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The way to a telescope column in the garden


Dr. Gerold Holtkamp, August 8, 2022


Inauguration of the garden telescope column
It's always nice when you can initiate something. This was also the case on July 30th, 2022, when my astronomical colleagues and I inaugurated my new telescope column together. In the best weather and 3c (coffee, cake, cold drinks) the "ceremonial act" took place. Before that, of course, lays the history of the column, a slightly longer story …


Good mood around the column

"Corona is to blame for everything" or observation from the garden despite light pollution
When the Corona pandemic broke out in March 2020, we were effectively confined to our apartment or house. You were almost not allowed to go outside. For a long time, no community action was possible. During this time, I dared to try to shoot objects from my garden with a travel mount, a 300mm telephoto lens and my Canon 500DA and Canon 6D deep sky cameras. Attempt because the garden is located in the Osnabrück city area. I didn't have much hope that this would happen because of the heavy light pollution. But I also used a CLS filter, and – oh wonder – I managed to get some quite passable shots. When the Nova V1405 Cas lit up in March 2021, I followed the development of brightness over a full year with my astro colleague Thomas Kunzemann, Thomas from Preußisch-Oldendorf, I mainly from my garden. From then on, the sky over Osnabrück was also open for me for astrophotography as well as photometry.

Borrowed instruments
That's the benfit of having a group of like-minded people in astronomy: you get a lot of support! A colleague (Achim Tegeler) had given me an 8"/1000mm Newtonian telescope, an apochromatic refractor 80mm/600mm and – very important (not always appreciated) an EQ5 mount. This gave me some – for me – beautiful shots, which of course had more detail than those taken with the simple 300 mm lens. The motivation to keep hold of astrophotography increased. I was also able to take advantage of the clear moments of the Osnabrück sky, which is often cloudy. There was no longer a long journey. If the north adjustment worked quickly – after all, it was a mobile tripod – two hours without clouds were often sufficient.

My own equipment
After the successful garden observations, the time had come in me: I wanted to buy something of my own. The choice fell – again after many consultations with the Astro colleagues – in favour of the AZ EQ6 mount. In addition, I could now call the APO 80/600 telescope my own.
Now all was well! Until one night I carried my telescope plus camera and tripod including counterweights under the roof of the patio to protect it from the threat of rain – all together at once! My back reminded me of that a few days later. Something had to be done! A solid structure was needed! But a real observatory hut would have been too big for the garden.

My own telescope column
After a long discussion about how much additional astro construction our garden would withstand, the decision was made in favor of a solid column resting on a concrete foundation. However, this was the minimum that is necessary. The mount should then be attached to the concrete column with an adapter. Both the column and the mount were to be protected from the weather by a wooden enclosure – in principle a small observatory building. The telescope and counterweights were to be set up or dismantled for observation, but this would not be too demanding in terms of weight or time. The telescope and mount should be controlled from the bicycle parking space. I would be very well protected from dew and wind. The position in the garden was clear to me from my previous mobile observations: as little direct light as possible and far enough away from trees and houses.

Again, I got support in the construction of the concrete adapter from the above-mentioned astronomical colleague. In his perfectly equipped basement precision mechanics workshop, everything was turned, milled and drilled. Together we also sunk the concrete into the ground, cylindrical 80 cm deep and 40 cm in diameter. The actual column consists of a KG pipe DN150 filled with concrete, which ends 70 cm above ground level. In addition, an empty conduit was laid in the concrete for the underground cable routing to the bicycle shelter. The telescopic adapter was inserted into the soft concrete at the top of the KG pipe.
After a week of thorough drying, the mount could be put on. In the meantime, the wooden enclosure had also been completed. Now all I needed was a clear night to get into the north.

After that, the (observational) world was simple. It now takes me a whole 20 minutes from removing the enclosure to putting on the telescope and connecting the various instruments to approaching a celestial object.

Finally, a small picture gallery of the development of the telescope column: