OBSERVATORY

The Jewelbox Remote Controlled / Automated Observatory, Cairns Australia

Equipment:

• ParamountME carrying a 500mm Classical Cassegrain reflector and STL11000 Camera with MOAG, AOL, and  Pyxis camera rotator.
• Losmandy Titan carrying a Takahashi FCT 150 and STL11000 Camera  and Celestron 9.25 inch Schmidt Cassegrain.

Considerations for a remote controlled roll-off roof Observatory in the tropics: Dealing with cyclones. Dealing with high humidity- Preventing mould developing on optics etc. High daytime temperatures. High night-time temperatures. Dew at night.
The observatory roof moves on tracks with metal wheels that have grooved concave edge that fit on a track. Also on the Eastern side of the building I have two horizontal wheels set in place to ensure the roof stays precisely in line and does not bind up by shifting sideways or out of alignment.

To prevent the roof lifting away in a cyclone, the wheels are facing inwards and the tracks for the wheels are on “C” channel steel struts. There are 4 secure tie down positions in addition to this that can be securely bolted down with an impending cyclone.  It is imperative in any remote observatory for the roof position to be able to be absolutely confirmed as properly closed or open via the PC and internet; therefore absolute position electrical switch indicators have been installed.

The roof slides forward and then the bolt on the moving roof sticks out through the hole on the fixing plate and then a washer and wing-nut can be screwed in place if a cyclone is approaching.


Because of the high flow of water running off the roof in tropical downpours, a gutter system is necessary.

The observatory is  air-conditioned to reduce daytime heat and more importantly to reduce internal humidity levels and prevent mould. This requires the observatory to be reasonably well sealed when closed. Having the observatory sealed, but still able to have a sliding roof which can overcome the seals was a challenge. The garage door motor had to be strong enough to overcome the resistance of the seals, and the roof had to still be able to slide unencumbered.

The back wall seal was the easiest as this is just a rubber pad for the back edge of the roof to close up to.
The front seal is a door striker plate system with a moulded aluminium plate mounted on top of the front wall and a plastic fin shaped to fit up to the plate attached to the base of the front ceiling of the roof:

The side wall seals have to allow the roof/ceiling to slide along then as the roof pulls back and opens and closes. These seals have to not cause any obstruction or jam the roof sliding mechanism in any way. This is the most challenging seal, and a brush strip seal was chosen:

In the wet season when the observatory has no prospects of being used for some time, I physically stuff some air-conditioning pipe insulation foam tubing into the gap created by a shelf I have installed close to the ceiling edges along the front and sides as these seals are not totally air-proof:

The inside view with the roof closed. The Takahashi FCT 150 is seen mounted on the Losmandy  Titan mount. A strip of foam tubing is seen in the background. In the wet season this will stuffed tightly on the shelf near the ceiling creating an improved air tight seal:

A dehumidifier is also run in the wet season:

The observatory is controlled by the M1 OASYS:

This utilises a home automation system and adapts it for the control of the observatory. It has a network interface and ASCOM driver that can control the roof garage door motor:

I use CCDAutoPilot to control the two  telescopes, the observatory roof, the camera rotator, focuser with FocusMax to automate focusing. CCDAutopilot also takes information from the Boltwood II cloud sensor and parks the two telescopes away from the roof and closes the roof automatically if clouds arrive. It is crucial to have sensors to confirm the scopes are in their park position, so that the roof will only move if this is the case. The M1 OASYS system has this as a feature:
The system will not open or close the roof if either of the scopes are not in the confirmed park position. The paramountME mount is very easy to setup for the reliable parking of the mount, but the Losmandy Titan mount had to have a special script written for it to send the mount to a pre-determined “park” position, as the ASCOM driver for the Gemini system was not able to park the mount properly.
The M1 OASYS software on the PC desktop:

I use a Ethernet power controller to switch the power to all of the observatory equipment on and off as required remotely via the internet. This device also allows me to reboot any of the observatory computers with a hard boot if necessary. The observatory air-conditioner has a switch connected to the M1 OASYS controller which automatically switches the air-conditioner off when the roof is opened and back on again when the roof reaches the closed position. The Ethernet power controller is used to power off the dehumidifier when the roof is opened and to switch it on when the roof is closed.

The Boltwood II cloud sensor:
The Boltwood II cloud sensor software in action on the desktop during a typical Cairns day:

I use a 3000VA Uninterruptable Power Supply to power the roof and the two telescope mounts so that with a power outage, the software will automatically park the two scopes then close the roof with plenty of power available through the UPS to do this. It is obviously important to be able to do this, so that with a power blackout there is no chance of the roof being left open exposing the expensive equipment to the random risk of rain:

The UPS and the M1 OASYS will email me to my mobile phone to let me know if there has been a power cut, and what the final roof status is with this event. I will also receive emails when the power is restored. I will also receive emails to my mobile phone if a close roof request was issued and the roof for any reason remains open for a set period of 20 minutes following such a command. I also receive emails from the observatory software ( CCDAutoPilot) when there is completion of an imaging run or termination of the imaging run because of severe prolonged clouds signalling the possibility of impending rain. I also receive an email from the M1 OASYS system confirming the roof has closed properly in the instance of a completed imaging run or where the imaging run has been automatically terminated because of adverse conditions sensed by the Boltwood II cloud sensor.

The roof almost closed:

The roof open with the 500mm Classical Cassegrain ParamountME still in the parked position:

The roof open with a view over the Takahashi FCT 150 with off axis guider STL remote guide head:

Inside the observatory:

The 500mm Keller Classical Cassegrain on the ParamountME parked with the roof closed:

Images

Video

Observatory outside	Observatory inside	Technology
Telescope		Telescope

"When darkness is at its darkest, that is the beginning of all light."   Lao-Tzu