Subject: APO 3.5-m Users committee minutes, 3/2/09

From: Suzanne Hawley

Submitted: Fri, 6 Mar 2009 21:45:53 -0800 (PST)

Message number: 1126 (previous: 1125, next: 1127 up: Index)

              APO 3.5-m Users Committee Phonecon, 3/2/09

Attending:  Suzanne Hawley, Scott Anderson, Mark Klaene, Russet 
McMillan, Bill Ketzeback, John Bally, Bruce Gillespie, Michael 
Strauss, Al Harper, Jon Holtzman, Rene Walterbos

Absent: Remy Indebetouw, Jon Fulbright


User feedback, comments from institutional representatives:

Princeton (Michael Strauss) - Michael gave thanks to the APO 
engineering staff for getting the telescope back together in time for 
Princeton users, who had a successful observing run.

Colorado (John Bally) - John reported that a user has a concern about the 
ability for some programs to get adequate calibration time with the recent 
increase of partial half nights and short monitoring programs.  Suzanne 
and Russet said that we have long been aware of the impact that short 
observing programs can sometimes have on adjoining half-night programs, 
and that we have tried to avoid conflicts and to arrange mitigations 
wherever possible.  The recent increase in short programs is largely a 
result of the favorable apparition of Venus.  Jon Holtzman said that it is 
almost always possible to get DIS calibrations done if you start earlier 
in the afternoon, and that it should be possible to develop a library of 
SPIcam sky and dome flats that would be suitable for most observing 
programs.  John Bally and Al Harper said that proposers should be able to 
specify in their proposals any extraordinary calibration requirements, 
those that might need special scheduling considerations.  Suzanne added 
that she often gives as recompense an extra half night to programs that 
are scheduled to share several half nights with short and/or monitoring 
programs.  Russet suggested that when these programs are given extra time 
as compensation, this could be noted in the schedule.  It is easier to 
juxtapose bright-time instrument programs with twilight programs and short 
interleavers than it is for dark-time programs.  Bill Ketzeback seconded 
the idea that special calibration requirements be listed in the proposals 
so that we can mount instruments early and get dome calibrations.  Also 
Bill pointed out that users should send requests for special calibrations 
with their setup requests at least two days ahead of their run.  Russet 
felt that it would be useful to hear feedback from a larger number of 
users on the subject, and Al and Bruce suggested that we post a 
description of our telescope scheduling process so that the users have a 
better understanding of the policies and trade-offs.  The group felt this 
would be a good idea.

==>ACTION:  Suzanne and Russet will write a draft description of our 
scheduling process for eventual user dissemination.

Johns Hopkins - no report.

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

Chicago (Al Harper) - Al had nothing new to report.

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

Virginia - no report.


Discussion of telescope/instruments report:

To the more detailed report below, Mark added his thanks to all the 
users for bearing with us throughout the period for which we have 
endured the problems, diagnosis, and repair of the tertiary mirror
mount and associated electronics.   For the time being, the 
telescope is in good shape.  With regard to instruments, 
the NIC-FPS new fan-out board should be installed sometime 
between April and fall, depending on the availability of CU 
resources.  Progress is being made on the Agile instrument 
rotator, which is undergoing tests and modifications.  There are Agile 
operating modes through TUI that have uncovered a timing flaw in the 
camera control software from the vendor.  Agile users should be aware 
of this, and they should study the updates recently made to the on- 
line Agile user documentation, discussed in more detail in a later 
topic of this meeting below.  Also, several of the shared site 
engineering staff will be stretched thin over the next few months 
working on high-priority SDSS-III projects.  Engineering work related 
to the 3.5-m will continue on a level-of-effort basis.


3.5-m Telescope, Instruments, and CIF Projects Highlights, 1/29/09 
through 2/27/09

                                Mark Klaene

0) Overview

Good weather continues.  A couple of winter storms passed through 
during the past month, leaving only a small amount of precipitation. 
Most recently, above-normal temperatures have made it feel like late 
spring. The principal telescope issue has been with pointing problems 
(around 3 arcminutes) that have been suspected to be related to the 
tertiary mirror mount.  This was traced to an intermittent problem 
with one of the three mirror-position encoders, which has since been 
replaced.  Both the 3.5-m and 2.5-m telescopes have been using this 
type of encoder for more than ten years and this is the first failure 
we have experienced.  The instruments are all working relatively well.

1) Telescope

The NA2 axis controller continues to perform well; its problems in 
earlier months may be behind us.

We had a couple of instances where the TCC froze, and this was traced 
to some weather data that was incorrect.  We now error-check this data 
before sending it to the TCC.

