Alternative to Pulsar dome rotator...

[Stuart1971]

Hi,

I am looking at automation a pulsar dome, but I don’t want to spend the £1300 they are asking for the pulsar  system, also I don’t need all the features that come with it, I am after just a simple motor system to drive the dome at sidereal rate, and maybe a hand control or similar to move manually when setting up...nothing fancy...is there anything out there....??

Thanks for looking

[pmlogg]

You won't find anything available off the shelf as each dome manufacturer tends to have their own bespoke system and none are cheap and cheerful.

If you search here you will find various solutions that have been produced DIY.  A lot of ingenuity has been shown and those who have come up with systems will be able to offer advice.

I was lucky to have the help of two Stargazerslounge users who helped me to automate one of the first models of Pulsar rotation systems, designed for the original dome version.  I had managed to buy that second hand.  Even that had to be modified a bit as it came from a 2.2m dome not the 2.7m version and it was really a clock work mechanism not designed for automation.  The newer domes are easier for rotation systems (including DIY) because Pulsar changed the design of the interface between the dome sides and walls.  That makes it easier to have a mains powered motor for rotation.  Mine is battery powered which is a significant limitation.

 

[tomato]

Alas, sidereal rate  wont work very well as the dome moves in azimuth and presumably you have an equatorial mount of some sort. But as @pmlogg has posted, there are lots of ingenious DIY solutions to be found under this forum title. My Pulsar dome has a rack and pinion drive to move the dome, its 12V and runs on a self contained battery that rides with dome. The 7Ah capacity means it will comfortably run an all night session between charges.  The drive can be run manually or for unattended operation, two low power lasers are mounted at the edges of the shutter aperture, and the dome nudges left or right if the dewshield on the scope breaks the beam(s). If you take out the automation aspect, it's a lot simpler, just a control box with two buttons to drive the motor in the two directions. 

The rack was located and purchased off the internet in straight lengths and carefully bent to match the radius of curvature  of the dome. I have to say it helped an awful lot to have access to machine tools and the technical expertise of @Tomatobro on this forum who put the whole thing together.

 

[Rusted]

I missed the Thursday afternoon lesson on electronics. [Back in the last century.]
So I use a friction roller and bicycle crank drive on my DIY dome base ring.
More recently upgraded with a chain drive to a lower crank within easy reach of my imaging desk.
The dome can get up to several hundred RPM in seconds and stops on a dime/farthing.
It would not be too difficult to rig up a remote system using a long drive rod from a warm room.
Not sure the Pulsar has a drivable base ring.