Hind High Vacuum Co (HHV) recently announced that it has bagged a contract from Physical Research Laboratory (PRL), a unit of Department of Space, Government of India, for the manufacturing and installation of a dedicated mirror coating plant for PRL’s upcoming 2.5-meter telescope. This telescope is a part of the Mount Abu Observatory which is located at the Gurushikhar peak of Mount Abu, Rajasthan at an altitude of about 5600 feet above mean sea level.
The mirrors of the telescopes are amongst the most important components for sensing radiations from distant sources. These need to be coated with a reflective thin film that aids efficient light collection. The reflective coatings are prone to environmental degradation which necessitates a re-coating. The existing coatings are stripped clean, and a fresh coating is then applied. These coatings are applied by vacuum deposition process to obtain the best properties in terms of reflectivity and durability. As the mirrors are sensitive, and one of the most expensive components in the telescope assembly, the coatings are carried out on-site. Thus, a vacuum coater is stationed on-site astronomical observatories for coating of the mirror at regular intervals.
Discussing the project, Prashanth Sakhamuri, MD, HHV, expounded, “Astronomical telescopic mirrors coaters require a technologically advanced high vacuum equipment design, engineering, and manufacturing. HHV has commissioned and demonstrated its coaters at various locations including demanding high altitudes going up to about 14,800 feet. The telescope mirrors size of up to 3700 mm diameter and weighing more than 4000 kg can be accommodated in HHV coating chambers with a maximum overall dimension of 4000 × 2100 mm. The coaters offer an automated and highly reliable process for coating mirrors with aluminium- and/or silver-based coatings.”