Following the tertiary mirror encoder replacement, telescope pointing 
was substantially improved.  However, we elected to continue with the 
planned controller upgrade and now have a 4th Galil controller that 
runs only the axial position of the tertiary.  This design is 
patterned after the secondary design and is substantially more robust 
than the earlier tertiary configuration.  The old Galil controller now 
runs the tertiary rotation, mirror covers, and eyelids.  During the 
engineering efforts, we also pulled the tertiary glass and serviced 
all the actuators.  We did find a few loose bolts which might have 
contributed to some of the positional non-repeatability we have seen 
in the new tertiary mount since September.  Very little observing time 
was lost to the tertiary engineering work and reconfigurations.

A new problem occurred with the altitude drive axis resulting in 
multiple errors.  The spare altitude drive box was slated to be 
installed on 26 February, but when the motor was removed it was found 
that the problem was with a bearing failure in the motor. The motor 
was quickly replaced and no science time was lost.

2) Instruments

DIS, SPIcam, and Echelle are fully operational.  A minor adjustment to 
the DIS cart was made.

NIC-FPS has been operational with no problems.  The new fan-out board 
design is complete and plans are being made for its fabrication.  The 
new board will be tested at UVa and CU, and then a plan for its 
installation will be established.  We hope to integrate and test the 
new board during the summer, but CU commitments to HST/COS may delay 
the installation schedule.

TripleSpec mounting is still less than perfect, but there have been no 
recent problems and the mounting operation remains tolerable.  The UVa 
team is also looking at issues of detector array power loss and is 
monitoring the situation closely.  We are also occasionally getting 
false temperature alarms for the Aux LN2 dewar.

Agile is still available at NA2.  Updates to the documentation have 
been made to keep users abreast on recent TUI and ICC developments. 
This includes changes in minimum exposure time, bias-image 
fluctuations on the first few images of an exposure sequence, and 
general control issues.   Further improvements will be slow in coming 
due to resources being tied up on other projects.  Rotator testing has 
been delayed in order to concentrate on the tertiary issues.

APOLLO remains operational.

3) CIF projects

The direct-drive critical design review will be held on 2 March 2009.



Agile usage in coming months:

Suzanne reported that the vendor-supplied Agile camera software has 
timing problems.  There is a workaround for both TUI and aacq, and
for both slow and fast readouts--see the updated Agile on-line user 
documentation, or talk to the site staff about the details.  Basically
the camera is power-cycled between exposure sequences, but this 
causes some variability in the bias levels for the first several
exposures of each sequence.  Since we are having difficulties 
getting the attention  of the camera vendor to effect a better 
solution, the situation is unlikely to change for some months. 
Agile users thus need to monitor their data closely, read the online
documentation and talk with site staff when they use the instrument.

In other Agile news, we now plan to delay the move of Agile to
the TR2 port with its own rotator for a few months, both so
that site staff can concentrate on the telescope drive axes
and to allow additional calibration data to be obtained while
Agile is mounted at NA2 with guider capability.  The users community
will be notified when we schedule the move to TR2.


Decadal survey "state of the profession" position paper:

There is a "state of the profession" group within the decadal survey
that is soliciting position papers on facilities and partnerships.
We have been encouraged to submit a paper on the nature of our 
consortium and general APO operations.  Since Suzanne is a member 
of one of the science panels, she cannot lead the position paper.
Therefore, Jon Holtzman, with help from Rene Walterbos, has agreed to 
undertake putting this paper together, which will also be helpful for 
us as a foundation for our own future planning.  Suzanne asked that if 
users committee members and other users want to be involved in 
assembling this paper, which is due March 15, that they should contact 
Jon Holtzman.


Instrument proposals/studies:

Suzanne reminded the committee that Cynthia Froning (CU) is 
leading a study to upgrade our direct imaging capability (ie SPIcam) 
and Eric Burgh (CU) is leading a study on upgrading the echelle 
spectrograph--requests for input and comments from the users 
community are being solicited.  Interested users should give 
discuss and give input to their users committee members.

A new proposal for upgrades to the Goddard Fabry-Perot was recently 
submitted by Bruce Woodgate, which describes adding an IFU 
spectroscopic capability and upgraded imaging capabilities. 
The committee members are asked to read the proposal and 
distribute it to their users for comments and feedback. 
Al said that he thought the proposal looked very good, and 
wondered about its potential impact to the site operations.  Mark 
replied that there would be work required for TUI integration. 
Suzanne added that we would like to hear from potential users on their 
interests in using the IFU spectroscopic capability, and what limiting 
magnitudes would be useful for their science goals.  Anyone interested 
in further information or providing feedback on the proposed GFP 
upgrade should send e-mail to Mark Klaene (mark at and 
Suzanne (slh at


Other items:

Suzanne offered her appreciation to the APO staff who worked long and 
hard to fix the tertiary problems over the past months, frequently 
under grueling winter conditions.



[open from previous months]:


[new actions from this meeting]:

==>ACTION:  Suzanne and Russet to write a draft description of our 
scheduling process for eventual user dissemination.


Next meeting: The next Users Committee phonecon will be on Monday, 13 
April, 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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