V. Drive

5.2 Celestron CompuStar Computer Control

A Celestron CompuStar computer control is the heart of the 22" drive system. The CompuStar was the first commercially available computer control system for the amateur market The CompuStar was produced by Celestron from 1986 to 1995, (1). The CompuStar controller moves the telescope by microstepping two SloSyn stepper motors. The CompuStar computer control provides a data base of 8058 objects including CNGC and Messier objects .The telescope has a maximum slew rate of 12 degrees per second, Figure 5.2.1.

Figure 5.2.1. A Celestron CompuStar computer controller was used for controlling the telescope. The CompuStar power supply is to the left and the computer controller is to the right. The RA stepper motor can be seed just below the roller assembly. The drive is powered by a 12 volt deep cycle marine battery.

 An Intel 8052 micro controller is the brains of the CompuStar. The CompuStar has some very nice features. The data concerning telescope position, speed, and object displayed simultaneously. This is a great advantage over the modern computer controlled telescope controls with a 2 line display. I find that moving through the menus cumbersome. The coordinates of objects are also not as difficult to key-in. The advantages of the newer computer controls is a much larger data base that includes planets, the CompuStar does not. I like the small size of the newer controls also. One big disadvantage for the CompuStar is the need for a lot of power about 12 amps. One does not use your car battery for powering the CompuStar if you want to drive home! For now I will stay with the CompuStar control system. Here are some brief specifications for the compustar.
Power Supply                              12V DC @ 18 Amps
RA Step Size                                 9/64 arc seconds
Dec Step Size                              15/64 arc seconds
RA Slew Speed                             6 degrees per second maximum
Dec Slew Speed                          10 degrees per second maximum
RA Set Speed                             15 arc minutes per second
Dec Set Speed                            25 arc minutes per second
RA Guide Speed                         15 arc seconds per second
Dec Guide Speed                        25 arc seconds per second

Star Catalogs
    Messier Catalog                   110 objects
    CNGC                               7840 objects
    REFERENCE                      240 Stars
    Limiting magnitude                -19.9

(1) Celestron Compustar fan page, http://home.online.no/~gibala/astro/cct/index.htm, 1998-2003.

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