Remote Observatory - Deep Sky - Glittering Lights

Why a remote observatory?

For work reasons several years ago I had to relocate from Italy, my home country, to Shanghai, one of the most light polluted cities in the world. From here there is almost no access to even moderate dark skies, not even driving for hours in the surroundings (the Yangze river delta is one of the most developed and populated parts of China). Frustrated by the impossibility of doing any imaging activity, I eventually decided to go remotely and build a little observatory under a true dark sky.

Location

My observatory is built in the property of Peter Starr, a former manager at Siding Spring observatory that lives down the road between Siding Spring and the town of Coonabarabran, the "Australia's astronomy capital" located 450 km north west of Sydney. Peter has built and runs Warrumbungle Observatory ( http://www.tenbyobservatory.com/ ), where he gives astronomical lectures to the public and offers hosting service to several remotely controlled observatories like mine. This site offers a very dark sky (SQM-LE average readings above 22 mag/arcs on most nights), strict light pollution control policy for years to come (the whole area is protected because of the proximity of the SSO), easy availability of electricity and security (my observatory is placed in Peter's backyard). As average, 60% of the nights are usable, with most clear nights available during the winter period, that down-under means from June. Being located at moderate altitude (560 meter above sea level), the night temperature is never too high even during the hottest summer nights, so the CCD cooling is always quite effective as it runs at -30C all observing nights. Internet connection needed to operate the scope is based on a dedicated long distance WIFI antenna and uses local 3G service. This connection is shared with some fellow astronomers in the property.

Dome

The first important thing I had to define when I decided to go remote, was the structure that was going to host the equipment. I analyzed several solutions and eventually decided to go for the 2.3 mt dome manufactured by Sirius observatories. The reasons for this choice were the followings:

a.A dome is more expensive that a roll off and requires more complicated controls but offers a better protection from the wind.

b.In case of power problems, a sudden weather change or a total system crash, a dome can close automatically without hitting the telescope OTA wherever it's pointing at, while in a roll off structure the OTA usually needs to be parked first. I didn't want to take the risk.

c.A dome has usually a smaller footprint than a roll off and, in particular, the size I chose didn't require any construction permission, making everything easier.

After confronting offers from half a dozen manufacturers, Sirius (that is Australian made) had an overall lower cost than other imported solutions. Furthermore I was confident about the construction quality since there were other Sirius domes already installed in the site that have been running without problems for quite a while. I can confirm after couple years of intense use that reliability proven to be very good since I never had serious issues.

My dome was bolted on a 2.4 meter round concrete slab, about 50 cm thick in the center and 20 cm thick on the border. In fact, because the telescope is remotely controlled and nobody is walking around the scope during the imaging session, a simple slab pad resulted more than adequate for the scope. The pier was custom made locally in Coonabarabran and is 122 cm high with a diameter of about 30 cm. As the dome, the pier was bolted to the slab once the mount was roughly aligned to the pole. Both power and network cables to Peter's house were drafted into the slab during the construction. Peter did most of the job, contacting the local contractors and making sure everything was properly done.

Mount and OTA

The mount I use is the Paramount ME. I have no particular notes here, simply this mount is up to its fame and it worked with exceptional precision since the first light. Currently my TEC140 APO is installed on the mount. I used in the past a Pentax 67 300ED(IF) telephoto lens (now sold), a very good lens designed for medium format cameras producing a great field of view with excellent correction and low chromatic aberration. The main CCD camera is a FLI Proline 16803, matched with its 7 position 50mm square filter wheel and a combination of Astrodon (Ha and OIII) and Baader (LRGB) square filters. Focuser is controlled by a Robofocus unit with a custom made bracket. For flat fields I use the Alnitak FlipFlat device that proven to be very good. I had some problems during the first installation of the FlipFlat while I was in Australia, being unable to have the unit properly working. The culprit eventually turned out to be a defective USB cable I was using instead of the one originally provided. However I was delighted by the excellent customer services of Alnitak, these guys spent literally hours on skype with me to find out the problem, supporting me in real time while running several tests until we found out the problem. Great company to work with and a real useful device. All USB and power cables to the OTA are routed through the mount to avoid any chance of tangling.

