The observatory


The observatory was designed as a roll-off-roof structure. Basically it is a simple garden shed 9x9 ft in size and was build 2002 in the foothills of the 'Odenwald' at an elevation of 900 ft (270 m). It is located at the edge of the small city of Weinheim and is close to the Rhine Valley and the Rhein-Neckar metro region with a population of approx. 2,5 millions. Close to the observatory the old castle Windeck sits on a hilltop overlooking the city. It was built around 1100 and today it is a popular destination for tourists and locals alike, with a beautiful view over the Rhine Valley. On days with good weather conditions the "Pfälzerwald" (30 miles) and sometimes even the distant french Vosges mountain range is visible. The location of the observatory comes with a fair amount of light pollution, but the milkyway is still observable and the limiting visual magnitude is around mag 5. 

The observatory is not connected to the power grid. All equipment runs on solar power or portable lithium batteries. The PV systems delivers 300 watts and is sufficient in the summer. The power demand for computer, camera, mount, dew control, focus and internet connection is about 120 watt. Most of the winter between November and March, there is only 3-4 hours of direct sunlight for the solar panels and that is not enough to recharge the batteries after 10 - 12 hours of nighttime operation. During that period I switch to portable lithium batteries.

The main telescope is a 14-inch Schmidt-Cassegrain from Celestron with a primary mirror of 356 mm and a focal length of 3910 mm. For asteroid astrometry the ccd camera is operated with a Optec 0.5x focal reducer in 2x2 binning mode. The resulting image resolution is 1.75 arcseconds per pixel and the field of view is 22.5 x 15.0 arcminutes large. That is quite small when it comes to searching for asteroid with large position uncertainties. I am using a SBIG ST-8XME ccd camera with a 15030x1020 pixel KAF-1603ME chip. Focus is maintained with an Optect TCF-S automated focuser with temperature control. Usually I use FocusMax in it's old free version 3.8.
The C14 rides on an Astro-Physics AP1200 mount and is controlled by an old version of TheSky6. For image acquisition I still use CCDSoft. Both software packages are scriptable. Years ago I started to write my own little VB-script that automates the astrometric program of the observatory and because it runs so reliable I avoid updating any of the software components. I just don't want to rewrite all of the code if I don't have any benefits. So I'll just stick to what i got. All of the new solutions like SequenceGenerator Pro, Ekos, N.I.N.A, Prism are mainly designed to target fixed coordinates and are not able to dynamically update the positions of a fast moving asteroid during the imaging session.
The control computer is a small netbook with an Atom processor running Windows. To save energy - especially because the observatory is dependent on batterie power – it could be beneficial to switch to a single-board computer such as a Raspberry-Pi. Compared to the netbook with a power consumption of 10-15 Watt a Raspi would only need 4-5 Watt maximum. That would also mean a transition from windows to linux. But that's part of a future plan.


Automation does not include the building. The roof is still opened and closed manually. But from this point on the script handles everything from pointing, focusing, camera cooling, target selection and shutdown. The observatory is connected to the internet via an 4G router with a maximum bandwidth of 50 MBit. All follow-up observations of already known minor planets are reduced and measured in the morning and sent then as batch to the Minor Planet Center. All observations of new objects from the NEOCP are handled immediately after the exposure is finished. That requires of course the observer (me) staying awake. But with a daytime job usually the observing is handed over to the computer around midnight and transitions to observing known objects with already better orbit solutions.