Tech ÔÇô Mounting the Renishaw Encoder Rings (Part 2)

Quite some time passed, since our last update, but we were not lazy ­čśë …

As already described in Tech ÔÇô Mounting the Renishaw Encoder Rings (Part 1) we started with the construction of the encoder mountings. We are now a step closer to adding the encoders to the telescope. We got the finished encoder mounts with the Renishaw-Encoders already mounted to them.

The encoder mountings are a quite complex part, thus it took quite a long time to figure out how to design them and make them. But finally we sorted out all problems a can now present our new encoders with their respective mountings:

The DEC encoder mounting with the premounted Renishaw Encoder (protected by the orange tape), (Photo by Gerald Maschek, 07.02.2020)
The RA encoder mounting, (Photo by Gerald Maschek, 07.02.2020)

The RA encoder mounting, also with the already premounted Renishaw Encoder (also protected by the orange tape), (Photo by Gerald Maschek, 07.02.2020)
We currently wait for the refurbished DEC and RA friction wheels which are currently in the sandblasting shop and are going to be hard chrome plated any time soon.

The sandblasted RA and DEC friction wheels waiting for the hard chrome plating, (Photo by Didi, 20.02.2020)

Now we need to attach those encoder mountings to the RA and DEC friction wheels and put all together on the telescope body.

So we are finally making big steps forward to reassamble the telescope again on its testing ground in Davidschlag. We are looking forward to have our first test-light before summer.

Stay tuned for future updates on the completion and test drive of the modernized Deltagraph!



Tech – Mounting the Renishaw Encoder Rings (Part 1)

Beside the work on the Kepler Remote Observatory building this fall, we also work on getting the telescope assembled again. One critical milestone for this are the absolute encoders and their mounting on the fork mount.

One of the main problems was to decide on the correct material for the parts. For several reasons and for convenience we decided to go with stainless steel.

We now got the first blank parts, which are now handed over to our partner for turning and milling the actual parts.


A still open point are the friction wheels. They are made out of a much harder stainless steel ÔÇö we still wait for the blanks for the friction wheels.

Once we have all parts milled and turned we will start rebuilding the telescope (already with the absolute encoders). We plan to have a first test run of the telescope this winter (but not at the actual Kepler Remote Observatory)

So stay tuned for more news regarding the telescope and its rebuilding process.


Under Construction – Securing the Dome from Snow

Last winter we observed that our dome is prone to let a lot of very fine snow particles inside. We observed some severe snow inside the dome, as you can see on the following picture.

Severe very fine snow inside the dome. Captured with the internal IR-Cam on 16.01.2019 (Photo by the Kepler Remote Observatory security system)

So we decided to update the dome with some special “snow deflecting systems”. One of the additions was mounted this fall (before it starts snowing again on 1100m above sea level).

After some examination of the dome, we came to the conclusion that the rather big gap between the dome and the building itself, is one of the main issues. Since this gap is necessary to let the dome rotate freely, we needed a special solution.

In our case, we think, a flexible cover over the gap will do the job. It will let the dome still freely rotate but otherwise cover the gap, so that the fine snow particles cannot enter the dome via the gap. We also installed a brush ring to hinder the snow from entering even more.

The first thing we had to do, was to install a metal mounting ring to get a stable foundation for the brush ring.

The metal mounting ring with cut-outs to follow the curvature of the dome. (Photo by Johannes St├╝bler, 15.10.2019)
The metal mounting ring already installed and the brush ring installed too. (Photo by Johannes St├╝bler, 15.10.2019)

The actual flexible cover, will be mounted on the gray curved part of the rotating dome (you can see it in the above picture directly above the metal mounting ring). Actually this fiber glass part is the source of the problem Ôćĺ it is way too small. It covers the gap just barely.

The additional flexible cover is a black natural rubber band. This rubber band will┬áextend the fiber glass part about 30cm and thus will make the gap hard to pass for the snow ÔÇö especially with the additional brush ring which makes it even harder for the snow.

