SGP and observatory control - recommendations wanted


#1

I think lugging my PMX about has given me a hernia. My better half says I can have an observatory. :heart_eyes:

I have very little experience with these but I’m trending towards a circular / dome variety (like Pulsar in the UK). Any recommendations on a dome control system that works well with SGP for trouble-free automatic dome positioning during slews, meridian flips and long sequences? I think Pulsar use the LesveDome system and I did see some earlier posts which suggest some issues.

Any help will be appreciated.


#2

Hi Chris,

Cant comment on what works best control wise with SGP as I opted for a ROR observatory from this lot (http://www.homeobservatoryuk.com/) more like an outbuilding than a shed, as this fitted in better with my situation here and less complexity in setup. Also like the access to the whole sky and the quicker cool down. I did seriously consider a Scopedome (http://www.scopedome.com/en/default.aspx), with euro rate and buying direct from the manufacturer is was par with fully automated local options. A friend did just that and had his installed over the summer and intends to use it with SGP but various unrelated issues has held up a fully linked up run but I have been though the software and run basic tests which all worked fine.

Cheers

Trevor


#3

Many thanks Trevor - I followed up on the links - the Norfolk ones look just perfect and my wife can grow flowers around it and pretend it is a shed. Did you put a motor on it and link it to SGP at all?


#4

It is a well made but is only 3 guys and most of the stuff they do is bespoke so lead time is long, took 5mths to deliver mine though should have been 4 but understandable reasons for the delay. I got a 7’x6’ version, which I did think may have been tight on space but pretty roomy which everything installed (straight walls are an advantage as well) - not sure how how the RC would fair but with the 106 the roof can close with the scope in any poistion, lose 10-15deg of sky this way but is the murk so not losing much.

I took their roof option, it is basically a sliding gate opener and some custom metal work and sits on the outside, works well though.

I got the impression automation is not their strong point, OK for me as had already started on a custom controller that handles the roof opening, only need to make two wires for a second ,simple as no sensors as you program the roof unit with the start, end positions.

roof in action

https://dl.dropboxusercontent.com/u/10508371/ObsBuild/File%2018-07-2015%2015%2013%2037.mov

The control side I wrote myself, handles the roof in conjunction with my own ASCOM driver (one quirk there that still trying to get to the bottom of as will see elsewhere here), also handles the power to all the equipment ensuring everything powers off after the camera has cooled, monitors SGP and controls the IR for the cameras switch off when integration starts and on when it ends, last stage is to integrate control of the alarm system as a couple of times forgot to switch mode and that kicked into life on a flip !

SGP controls it all perfectly, provided I remember to tick the tick to Slave to Telescope checkbox every time , run a few nights unattended with flips and bar a couple of self induced issues all has worked flawlessly

More than welcome to come and have a look

Trevor


#5

Hi
Far to good

that means I am going to have to motorise mine :smile:

Harry


#6

Trevor, that is quite an installation! Is that the 6x9 version? I was only going to use mine for imaging so would attach my interface box and the NUC to one side of the pillar and just run three DC cables and a Cat 5 cable down the pillar. I might put my bench DC power supply in the shed and just connect up to mains when I needed it. My backup power would be a few batteries with a series diode.

Does the shed come with a floor, or did you just tile over a concrete base? I have sent them a few questions to see how tall the unit is. I have to think about both the RCT and the FLT132 clearance

regards

Chris Woodhouse
www.digitalastrophotography.co.uk


#7

Chris

I got my ROR via Ian King Imaging and it is a design and build from Dave Jackson of Hitec Astro. I have the 7’ x 7’ option for the scope room and a 7’ x 6’ warm room, motorised roof and now ascom controller for the roof. I had to provide the concrete base and pier block, the team did the rest. My obsy featured in Sky at Night mag too :smile:.

Just another line of enquiry for you.

Regards,

Barry


#8

Thanks Barry - This hernia is proving to be very handy. Frustrated portable imagers take note :wink:


#9

Perhaps I should productionize my dome controller.

Digital compass sensor on the dome, broadcasting the dome compass heading to a dome motor controller running on an Arduino driving a DC dome rotation controller.

ASCOM driver on the PC that handles converting the compass direction to True directions.

There are two around so far…

Chris


#10

This is a 7’ x 6’ - the roof rolls off on the long side

Layout within the garden

https://dl.dropboxusercontent.com/u/10508371/ObsBuild/Layout.jpg


#11

I have an ROR from Foster Systems. He also does dome controllers. His support can be less than ideal (hair pulling sometimes, specifically when he’s doing new software upgrades), but the hardware is robust and ‘just works’. But, always keep a old version of the software around from when it did work. He tends to throw updates out, removes the old version, and leaves it to the group to figure it out :).


#12

Hi, interesting thread for me as I am working through the same process. I have a Pulsar 2.2 Meter dome and I opted to go the DIY route for dome automation. Currently I have the dome rotation mechanics fairly well sorted - stepper motor and timing belt with an Arduino controller. I am not up to writing ASCOM drivers so my design is based around the Levesdomenet software. I am sure this will work but it seems rather - hmm - unelegant compared to ASCOM talking directly to my Arduino Mega.

I was very struck by Chris’s comments about using a digital compass to send the azimuth information. I would love to go this route so if Chris would like to make it 3 people using this system, I would love to hear from you! - hughgilhespie@gmail.com.

Regards and thanks.

Hugh


#13

The other system I have seen in an old Springer book does not rely upon a ‘controller’ as far as I could see. It uses proximity sensors mounted to the OTA that pick up on the position of the dome opening and move it accordingly.
Having mocked up the appearance of the alternatives in my small garden, a small ROR design was preferred for cost and aesthetic reasons. I can use the ASCOM safety monitor to trigger a telescope park and the relays from the AAG cloudwatcher can trigger a roof close.


#14

I cannot speak for automation, but I also have an observatory from Home Observatory UK. A pleasure to deal with, although, as a previous poster has suggested, I did experience some slippage on the original quoted timescale - but only a few weeks.

I can’t speak highly enough about the finished product though - I am very pleased with it.


#15

Hi Chris;

This seems to be very, very and even very interesting!! I use a Graycoder together with lesvedome steered by SGPro. In the end position accuracy is never spot on…

Just a Q; are there traces on the net of your project, or is it possible to share some plans or so?

I already read about “Digital Compass” oriented domes but never knew how to integrate them…

Very best & CS!

Lex


#16

One other idea popped into my head - there is another thread about Tektite Skies, that images the sky and detects stars and clouds - if the video camera sat on the telescope, it could detect the sides of the dome and give out directions to keep the dome slit centralized. That would be quite simple to implement I would have thought.


#17

What I did was use a HMC4883L digital compass module connected to a microcontroller and a small RF transmitter to send the dome compass position when it changed. I used a PICAXE processor and managed to get the power consumption down enough that it could run continuously on 2 AA batteries.

Then I had an Arduino with a RF receiver to receive the data and convert it from an XYZ compass vector to a dome heading. This handles the dome motor (12V DC) using a Pohulu digital motor controller board.

And an ASCOM driver that gets and sets the dome position and does the calibration by communicating with the Arduino.

That’s as far as I’m prepared to go. This isn’t finished enough to be able to publish circuits and code with any real expectation that it would work without a lot of support.

Chris


#18

Doesn’t seem to be easy feasi… I will start to Google on this parts :+1:t2:
Thanks for the infos and the fit idea!!

Best & CS!!!

Lex


#19

Hi Chris;

Any news on your project?

Best & CS!!

Lex


#20

It’s still working.


www.mainsequencesoftware.com