Weather Station

Together with Angus Lau, a buddy astronomer that has a dome next mine ( http://anguslau.smugmug.com/, http://www.jadescope.com/ ), we share a weather station built around a small custom made mini PC based on a Atom D525 processor with a very low consumption. This weather station is running 24/7 and is equipped with a SBIG allsky cam, a Boltwood sensor and a SQM-LE and provides real time information about both weather and darkness conditions at the site. Above is a typical image from the AllSky camera and an example of SQM readings on a clear night, note as the readings goes slightly down the second part of the night as the winter Milky Way got a zenith and the is Moon next to rise. Each point is the average of 5 readings and correctly offset to compensate the enclosure darkening.

Other Devices

To automate the Observatory I had to install many other devices.

REMOTE POWER CONTROL: I opted for a Digital Loggers Web Power Switch, a quite cheap yet perfectly working solution to remotely control the power of all the devices mounted. Not available in Australia, I had to order directly from the USA. This units can also run on automated scripts, a useful feature required by automation programs like ACP Scheduler.

PC: I installed a Lenovo TS130 tower server with i3 processor, 8 GB ECC memory, 2x1TB HD in Raid running Windows 7 pro. I used a locally assembled PC at the beginning but it had the power supply failing after one year due the high usage and environmental condition in the dome. Considering the PC is always on and temperature in the dome can be quite high during the day and humid in the night is important to opt for a robust and reliable system.

CLOUD SENSOR: I use a AAG Cloud watcher to monitor the sky conditions at the site. This unit unfortunately failed to work after 2 months (both lights and humidity sensors). However the manufacturer (Lunatico Astronomia) recognized the problem as being an original defect of the unit and sent an improved replacement unit free of charge, another good example of good customer customer oriented company. I didn't have issues anymore with the unit, proving itself very reliable. The Cloud watcher, apart from monitoring the sky conditions during the imaging session, has also a safety switch that triggers the dome shutter to close in case of bad weather, even if the PC is not working, providing a last safety barrier in case of extreme events.

IPCAM: I used a FOSCAM camera but unfortunately failed after few months. I need to replace it with a better and more reliable camera.

NETWORK DEVICES: all observatory network is running on a Linksys switch and is hardwired using Cat5 ethernet cables.

Also a number of 12 Volts power suppliers are installed in a rack to power all low voltage devices in the observatory (CCD, robofocus, mount, dome etc). Each power supply is powered by a dedicate socket of the Web Power Switch so I can turn on and off every single device remotely or locally using scripts.

UPS: to protect all the electronic devices I use a Socomec ITYS 1 KVA pure sine wave online UPS. I didn't considering this device at the beginning but eventually its purchase resulted very useful to protect all electronics by surges, voltage fluctuation etc.

Software

My PC is running Windows 7 pro 64 bits. The camera uses MaximDL, the mount TheSkyX+TPoint (I had to upgrade from TheSky6 I used due to incompatibility issues with Win7/64), the focuser Focusmax (a great freeware!). To have an efficient remote observatory the automation software is the key factor. ACP suite (ACP+Scheduler) is the automation software of my choice. Before every evening session the software automatically checks the weather, if fine it powers on the needed devices, opens the dome, cools the camera, waits for the end of astronomical twilight, opens the flip-flat, focuses on a suitable star and than decides the best objects to imagine according the list I have input until all requested images are taken, even if it could takes several days or weeks to complete. In the morning it closes the flip-flat, parks the scope, closes the dome, warms up the camera and powers off the unused devices waiting until next evening. If clouds roll in during the night the observatory is paused and the dome closed until the sky clears again. All I need to do is to check every few days all is working fine and to add new targets when the current ones are completed. All is done through a very convenient web interface. If necessary I can remotely control my PC desktop with Radmin, a powerful yet inexpensive remote desktop utility.

Glittering Lights

My Remote Observatory