The final rubber band covering the gap between the rotating dome and the building. (Photo by Johannes St├╝bler, 22.10.2019)
Before the installation of the natural rubber band with the metal mounting ring already installed. (Photo by Johannes St├╝bler, 15.10.2019)
Finally with the installed natural rubber band. (Photo by Johannes St├╝bler, 15.10.2019)

So finally the snow can arrive at the location. We are now very curious how this modification of the dome holds up against the harsh winters up there.

There are still some things to do at the Kepler Remote Observatory before the winter really hits:

  • Installing better surveillance cameras inside the dome to be able to track if and how much snow will still enter the dome
  • Installing an all sky cam
  • some local server work we can’t do remotely

Aside the Kepler Remote Observatory building, we are also working on the telescope:

  • We now got the material for the absolute encoder ring mountings Ôćĺ therefore we started with the manufacturing of the mounting parts (read more in the future)
  • We are also working on the motorized main mirror and corrector covers
  • We plan a test of the telescope already this winter (although not on the actual Kepler Remote Observatory)

I know it was quite a long time since our last update, but be sure, we are working hard on the project. It is just not always time to write something in the blog.

But stay tuned for further hopefully interesting stories regarding the construction of our remote observatory in the Alps.

Star Park Hohe Dirn: Public viewing

On the weekend from Saturday 26th October to Sunday 27th we had a public viewing event, held by our partners the Sternfreunde Steyr. Due to the quite good weather conditions a lot of visitors showed up at the Star Park in 1100m. Also two colleagues with their quite impressive 20″ and 22″ Dobson-Telescopes where present – you can imagine what a great view we had.

We watched for example the western Veil Nebula (NGC 6960), the Crab Nebula (Messier 1), or the Horsehead Nebula an alot of other objects in a staggering detail.

The visitors (>50) where quite impressed from the “Star Party” and asked a lot of questions regarding the objects we watched, the Star Park and of course the Kepler Remote Observatory project. We happily answered all of them.

Now have a look at some of the impressions caught during the night by our colleagues.

One of the two big Dobson telescopes (22″, f/4.8, GoTo). (Photo by Johannes St├╝bler, 26.10.2019)
The second big Dobson telescope (20″, f/5, GoTo). (Photo by Johannes St├╝bler, 26.10.2019)
The sky above the Kepler Remote Observatory. In the foreground a small photographic setup on our new external post. (Photo by Johannes St├╝bler, 26.10.2019)
The “Window to the stars” of the Kepler Remote Observatory. (Photo by Johannes St├╝bler, 26.10.2019)
The “Window to the stars” of the Kepler Remote Observatory. (Photo by Johannes St├╝bler, 26.10.2019)
The Milky Way above the Kepler Remote Observatory. (Photo by Johannes St├╝bler, 26.10.2019)
Star trails above the Star Park Hohe Dirn. (Photo by Johannes St├╝bler, 26.10.2019)
Star trails above the Star Park Hohe Dirn. (Photo by Johannes St├╝bler, 26.10.2019)
Star trails above the Kepler Remote Observatory. (Photo by Johannes St├╝bler, 26.10.2019)

We also installed an All Sky Cam this day and updated the external surveillance cameras (external dome surveillance) since one of them was quite crap.

More about the All Sky Cam in a future post. So stay tuned for an update on this.

We also installed the internal dome surveillance cameras which are used to check the dome and the installed telescope during operation.

Tech – Server

Finally our command and control servers for the telescope arrived. Now we can port the already set up and tested environment from a desktop PC to a “real” Server. This added a lot of headroom for the virtualization of our productive environment.

The next task is the conversion from our virtualized Windows only command solution using ASCOM to a virtualized Linux only solution using INDI. The past showed that ASCOM is not up for the task handling such a project.

