Newsletter - 19 January 1996
************************************************************************
* *
* CANADA-FRANCE-HAWAII TELESCOPE email newsletter *
* *
* This is another update concerning the current status of instruments *
* at CFHT. Comments and suggestions about the newsletter may be *
* emailed to newsletter@cfht.hawaii.edu. *
* *
* Also consult the CFHT World Wide Web Pages at: *
* http://www.cfht.hawaii.edu *
* or http://cdsweb.u-strasbg.fr/cfht_manuals.html *
* *
************************************************************************
Date: 19 January 1996
Contents:
- IR Secondary Mirror Accidents and Problems with the Primary Mirror
Supports:
- CCD news
- UPDATES FOR Semester 1996II Proposals
- Outcome of the December 1995 Board Meeting
(Budget cutbacks; restructuring; instrumentation plan)
------------------------------------------------------------------------
IR Secondary Mirror Accidents and Problems with the Primary Mirror
Supports:
On January 4, while landing the f/35 IR upper end on the telescope,
a section of the secondary mirror rotation mechanism together with
the f/35 secondary mirror and its chopping system separated from the
upper end. The parts which fell were arrested by electrical cables
after travelling roughly one meter. In the process a glass mounting
ring on the back of the f/35 secondary mirror and a small, optically
inactive area on the front surface of the mirror were broken and
parts of the chopping mechanism were damaged. As a result of this
accident the f/35 secondary mirror is out of commission for at least
a few months.
We have been in contact with the mirror's fabricator, Contraves USA,
who have offered to help with efforts to put the mirror back in
service for the July 1996 observing run. At the moment we are
hoping to have the mirror back from Contraves by mid May.
The accident was the result of an abnormally hard landing of the
upper end on the telescope coupled with the fact that 12
bearing-retaining-screws in the rotator were missing. These machine
screws were intended to secure the rotation stage to the upper end's
fixed mechanical structure. Apparently they were never installed at
the time of fabrication and have been missing since the initial
commissioning of the original IR upper end. Their location is such
that visual confirmation that they were in place would have been
possible only after considerable disassembly of the rotator
mechanism.
In response to this accident, after the installation of the 12
missing screws and an inspection of related mechanics, we decided to
place the 'old' f/36 IR secondary mirror into service in a
mechanically locked condition without electrical controls. The f/36
mirror accordingly was re-coated in the Waimea coating facility and
mounted to the IR upper end mechanics on January 5.
On January 6, after landing the upper-end handling fixture onto the
IR upper end structure while both units were still on the 5th floor,
the handling ring jarred the upper end. The resulting shock
fractured the mounting ring on this second IR secondary mirror. It
too is out of commission. We have no plans at present to put the
f/36 mirror back in service.
As a result of these accidents we are instituting a Technical
Emergency Procedure Policy and have instituted a review of our upper
end handling procedures so that these types of incidents will be
avoided in the future.
* * *
One of the routine maintenance activities during last summer's
telescope shutdown was the replacement of the 24 pneumatic membranes
which are part of the primary mirror axial support system. In late
October one of these membranes failed. As a result, we were forced
to shut the telescope down for a night while the primary mirror was
removed and the pneumatic system was inspected. The result of the
inspection was rather alarming. Of the 24 newly installed
membranes, 13 had degraded to the point of needing replacement,
leaving us with 9 active spares.
Apparently the spare membranes, contrary to our expectation based on
advice from the fabricator, had degraded while in storage. Close
inspection of unused membranes did not indicate any problems
however. Shortly after discovering the problem, the supplier
notified us that the original membrane fabricator had gone out of
business and that they were unable, after considerable effort, to
find the molds needed to make more.
At this point we were in a race to procure viable spare membranes
before another failure of the primary mirror supports. We lost the
race this past weekend with the failure of another membrane. These
past several days have seen us again shut down for 1 night to
restore the mirror support system. Nine membranes were replaced.
Four others show signs of degradation but were not replaced since no
further spares are available.
At the moment our mechanical engineer, Rohendra Atapattu, has
received an external report on the membrane failure mechanism (ozone
degradation appear to be the culprit) and suggestions for an
improved rubber formulation. According to these external experts
however, the formulation we currently use is apparently well
engineered for the application. We have selected a fabricator and
initiated an order for new membranes. We hope to have two complete
sets in hand within four weeks.
Derrick Salmon, Director of Engineering Jan 16, 1996
----------------------------------------------------------------------
CCD news
ORBIT1: [2048x2048 15 micron pixels, thinned, AR coated] There was
considerable difficulty "pinning" the response, so the device was
returned to M. Lesser at Steward Observatory for analysis. It was
decided to strip the two-layer AR coating and re-coat. We are
awaiting the results of this work.
STIS2: [2048x2048 21 micron pixels, thinned] Successful run with the
SIS spectrograph in January. Some pickup noise problems were
encountered but should be fixed by now. The dewar might have a
slight vacuum leak, which would be fixed as soon as the device is
not scheduled for an observing run.
UBC1: [4096x200 15 micron pixels, thinned, dual layer AR coating]
Undergoing testing at UBC. May be available for the March GECKO run
using a UBC controller.
S. Milner & J. Glaspey
-----------------------------------------------------------------------
UPDATES FOR Semester 1996II Proposals
1. CFHT has reached an agreement with UH IfA to offer the 8K x 8K CCD
camera developed by G. Luppino and associates to the CFHT
community. The pixel size is 15 microns, corresponding to
approximately 0.2 arcsecs at prime focus, giving a field of view
of 30 arcminutes on a side. V, R, and I filters are available.
