Columbia University Astronomy Big Dome Telescope Start up/shut Down Start Up 1. Get the Eyepieces: Go into the transit room and get any eyepieces you will need. The telescope in the big dome takes both the standard 1.25 eyepieces and the larger 2 eyepieces. a. Choosing the right eyepiece: As a rule of thumb, larger focal length eyepieces (e.g. 35mm, 41mm) have lower magnification and larger fields of view. Conversely, smaller focal length eyepieces (e.g. 10mm) have higher magnification and smaller fields of view. The right eyepiece is somewhat a matter of preference, but if you re going to be looking at something big like the Moon, you probably want a long focal length eyepiece to see the whole moon (unless, of course, you re just focusing on a single crater). If you re looking at double stars, you might want a small focal length eyepiece to get a close-up view or you might want a long focal length eyepiece so you can see the binary system contrasted against a field of mostly single stars. 2. Open the Slit: Verify that the objective cover is on the telescope, and then open the slit. To open the dome slit, pull the ladder over to the big wheel mounted on the dome and turn it counter clockwise until the slit opens all the way. 3. Remove the Cover: Take off the objective cover (the big cover over the business end of the telescope). 4. Put in the Eyepiece: Place an eyepiece in the diagonal 1
a. If you re using a 1.25 eyepiece, you ll need to make sure the adapter ring is in the 2 diagonal. b. If you are using a 2 eyepiece, take the adapter ring out of the 2 diagonal and place the eyepiece straight in. 5. Power up the telescope: Turn on the power to the telescope using the switch on the base of the mount, and allow the telescope to boot up. The telescope will spend some time moving (slowly) as it initializes its drives. After about 45 seconds, the display on the control paddle will say Press 0 to align or MODE for Menu. Press the MODE button ~4 times until the screen says, Select Item: Object. 6. Move the dome: Using the lever near the steps, rotate the dome until your object of interest is visible out of the dome slit from the position of the telescope. Three important notes about dome rotation: The dome rotation lever has three speeds. Feel free to use the slowest two speeds, but do not rotate the dome in the top speed as this may damage the dome. It is important not to move the observing platform up and down using the switch next to the dome lever. This can cause serious damage to the stairs leading up to the dome. You should never need to move this platform with the currently-installed telescope Try to avoid moving the dome through its trouble spots, indicated by blue tape on the dome wall. When the slit lines up with these spots, the dome can become stuck. The arrows represent the preferred direction of motion. The dome does not seem to get as easily stuck when it is being rotated in that direction. If you must move through a trouble spot, move it through at one of the higher speeds. Most importantly, do not let the dome stop in the trouble spots ; it will likely be very difficult to rotate the dome from those positions again. 2
7. Move the Telescope: Once the telescope is fully functional, you can use the four arrows on the paddle to move the telescope. a. To change the speed of motion, you can hit the #1 key ( Speed ) key and use the arrows on the bottom of the paddle (pointing up and down) to page through the speeds. There are two sets of notations for speed: a.i. Multiples of the tracking speed (e.g. 2x, 8x, 16x) for very fine motions, and: a.ii. Number of degrees per second (e.g. 0.5 /sec, 1.5 /sec, 3 /sec, Max ) for faster motion. b. Generally, you should use one of the fastest speeds for moving the telescope to a target and one of the slower speeds for centering the object in the eyepiece. 8. Turn on the Telrad: Using the switch on the side of the Telrad, turn on the target light. 9. Center on a bright object: Using the Telrad, and the arrow keys on the paddle, point the telescope near an object you know. This can be a bright star (the best option), a planet, or the Moon. Center the object in the Telrad. 10. Course Focus: Look through the eyepiece of the telescope. If you need to focus the telescope, first UNLOCK the focus (turning the large knob near the top of the telescope clockwise), and then turn the smaller focus knob to adjust the focus. When you have the focus roughly right, re-lock the focus by turning the focus lock knob counter-clockwise. a. Note: Because of the design of the telescope, focusing will also likely shift around the object in the eyepiece. Recenter using the paddle if you need to. 11. Fine Focus: Using the paddle, press the #4 key ( Focus ). Using the up and down arrows at the bottom of the paddle, adjust the speed of the fine focus. Then, using the left and right arrows near the top of the paddle, adjust the actual focus. When 3
you push those arrows you should hear a small motor running that makes fine adjustments to the focus. Note: If you are only going to be looking at bright stars or planets that you can easily find unassisted, you re done. You do not need to continue on to steps 11-12 and can skip to step 13 when you re ready to shut down. If you want to point at fainter objects, however, you need to sync the position of the telescope (see the following steps) 12. Position Sync: Depending on what you used as your first bright target, select the appropriate category on the paddle: a. For Stars: a.i. Push the #6 Button on the paddle ( Star ) a.ii. Choose the way you want to look up your object using the up and down arrows at the bottom of the paddle (e.g. Named, SAO Catalog, etc.) and press ENTER to make your selection. a.iii. a.iv. Page through the list of objects (again using the up and down arrows at the bottom of the paddle) or enter the number code for the object, where appropriate. Press ENTER. Press and hold the ENTER key for ~2 seconds. When you release the key, the display should say, Press ENTER to Sync. a.v. Press ENTER one last time to sync the telescope to the object you ve choosen. b. The procedure is exactly the same for the Moon or Solar System Objects, except you hit the #5 button ( SS ) in step i. 13. Moving to a New Object: a. Use the buttons on the paddle (see table on right) to select the type of object you want to move to. b. Either select the specific object from a list using the up and down arrows at the bottom of the paddle or enter the catalog number using the number keys. 4
Shut Down c. Press and release the ENTER key. d. Press the GOTO button. The telescope should automatically move to the new position. 14. Move the telescope to the Park Position: The proper position to Park the telescope is on the meridian. The telescope fork should be horizontal and the telescope should be perpendicular to the fork, pointing North. 15. Power off the Telescope: Switch off the Power button and replace the telescope s paddle in its holder. 16. Replace the Objective Cover: Put the big lens cap on the telescope. 17. Close the Dome Slit: Turn the big wheel clockwise to close the slit. 18. Replace the objective cover on the telescope. 19. Remove the eyepieces and place all of them back in the transit room: It s critically important that the eyepieces make it back into the proper storage location. Not only do the cases protect them from dust or damage, but it will ensure that the next person to use the observatory will be able to find the necessary eyepieces. 20. Make sure the telescope and all lights in the dome are off: Look back into the dome as you close up. Are all the lights off? Is the Telrad off? Is the telescope s power off? Is the dome slit closed? Everything should be locked, dark, and quiet. APPENDIX Troubleshooting: 5
A) If the telescope doesn t appear to move when you push the arrow keys, verify that the speed is set to a reasonable rate. If it s set to 2x or 4x, you will almost certainly not notice its (very slow) motion. B) Occasionally, when you move from step 11 to step 12, the telescope will lose its Syncing. The best first step is to just retry step 11, which works most of the time. If that doesn t work, try turning the power off to the telescope, then turning it back on. C) If the dome becomes stuck, you should try one of the following: a. Try moving the dome in both directions at both slow, medium, and high speed, using the lever. b. If that doesn t work, you will need to recruit some volunteers to push the dome around as you push the lever into the high speed mode. 6
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