Otto Struve 82-inch Telescope

The 82-inch (2.1 m) Otto Struve Telescope (OST) was dedicated May 5, 1939. The University of Texas at Austin operates the facility through the support of the state of Texas and offers time at no cost to users. ARGOS is mainly used for time-series photometry and SQUEAN for visual observing. Only one instrument can be mounted at a time. The instruments are scheduled for use in blocks based on proposal selection and science scheduling constraints. Classical observing is available to all proposers. Please note that UT Austin proposals are prioritized over others.

Information For Observers

Video Tutorials - almost everything you need to know about how to use OST, especially for ProEM. Observers should watch videos 1..8. Observing Support members should additionally watch 9..13.

Observer’s Checklist - summary of startup, observing, shutdown procedures, observing limits and safety, and how to request help.

ARGOS/ProEM Observer’s Guide - observing guide and technical information about ProEM.

Super Tracking - time series and spectra demonstrating OST’s superior tracking accuracy to support time series photometry.

Public Access

By Kent McMillan

The 82-inch Guided Tour includes admission to the Visitors Center, as well as a guided tour of the 82-inch Otto Struve telescope. Guests will visit the dome building and observing floor, learning about the history of the Observatory and operation of the 82-inch telescope, then and now. Duration is approximately 75 minutes. The 82-inch Telescope is not wheelchair accessible. Transportation from the Visitors Center to the summit of Mt. Locke is provided. Reservations Required.

Technical papers.

The story of Super Track!

Spectral Analysis servo tuning for telescopes

How the amazing Set Mechanism works!

Declination Drive Rebuild of 2009: first improvement.

Control Systems and Features

Remote observing capability with two-factor safety app running on the remote observer's computer, including remote control of dome slit, windscreens, mirror cover, and baffle tube. (Please check for availability.)
Safe automation to target in 2 clicks in an easy graphical interface. Catalogs include FK5, YBS, NGC, Messier, Index, and targets in J2000 and B1950.
Dome automation follows telescope during tracking.
Excellent HA tracking, with actual on-sky rms tracking noise of 0.1 arcsec relative to the commanded rate. See Super Tracking.
Autoguiding tuned to OST's step response with closure of both position and velocity loops. The Point-spread calculation accurately locates the centroid on a slit, with a custom version for Texas A&M's ETSI.
Ephemeral tracking using JPL Horizons data. Track rates in arcsec/sec cover +1<HA<+18 and -150<DEC<+150. Watch OST track a Soviet Molniya satellite (2-second integrations @ 15fps), open-loop i.e. no guiding.

Optical Specifications

Primary Mirror	Prime focus f/3.9	Cassegrain focus f/13.7
Diameter: 2.08m Material: Pyrex® Thickness: ~30cm Weight: 1900kg	Focal length: 8.13m Plate scale: 25.4 arcsec/mm Field angle: ~63 arcmin	Focal length: 28.53m Plate scale: 7.2 arcsec/mm Field angle: ~20 arcmin

Historical

Construction	Contractor	Telescope & Dome
Started: 1933 Completed: 1939 Dedicated May 5, 1939	Design: Otto Struve Telescope: Warner and Swasey Co. Dome: Patterson Leitch Co. Optics: C. Lundin	Telescope Weight: 41 t Polar axis bearings: SKF double race Dec axis bearings: tapered roller Dome diameter: 19m Dome weight: 104 t

Need more technical information? Contact John W. Kuehne.