Subject: APO 3.5m users committee minutes, June 2010

From: Suzanne Hawley

Submitted: Sat, 19 Jun 2010 12:16:06 -0700 (PDT)

Message number: 1188 (previous: 1187, next: 1189 up: Index)

              APO 3.5-m Users Committee Phonecon, 6/14/10

Attending:  Suzanne Hawley, Mark Klaene, Michael Strauss, Bill Ketzeback,
Jon Holtzman, Remy Indebetouw, Scott Anderson, Bruce Gillespie

Absent:  Al Harper, John Bally, Jon Fulbright


User feedback, comments from institutional representatives:

 	Chicago (Al Harper) - no report.

 	New Mexico State (Jon Holtzman) - Jon had nothing new to report.

 	Washington (Scott Anderson) - Scott had nothing new to report.

 	Colorado (John Bally) - no report.

 	Princeton (Michael Strauss) - Michael said "we've been happy."

 	Johns Hopkins (Jon Fulbright) - no report.

 	Virginia (Remy Indebetouw) - Remy mentioned that a UVa user has been 
repeatedly "clouded out" during scheduled observing time.  Suzanne and 
Remy said that they are trying to compensate by using DD time and raising 
the internal priority at Virginia.


Discussion of telescope/instruments report - Klaene:

Mark highlighted the recent cloudy weather and the return of Miller 
moths -- whether the new drives are better or worse when they run over 
a moth has yet to been determined.  The main issue this past month has 
been azimuth axis drive resonances during slews and drive startup.  A low-pass 
filter was installed in the drive system, and after adding an additional 
amplifier the drive system is working much better.  The altitude axis 
also experiences resonances that are excited at low altitudes; it will get 
the same treatment as the azimuth axis.  For the instruments, there were no 
significant problems, although we saw instrument temperature fluctuations due 
to the warm ambient air temperatures.  Given the recent and long-term problems 
we have had with mechanical cryo-coolers, Suzanne and Mark stated that 
we will not consider such cooling systems for future instruments.  The 
NIC-FPS fan-out board is still being worked on at Colorado.  The spare telescope 
drive box and motor will be ready in July.  Improving high-altitude tracking 
remains in the work plan.


 	3.5-m Telescope, Instruments, and CIF Projects Highlights, 5/4/10 through 6/10/10

0) Overview

Spring finally showed up bringing a heavy pollen season and lots of Miller 
moths.  Wind has generally been milder than some seasons and we have 
actually seen a little rain.  Blowing sand has also generally been lower 
than a typical spring.  After a lot of work by Fritz and others we seem 
to have made major strides in improving the axis controller performance 
on the azimuth axis. The problems we were seeing did not affect a lot of 
users but were certainly irritating and needed correction.

1) Telescope

Fritz managed to get the low-pass filter in the az controller servo loop 
but it was attenuating the servo drive signal too much so an external 
amplifier had to be installed to provide additional gain for the 
post-filtered signal.  This allowed for better servo tuning and resulted 
in reduced tracking error and resonance.  A similar approach is now 
planned for altitude.

We are still investigating improvements in high altitude tracking but 
little progress has been made due to weather and other priority issues.

2) Instruments

SPIcam, DIS, TripleSpec, NIC-FPS, the Echelle, and Agile ran with no 
serious problems.  Due to some very hot daytime temperatures DIS and 
SPIcam and even Echelle temperatures were running higher than we like 
during the day and only after sunset and dome ventilation recovered to 
acceptable limits.  We have been unable to find anything wrong with the 
camera cooling systems but are placing instruments on the vacuum pump 
when available to try and improve these temperature transients.

The new NIC-FPS fanout board testing at CU has been slowed due to problems 
with the spare Leach controller.  The controller was sent back to Bob Leach 
who found a couple of problems.  The output is now stable but there is a 
discrepancy in the gains between the two channels that is still being 

3) CIF projects

The spare telescope drive box machining and fabrication continues; some 
parts are assembled and additional spare components have been delivered. 
A complete spare motor assembly will be finished this summer.

