The PRL 2.5m telescope project is a state of the art technological development taken up at Physical Research Laboratory (PRL) in collaboration with Advanced Mechanical and Optical Systems (AMOS), Belgium. The design of the main tube is a Ritchey-Chretien (RC) configuration, i.e. a hyperbolic concave primary mirror (M1) and a hyperbolic convex secondary mirror (M2) sharing a common conical focus. The plate scale of the telescope equals 10.313 arcsec/mm. The focal plane is 2.1 m behind the vertex of the M1. The effective focal ratio of the telescope is f/8 with the operational waveband of the telescope between 370-4000 nm. The size of the primary mirror is 2.5m supported over 42 axial and 18 peripheral actuators. The meniscus primary mirror has the advanced Active Optics system which corrects for mirror deformations actively during operations. Wavefront sensor (WFS) is the brain of the active optics system which analyse and command the actuators for required corrections in primary mirror.
The secondary mirror is mounted over the Hexapod with baffle tree mechanism and has five degree of freedom (tip, tilt and focus) to correct for the aberrations. The telescope is made for an unvignetted Field-of-View (FOV) of 25-arcmin diameter at the main port. Two side ports are designed for FOV of 10 arcmin diameter. There are two separate M3 mirrors to direct the central light to two side ports respectively. One of the M3 mirror is equipped with tip-tilt mechanism which will compensate the first order atmospheric seeing conditions and thus will improve the star image size giving a clearer and crisper images. It has a pointing accuracy of 2 arcsec RMS absolute and 0.5 arcsec RMS differential. The tracking accuracy of the telescope is 0.2-0.5 arcsec RMS in close loop with Auto guider unit.
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The 1.2m telescope was designed and built indigenously by the SHAR Center of ISRO. The telescope is on a fork mounted equatorially. All the original electronics has been replaced by PRL's engineers in recent times and the current version of the electronics and control/drive system is controlled by a Linux PC. The software is also developed in house. Apart from normal 'sidereal' tracking, it is also possible to have non sidereal rate tracking for observing fast moving objects like comets and asteroids.
Telescope is operational since December 1994.
Various back-end Instruments that are available with the telescope at present can be found here
Automated Telescope for Variability Studies(ATVS
"Automated Telescope for Variability Studies" or ATVS is a newly installed observing facility at MIRO Observatory. This is a CDK20 system provided by Planewave instruments Pvt. Ltd. The Planewave instruments CDK20 is a 20 inch(0.51 meter) f/6.8 corrected Dall-kirkham Astrograph Telescope. ATVS is completely automated robotic telescope and hence can be operated remotely from anywhere in PRL network. Apart from the back end instrument, ATVS system comprises Boltwood cloud sensor, all sky camera, Shutter drive and control system, and dome drive and control system auxiliary devices coordinating in robotic operation. The driver for operating the different components of ATVS system are developed in house.
This is a CDK17 system provided by Planewave instruments Pvt. Ltd. The Planewave instruments CDK17 is a 17 inch(0.43 meter) f/6.8 corrected Dall-kirkham Astrograph Telescope. Telescope became functional from January 2019.
This telescope has Filters :
Astronomy standard Bassels's BVRI filters.
The Telescope is utilized for exoplanet transit follow-up observations using the choice of the following sensors given in the table below:
TRIUS PRO-814 (TRI) CCD provides a field of view (FOV) of 14.60 arcminute × 11.70 arcminute with a pixel scale of 0.26 arcsecond.
ANDOR iKon-L 936 (ADR) CCD provides a field of view (FOV) of 32 arcminute x 32 arcminute with a pixel scale of 0.95 arcsecond.
Sensitivity: 1-2 millimag in differential photometry using slight defocused images of 4-6 arcsecond star psf FWHM.