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Around 6 months ago, I ran a trial on Global Rent-a-Scope (GRAS). This system runs on quite high-end imaging automation software called ACP Observatory Control. It allows a user to control an imaging telescope from anywhere in the world. The obvious advantage of this is that from a cloudy UK during the day you can be controlling a scope in crisp clear skies in Mexico or Australia.

Seeing this in action gave me a lot of inspiration. Building this sort of system for imaging in the UK gives you a huge advantage, you can use every single bit of available darkness and clear skies, without losing sleep. ACP involves quite expensive software and hardware, but given automation is my profession, I thought, it can’t be that hard…right?

I’ve been building and testing for following system for the past few months. The two main programs it uses are CCD Commander, which is similar to ACP (www.ccdcommander.com) and Homeseer, which is a Home Automation program (www.homeseer.com).

Software Configuration: CCD Commander

CCD Commander provides the automation of the all the mount control, auto-guiding, and imaging CCD functions. It can also automate auto-focus by using Focusmax, but I haven’t fitted stepper motors to my focusers yet. Once you have made an imaging plan for the night, it runs each of the actions.

CCDC can operate along with MaximDL for all the key imaging related functions, but for full observatory automation it needs some way of interfacing with external equipment for roof control and weather sensing. The recommended way to do this in CCDC is to use a Weather Sensor such as the Boltwood from Diffraction Limited (www.cyanogen.com) and an ASCOM compliant dome controller such as LesveDome (www.dppobservatory.net)

The Boltwood was out of the question as it was too expensive, and LesveDome wouldn’t give me the flexibility I would need for a roll of roof design with added functions, so I decided to use Homeseer.

Software Configuration: Homeseer

Homeseer is primarity for Home Automation purposes, but being an open-ended interface with a huge number of plugins, it works well in a variety of uses. In this case I use it along with a Velleman K8055 USB Digital I/O board (www.velleman.eu) to provide interfacing with the observatory.

This does a few critical functions in the workflow. While CCDC is running an imaging session, Homeseer will monitor both a rain sensor and an security beam. If it detects rain it will notify CCDC by editing a Boltwood formatted text file that CCDC is monitoring. CCDC will then stop the session, park the mount on it’s side and notify Homeseer that it can now close the roof. If it detects an intruder via a security beam it will also follow the same procedure.

As my Observatory is a small motorised roll off roof, the scope has to be parked on it’s side to allow the roof to close. This raises the obvious problem. To allow the roof to close with any degree of certainty, I really need to know the scope position. To combat this, I have fitted an IR Beam Kit to both the scope and the Observatory wall. This gives a contact closure to the input the K8055 when the scope is in its parked position. This allows Homeseer to then close the roof, if it doesn’t, it fires a alarm event.

There is also a sensor that monitors the position of the roof. If the roof doesn’t close after it should, this also fires an alarm event.

Homeseer can also make use of another Home Automation protocol called Xap. This allows networked communications between Homeseer and either other versions of Homeseer, or different compatible applications. In this case Homeseer on the Observatory PC can communicate with a version of Homeseer running on my Laptop in the house. This means that if any of the error functions happen during the session (Rain, Intruder, Roof Fault) an alarm can be ran on the laptop, waking me up. I see this as being really crucial to the whole process, as a number of things could go wrong.

If the session is complete without any errors, Homeseer can then switch of power to the mount and CCDs. As my CCD has a built in shutter, there is also the option here for allowing CCDC to automatically takes bias frames, dark frames, and flat frames by mounting a Electro-luminescent Panel on the Observatory wall. Given the scripting power within Homeseer, it’s even possible then to stack the images in Deep Sky Stacker

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2 Comments

  1. Have bookmarked this article, as my obsy will be calling out for this kind of automation (just because I`m a techie, and enjoy this kind of stuff 🙂 )

  2. Brilliant! You are going to have to build me what u have!! 😀


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