IAO
Indian Astronomical Observatory - Hanle
2M HCT

Overview.Facilities.Mets.HDSR.Contact.

Himalayan Chandra Telescope (HCT)

May - August | 2025 | Cycle 2 & January - April | 2025 | Cycle 1

hct-schedule
guidelines

2025_Cycle01

hct_proposals

Important Notices For All Observers

The Telescope will not be available for regular observations during August 04 to August 19, 2025 due to planned Annual Maintenance.
The Service mode observations with HCT has been stopped. The PI/Co-Is of the proposals are requested to be physically present at CREST during their observations.
The HFOSC CCD1 system is in use since CCD2 system needs maintenance.
The HESP instrument is available for observation.
To ensure the safety of components, the telescope will not be operated when the ambient temperature is below -20 deg C. The dome shall also be closed at this temperature limit.
HCT Call for Proposals
INFORMATION
HCT proposal submission

2M Himalayan Chandra Telescope (HCT)

2M Optical Infrared Telescope

hct

First light obtained on September 26, 2000
Telescope Released for Science Observations Beginning 2003 May

A 2-m aperture optical-infrared telescope, the Himalayan Chandra Telescope (HCT) manufactured by the EOS Technologies Inc., Tuscon, Arizona, USA is installed at IAO. The telescope is remotely operated from CREST, Hosakote, via a dedicated satellite link.

The telescope is equipped with 3 science instruments which are mounted on an instrument mount cube at the cassegrain focus of the telescope. The instrument mount cube has four side ports and an on-axis port, which makes all three instruments available mounted on the telescope.


Available Instruments

The instruments currently available are the Himalaya Faint Object Spectrograph (HFOSC), the NIR Imaging Spectrograph (TIRSPEC), and the Hanle Echelle Spectrograph (HESP).

hfosc
tirspec
hesp

Telescope Specifications

Aperture

2.01 metres

Mirror Material

ULE

Optics

Ritchey-Chretien

Mount

Altitude over azimuth

Focus

Cassegrain; provision for Nasmyth

F-ratio

f/1.75 primary; f/9 Cassegrain

Image Scale

11.5 arcsec/mm

Field of View

7 arcmin; 30arcmin with corrector

Image quality (zenith)

80% power < 0.33 arcsec dia; 90% power < 0.73 arcsec dia

Jitter & periodic errors

< 0.25 arcsec on each axis

Pointing accuracy

< 0.45 arcsec over 17 arcsec move;
< 1.5 arcsec for > 10 deg move

The telescope tracking tests indicate that a tracking accuracy (open loop) of 0.5 arcsec over 10 minutes is met at a good fraction of telescope positions, except at higher elevations, where the tracking worsens, resulting in a mean (over all telescope positions) accuracy of 1.38 arcsec over 10 minutes.
A pointing accuracy of 3 arcseconds has been achieved.
The image quality is estimated to be about 0.7 arcseconds diameter (80% power).
The autoguider (AUGUS) developed at the Copenhagen University Observatory was installed in May 2005. The AUGUS can guide on a 17 mag star in 4 second integration, and uses the HCT Observatory Server interface to close the guiding loop.


Last updated on April 11, 2025