Python control of SynScan handset

[SteveBz]

Hi Guys,

I'm trying to automate my scope and I've upgraded from a Skywatcher Enhanced handset controlled by an Arduino to a goto Synscan controlled by a Raspberry Pi with Python. I have control of the handset now, but I'm having difficulty interpreting the manual. It says send the slew command (eg 'P' +chr(2)+chr(16)+chr(36)+chr(rate))or something like that. Rate is supposed to be 1-9 or zero for stop, but there are 10 rates with 0 =. 5x. How does that work? Does it mean 0.5x is not available? I'm a bit thrown.

Regards,

Steve.

 

[JamesF]

18 minutes ago, SteveBz said:

Hi Guys,

I'm trying to automate my scope and I've upgraded from a Skywatcher Enhanced handset controlled by an Arduino to a goto Synscan controlled by a Raspberry Pi with Python. I have control of the handset now, but I'm having difficulty interpreting the manual. It says send the slew command (eg 'P' +chr(2)+chr(16)+chr(36)+chr(rate))or something like that. Rate is supposed to be 1-9 or zero for stop, but there are 10 rates with 0 =. 5x. How does that work? Does it mean 0.5x is not available? I'm a bit thrown.

What do the rest of the slew command parameters do?  Tell it how much to move?  If so then presumably having 0 for "stop" is meaningless?  Or is it "slew until I tell you to stop"?

James

[Dr_Ju_ju]

Why not lose the handset & drive the mount directly ?? 

[SteveBz]

8 hours ago, Dr_Ju_ju said:

Why not lose the handset & drive the mount directly ?? 

Hi Dr Juju,

You said that before, and I'd love to. It just a long process. I think you saw my previous attempt, but it's on pause until I can get something working to look upwards. Then I'll have some spare time.

Regards,

Steve

 

[SteveBz]

9 hours ago, JamesF said:

What do the rest of the slew command parameters do?  Tell it how much to move?  If so then presumably having 0 for "stop" is meaningless?  Or is it "slew until I tell you to stop"?

James

As I read it, it's slew until I tell you to stop. 

I've attached the full protocol, but as I understand it, the first three parameters are "fixed rate slew", "positive or negative" and "RA/DEC", not necessarily in that order.  Then you give it a rate.  Like this:

The text says:

For fixed rates, simply use a value from 1-9 (or 0 to stop) to mimic the equivalent hand control rates.
Note: in most configurations, issuing the slew commands will override (or conflict with) the tracking mode of the
mount. Hence it is always best to disable tracking first using the Tracking Commands, issue the slew command,
and then re-enable tracking. The main exception to this is when tracking equatorially - the fixed rate slews at 1 or 2
will not override tracking. This can be useful to simulate auto-guiding.

But the rates are:

So there seems to be a tension between the two definitions over what happens for zero.

I may just test it, but it's hard to measure rates like .5x and 1x, without a vernier calliper.

Regards

Steve

synscanserialcommunicationprotocol_version33.pdf

[SteveBz]

9 hours ago, Dr_Ju_ju said:

Why not lose the handset & drive the mount directly ?? 

Have you done this? 

You've got quite a lot of Newtonians.  Is there much difference between them?  I have a 114 mm and 200 mm and the difference is so huge I only use the smaller one for outreach and testing.

Steve.

[SteveBz]

Just found a Celestron manual with 9 settings.  Maybe I just need to test it.