Winter at Star Park Hohe Dirn – Impressions 3

Some time has passed since our last update on the project “Kepler Remote Observatory”. This had some reasons. The first one, with the most impact, is the current weather and snow situation in the Star Park.

We had well above 1.5m of snow and on certain spots far more, as you can see on the following pictures showing (or better NOT showing) the building of our colleagues the Sternfreude Steyr (thanks to Bernhrad Mayr for letting us use his pictures, find more pictures on his Facebook site):

A panoramic view of the observatory site. To the far left the building of the KRO, in the center and right, the building of the Sternfreunde Steyr covered nearly entirely by snow and their two domes. (Picture taken by Bernhard Mayr, Sternfreunde Steyr, 16.01.2019)
Foto of the KRO dome and the sun emerging in the south east. (Photo by Rudi Dobesberger, Sternfreunde Steyr, 06.02.2019)
View from the “Anton Schosser H├╝tte” down to the Star Park (middle – right). The general view direction is north-east. (Photo, Rudi Dobesberger, Sternfreunde Steyr, 06.02.2019)


The following gallery shows some additional impressions from the beautiful winter in the Austrian mountains:


Luckily the KRO itself was quite free of snow and accessible. The only problem was getting up the mountain. This was the main reason why the work stood still over the winter. We couldn’t reach the Observatory with construction equipment.

The building and dome of the Kepler Remote telescope, quite free of snow. (Foto by Bernhard Mayr, Sternfreunde Steyr, 16.01.2019)

And what are the other reasons, why construction work stood still at the observatory?

Well first of all we dismantled the telescope at its current location. You can read more about this process in this post.

We also started the telescope improvement (adding encoders, adding a motorized mirror cover). You can read more about this in this post.

(* Featured image by Rudi Dobesberger, Sternfreunde Steyr)



Tech – Motorized main mirror cover

Over the winter it was not possible to work at the KRO site to finish electrics and other building related stuff due to heavy snowfall (Read in an upcoming post more about the weather conditions at the KRO site).

However, due to this circumstances we had time to dismantle the telescope in Davidschlag (Want to know more?) and start with the technical updates we have planned for it.

One of these updates is building a main mirror cover to prevent the mirror from gathering dust when not used.

For this we had to develop a light weight motorized construction, which we can add to the mirror box.

We came up with a light aluminum frame (split into two flaps) which is powered by a 12V Motor.

The frame now looks like this (without flap cover):

The finished main mirror cover frame with the small 12V motor on the right, powering both cover flaps. (Photo by G├╝nther Truhlar, 07.02.2019)

The following video shows the frame in action:


Tech – Dismantling the telescope

Since the winter was/is very hard in the alps, at least on the top of the mountains, and we couldn’t work at the observatory site, we had some time to work on the telescope. To be able to do so, the first thing was, dismantling the telescope at its current location, Davidschlag.

A last picture of the old telescope on its original location. Next time when it is back there, it will be highly updated and initial testing can begin. (Photo Erich Meyer, Erwin Obermair, 1999)

We found a day where we didn’t had any snow and the weather was fine enough to.

So we organized some transport capabilities and some aid to handle the fairly heavy telescope parts and start dismantling it.┬áLuckily we didn’t had big problems, it all went quit well and so the telescope was in pieces and packed after a few hours. The following pictures show the process.



We have also made a timelapse video of the whole day:


We temporarily stored the telescope in a garage of an observatory colleague and we started working on improving the tech, namely the encoders and the motorized main mirror cover.

Tech – LBB (Biss-C protocol converter)

As mentioned in several prior blog posts (Tech ÔÇô The Telescope Mount, Tech ÔÇô First Hardware/Software Test, Tech ÔÇô Alignment & Guiding (Take 3) ÔÇô Fail, Tech ÔÇô Telescope Control (Part 2) and Tech ÔÇô Using Renishaw Absolute Encoder) we plan to use absolute encoders on our telescope mount.

As we found out, the Sidereal Technology SiTech Servo II supports absolute encoder we decided to go for it. To be able to connect the 26bit Biss-C compatible Renishaw Resolute read heads to the SiTech Servo II (which speaks RS232 and not Biss-C) we needed to obtain a small interface box provided by Sidereal Technology: the so called LBB (Little black box).


Essentially it is a prtocol converter which converts the Biss-C protocol electrically and logically to the RS232 interface of the SiTech controller.

Therefore you find some level converters and a small microcontroller inside this box.


So what’s next?

We now have to order the correct sized encoder rings and read heads (in our case the 413mm diameter ring for the RA and the 200mm diameter ring for the DEC axis) and once we got them adapt the mount to be able to mount the rings to it. The main problem here will be to find a suitable and easily adjustable read head mount (the tolerances here are quite narrow). But let us discuss this in another post.


Tech – Dome Improvements

As mentioned in Tech ÔÇô The Dome and Under Construction ÔÇô The Dome, we are using a ScopeDome 4m dome to house our telescope.

The stock dome itself is quite well made, but we identified some points to need some improvement – mostly related to the harsh conditions we face in the winter (high snow, fast winds and low temperatures).

The first issue we will solve is related to the shutter mechanism. This was identified through a small incident: we had some very strong winds a few weeks ago, and the wind managed to lift the shutter a little bit so that the drive gear jumped out of the gear rack.

The detached gear. (Photo by Rudi Dobesberger)

We are currently investigating on how to improve this situation. The Problem is, that the shutter has too much play, and therefore it is possible that the gear jumps out of the gear rack.

We think that in this case the wind entered the dome through the several gaps at the shutter and at the gear rim.

To prevent that the wind pull through the dome in the future and to prevent drift snow to enter the dome, we installed a rubber lip at the shutter.

The ready installed rubber lip, which should prevent drift snow and wind inside the dome. (Photo by Joe St├╝bler, 17.11.2018)
Detail photo of the installed rubber lip. (Photo by Joe St├╝bler, 17.11.2018)
The right hand part of the rubber lip. (Photo by Joe St├╝bler, 17.11.2018)

We also plan to install similar lips inside and outside the gear rim, to prevent that insects have easy play when entering the dome.

Another improvement dedicated to the gear rim, was to exchange all screws with stainless steel screws. We also reworked all gear rim mounting holes to make sure, the rim is 100% even and therefore the dome can run very smooth and the driving gear doesn’t get detached from the gear rim.


Star Park Hohe Dirn – Impressions 2

On November the 10th 2018, we had another work project to do (Under Construction – Electrics (Part 2) ) at the KRO. So we left the fog in the valleys behind us and enjoyed the perfect weather on the mountain tops.

Below you’ll find some impressions of this day.

At such days the peak of the Hohe Dirn is quite crowded and it was quite difficult to take some shots without hikers on the road. Another side effect is, that we have to constantly explain to tourists what we are doing here.

Under Construction – Electrics (Part 2)

As installing all the electrics is quite some effort, we had to spend another day installing them.

This day was entirely dedicated to install all power sockets in the engineering room and the dome itself.

Installing the power sockets in the engineering room. (Photo by Robert Mayrhofer, 10.11.2018)
Installing the power sockets in the dome. (Photo by Robert Mayrhofer, 10.11.2018)

There are still a lot of things open, we have to do in the near future:

  • installing all switches
  • finalizing the switchboard
  • ┬áinstalling the lights

Some of the tasks are currently blocked by the carpenter. He has to finish the ceiling and the staircase to the dome. After this, we can install the lights and switches (some of them will be mounted directly on the staircase).

But these things are subject matter for another post, and day, dedicated to electrical installation.