Construction and Interfacing of a Solar Telescope

Jon Turner

University of Northern Colorado

Overview

• Directs sunlight to a fixed target

• Three mirrors: two stationary, one moveable.

• Guided using computer controlled stepper motors.

• 60 foot vertical shaft

Uses

• Lecture demonstrations• Solar astronomy• Spectroscopic analysis• Sunspot tracking• Digital imaging• Eclipse viewing• Atmospheric studies

The Dome

• Made by Technical Innovations, Inc.

• Located on the roof of Ross Hall of Science

• Installed during renovation of 2003

• 6 foot diameter

Collector Mirror

• Alt-azimuth configuration

• Two rotation stages

• Two stepper motors

• Located inside dome

Stationary Mirrors

• Director Mirror• Located inside dome

directly above shaft• Projects beam vertically• Welded angle iron support

• Lab Mirror• Projects beam horizontally

into Optics Lab• Bottom of shaft filled with

sand

Computer Interface

• Dedicated computer has Advantech PCI bus interface card

• Has 16 digital output channels, counter/ timer and D/A , A/D conversion capabilities

• Connects to breakout board through 68 pin SCSI cable

Heliostat Control

• Windows based GUI• Original software

designed through a collaboration of students and faculty

• Allows bi-directional control of each motor

• Variable slewing rates

Current Events

• Allows for remote operation of the dome via computer

• Mounted inside dome• Requires connection

to dome motors and power supply

Dome Control

• Software included with dome

• Controls opening, closing, rotation

• Display of current position

• Links to popular telescopes

Current Events

• Ensure appropriate input signal to motor controller cards

• Enclosure containing: motor controller cards, power supply, relays, temperature sensor, fan

• Placement and alignment of mirrors

Budget Summary

• Dome - $20,000• Mirrors - $1960• Motors - $40• Motor Controller cards - $110• Rotation stages - $987• M1 and M2 mounts - $900• Computer - $1100• Internal pc card - $650• H-Alpha Filter - $4200• Cables, Miscellaneous - $200

Total - $30,147

Future Plans

• Tracking Algorithm• Dome control integration• Full system automation• CCD Imaging• Hydrogen-Alpha filter• Spectroscopic analysis• Weather Alerts (auto-shutdown)• Live image monitor• Upgrade to materials with low thermal expansion• Vibration suppression

Acknowledgments

• Sponsored by NASA funds distributed by Colorado Space Grant Consortium

• Dr. Kendall Mallory – Dept. of Physics• Dr. Robert Walch – Dept. of Physics• Dr. Dick Dietz – Dept. of Physics• Ken Cochran – Instrumentation & Fabrication• Chad Lane and Jake Miller – Earth Sciences