Sky Commander

 

What is the Sky Commander? – The Sky Commander is a small self contained computer designed for the specific purpose of locating and identifying celestial objects with a telescope.

How Does it Work? – The computer ‘reads’ the position of the telescope with the use of two optical encoder modules. The encoders are attached mechanically to the telescope axes in such a way that the encoder shaft turns as the telescope is turned. At the beginning of an observing session, the user initializes the computer by pointing the telescope at two different stars. By sensing the change in position between the two stars, the computer is able to fix on the orientation of the both telescope and sky.

How do I point the telescope to an object? – A six button keypad and LCD display form the easy operator interface. First you select a catalog, e.g. Messier, NGC or Planet. Then you enter the catalog number (four digits). Arrow buttons are used for this purpose. Pressing the ENTER button makes the object ‘current’. The user moves the telescope while watching the LCD. As the scope moves closer to the target object, the display digits roll down to zero in AZ and EL. Arrows are displayed to indicate direction.

What does the display show me? – The Liquid Crystal Display (LCD for short) shows you the position of the telescope in RA and declination, or the relative position of the scope to the target object (‘zero in’ display). It also shows you the current catalog and object number (used for object selection) and some information such as object type, magnitude, and constellation.

How do I get it set up on my telescope? – The Sky Commander works on both Alt-Azimuth (e.g. Dobsonian) and equatorial type scopes. Sky Engineering supplies a general purpose encoder mounting kit (pn ALT-AZ-1000) for Dobsonian type scopes. Since it is a general purpose kit, some modifications may be required to make it work depending on what scope you have. Dobsonian type scopes are by far the easiest to fit encoders because there is generally plenty of room to work with. For other type scopes, the Sky Commander will work with most commercially available encoder setups. A standard encoder cable connector (modular RJ45 also used for computer network cables) is used.

What’s the deal with encoder resolutions? – Angular resolution of the system is determined by the encoders themselves. The Sky Commander can handle a wide range of resolutions. Typical encoders are 4000 step per revolution, but other resolutions are also used, (2160, 4096, 8192, etc). The important thing is that you enter the encoder information into the Sky Commander so it knows how many counts per degree of scope rotation. This information only needs to be entered one time, but can be changed whenever needed.

Do higher resolution encoders mean higher accuracy? – Possibly, but be aware that the encoders themselves have an inherent ‘runout’ error which may exceed the step size, especially for the higher resolution units.

What is the RS232 connector for? – RS232 is a standard for serial communications between computers. In the Sky Commander it is used to tell a PC the position of the telescope so it can be displayed on the screen. In this way the user can tap into the huge resources provided by many Astronomy programs. On the XP4 RS232 is used as a ‘Flash Port’ when updating the software or internal database.

How is the Sky Commander powered? – The Sky Commander is powered from an internal 9 volt battery which will last a very long time (about 40 hours) under normal use. There is also an optional 2.1mm (5.5mm OD) power jack for connection to 12 volt DC.

What do I need to buy? – If your scope already has optical encoders installed with a standard encoder cable, you need just the Sky Commander XP4 itself, CMP-XP-4000. If you have a Dobsonian scope you will need the SYS-XP-4000 (includes cable and two 4000 step encoders) and Dob kit, ALT-AZ-1000.

Products

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Sky Commander XP4 Computer w/ Flash Cable, Manual

The XP4 is based on the original Sky Commander DSC design but with the following important hardware upgrades: * 4 times the internal memory space – 512kB vs 128kB, allowing room for many more objects to be stored, up to approximately 30,000. * Memory is Flash type – this means it is re-programmable in the unit. No need to physically replace an OTP (One Time Programmable) EPROM in order to upgrade. Connect the XP4 to your PC and run the XP4_Boot-Flash_Utility to upgrade. Flash memory has virtually unlimited reprogramming cycles. * Encoder ‘Fast-Tracking’ – This is the first important upgrade supported in version 4.2. It allows use of very high resolution encoders, up to 24576 count without the problem of loosing encoder counts if the scope is moved quickly. It is also useful on very small scopes that can move quickly. This feature operates only while external 12 volt power is applied because it uses more power than an internal 9 volt battery can supply. * New custom ABS plastic enclosure with externally accessible battery compartmnet for easy battery replacement.


Our price: $295.00 (€256.65)
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Sky Commander XP4 w/ Flash Cable, Manual, 2- 4000 step encoders and encoder cable.

Sky Commander Computer with Encoders

What is the Sky Commander? – The Sky Commander is a small self contained computer designed for the specific purpose of locating and identifying celestial objects with a telescope. How Does it Work? – The computer ‘reads’ the position of the telescope with the use of two optical encoder modules. The encoders are attached mechanically to the telescope axes in such a way that the encoder shaft turns as the telescope is turned. At the beginning of an observing session, the user initializes the computer by pointing the telescope at two different stars. By sensing the change in position between the two stars, the computer is able to fix on the orientation of the both telescope and sky.


Our price: $410.00 (€356.70)
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Sky Commander Encoder Installation Dob Kit

General purpose encoder mounting kit for Dobsonian type scopes. Includes all hardware
for attaching encoders to dob type scope.
Order encoders and cable separately.


Our price: $60.00 (€52.20)
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4000 Step Encoder

4000 Step Encoder


Our price: $60.00 (€52.20)
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6 foot long RS232 cable for use with PC

6 foot long RS232 cable for use with PC
Note: if you need longer length, up to 18', add $1 per foot. Specify when ordering.


Our price: $20.00 (€17.40)
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Encoder Cable

Standard 6'-EL x 8'-AZ encoder cable


Our price: $20.00 (€17.40)
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Encoder Mounting Arms

Encoder Mounting Arm (with RJ11 to 5 pin adapter) comes in 4 lengths


Our price: $10.00 (€8.70)
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RJ11 to 5 Pin Encoder Adapter Cable

RJ11 to 5 Pin Encoder Adapter Cable Available in two lengths


Our price: $10.00 (€8.70)
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Sky Commander AC Adapter

10 Watt AC to DC power adapter. Use to power Sky Commander externally. 6' cable.


Our price: $18.00 (€15.66)
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Sky Commander DC Adapter

External power cable with cigarette lighter adapter and standard 2.1mm ID / 5.5mm OD power plug.


Our price: $15.00 (€13.05)
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