Measure Declination arc

I have a remote application to measure the telescope drift rate at various points along an objects declination arc. For each point, I need to have Voyager:

  1. Slew Telescope to RA, DEC (regular GOTO, precision not needed)

  2. Execute a script (which will take a number of images at that location for analysis by the 3rd party application). The script cannot do the slew because the RA and DEC are different for each point.

Looking at the Voyager Application Server protocol document I see a command for executing a script: “RemoteRunExternal”

but I don’t see one for slewing the telescope to an RA,DEC location.


Hello Craig,

yes correct … protocol was born for Array control … and the array element usually are a client not having control of mount.

I can add command for slewing RAD e DEC and ALT AZ if you need.
Just tell me

Just for info , are you sure DragScript cant help you on do this ?

All the best

Hi Leo,
I can use DragScript if there is a way to send a text message by UDP to an IP address and port. In the DragScript, I can slew to an RA and DEC and execute a script. But, before the script is running I need a 3rd party app to begin a training process. So I could do something like this:

Set HourAngle to -3
With Hour Angle determine RA,DEC
Slew Telescope to RA,DEC
Send UDP message (“Begin Training”,
Start sequence A
Add 1 to Hour Angle
If Hour Angle > +3 then break
End of Block

Each sequence will shoot 10 images at the RA,DEC position. The 3rd party app will measure plate solve each image and calculate the drift. An average of the 10 drift values will give a drift rate for the telescope at that DEC and HA which will be added to a model for later use in adjusting the telescope tracking rates during unguided imaging.


Ah ok … the first thinking is you can send a text message by UDP , realize a script or exe (i think you are programmer) that do this and accept text ip and port like parameters or so.
In your dragscript call this exe with execute external script/exe block at line where now i read “Send UDP …”

Second way is i’ll add a block doing this.

let me know

Hi Leo,
I found another way to do this. My program (Lazarus code) currently talks to SkyX and Pinpoint. I can connect it to Voyager. To do a Declination Arc measurement run my program would then get the Local Sidereal Time from SkyX and with the Hour Angle it can calculate the RA and DEC. This is sent to SkyX to slew the telescope, then a command is sent to Voyager to start the sequence. The sequence will shoot 10 images and my program will use Pinpoint to plate solve each image and measure the telescope drift. When finished my program can then repeat the process with the next hour angle until finished.

This means no changes to Voyager would be required.


Ok Craig… anyway i’m happy to change something … can be useful for all …
I think i’ll add some new blocks about …