Operating the Thorrowgood Telescope

The Thorrowgood telescope is approximately 150 years old, built about 30 years after the Northumberland. It is a smaller refractor telescope but still provides excellent views of the night sky.

Before Using the Telescope

• Check the weather: Do not open the dome if it is raining
• Bring a red light torch to preserve night vision
• Remember that the telescope is unavailable on Wednesday evenings from October to March (used for Public Observing)
• Get the key from Churchill College Porters’ Lodge using your ObsCard

Initial Setup

1. Enter the dome (no alarm system for the Thorrowgood dome)
2. Turn on the red lights
3. Remember to fill in the Attendance Book in the Northumberland dome before starting your session
4. Ensure the telescope is unclamped before attempting to move it

Important Warnings

• Move the telescope slowly and with care
• Only move in right ascension (RA) when the appropriate clamps are unclamped
• Do not move the telescope by holding the eyepiece, focuser, or finderscope
• Ensure the telescope does not hit any part of the dome while moving it

Opening the Dome

1. Point the telescope away from the slit to protect the optics from debris
2. Unlock and open the dome slit
3. Rotate the dome as needed to align with your observation targets
4. Be aware of the dome’s rotation limits

Removing the Lens Cap

Carefully remove the lens cap, ensuring you don’t touch the optical surfaces.

Finding Objects

The Thorrowgood has a different system than the Northumberland:

1. Use the setting circles on the telescope to locate objects by their RA and DEC coordinates
2. The RA circle may need calibration - check the ObsBook for recent notes
3. The finderscope can help with locating objects once you’re in the general area

Using the Tracking System

1. Ensure all clamps are properly engaged once you’ve found your target
2. Turn on the tracking motor to compensate for Earth’s rotation
3. Make small adjustments as needed using the fine controls

Eyepieces and Filters

• Never touch the glass surfaces of eyepieces
• Lower focal length eyepieces provide higher magnification
• There are eyepieces specifically for the Thorrowgood telescope
• Make sure eyepieces are properly secured before use
• To focus, use the focusing mechanism on the telescope
• Appropriate filters are available for specific observations (lunar, planetary)

After Observing

1. Make sure any motors or tracking systems are switched off
2. Replace the lens cap
3. Return all eyepieces to their proper storage location
4. Close the dome
5. Return the telescope to its parked position
6. Return any other equipment used
7. Sign out in the Attendance Book in the Northumberland dome
8. Turn off the lights
9. Securely lock the dome before leaving
10. Return to Churchill to hand in the key and collect your ObsCard

For any queries or observing ideas, contact the CUAS Observation Secretaries at cuasobserv@gmail.com