Look for a document on the CFHT WWW pages giving detailed
specifications.
2. The progress of the Adaptive Optics Bonnette is essentially on-time.
Engineering and commissioning will take place during the 96I
Semester and the AOB is expected to be ready for general visitor
use early in the 96II semester. A draft document summarizing its
anticipated capabilities is available on the WWW. Briefly, full
correction (up to 19 modes) should be possible using on-axis guide
stars down to magnitude R=15 or with only tip-tilt correction down
to R=18. Initially, imaging will be possible at the corrected f/20
(output) focus in the visible with FOCAM, covering a field of
almost 90 arcsecs (but with poor sampling of the best image
quality PSF), and using the Redeye Narrow near-IR camera, covering
a FOV of nearly 20 arcsecs.
3. A fiber-feed is being developed from the f/8 cassegrain focus to the
GECKO coude spectrograph to replace the Red and Blue mirror trains.
GECKO runs will be scheduled to use the fiber-feed starting in
96II. (The UV train will be maintained for observations at bluer
wavelengths.) [PLEASE NOTE THE DELAY MENTIONED IN THE FIRST NEWS
ITEM!]
4. Service observing will be offered for imaging with FOCAM, MOCAM,
OSIS and the Redeye Wide cameras for runs of three (3) nights or
less. Proposals should include detailed observational information
by filling out the template provided with the proposal form.
5. OSIS availability: The visible-near infrared replacement optics for
the SIS spectrograph, referred to as OSIS, are expected for
delivery and installation in early 1996. Proposals may be
submitted to use this spectrograph either with a CCD for visible
wavelengths or with a HgCdTe near infrared array for imaging out
to 2.5 microns, or low-resolution spectroscopy out to 1.8 microns.
Check the CFHT World Wide Web Home Page in late February or email
to directors@cfht.hawaii.edu to receive more details about the
expected capabilities. Actual availability will depend on the
schedule and success of the switchover.
6. The ARGUS mode of MOS to do integral field spectroscopy using fiber
optics is now supported. The useful field of view is 12.8" by 7.8"
and the following grisms are available: V150, O300, R300, and
O600.
7. Improvements to the Redeye camera controller have resulted in much-
improved reliability of the BEAR (FTS + Redeye Narrow) scans.
-------------------------------------------------------------------------
Outcome of the Decmeber 1995 CFHT Board of Director Meeting
1. Cuts in the operating budget; lay-off plan
Due to the serious economic situation they are facing the three
funding agencies, NRC, CNRS, UH, have asked the Executive to cut
the annual operating budget by 10%, for a total saving of $M 3
over the five years, 1996 to 2000. To maintain CFHT at the
leading edge of the competition they arranged for CFHT to receive
an instrumentation fund totaling $M 5 and to create a contingency
fund of $M 1. These $M 6 will be raised from the $M 3 saved from
the 10% cut in the operating costs (the total budget of CFHT being
frozen for 5 years at the level of 1995) and from $M 3 of
additional funding raised by NRC and CNRS.
To maintain the budget within the allocated targets the Executive
has had to reduce all three principal components of the budget:
capital expenditures for new projects, general operating
expenditures, and personnel expenses.
The most sensitive part was to reduce personnel expenses: a
lay-off plan terminated 4 positions on March 31, 1996. and a one
engineer position will not be replaced after a retirement in March
1996.
2. New management structure
The agencies and the Board have adopted the a new management
structure effective from January 1996.
The new executive has four members: one Executive Director (Pierre
Couturier renewed until July 1999), a Director of Finance and
Administration (Claude Berthoud), a Director of Engineering
(Derrick Salmon has been appointed from January 1996) and a Senior
Resident Astronomer who will be appointed mid-1996, once the
successors of three departing Resident Astronomers are known.
John Glaspey will continue as Associate Executive Director until
his term expires at the end of July 1996.
All engineering groups now report to Derrick, who has
responsibility for management, planning and budgetary matters
relating to technical operations.
3. The implementation of the Wide-Field Imaging Program
The Board approved a re-instrumentation plan of $M 5. CFHT has
received appropriations as of January 1996 for $M 2. The
instrumentation plan will cover the following instruments and
studies:
- 1k x 1k NIR camera, optimized for use with the Adaptive Optics
Bonnette.
- UH 8K camera duplication, by an 8k x 10k mosaic with thinned
CCDs
- Image quality improvement studies to evaluate efficiency,
schedule and cost of possible systems for the improvement of image
quality at prime focus.
- 2k x 2k IR camera: feasibility studies for a dual optics 2k x 2k
IR camera which would be used with OSIS and for imaging at direct
f/8 focus.
- 1-degree field MEGACAM camera: studies will be done on the
conceptual design of a camera for imaging a 1-degree field of view
using a mosaic of thin CCDs, to develop a survey programm at prime
focus and to prepare a data pipeline and major software
development.
- Preliminary studies of long term options for CFHT: funds are
appropriated to start working groups and engineering consultions
for comparative feasibility studies of long term options: a) a
new cassegrain focus with tip/tilt secondary mirror; b)
installation of 6-8 meter telescope in the CFHT dome.
In conclusion, CFHT has a good future and a program to prepare for
the long term.
Return to CFHT Home Page