The first task of these new servers would be running the surveillance cameras and providing us some real time insights into the dome and the observatory surroundings during the next winter – this will help us to harden the dome against moisture and snow intrusion.

Some pictures from us setting up the servers.

(Photo by G├╝nther Truhlar, 02.07.2019)


Under Construction ÔÇô Electrics (Part 3)

After the rather strong winter at our observatory site, the weather got fine and we could continue with the electrical work at the observatory.

Some finalization of the electrical wiring and mounting of some surveillance cams were open from previous year.

So we meet at the observatory on 23.06.2019 and finished the work.

We also reinstalled the renewed working desk. So finally we have a desk – chairs are still missing ­čśë …

Here are some photos of the construction work ongoing. 

And an impression of the location of that day.

(Photo by G├╝nther Truhlar, 23.06.2019)

Project presentation at the 22. Minor Planet Conference

This years German minor planet conference (German) organized by the VdS-Fachgruppe ÔÇ×Kleine PlanetenÔÇť (German) in Salzburg at the Vega Observatory (German) was also a chance for us to present the project to a professional audience.

The project was very well received and some cooperation may arise from this meeting.

(Photo by David Voglsam, 16.06.2019)
(Photo by David Voglsam, 16.06.2019)

Tech – Reassembling the Telescope (Part 1)

After we got the telescope body back from sandblasting and painting (read here what happend) we were ready for the first test fit. We need to find out the margins we have to add the absolute encoders and their mounting mechanic.

We also measured out the dimensions of the ball bearings we need to mount the encoders.

(Photo by G├╝nther Truhlar, May 2019)

After the measuring was done we disassambled the telescop again to prepare it for mounting the encoders. Therefore we have to wait for the delivery of the ball bearings and some metal parts.

Once we received all parts we assamble the whole telescope and bring it back to its original loaction in Davidschalg for testing. When all works fine, the installation of the telescope at the Kepler Remote Observatory site in the Star Park Hohe Dirn is planned for next year.

Tech – Sandblasting and painting the body

Since we dismantled the telescope for technical enhancement, we also took the opportunity to repaint it. However, this brought up some minor problems.

The first one was, that the steel body of the OTA was not manufactured really precise. So after removing all the filler, we saw a very wavy main mirror box and spider ring.

Another Problem was, that with the sandblasting, not all of the filler has been removed, which lead to some sections (especially on the spider ring) with a lot of tiny ripples.

Waviness and filler residues on the spider ring. (Photo by G├╝nther Truhlar, 27.01.2019)
The sandblasting also reveals some inaccuracy in the welding seam. Fortunately this is just an optical “problem”, the welding seam itself is ok. (Photo by G├╝nther Truhlar, 27.01.2019)
Filler residues on the underside of the spider ring. These need to be removed entirely before repainting the telescope. (Photo by G├╝nther Truhlar, 27.01.2019)

For now we roughly painted it again to prevent it from corrosion, but we also came to the conclusion, after full update, we have to redo the paintjob properly, removing all the rest of the original filler, applying new filler again to remove the waves and ripples in the metal frame and paint it again.

To be honest, doing the paintjob prior the mechanical enhancements was not very smart, so we were not really concerned due to the poor first “paintjob”. Now we do not need to care that much about the paint since we have to repaint it anyway in the end.

The night in the Star Park – Impressions 4

Thanks to our partners, the Sternfreunde Steyr, and their effort walking up the mountain during difficult snow conditions (>1.5m of snow) we can show you some current impressions of the night sky in the Star Park Hohe Dirn and the KRO.

Thanks to Rudi Dobesberger , who take those magnificent shots of the night sky (see more photos from Rudi at his facebook page).

Star trails over the Star Park Hohe Dirn and the KRO. (Photo by Rudi Dobesberger, Sternfreunde Steyr)
Venus and Jupiter in front of the Milky Way. (Photo by Rudi Dobesberger, Sternfreunde Steyr)