Company Seven.

  C-7 Home Page C-7 News Consignment Library Products & Services Product Lines Order Search

Questar Distribution News Notes & Interesting Articles Overview Pricing Products Service or Repair

Questar Telescopes LD Surveillance Systems LD Microscopes Accessories

Questar logo from 1990's (27,482 bytes)


Questar 3-½ Electronic Dec Control 136,956 bytes The original internal Powerguide system of the 1980's and its successor the Powerguide II are each an electronic regulated drive and corrector system powered by one 9 volt battery that allows the user to operate the Questar at a precise Sidereal or Lunar rate anywhere in the world - north or south hemispheres, completely independent of wall current or other external power sources. The Powerguide also provides the means to vary the rotation speed of the Right Ascension motor to make fine tracking adjustments. The internal Powerguide systems are arguably the most important innovation that has been developed for the Questar since its introduction.

Powerguide II can only be installed either when the telescope is ordered new, or if it is returned to us for the retrofit. It is not recommended for the consumer to attempt install this option. Furthermore, since Powerguide II requires adding a new, thicker cover plate over the bottom of the base, some modifications may need to be made to the Questar Carrying Case in order to accommodate a slight increase in the height; we can usually accomplish this at no extra cost. Owners of a Questar 3-½ telescope with the original style Leather Case will need to order a newer case to accomodate the telescope with the Powerguide II retrofit.

Right: Questar Duplex with the Powerguide II controller, in Pole Aligned orientation on provided table top tripod legs (136,956 bytes).
Click image to see enlarged view (304,898 bytes).

Background The Questar 3-½ and Questar Seven telescope drive fork bases are furnished with a fork style drive base with a set of three very lightweight alloy legs. The legs thread into the drive base at two points on the side, and one at the bottom to form a tripod that is adjustable for latitude. This tripod permits the telescope to operate off of a table top. Alternatively, the telescope may be Pole Aligned atop an optional field tripod such as the Questar Tristand. The fork mount is normally provided with a 120 Volt A.C. (or 220 volt optional) motor system with an AC power cord. The AC cord plugs into a US style wall outlet and this starts the fork tracking at a Sidereal rate that permits accurate tracking of stars, planets and most other celestial objects as the Earth rotates. Persons overseas can either have the two prong cord plug changed to fit the wall outlets of their country, or use a wall plug adapter (sold at most travel shops) to convert the US plug to fit. Since the standard synchronous motor of the Questar base is a non reversible one must specify either North or South Hemisphere when ordering this drive system, to go to an opposite hemisphere one could order a reversed motor and have that installed prior to their visit; this is a somewhat inconvenient solution. This basic arrangement is completely satisfactory for a person who operates the telescope only from one location that has A.C. mains power such as at a school or at home.

Powerguide II is the optional quartz crystal frequency regulated drive system for the Questar. A drive base equipped with Powerguide II incorporates a servo motor with drive corrector circuitry powered by a common alkaline 9 Volt D.C. battery housed in the hand-held controller. The endurance of this highly efficient system provides up to fifty (50) hours of service and even longer with a 9 volt lithium battery. This capability to operate form a battery eliminates the need to be located near an AC power source.

No AC Power Needed! 37,600 bytes     9 Volt Battery 8,355 bytes

The hand-held control paddle controls all functions including the selection of drive rate (Sidereal or Lunar), fine speed correction changes of ±1.4 or 10X Sidereal. All control is done with the "On Off" switch and four (E-W-N-S-) push buttons; there are no switches on the drive base - all is on the hand paddle that plugs into the bottom of the base. An internal Quartz reference circuit continuously checks motor speed every 0.6 Arc Sec. and adjusts it as necessary. But the most important aspects of this option are that it frees a person to travel around the world, to the North or South Hemisphere independent of external power supplies.

The development of the 9 volt Powerguide systems was accompanied by the introduction of an optional Motorized Declination Assembly for the Questar 3-½ Fork. This accessory includes a Declination Hand Control wheel that replaces the original, and the Motor and Support Frame that is attached onto the Fork Tine meshing with the new Declination Hand Control wheel. The Questar 3-½ Motorized Declination Drive and the Questar Seven Motorized Declination Drive options are for use only with those Questar Fork Mounts that incorporate the Powerguide II drive and control system.

