5 Conclusions

It is important to know the local seeing condition as it decides the height for locating an optical telescope above the ground. The surface layers up to 12 m above the ground significantly deteriorates the stellar images at the Devasthal site. Its contribution due to 6 to 12 m slab is $\sim\! 1.28$$^{\prime\prime}$. This value reduces to $\sim\! 0.3$$^{\prime\prime}$ for the 12 to 18 m slab. A seeing of 0.65$^{\prime\prime}$ can be achieved by putting the telescope at a height of $\sim\! 13$ m above the ground. A better value for seeing $\sim\! 0.5$$^{\prime\prime}$ can be obtained, if the telescope is located above 18 m from the ground. Although during the last few years, enormous efforts have been made for characterizing the sites astronomically but very few observatories have the desired database. The largest database has been established by ESO at La Silla and Paranal, developing a very extensive and reliable seeing monitoring using various instruments, as well as the ORM at La Palma. It is intended to carry out both DIMM and microthermal measurements and to use All Weather Station for obtaining more information about the Devasthal site. This program will provide us a large database on both astronomical and meteorological data at Devasthal site.

Acknowledgements

The authors are indebted to all those who helped in the recording of microthermal and DIMM measurements at Devasthal site. The discussions held during the designing stage of the instrument with Prof. S.N. Tandon are gratefully acknowledged. We also thank Mr. R.C. Pant for his valuable contribution in setting and maintaining the instrument at the site. The comments given by the referee Dr. J. Vernin are gratefully acknowledged which helped in improving the contents of the paper.