Control of dome to keep telescope in centre of slot

[David at Bythel Obs]

Hi

i have a pulsar 2.7m dome that I need to automate to keep Astro scope in centre of dome opening during long exposures. Any thoughts as Pulsar kit doesn’t have the software to slave telescope to slot

thanks

[AstroKeith]

Their normal dome drive has an ASCOM interface,

[scotty38]

I use NINA to control mine.

[tomato]

If you have an older dome that isn’t compatible with Pulsar’s current drive system, then you have a couple of options:

Try and find one of the older Pulsar motorised systems which is ASCOM compatible, they do appear in the ads from time to time, or:

Build your own motorised system which is ASCOM compliant or use some form of bespoke controller. I use the latter, which uses an encoder and software rate control, based on a calculated azimuth rate for the chosen object and/or laser beams either side of the aperture which triggers a predefined dome nudge when the scope tube breaks the beam.

I have to say this is not my handiwork. My brother @Tomatobro on here, who is a retired mechanical/electronics engineer, designed and built the system. After a couple of years of fine tuning it now works very well and allows unattended imaging sessions.

[LuckieEddie]

Another alternative to 'rolling your own' completely from scratch is the Observatory Control System (OCS) which is open source SW & HW authored by Howard Dutton who also created the OnStep telescope control system. There are ASCOM drivers available. See https://onstep.groups.io/g/onstep-ocs/topics.

[pmlogg]

The 2.7m dome design has changed a couple of times and with it Pulsar's system for rotation.  The oldest version, which I have, has a two piece shutter.

Could you post images to show the wall arrangement as that was the big change that made later models easier to automate. 

In terms of control systems there is an Ascom programme called Levesdome.net which works with a Velleman kit circuit board.  The programme is specifically written for dome automation.  I used an original Pulsar dome rotation system for a 2.2m dome, bought second-hand, modified it to fit the 2.7m dome then added switches and other components to run it using Levesdome.  You can find mine and other peoples solutions in this topic area.

[Grant_FLO]

On 08/03/2023 at 13:48, David at Bythel Obs said:

Hi

i have a pulsar 2.7m dome that I need to automate to keep Astro scope in centre of dome opening during long exposures. Any thoughts as Pulsar kit doesn’t have the software to slave telescope to slot

thanks

The Pulsar software is fully ASCOM compatible so it will keep the slot / shutter centred on where the scope is pointing automatically.