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The Doghouse Observatory 10-inch Meade LX200 Schmidt-Cassegrain


(Rev. August 09, 2011)


The 10-inch telescope is a Meade LX200 Schmidt-Cassegrain and is found in the Doghouse next to the 6-inch refractor (see Chapter 3). The Schmidt-Cassegrain is equatorially mounted and is driven by an electric clock drive, and its motion can be operated from a hand-held control paddle. The Doghouse telescopes should not be used until you have been shown how to use these telescopes and have been given permission by a TA or faculty member to use them on your own (i.e., checked out).


Operation of the 10-Inch Meade Telescope

  1. Roof: The roll-off roof of the Doghouse is operated manually with the crank beside the door. There is a vice clamp holding the chain in place which must be loosened before opening the roof. Be sure to reclamp the chain tightly after closing up for the night. Never move the roof unless both telescopes are horizontal and clear of its path. Refer to the Open/Close Checklist for the Doghouse Observatory (Chapter 3).

  2. Objective Cover: Remove objective cover carefully. Be careful of the corrector plate just beneath as there is no handle on the cover. Be sure to replace it when you are finished observing.

  3. Telescope Power: Turn on the power strip located at the base of the pier on the lower east side of the pier. Then, place the ON/OFF switch located in the upper right corner of the power panel (11) to the ON position. The telescope should now be receiving power.

  4. Declination Clamp: Loosen the declination clamp. This clamp is a palm sized knob with a grooved edge located in the center of an aluminum ring on the outside of one of the fork arms. Loosen the clamp by turning the knob counterclockwise. Once the clamp has been loosened, move the telescope to $0^{\circ}$ declination by aligning the 0 on the declination setting circle (3) with the declination pointer (4) on the fork. Tighten the declination clamp.

  5. Paddle and Drive: The paddle controls the slow motions and the drive. Use the direction keys on the control paddle (12) to slew the telescope in the east-west direction until the right ascension pointer (9) is at zero hour angle. This is accomplished by aligning the right ascension pointer (9) with the hour angle pointer (16) located just above the center of the power panel on the drive base. Note that the telescope has variable slew rates: slew, find, center, and guide corresponding to the buttons on the keypad with the numbers 7, 4, 1, and 0 respectively. An abbreviation for each slew rate is written above the corresponding number on each button. Simply press the appropriate button to change to the desired slew rate.

  6. Star Alignment: The celestial coordinates must now be set by aligning the telescope with two reference stars. At this point the menu on the control paddle should read:

    $\rightarrow$ TELESCOPE
    Make sure that the arrow is pointing to the TELESCOPE option and press the key marked ENTER. The menu should now read:
    $\rightarrow$ 1) SITE
      2) ALIGN

    Press the NEXT key to move the arrow down to the ALIGN option and then press ENTER. The menu should now read:

    $\rightarrow$ 1) ALTAZ
      2) POLAR

    Make sure that the arrow is pointing to the ALTAZ option and press ENTER. If the menu DOES NOT change, but the checkmark on the right of the menu moves to ALTAZ, press ENTER again. The menu should now read:

    1 Star or
    2 Star Alignment

    Press the key with the number 2 on it to select Star Alignment. You will now be asked to pick two stars from a list contained in the telescope's computer. The computer will then ask you to center these two stars in turn in order to set the coordinates for the telescope. The menu should now read:

    Level base, then
    press ENTER
    The base has already been levelled so go ahead a press ENTER. The menu now reads:
    Press ENTER, pick
    align star 1

    Press ENTER to get a listing of the stars available in the computer's memory. Use the NEXT and PREV keys to move the arrow to the star of your choice. Once you have found the star that you wish to use, press ENTER. The menu will then read:

    Center Starname
    then press ENTER

    Use the control paddle to slew the telescope to the star that you have chosen and center the star in the field of view. DO NOT LOOSEN ANY CLAMPS OR MOVE THE TELESCOPE BY HAND. This will cause the computer to lose track of where it is in the coordinate system. Once the star is centered press ENTER. The menu will then ask you to go through the procedure of picking and centering a star once more. Press ENTER, pick a second align star just as before, USE A DIFFERENT STAR THIS TIME, center the star, and then press ENTER. The computer should now be oriented and happy. The menu on the control paddle should have returned to the first option:

    $\rightarrow$ TELESCOPE

  7. Locate Messier Object: The telescope can now be easily moved to any Messier object by pressing the key which has an M for Messier above a number 9 on it to obtain:

    M object:

    Key in the Messier number of the object that you wish to find and press ENTER. The menu now displays some information about the object such as its magnitude, what type of object it is, etc... Press GOTO and the telescope will automatically slew to the object. Use the control paddle to center the object in the field of view.

  8. Locate NGC Object: You can just as easily find objects whose NGC number you know by pressing the key marked with CNGC above the number 3.

  9. Eyepieces: Eyepieces are stored in the eyepiece box on the shelf in the corner of the Doghouse. Most objects are best viewed under low or moderate power, rather than high power which is recommended for high surface-brightness objects such as planets and double stars. Replace the eyepieces in the eyepiece box before leaving.

Closing Down

Stow the 10-inch Meade

Secure the doghouse

Observer's Room (Room 106)

Secure the Observatory and Grounds:

Those are the basics. To learn more about all of the fancy features on the telescope consult the LX200 manual located in the Doghouse or in the TA filing cabinets.

Figure 1: Meade LX200 Schmidt Cassegrain Telescope

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