We have an RFP out to upgrade the 5-ton hoist in the dome that is used 
for M1 mirror movements to a variable frequency drive.  The new drive 
will give us finer control when removing and re-installing the primary mirror.

High-altitude tracking is still being investigated.  We have confirmed 
that M1 comes off the transverse actuators as early as 82 degrees and 
that we have seen 30 or more arcsec of image motion that the 
auto-guider cannot correct when operating above 85 deg altitude.


Summer engineering update - Klaene:

Mark said that the summer shutdown will be conducted from 26 July 
through ~14 August (weather permitting).  This is a relatively short shutdown, 
which will entail washing the primary mirror, servicing and recoating 
the secondary and tertiary mirrors, and annual instrument maintenance. 
Since we're coming out of the shutdown during the monsoon season, the 
date that we return to science observing will depend strongly on the weather.


Echelle upgrade update - Gillespie:

We are tracking down the echelle documentation so that we have a 
baseline collection before launching into the upgrade.  Yerkes has just 
sent us a couple of boxes of documents, and we have identified other 
echelle materials currently in the custody of Shu-I Wang, Lew Hobbs, Don 
York, and Dan Schroeder.  All the documentation should be on-site 
at APO by the end of summer.  Jon Holtzman is leading the echelle upgrade 
project, and is preparing a description of the upgrade plan.  A 
preliminary design review of the upgrade is planned for this fall.


APO futures committee - Hawley, Gillespie:

An ARC Futures Team, consisting of Mike Shull, Suzanne, Daniel Eisenstein, 
Michael Strauss, and Bruce have begun the process of determining APO's 
future in the post-2014 time frame.  The main elements being considered 
are soliciting a program for the 2.5-m telescope after SDSS-III, the 
evolution of the ARC institutions and shares, and new instrumentation. 
A larger Futures Committee needs to be formed, with representatives from 
the ARC member institutions plus a subset of the SDSS-III collaboration. 
This committee will be tasked with reviewing the Team's recommendations, 
and providing an information conduit back and forth with the 3.5-m and 
SDSS-III constituencies.


Summer meeting schedule - Hawley:

As is our tradition to skip one of the monthly meetings in the summer, 
we will skip July and hold our next Users Committee telecon on 16 August,
after the summer shutdown activities are completed.


Miscellaneous topics:

Bruce mentioned that Bill Ketzeback now has the long-lost Gascoyne 
corrector lenses that were originally manufactured (back in the late-80s?), 
which could enable the 3.5-m to produce a fairly wide-field corrected 
focal plane.  We don't know much about the optical properties of the 
lenses, but these could be reverse-engineered.

Remy asked if anyone is using TripleSpec in extended-source mode, via 
scripts.  Michael Strauss said that the Princeton users would be very 
interested in this capability.  Jon Holtzman thought it would be a great 
thing to have, and could be implemented by borrowing from NIC-FPS software. 
Suzanne said that we should look into this as a high priority.



[open from previous meeting]:

===> ACTION:  Users Committee members should poll their users to find 
out how important it is to their science programs to track targets within 
5 degrees of zenith.

 	STATUS:  Comments were heard from three institutions, which basically 
said it would be nice, but not a big deal, to go to higher elevations. 
The action will remain open until next meeting for additional user comments.

===> ACTION:  Users Committee members should forward the NIIS white paper 
to their users, and potential users should send any comments or questions 
to Suzanne Hawley.

 	STATUS:  This action is CLOSED.  No user comments were received. 
When it is ready, NIIS will come to APO as a visiting instrument.

[new actions from this meeting]:



Next meeting:  The next Users Committee phonecon will be on Monday 16 
August at 8:30 AM Pacific Time.  The agenda and other materials will be 
sent to the committee members during the preceding week.

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