The Powerguide II consists of several components:

  • Power and Signal Cable

  • Powerguide II Hand Held Controller

  • 9 Volt Alkaline Battery (Lithium battery recommended for longer life or operation in extreme cold climates)

Set up and Operation:

  • Pole Align the Questar Fork Mount. The drive will not track accurately without the mount being reasonably well oriented to the celestial pole.

  • Connect the provided six pin module cable from the jack at the base of the Fork Mount into the top left jack on Powerguide II Hand Control. Note, the six pin should be plugged in only into the jack on the left side; the right side jack accommodates the cable that connects the Motorized Declination Vernier Drive.

  • For Northern Hemisphere Sidereal operation slide the power switch to "On"; this is the default startup setting. The red LED should light indicating proper operation. For reversed motor operation in the Southern Hemisphere press both the North and South direction buttons while simultaneously sliding the power switch to "on".

  • To set Northern Hemisphere to the slightly faster Lunar rate press both the East and West direction buttons while simultaneously sliding the power switch to "on". For Southern Hemisphere Lunar rate reversed operation press all four the North and South and East and West direction buttons while simultaneously sliding the power switch to "on".

  • Right Ascension functions are controlled by the left (West) and right (East) push buttons, while Declination with the optional Declination Motor are controlled by up and down buttons. Note for Southern Hemisphere operation, these directions will appear reversed.

  • Pressing either the North, South or West buttons accelerates the R.A. or Declination drive motors to fine adjust centering a target by moving at 1.4 x the standard Sidereal rate, a 35% speed increase. Note pressing the East button stops the R.A. drive motor so that the Earth's rotation causes the object to drift apparently to the East, releasing the East button resumes tracking. These functions are reversed for Southern Hemisphere operations.

  • Pressing the North, South, East or West buttons while then pressing and holding the opposite direction push button accelerates the R.A. or Declination drive motors to 10 x the standard Sidereal rate, a 1000% speed increase. This is useful for initial centering of a target that is far off center, or for perusing through an area of sky congested with targets.

Questar Powerguide II base with cable socket 323,230 bytes Note: the Powerguide II is expressly designed for use only with the Powerguide II Motorized Declination Drive, and not with that of the original Powerguide. Any attempt to use the Powerguide II or its Motorized Declination Drive with any other system is likely to result in damage to the motors and possibly to the controller as well.

Furthermore, note:

    1. Company Seven does highly recommend the Powerguide II option as a tracking system and fine positioning aid. However, it is not a high speed slewing motor designed to drive the telescope across large areas of the sky. Nor is this a 'Go To' computer controlled set.

    2. The base of the basic Questar astronomical telescope models would incorporate either a 115 or 220 volt AC motor and with a suitable AC power cord. However, when the Powerguide II option is built into a Questar base then the AC power cord is not needed and so Company Seven does not include the AC Power Cord with a new telescope that has the Powerguide II option.

    3. If you send your older Questar telescope in for a Powerguide II retrofit then be sure to ask if you wish to have the original AC motor and power cord returned to you.

Right: Questar Powerguide II Cable Socket in the bottom of the telescope Base (83,030 bytes).
Note this is where the Serial No. is engraved on a Questar Standard 3-½ or Questar Duplex telescope. Click image to see enlarged view (323,230 bytes).

Below Right: Questar Powerguide II Hand Control with Cable (79,888 bytes).
Click image to see enlarged view (200,400 bytes).

Questar 3-½ Electronic Control side view 79,888 bytes Powerguide II Drive Specifications*
    Motor Type Digital Feedback Servo
    Motor Max. Torque 100 oz.
    Power Requirement 9 Volt D.C.
    Polarity Protection Yes
    Nominal Current Draw 1 milliamp
    Speeds 1.4X (35%) or 10X (1000%) Sidereal Rate
    Control Cable Connectors Modular 6 pin (RJ12); replacement cord available world-wide
    Hand Control Dimensions 3.7 x 2.4 x 1.2 inch / 95.15 x 59.97 x 29.4 mm
    Hand Control Weight (with battery) 4.2 oz. / 118 Gr.

We invite you to visit our showroom near Washington, D.C. to see a Questar first hand. Or contact us on line or by E-mail to, or by telephone at 301-953-2000. The showroom is open Monday to Friday 11 am to 6 pm, Saturday 11 am to 5 pm. We are closed on Sundays, on U.S. Holidays, and from 25 December through 1 January inclusive.


Contents Copyright 1994-2006 Company Seven All Rights Reserved