The University of Minnesota Astronomy Department 10 Refractor TA Manual

Transcription

1 The University of Minnesota Astronomy Department 10 Refractor TA Manual By John C. Martin, PhD 2005 August 30 (Head TA: Crystal Austin)

2 Contents 10 Telescope Do s And Don ts... 1 Opening Up the Telescope... 2 Normal Telescope Operation... 3 Setting Circles... 3 Tips for Solar Observing... 4 Bug-a-boos of Solar Observing 4 Putting the Telescope to Bed 5 Common Mechanical Problems and Their Solutions... 6 Dealing with an Unwelcome Visitor.7 Common Questions Asked By Visitors 8

3 10 Telescope Do s and Don ts 1. You are ultimately responsible for anything you or anyone else dose to the telescope while you are operating it. Take this responsibility seriously. 2. NEVER NEVER NEVER!!! Touch the objective lenses of the telescope or the finder telescopes with anything! (However, you are encouraged to clean the eyepieces. There should be a box of lens tissue for that on the observing desk.) 3. People who have not received training are not allowed to operate the 10 telescope by themselves. (Do not lend your key to an inexperienced friend) 4. ALWAYS fill out the log book every time you come into the dome to do something. 5. ALWAYS fill out the maintenance log every time you fix, clean, or tighten something on the telescope, dome, lighting, or display cases. 6. Do NOT unscrew the diagonal on the tailpiece. Be careful when you are rotating it around not to unscrew it too far. 7. Do NOT allow a visitor to focus the telescope themselves unless you are right there to instruct them or help them. Racking the focus out too far will break the mechanism. 8. Sometimes it helps the atmospheric seeing if you close the door to Rm 450. It takes about five minutes for the atmosphere to equalize after the door is closed. (This gives a good opportunity to explain what seeing is and how dome construction has changed to accommodate it.) 9. Always clamp the telescope when you step away from it. Never trust it to be in balance. 10. Mistakes happen. Always report any problems with the telescope even if it is your fault.

4 Opening Up The Telescope 1. Turn on the dome lights. (Don t stumble around in the dark) 2. Start an entry in the telescope log book. 3. Plug-in and open the dome slit. Unplug and coil the cord when you are done. Be careful of how the cord dangles when you recoil it. You don t want it catching on things as the dome rotates. 4. Pull off the telescope shroud. Fold it. Put it where you can find it when you close. 5. Remove the lens covers. Never assume that the telescope is in balance when you do this. 6. Turn on the telescope/dome power. 7. (optional) Turn on the lights in the display case. 8. Turn down the dome lights.

5 Normal Telescope Operation 1. Locate your object in the sky. 2. Rotate the dome to the proper position. 3. Unclamp the telescope 4. Aim the telescope using the finder telescopes. 5. Center the object in the main eyepiece. 6. Clamp the telescope 7. Focus the main eyepiece. 8. Use the slow motion controls to fine tune the centering Setting Circles 1. Follow the normal procedures to find a star with a known RA and Declination. 2. Reset the telescope RA circle to the RA of the star. 3. Note and difference between the Dec listed for the star and the Dec on the telescope circle. 4. Move the telescope to the RA and Dec of your target (accounting for any difference noted in step 3).

6 Tips for Solar Observing Observing the Sun is a very good way to introduce 1001 students to the telescope without requiring them to come out in the evening after dark. However, you should not use the telescope to observe the Sun unless you have learned how to do it properly! Observing the Sun can be dangerous! You and the department incur liability when you require a class to do it. If you know what you are doing and behave responsibly you can minimize the risk to yourself, your students, and the department. I suggest that you use the projection screen method that I will demonstrate during telescope training since it is the safest of the available methods. Bug-a-boos of Solar Observing 1. NEVER NEVER NEVER! Look through the eyepiece with your eye or allow anyone to look through the eyepiece with their eye. Sternly warn anyone with you not to do this before you start. 2. Remove the lens covers from only the telescope/finder telescope that you are using to observer the Sun and leave the others on. 3. NEVER! Leave the tailpiece unattended while the telescope is pointed at the Sun. 4. Be aware that the telescope may be out of balance and heavier on one end when you add equipment to that end. 5. Be aware that parts of the telescope get very hot very quickly when it is pointed at the Sun. 6. NEVER! Leave anything flammable (i.e. a white piece of paper being used as a projection screen) behind the eyepiece unless you are there to take action in case it immolates.

7 Putting the Telescope to Bed These procedures are outlined in the front page of the log book 1. Rotate and park the dome with the slit facing south. 2. Plug-in and close the dome slit. Unplug and coil the cord. 3. Turn off the telescope drive. 4. Put the lens covers on the telescope and finder telescopes. 5. Park the telescope over the pier (with Dec = 90) and clamp it. 6. Drape the shroud over the telescope. Be sure to cover the tail piece and as much of the gear work as you can. 7. Put the ladders where no one will trip over them. 8. Complete your entry in the log book! 9. Turn off all the lights (display case, dome, desk, etc.). Be sure that you turn off the lights on dimmer switches and don t just turn them down. 10. Close and LOCK the dome door.

