Guide Pratique |
OHP Home Page
![](t80-c.jpeg)
Haute-Provence 80-cm telescope CCD camera
Version Française
News:
- We are making available an Andor DW-436-BV system, the spare camera of the
TAROT projet
(PI Michel Boer). This camera has a 2048x2048 pixel Marconi
back-illuminated CCD cooled by a 5-stage Peltier system to -50 C.
See ANDOR for more details.
The field of view is
7x7 arc-min (pixels of 13.5 microns). The Cassegrain adapter is the same with
the same filter set. The acquisition software is
AudeLa. See also
obs-psr for more information.
Introduction
The OHP 80cm telescope, financed by the Dina Foundation and designed
by A. Couder, was built in Paris ca.1930 and was set up at Forcalquier in
1932 prior to the founding of OHP. It became the second to be installed in
Saint Michel (after the 1.20m), where it was re-commissioned in 1945. It is
used now exclusively in its f/15 Cassegrain configuration, although a f/6
Newtonian focus could still be accessed if necessary. The focal distance is
12 meters, yielding a focal plane scale of 58 µ per arc-second. The
refurbishing of the 80-cm telescope started a couple of years ago but much
remains yet to be done.
An adapter (on extended loan from the Bureau des Longitudes and built by the
Observatoire de Bordeaux) was fitted to the telescope in early 1996. This
adapter houses a 6-position filter wheel, an iris shutter and an
auto-guider. The dewar containing the CCD and the preamplifier are attached
to the adapter. The camera controller is bolted to the Cassegrain
base-plate. The signal from the controller is transported to the observing
room by an optical fiber cable. The ensemble adapter+dewar+controller is
called the CCD camera. All basic functions of the camera are
computer-controlled from the observing room, with the exception (for now) of
the filter wheel --whose position must be selected manually at the telescope.
Pointing and slewing, as well as turning the dome are done
manually.
Filters
The
filter wheel accepts 6 filters of 50-mm diameter. They are twins of those
used at the 1.20m. Several broad-band filters exist (U, Cousins BVR and Gunn
uvgriz. The Gunn i is used as a 'Cousins I' since the transmission curves
are quite similar). Interference filters centered on interesting emission
lines are also available. Each filter is fitted with an optical compensator
so that no change in focus is needed when using different filters.
Filter transmission curves
List of all available filters
Pointing and Tracking
The telescope's drive electronics were developed in-house.
Actual tracking of the telescope is done by a stepper motor which drives
a tangent screw/sector-wheel system for as long as 3 hours. The sector-wheel
must be reset after this time interval. The telescope coordinates are now
still set by using the original setting circles.
S.A.Ilovaisky
26 June 1997;
updated 28.05.06
|