Written in Borland Pascal for Windows
By Brandon S. Jones
B.S.JONES@BHAM.AC.UK
This is a simple LX200 controller for help as an observation tool with other
software tools such as Electronic sky maps and so on , or to manipulate the scope
while you are setting up a CCD camera for example.It was written purely because
I found using the handcontroller difficult for some operations especially focussing
using the electric focusser,I could never remember the alignment star numbers or
what method to set up the reticle illuminator and some of the Meade Position data
did not match up with that in books I possessed and I wanted a quick means of
slewing to objects that I regularly look at as well as the occasional messierthon.
The program allows you to ...
Input position data and make the Scope go to it.
Input the time and reset the scope time clock.
Input the Sidereal Time to the Scope clock.
Input Meade Star Number Requests and go to them.
Select a Planet and go to it.
Focus the scope using the standard focussing motor by mouse click
Set the reticle status ie brightness and flash mode
Make the scope go North
Make the scope go South
Make the scope go West
Make the scope go East.
Set the Slew,Find,Control,Guide modes
Emergency STOP slew control in the center of the compass binacle.
Allows listing of Messier objects that when clicked on the scope goes to them
Allows listing of Standard Guide stars and their numbers for reference and
for syncing the scope by double clicking on them.
Allows list of observing run of objects ,clicking on them makes the scope go to them.
Gives joystick control over direction and focus in out modes.
Real time clock on display.
Gets on request local and sidereal time from LX200 and displays it.
Display of last operation command sent to scope.
Camera Exposure timer with timeout beeps.
SYNCING THE SCOPE
Use the controls on the list box to select the reference star that you wish to
sync on to.Double click on the star number and a box will appear asking if you
wish to sync or not.The scope will now be synced to the accuracy of the star in the
Meade database if you answer OK.As there are no beeps or controller display
messages if you want to see this happening then after switch on and manual
allignment of the scope set the display on the hand controller to read right
ascension and declination.On syncing
the scope via this command you will see the values change.
The controls come in the form of standard Windows buttons or
Click Sensitive bitmap representative controls.The controls have click down or
click up sensitivity eg if you use the left mouse button and click on the focus in
control and hold the button down the focus motor will continue winding in the
focus knob.Release the mouse button and the focus motor stops.This also applies
to the direction controls on the compass binacle.The reticle controls only operate
on left mouse button click down.The center of the sensitive area on each control is
the letter or number.
The Joystick
This is really a toy item that is most useful for focussing as it gives you
the ability to keep your eye on what you are focussing without the problems
of the buttons on the Meade hand controller.I intended the direction control
for when I have a fast scan 0.2 lux tv camera on the scope used for planetary
viewing so that I can walk the image about the screen and focus it,however it
may be useful for other things,such as using the scope to scratch your nose.
This must be setup before it will work each time the program is run and the
joystick is used this takes about 30 seconds of time.The program gets a standard set of
values from the LX200.ini file.These are the values for the original test joystick.
By looking at the information list boxes the values read during the setup procedure
can be noted and read.If several tries at this are done then an average set of values can be obtained
for the N,S,E,W and center values.The LX200.ini file can then be edited to the correct values
which are loaded from the file every time the program is started.
This allows the use of a standard 100k ohm potentiometer type of joystick to be
used connected to the standard IBM gameport.The program allows you to set up
the control to match your joystick characteristics by taking readings on request
at the four extreme positions of the joystick 90 degrees apart that represent North
South East and West.The center position is also taken.For focussing the East West
positions are ignored and the North South positions allow in and out focussing.
The center position of the joystick always tells the scope to stop
The software only looks at windows of the joystick values so that to emulate
four switches that are active one by one for each compass extreme and off in
the center..
A simple focussing control can be made out of a 100k pot with a knob.AS long as it is
connected to the "Y" pair of pins on a 15 pin joystick "D" type connector it should work.
The ideal pot for this sort of thing is a thumbwheel type.You can then use your thumb to
control focus in out.
Remember that a joystick can be tested by running the MSD program from
microsoft.
The Pin numbers used for the "Y" pot were pins 1 and 5 ...for the "X" pot
pins 1 and 3 on the 15way dtype connector for the joystick.Remember that pin
1 is the machines +5 volts.
Direction
In this mode only pushing the joystick lever to the position extreme will result in
a position message being sent once to the scope.Sampling is done on a 300ms basis.
Eg if you move the stick to the North position then a move north message is sent once,
when you move the stick back to the middle the command is cancelled and the scope
is stopped.Messages of what is going on are shown in the messagebox.
Focussing
This is the same as direction except that only north south motions are used for focus in
and focus out with stop focus being in the middle.Messages of what is going on are shown
in the messagebox.
Setup.....
North on hitting the enter key or clicking on the mouse then a low number should
appear in the message box.
South on hitting the enter key or the mouse button a high value should appear in
the message box.
West on hitting the enter key or the mouse button a low value should appear in the
message box.
East on hitting the enter key or the mouse button a high value should appear in
the message box.
Center it does not matter what the value is for this ,it only matters if you are obtaining
values for insertion into the ini file.
If this does not happen then the joystick wiring on the potentiometers should be
swapped over until the setup is correct ie the high and low values may need swapping over
on east west or north south.