8 Common Mechanical Problems and Their Solutions Something was broken when I arrived. Note it in the log book. If it makes it impossible to use the telescope and you don t know how to fix it, shutdown the best you can and go home. Notify the head TA about it ASAP. The telescope is not tracking properly. - Check the telescope power. Is the motor spinning? If not note the problem in the log book and to the head TA the by the next day. - Did someone leave an attachment on the telescope affecting its balance? If so, remove it. - Check if the gears are meshing properly. If there is something loose and obvious, then tighten it gently with your fingers. (Do not use tools unless you really know what you are doing!) Report the problem in the log book. The power went out. Park the telescope as you normally would with the lens covers on and cover it with the shroud as completely as possible. Stick around awhile to see if the power comes back on enough for you to close the dome slit. Make a note in the log and check back later to see if the power is back on to close the dome. Let the head TA know this happened. I can t rotate the dome. Make sure that the telescope power is turned on. The telescope power must be on to rotate the dome. If the telescope power is on and the dome still won t move is the dome motor running? If it is, the dome sometimes stalls. Try rocking the dome one way and then the other to work it loose. If that doesn t work, get someone to hold down the button to move the dome while you climb the ladder and push on one of the girders. As a last resort, get the three prong extension cord out of the UITP equipment. Plug the dome into the nearest wall socket using the extension cord. Close the dome slit. Make a note in the log. And let the head TA know by the next day that the dome is broken. In the unlikely event that the steel dome cable snaps, it is very loud but don t panic. Simply end observing for the night and follow the last resort instructions above. I made a mistake and broke something. Don t panic. Mistakes happen and often things seem worse than they really are. Note the problem in the log book and notify the head TA about it ASAP.

9 Dealing with an unwelcome visitor On one rare occasion (that we know of) the person manning the 10 telescope for Friday night open house had to deal with a visitor who became increasingly agitated and unwelcome. First of all, this is not normal. You should assume that almost every visitor to the telescope is there because they are friendly and interested. There are a few regulars at Friday night telescope viewing who may not seem completely normal to you but they are friendly and not a threat to you or other visitors under most circumstances. This section is to provide some pointers for dealing with the very rare unfortunate circumstance of having an unwelcome visitor. Always deal with every visitor in a polite and deferent manner. If you have a heckler, kindly ask them to give other people a chance to ask questions. Normally if you politely ignore these people and don t become agitated yourself then everything turns out fine. If a visitor becomes agitated and you are concerned for your safety and/or the safety of the other visitors follow these steps: 1. Ask the person to go down stairs with you to Rm 450 to talk. If you can come up with any safe way to coerce them out of the dome use it. 2. If you cannot coerce them out of the dome, calmly and politely ask another visitor to go find your partner and bring them to the dome ASAP. Try to work yourself into a location near the stairs but not blocking them (so that if your problem chooses to flee, they can unabated but so that you also have quick access to the stairs). Do not leave a problem person in the dome alone with other visitors. 3. If you are alone in the dome with this person, leave the dome yourself as calmly as possible and find your partner ASAP. 4. When you have successfully found your partner, quickly and calmly explain the situation to them. One of you should use the TA office phone to call campus security immediately. 5. Politely and forcefully ask the problem person to leave. The keys to dealing with this situation roughly in order of importance are to: - avoid any potential conflict with a visitor - remain calm and do not cause a panic - protect yourself from physical harm - protect the other visitors from physical harm - remove the problem from the premises - inform campus security

10 Common Questions Asked By Visitors How old is the telescope? It was purchased in 1896 and installed in When was the telescope moved to the roof of the Physics Building? 1938 Is this the original dome? We don t know. But from its construction we think that it might be. How much did this telescope cost? It was bought for $6800 from Warner & Swasey of Cleveland, OH in Today it is a priceless antique. How much does the telescope weigh? We don t know exactly. The telescope is machined entirely from steel with brass fixtures. The best estimate is that it weights about 500 lbs with the lenses and counter weights. How did the telescope track in 1897 without an electric motor? The telescope used a falling weight (through the middle of the hollow telescope pier) to provide the power to run the clock drive in a manner very similar to a grandfather clock. How deep does the telescope pier extend down? The telescope pier extends about three feet below the floor you stand on and is bolted to the roof of the building. It does not extend to bedrock below the building. Does the department own other telescopes? Yes. We own two larger telescopes at O Brien (30 telescope) near Stillwater, MN and at Mt Lemmon (60 telescope) in Arizona which are used primarily for infrared research and are not open to the public. We have bought into the Large Binocular Telescope (Arizona). It is a small share (about 5%), equivalent to one week of time a year on it. How can a telescope that is so old still work? As long as the glass objective lens for the telescope is still in working order, simple regular maintenance of the mechanical parts is all that is needed to keep the telescope working. A lens that is 100 years old works just as well as one just built. (Maybe better since they really knew how to grind them well by hand back then.) Other topics it helps to know about and explain in simple terms: basic telescope design and optics, atmospheric seeing, light pollution, the types of research going on in the department, fun facts about the objects being viewed through the telescope. Be aware that the LBT is a political hot potato with Native American groups. It is best for you to sidestep the issues and refer any questions to the department office.