| Abstract : | To further safeguard the 3.6m Devasthal Optical Telescope (DOT) in its dome, an arrangement has been designed and developed in-house for filling the gap of about 150 mm between the fixed and rotating dome structure. The arrangement consists of brushes fixed with their mountings on the inner circumference of the dome to act as a flexible seal for the dome. It was designed to protect the delicate telescope components and instruments from high humidity, dust and fog etc. entering from the dome outer gap. The arrangement will provide an effective barrier during heavy rain and high winds experienced at the Devasthal site. The mechanical and chemical properties of commercially available industrial brushes were studied to select the appropriate brush material. A prototype of the brush was initially prepared, fixed and tested with DOT dome for about one year. Material tests on brush samples were conducted for ascertaining their suitability for the desired application. The mounting arrangement of brushes was fabricated at the site and its design facilitates the replacement of worn-out brushes over time. Fixed brushes will serve as an effective seal for the DOT dome. |
