Sony SXV-M5C user manual What you need

Handbook for SXV-M5C Issue 1 August 2004

The advantages of S.T.A.R. are very great, but there are two negative aspects, which you should be aware of. The main loss is in the sensitivity of the CCD, as only half of the pixel area is integrating an image at any one time. This is slightly offset by the halving of the dark current, which also results, and can be completely compensated for by increasing the exposure time – not a big pro blem when the camera can guide itself! The other problem is that the CCD amplifier must be switched on momentarily to read out each guider frame. Despite the short times involved, this results in some contamination of the upper left hand corner of the image, by light emitted from the amplifier transistors (electro luminescence), and this needs the subtraction of a special dark frame to remove it. However, the glow is quite faint and may be ignored on many images, or it can be removed with the ‘Gradient filter’ in the ‘Filters’ menu.

What you need:

To use S.T.A.R. 2000, you must have a telescope with ‘Auto guider’ capability. Most modern SCTs have this facility in the form of a 6 pin ‘RJ11’ telephone style connector on the mounting base or handset. If your ‘scope is ‘ST4 compatible’ it should work with S.T.A.R. 2000. Adaptors for other mounts, such as the Vixen Skysensor, are available from Starlight Xpress. In the case of a ‘difficult’ mount, an add-on relay box is available to switch higher currents and opposite polarity circuits. The system has been tested with the LX200, LX50 and Celestron CI700 German mounts with good results, but almost any modern mount will work well. Please note that the RJ11 cable supplied with the camera has the connectors fitted on opposite sides of the 6 way cord – other cables may not be c ompatible!

Setting up the system:

For best results, it is important to set up your telescope mounting as accurately as possible. Alt-Az mounts can be used with S.T.A.R. 2000, but will cause field rotation during exposures and are often rather poor at smooth tracking. We recommend that you always use an equatorially mounted ‘scope, with its polar axis accurately aligned on the pole. If your mount is prone to sudden shifts of aim point during tracking, usually due to poorly made gears or bearings, then S.T.A.R. will be unable to fully compensate and some trailing will result. Slow and smooth errors in position are well corrected and so this is what you should aim for. Check that all your drive gears are firmly fixed to their shafts (loose gears are surprisingly common!) and that they engage closely, without binding. The tracking of many mounts can be improved by adding a deliberate bias to the East. A small weight on the Eastern fork tine will usually be effective.

Connect up the computer and camera in the usual way and install the camera onto the telescope. Next, take the 6 way RJ11 telephone lead and plug one end into the guider output of the SXV camera. This output is a ‘switched’ signal, compatible with inputs designed for use with an ST4 guider. It is also possible to use a serial connection to an LX200 compatible RS232 input, but to do this you need to have a serial port to RJ11 cable from the back of the computer to the RS232 input of the mount. This connection allows other ‘goto’ control signals to be sent to t he mount, but may be less convenient if you do not require this facility. Which output you use will also depend on your telescope, but the Meade LX200 and its clones are compatible with serial control, although the LX200GPS still has a software issue at the time of writing. All other

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