be implemented on a time scale 
of less then nine months.  However, the TSS group subsequently discussed 
alternative support models and have restructured their support of JCMT 
operations, most notably the shedding of some of their daytime support 
duties, to cover the lost time.  Therefore, JCMT once again is supporting 
its full 16-hour operational model, with no expected lost time between now 
and the implementation of remote observing.  The downside to this plan is 
that extended observing will be a less frequent event.  However, this plan 
has allowed the remote observing team to slow the pace of development 
somewhat, allowing implementation a bit further down the road than 
originally anticipated, and hopefully allowing for a more robust system 
due to the extended and less-hurried development period allowed by the new 
TSS support model.

Antenna and Instrumentation

The TCS has begun a multi-step migration to UNIX, the first part of which 
has been successfully tested and implemented.  Recent inclinometry and 
pointing tests with the new TCS demonstrate that the correction for 
meridian-crossing is working better.  A small elevation-dependent focus 
shift has been discovered in the z-axis and corrected.  The dish surface 
is performing well and will soon be tested again following adjustments to 
the holography receivers, although additional tests have been somewhat 
delayed due to a temporary reallocation of staff surface responsibilities.

Receiver A continues to function well following its recommissioning after 
helium cryostat repairs.

Receiver B is performing satisfactorily, excepting an occasional 200 MHz 
offset in tunings due to a 50 MHz shift in the Gunn oscillator output 
frequency. This problem can be worked around either by verification of 
line positions on calibrators or other sources with strong, known signals, 
or by a quick slewing of the antenna to the zenith to check a counter in 
the receiver cabin that monitors the Gunn oscillator output frequency. 
Also, single-sideband performance has improved recently due to mechanical 
modifications that improved rejection of the image sideband.

Receiver W is working okay in C-band.  However, D-band is currently 
unavailable due to the off-island repair of the local oscillator source, 
which has been accomplished and the part is on its way back to Hilo.

The DAS is performing well, as are the IFS, the IFD, and the heterodyne 
polarimeter.

SCUBA is working somewhat better following a full warm-up of the entire 
instrument to ambient temperature and a subsequent limited warm-up.  Most 
of the large, migrating noise issues have been solved, although occasional 
lower-level, apparently-random noise has appeared on occasion.  It is 
substantially less severe than the previous problems and we hope to remedy 
this soon.  This problem has not yet affected the central photometry 
bolometers in either the long-wavelength or short-wavelength arrays.

The SCUBA polarimeter is functioning once again following a failure and 
subsequent replacement of two of its cables.  Please note that the staff 
contact and responsibility for this instrument is changing.

Notes for Observers

We would like to remind observers to carefully review their observing 
templates before submitting them so as to contribute to a more efficient 
and less error-prone execution of their programs in queue/service mode by 
the TSS, or the observer if he/she happens to be familiar with the mode of 
observing. Thoroughness (sans superfluity) and lucidity are welcome sights 
during early morning template review at altitude.  Also, early submission 
of templates is highly encouraged.  Early semester weather that tends 
excessively towards one end of the spectrum or the other often leaves us 
having to implement less-suitable programs from other weather bands or 
member countries or with lower scientific rankings.  Prompt filing of 
templates will possibly increase the likelihood and timeliness of 
finishing a program.

Observers are also reminded that there are country-specific guidelines on 
the permitted weather grades in which they can observe their own program 
when they observe in person.  If you are uncertain of these rules, please 
contact your country's Hilo-based scheduling representative.

As noted above, extended observing will be somewhat curtailed on account 
of the support changes which have reinstituted full support for the 
16-hour operational mode.  Also, observers are reminded of the importance 
of having a safety briefing with their staff contact, and of communicating 
with the on-duty TSS before commencing transport between Hale Pohaku and 
the summit.

For those observers who have scheduled, overriding Target-of-Opportunity 
proposals, we encourage not only the prompt sending of electronic mail to 
your country's Hilo-based scheduling representative and the TSS group at 
jcmt_to@jach.hawaii.edu, but also contact by telephone to insure prompt 
follow-up with time-dependent observations.

Miscellanea

In addition to our TSS-specific web pages which Ed Lundin has worked on 
for several years and which I will probably soon take over from him, I 
have developed what I hope to be a concise and centralized set of links 
useful to both observer and TSS.  While this project was delayed during 
the development of the new JCMT web site by Robin Phillips, now that that 
site is stable again, I shall to continue work on it and incorporate more 
of the new web site into it.  If you are interested, please visit 
www.jach.hawaii.edu/~jkemp/links to see the work in progress. Please note 
that some links are restricted to the JAC network and/or staff.  Comments 
welcome.

Several TSSs received some degree of financial support for attending 
conferences in the early months of 2001.  Thomas Lowe and Jim Hoge 
attended the Gemini-Subaru Astrophysical Ages and Time Scales conference 
held here in Hilo and I attended IAU Colloquium 183 - Small Telescope 
Astronomy on Global Scales.

For those of you reading a hardcopy of this article, or viewing it in any 
medium besides the world wide web, please note that this article, and its 
subsequent companions in The Nightwatchman series, appears at 
www.jach.hawaii.edu/~jkemp/nwm.

La Citation du Semestre

An immense pride was buoying us up, because we felt ourselves alone at 
that hour, alone, awake, and on our feet, like proud beacons or forward 
sentinels against an army of hostile stars glaring down at us from their 
celestial encampments. ... Standing on the world's summit we launch once 
again our insolent challenge to the stars!

Filippo Tommaso Marinetti, Fondazione e Manifesto del Futurismo, 1909

Happy equinox and African solstice eclipse chasing!

Jonathan Kemp

www.jach.hawaii.edu/~jkemp

j.kemp@jach.hawaii.edu