| Issue |
Astron. Astrophys. Suppl. Ser.
Volume 144, Number 2, June I 2000
|
|
|---|---|---|
| Page(s) | 349 - 362 | |
| DOI | https://doi.org/10.1051/aas:2000213 | |
| Published online | 15 June 2000 | |
Evaluation of Devasthal site for optical astronomical observations
U. P. State Observatory, Manora Peak, Nainital 263 129, India
Send offprint request to: R. Sagar, e-mail:sagar@upso.ernet.in
Received:
20
May
1999
Accepted:
7
March
2000
Based on an extensive site survey conducted during 1980-1990
in the Shivalik Hills of the Central Himalayan range, a promising site
Devasthal has been identified. The longitude and latitude of
Devasthal Peak are 79° 41′ E and 29° 23′ N.
It is situated at an altitude of 2540 m and
about 50 km by road from Nainital towards East.
The surroundings
of Devasthal are thinly populated and it is logistically well suited for
establishing modern optical observational facilities.
The prevailing wind
direction at Devasthal is NW. For a large fraction of the night time,
variation in the ambient temperature was less than a degree and wind speed
was less than 10 m/s. During spectroscopic nights (> 200
in a year) relative
humidity is less than 80% for about 70% of the time.
During 1997 and 1998
seeing measurements using differential image motion techniques have been
carried out close to ground at two locations namely Site 1 and Site 2
in Devasthal.
Our observations for Site 1 carried over
88 nights
yield a median seeing value
of 1
4.
For
Devasthal Site 2
observations carried over 37 nights yield a median
seeing value of 1 1.
Devasthal Site 2 has therefore been selected
for locating a modern 3 m optical telescope.
Key words: site testing / atmospheric effects
© European Southern Observatory (ESO), 2000