As this calibration does not depend on the resistance of the pot this should work for other pot values.
Communications
This is on Com1 only at 9600 baud 8 bits one stop bit no parity
Clicking on the READLX200\Sidereal time sends a message asking the LX200 for the
sidereal time which is displayed in the message box.This shows that communication is
possible in both directions ok as well as being useful.
It may or may not be necessary to disable the handshaking on the RS232 port.
For example on the 25 pin connector this can be done by wiring together pins
4,5,6,8,20 with link wire.The equivalent must be done on the nine pin connector with different pin numbers ie the same signals must be tied together where possible not the same pin numbers
on the nine pin connector.
Pins 2,3 ,7 are the normal transmit data,receive data and ground connections.The wires to pins
2 and 3 may need swapping over.
The List Menu..
Clicking on this loads the observation file into the relative list box.The Messier and alignment star
boxes are loaded at start of program.For the Messier or the Observation
run list boxes scroll down to the wanted object then double click on its text.A box will appear
asking whether you wish to send the position change to the scope or not.
The alignment star list box is scrollable and is intended for reference purposes and scope
syncing.
The observation file format
There are three DAT files , Observe.dat,messier.dat and guide.dat these should be in the parent directory with the controller and so should any other observation type of dat file as well.The LX200.ini file should be in the windows sub directory.You can make as many observation files as you like you just give them
different names as the loading process is via the usual windows file input box.
The observe.dat file contains the observation data.This can be edited as it is a text file
and must be done so with a TEXT EDITOR such as notepad or microsoft EDIT.
If you make mistakes in the file format the program will tell you so and not allow the
faulty data to be sent.
To add a new object eg
type its NGC number or a name followed by an equals sign(The equals sign is the delimiter)
the format is then RA then Declination (which is the important part)
eg hours ,minutes , decimal minutes then positive or negative sign to represent north or South
then the degrees and minutes note there is no comma between the RA and the positive or negative sign.
eg.
NGC4156=20,34,4+72,34
mystar=21,01,8-20,45
mycomet=08,01,8+25,44
Look at the file for an example and leave no wasted space at the end of the file ie the end
should be the last entry only.
The list boxes should hold 64k of data before crashing out ,this is only intended as a simple
data base that can be edited prior to an observation session and then used to look at a few objects.
The Messier source is identical and that holds a 110 object listing.
Any of the positional data can be corrected in any of the DAT files if found in error at a later date.
The idea is to keep favourites in the file and add others when necessary.
Meade Data Menu..
This allows input of meade star numbers 0 to 9999 and then slews the scope to them.
Planets are available,simply click on the planet name to slew to the planet requested.
If it is below horizon a returned Meade message will appear telling you this.
Camera Exposure Timer
To set a time use the Set menu and click on timer,this allows you to set the count down time
in hours minutes and seconds.All of the boxes must be filled in,put a zero if necessary in a box.
On the exposure timer face there are two red letters "S" for start timer and "R" for reset timer.
Clicking on these will perform those functions.
Clicking on anywhere in the middle of the time display will stop the timer.Resetting it puts it
back to the starting input values and stops it ready for use ,or clicking on the start control
sets it running again. On the last ten seconds it will beep once and at the end will sound again.
The sounds produced depend on what is set in the Sounds section of the
WIN.INI file that is customisable from the windows control panel.
eg [SOUNDS]
SystemAsterisk=C:\WINDOWS\WAVES\ROOSTER.WAV,Asterisk
Systemdefault=C:\WINDOWS\WAVES\DING.WAV,Default beep
In the case of my machine here at ten seconds it dings to let me know time out is imminent.
At timeout it rooster crows cock a doodle do.You can edit these to anything you like or
just the standard short beep.If a sound card is fitted there will be no timing error.
Without a sound card the system is held up for the time of the sound message.If it
is less than one secod there is normally no problem.So save long recorded sound messages
like "wake up dosy the timer has finished" for the final timeout message....
At the start of the timer the RTS signal "Request to send" pin ie pin 4 of the 25 pin dtype is set
to +12 volts relative to machine chassis ground.At the timeout of the timer this is reset to -12volts
relative to chassis ground (RS232 signal levels).Stopping the timer does not reset
this signal to -12volts.Resetting the timer will do this. What this means is that if you take a
typical high gain NPN transistor.(BC184,BC182L,BC109 etc etc)
Connect the RTS signal pin to its base via a 10k resistor.Connect the emitter to Chassis ground.
Connect a protection diode(simple silicon signal diode or rectifier diode) with its cathode to
the transistor base and its anode to chassis ground.The transistor can be used to directly operate
a camera shutter via its collector and earth ground or if you put a suitable relay in the collector
,the relay contact can be made to operate a camera shutter or some other gear via its contacts
closing.
Installation
Load the files into a directory of your choice on whatever drive of your choice
After making a new program item in windows in a group of your choice set the path to
the same directory in the working directory part of the program properties otherwise
error messages will appear saying that it can not find the startup files on running the program
Copy the lx200.ini file to \windows.If the program when run asks for bwcc.dll one is supplied
with the files.There is a copy of rooster.wav also supplied with the files.