Northumberland Telescope Guide

Introduction

The Northumberland telescope is over 180 years old, built in 1838 from a design by George Airy. It is a 12-inch refractor with a 20 ft focal length (6096 mm, f/20) and was one of the largest telescopes of its time. It is mounted on an English equatorial mount. The Thorrowgood telescope is only 30 years younger; both are historical relics in their own right, and still provide fantastic views of the night sky. For many years, CUAS members have had full use of these telescopes.

Before Going to the Telescopes

Weather Checking

You cannot open the roof of the telescopes if it is raining, not to mention that it would be too cloudy to see anything anyway. This means you need to check the weather first, by looking out of the window before you leave, and/or using one of the other options:

Getting Hold of the Key & the Alarm Code

To get hold of the key, go to Churchill College Porters’ Lodge. You must hand over your ObsCard and sign for the key there. Make sure you have the key with you at all times, particularly when you leave the domes. The entrance doors to both domes lock upon closing, and you don’t want to be stranded outside at night.

It goes without saying that you should never hand the key over to anyone that doesn’t have their ObsCard, but if you wish to hand over the key to another observer, this second observer will need to have signed, as otherwise the first observer will be held accountable if the key is missing. If need be, the second observer can sign at Churchill and then instead hand their ObsCard to the first observer, who can then swap their ObsCard when they get back to Churchill. The second observer can then pick up their ObsCard at the end when they hand back the key. If such an event occurs, it should be documented in the book in the Northumberland annexe and countersigned by both parties.

Bringing along a few friends is fine, but if you would like to bring a large group, i.e. more than 5 people, please ask the Observation Secretaries (ObsSecs) first: the email address is at the end of the guide. Alcohol and observing do not mix, so don’t try it. Remember that you are dealing with very precious, historical instruments!

If you wish to use the Northumberland dome, make sure you know the code to disable the alarm in it. The alarm was installed mainly due to the refurbishment of the dome in 2013 (it is now made of copper) and starts sounding immediately when you unlock and open the door. Upon request by the Institute of Astronomy, the code will only be given to you when you complete the ObsTest. If you forget the code, email the ObsSecs.

If you do accidentally open Northumberland dome without knowing the code, don’t panic! Enter the dome, turn on the lights and use the telephone installed there to call University Security at 31818. Explain the situation to them, and they should be able to advise you further. As the alarm is rather loud, it may be difficult to have a conversation from within the dome, so alternatively you can call them from your mobile phone; the external number is 01223 331818, you may wish to save this number. If you allow the alarm to go for more than 20 seconds, security will automatically be called – if you subsequently disable the alarm yourself, call security yourself and explain to them what has happened.

Note: If you do get stranded outside, you have three options:

  1. If you’re at the telescopes during working hours (9-5) for some reason when this happens, go to the reception of the IoA (Hoyle Building) and ask for help.
  2. If you have a phone on you, or you somehow managed to leave the door to Northumberland open, you can contact University Security at 01223 (3)31818.
  3. If you do not have a phone on you and can’t easily get hold of one, go to Churchill College Porters’ Lodge and ask the porters to call University Security for you.

Keeping Record

Before observing, head straight to the Northumberland dome. To the right of the alcove with the computer in it, there is a desk with two books that need to be filled in.

Attendance Book

Sometimes called the “LogBook”. This must be filled in every time you use the telescopes. Fill it in with your name (full name, not initials), the number of observers (yourself + any guests), the activity you’re doing (you will be observing, so write obs), the telescope you’re using (e.g. N for Northumberland), and the time you arrive and leave. Note that all ObsCard holders should individually sign in and out with the time they arrive and leave.

ObsBook

Put in here notes about any observing you did, and also any problems you noticed with the telescopes, like the RA screen in Northumberland not working, or the RA cylinder of Thorrowgood not being calibrated properly. If you notice that the telescope had not been properly put away by the person before you, or if you notice any defect or even if you happen to break something, do report it. Be honest, everybody makes mistakes and it is very important that everything is documented so that the people at the IoA who look after the telescopes have it easier to fix it. If you find a problem with the telescopes you should also email the ObsSecs, as they will know whether it is a serious issue and can pass it on to the right people if necessary.

General Rules

When observing, please remember:

Operating the Northumberland Telescope

Initial Setup

  1. Enter the dome and deactivate the alarm by entering the code
  2. Turn on the red lights (switches to the right of the door)
  3. Fill in the Attendance Book (your full name, number of observers, activity, telescope, arrival time)
  4. Ensure the telescope is unclamped at the base before moving it

Important Warnings

Opening the Dome

  1. Point the telescope away from the slit to protect the lens from debris
  2. Unlock the dome by pulling the rope on the left of the slit with the metal latch locking it (pull the side with the weight attached)
  3. Open the slit using the pulley to the right of the slit
  4. Make sure the latch doesn’t fall back and prevent opening
  5. Open the slit enough so that the edge has moved beyond the edge of the dome at the bottom
  6. To rotate the dome roof, use the pulley to the left of the rope with the latch
  7. Rotate slowly and be aware you cannot move it through the north part where there are struts

Removing the Lens Cap

Remove the plastic bag covering the end of the telescope and the lens cap underneath. You’ll need to bring the end of the telescope quite low, but be very careful not to point it below the horizontal.

Finding Objects

The program “tcs” should already be running on the computer. If not, double-click “Telescope Information Panel” on the desktop.

Use these commands in the terminal:

Once you’ve selected your target, move the telescope to about 30 seconds below the right ascension given in “Target” to give time for the object to move into position while you’re turning on the motor.

Using the Motor Drive

  1. With the worm disengaged and the 3 hand-wheel clamps unclamped, verify the wheel rotates independently of the polar axis
  2. Engage the worm with the wheel and allow it to mesh fully
  3. Switch on power to the controller box by turning the rotary switch clockwise
  4. Tighten the hand-wheel clamps at the lower edge of the wheel and the clamp at the top edge (the RA display should slow down and stop)
  5. Use the guiding and setting motions on the hand-paddle (+ and - buttons) to adjust the position
  6. The large rectangular button (red/yellow) selects sidereal rate (red) or lunar rate (yellow)

Eyepieces and Filters

After Observing

  1. Make sure the motor is switched off and all three clamps and the worm are disengaged
  2. Ensure the computer monitor is left on
  3. Replace the lens cap and bag (and finderscope cap if used)
  4. Make sure the focuser is unlocked, and the extension tube and 40mm eyepiece are in the telescope
  5. Return all eyepieces to their boxes
  6. Rotate the dome so the slit is over the door
  7. Point the telescope away from the slit before closing the dome
  8. Close the dome and lock the latch
  9. Return the telescope to a vertical position
  10. Return the large observing chair to the West
  11. Return any other equipment used
  12. Sign out in the Attendance Book
  13. Turn off the lights
  14. Turn the alarm back on before exiting (key in the code and exit within 20 seconds)
  15. 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