http://hdl.handle.net/2248/5068 Search the Channel search http://prints.iiap.res.in/simple-search http://hdl.handle.net/2248/5830 Title: Development of a temperature controller for the order-sorting interference filters<br/><br/>Authors: Banyal, R. K; Ravindra, B<br/><br/>Abstract: A Fabry-Perot narrow band imager (NBI) is being built for solar studies at IIA [1]. The NBIhas an order sorting pre- lter that selects an optical beam within desired wavelength band. Aconstant temperature is required to keep the transmission response of the interference lter stableduring the observations. This technical report describes the design and construction of a digitaltemperature sensor and control system for the pre- lter assembly. Temperature measurement andthermostat operations are performed by DS1621 -a semiconductor IC from Maxim. An I2C serialinterface (also called 2-wire interface) was developed using computer's parallel port. The design ofthe I2C interface circuitry and LabVIEW programmes to implement serial communication betweenthe temperature sensor and the PC are described in details.The device operation is validated andresults of laboratory test are presented.<br/><br/>Description: Open Access http://hdl.handle.net/2248/5747 Title: Solar G-band observations at Merak, Leh/Ladakh<br/><br/>Authors: Vasantharaju, N; Dorjey, N; Ravindra, B; Prabhu, K; Rangarajan, K. E; Prabhu Ramkumar, B; Sankarasubramanian, K<br/><br/>Abstract: G-band observations are important for the study of dynamics of magneticfeatures in the solar photosphere and they are carried out using largetelescopes, larger than 30 cm. We installed a 40 cm DFM telescope atone of the good sites (Ref:Site survey report submitted to Dept. ofScience and Technology, India) in India; Merak in the district ofLeh/Ladakh. We designed, fabricated and installed a back end instrumentwhich involves a band-pass filter at G-band wavelength (430.5nm) tocarry out observations of the solar photosphere on regular basis. Inthis paper, we report the installation of the telescope and the solarobservations made with this back-end instrument. We present the detailsabout the instrument used, data calibration and comparison with similardata obtained from space. We also discuss how the system can beimproved for better quality images in the near future.<br/><br/>Description: Open Access http://hdl.handle.net/2248/5637 Title: Re-aluminization of 2M Himalayan Chandra Telescope primary mirror<br/><br/>Authors: Kemkar, P. M. M; Saxena, A. K; Nirmal Kumar, P. K; Ismail, R; Sagayanathan, K<br/><br/>Abstract: The purpose of this document is to establish the general requirements for handling and coating of the primary and secondary mirror of 2M Himalayan Chandra Telescope (HCT) at the observatory Mirror Coating facility, Hanle. The optics of the telescope represents the major investment in project time & cost and also must be protected from damage during handling. Safe lifting equipment and procedures for maneuvering the mirror out of the telescope are mandatory. The complete scope of study for aluminization includes, removal of mirror from the telescope, transportation and unloading, mirror preparation (stripping and cleaning), interface with the coating chamber and putting back the mirror into the telescope with the necessary alignment, performance verification tests and tuning the correct warping harness. This report limits the discussions to mechanical handling issues during aluminization.<br/><br/>Description: Open Access http://hdl.handle.net/2248/5353 Title: Solar Powered Dome Shutter Control<br/><br/>Authors: Ravi, K; Anbazhagan, P; Ramachandiran, A; Venkateswara Rao, S<br/><br/>Abstract: Conventional Telescope Dome Shutter Control has bi-parting shutter driven by a AC three phase induction motor to which AC power is fed through circumferential busbars. These busbars frequently requires maintenance and some times hazardous to human being in case of open type busbars.A different approach is implemented to eliminate the use of busbars. The Power source required for Dome Shutter is made available on the Dome itself which will avoid the use of busbars. To have a simple and loss less Shutter Drive, a DC Source, by means of battery, is used to drive a DC motor through a Gear Box. The DC source recharged by a suitable Solar Panel fixed at outside of the Dome. Local control on the Dome Shutter Control Unit and remote control through Radio controls are available for Shutter Operations.