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| The 85cm reflecting telescope |
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Scientific goals of the 85cm telescope:
The 85-cm Cassegrain telescope
is one of the NAOC facilities, dedicating to the photometry of short-period
pulsating variables, eclipsing binaries, white dwarfs, cataclysmic variables
and related stars. This telescope is available to professional astronomers
from anywhere in China (in the world in the near future) who wish to observe.
Since 1995, the telescope has been fully putting into photmetric
observations of Delta Scuti stars, Eclipsing binaries and White
Dwarfs. By now, this telescope has contributed a lots to the WET
(Whole Earth Telescope) campaigns on white dwarfs and subdwarf
B pulsating stars and the STEPHI (STEllar PHotmetry International)
on Delta Scuti stars.
Normally, the WET was organized once or twice each year by American
astronomers at the University of Texas and the Iowa State University,
the latter is the headquarter of all WET runs. The three-channel
photoelectric photometer is especially designed for the WET campaigns.
Initially, the STEPHI was organized each year by French astronomers at
Observatorie de Paris, Meudon. STEPHI runs use a four-channel French
photoelectric photometer. Besides participating these two main
cross-continent multisite campaigns, Chinese astronomers also join or
organize some small international multisite observations on this
telescope. In order to increase scientific producitivities, astronomers
in non-variables are also encouraged to make use this telescope in
recent years. Astronomers from Yunnan Observatory, Taiwan and other
universities also observe with this telescope each year. |
Photometers in use:
Currently there are 3 photometers available for observers to chose
for their specific missions.
(1) Three-channel WET high-speed photoelectric photometer(3-CH)
The 3-ch photometer equiped with standard Johnson UBV filters.
But without filter-wheel controler, so observers need to select or
switch them manually. This photometer is controlled by a DOS program
called Q9. The output data of the photometer are in ASCII format,
and they can be processed with the program QED or its X-window
version XQED. In use of this photometer, observers can monitor the
target, sky background and a comparison star within about 15 arc minute
from the target, simultaneously. Q9 display light curves of the three
channels in a real-time mode, so observers can see the ligth variations
during the observations. As for guiding, the photometer uses part of
the comparison channel light and displays the comparison's image through
an ST6 CCD. The data file is small, after observations, observers can
transfer their data to their home institutions by our
Internet connection, or just save them onto a 1.44MB floppy disk.
(2) Four-channel Chevreton STEPHI photoelectric photometer(4-CH)
The 4-ch photometer has the colone of Stromgren uvby filters equiped.
Normally, one can use two filters at the same time. The integration
time using this photometer is commonly 1 second. So after a full night
run, the data file is big. The control and data-taking prgroam runs in
MS-DOS mode, is also graphic -- observers can see the light curves on
each channel. (3) Apogee AP7P CCD Cassegrain direct imaging photometer
This CCD photometer served as our experimental photometer for the
image quality at this telescope. Observational results show that
the data are quite good. So astronomers have used it for some two
years since the winter of 2002.
In a near future, a new liquid Nitrogen colled scientific CCD camera
is expected to be installed in the place of this Apogee AP7P CCD.
There are stardand Johnson BV filters available for choice -- automatic
switch is not provided, use one filter each night is suggested. The CCD
sized 512x512 pixels with a full field of view of about 15 arc minutes.
The data are saved in standard FITS format. Zhou Aiying has written
IRAF scripts for automatic aperture photometry of the images obtained
with this CCD at 85cm telescope. For use of the scripts, please contact
at aiying@bao.ac.cn. Observers' data will be burn onto CDs at the end
of their run, or they can transfer to their home institutions by FTP
or SFTP after observation each night. |
Applying for Observing Time at the 85-cm telescope
If you are interested in using our telescope and instruments (or wish
to bring your own instrument), you should complete an application form
and e-mail it to aiying@bao.ac.cn. The telescope time application
form is a Microsoft Word document into which you enter details of your
application. Applications are welcome any time before our deadlines.
The tables of observing times for the 85-cm telescope are arranged
every six months. Remember to check this schedule for possible changes
which may affect your observing run. If you want to make changes to
your observing request, contact aiying@bao.ac.cn.
Deadlines for Observing Applications :
25 December for next January-June observing season
25 June for next July/December observing season |
 Aperture: 850mm
Focal ratio: f/15
Focal plane scale:
16.2"/mm
photometers:
 3-ch photometer
4-ch photometer
Apogee AP7P CCD photometer |
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