LX200GPS.CRCM.NET (Astronomy)
The Construct & modification of a Meade LX200GPS Telescope.
Meade LX200GPS Telescopes (OTA optical & mechanical Simulator)
These files were last updated 1300 GMT, 10 November 2007
If you have a Meade 8" LX200GPS telescope everything is set up and ready to go!
The only thing that you may wish to do immediately is calibrate the FOCUS KNOB default position.
This is relatively easy to do;
1) Focus your Telescope on a STAR.
2) Measure the distance from the REAR PORT to the IMAGE PLANE.= D
3) Unlock the Primary Mirror.
4) Move the Primary Mirror fully forward counting the number of Focus knob turns. = SF
5) Move the Mirror fully backwards and count the number of turns. = FB
6) Calculate the Focus position offset from the mid point. T0 = FB/2
7) Calculate the Star Focus from the mid point. TS = SF-T0
8) Note the Air Temperature & Telescope Temperature
Now in the Simulator, Set the "Ambient Air Temperature =" and "OTA Temperature = "
Then adjust the value of the parameter "Focuser Turns from mid point =" until the parameter "Back Focus in mm =" displays your measured value "REAR PORT to the IMAGE PLANE.= D"
{if you are experienced with Excel you can use the SOLVE function. Unprotect the sheet first}
Note the displayed value of "Back Focus in mm =" as BF = {displayed value}
The offset in Primary Mirror Default position is now calculated as;
OFFSET = (BF - D)*OneTurn
OneTurn = 0.907142857142857
The final thing to do is to adjust the Simulator parameter "Primary to Secondary Centre spacing @ T=0"
this is set on the constants page. Edit the default value by adding OFFSET to it. (note. if OFFSET has a negative value you subtract) The Simulator is now calibrated to your Telescope and should predict the performance of your telescope accurately.
At manufacture, there will be variations in the components used and these will result in deviations from the defaults given. It is possible to refine the accuracy of the Simulator by adjusting all or any of the input default parameters to reflect your particular telescope. It may be customised for any size of telescope. Details of how to characterise your telescope are given else ware.
Please address queries to conrad@crcm.net with an e-mail title of "simulator"
All Data, a copyright of Conrad Maloney (CRCM Networks, United Kingdom)
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