Remote operation

Moana at DSO.


Road trip:

I installed the system in my back yard, on a tripod, and got it running for a last test. Once I was satisfied the system was complete and running, I packed everything to boxes that I sealed with tape. The OTA went into plastic bags (big “contractor bags”) then into a thick sleeping bag to be protected during transportation. The sleeping bag is much lighter and easier to manage than making a large and heavy plywood box for transport – I have one of those and it is a giant hassle to transport and store. I also packed my collimation tools and a very complete toolbox, plus some clothes.

For the trip I remove the primary mirror from the OTA and transported it, still in its cell, in a protected box, laying horizontally.

The day before the trip I packed everything in the back of my car, ready to go. On the big day I left just before rush hour, around 6am. I arrived at DSO at about 4pm, after a long but uneventful trip. The last mile of the dirt road had been destroyed by heavy rains, and it was pretty bad, even to my loose standards.

Mount and scope setup:

Although I arrived late, I decided to install the scope and engaged in a race against the clock to be done before night. The install was much like installing on my tripod in the back yard, except I put oil on all the screw taps, so at the end of the lease when I remove the gear, the screws won’t get solid rusted in their sockets. I had the mount set up, the scope on the mount, and the balancing done within one hour and a half of intense work. Note: if you mess with oil and optics on the same day, have some latex gloves.


After the trip on the bumpy dirt road and the reinstallation of the primary mirror, I had to go through a full collimation. I usually proceed with my Howie Glatter laser. It is fairly straight forward. Then P., who was installing a dual FSQ106 on the next pier, passed me his Takahashi collimation tool, to check my primary centering. The results from the laser and the collimation tool were widely different, which left me completely baffled. The 2 tools were perfectly self consistent, gave perfectly reproducible results, but those result were not identical, and by quite a big margin.

Polar alignment:

At that point the sun had set and it was getting dark. I then proceeded with polar alignment. I had expected to use the Rapas (AP’s Right Angle Polar Alignment Scope), which usually gets me to a few arc minutes of alignment in less than 1mn of work. However Polaris is not visible from my Pier (obscured by the rolling roof). That was a giant bummer. From there there was many other options (NINA’s 3 star align is one), but the one I was most familiar with at that point was to use drift align. So I used Phd 2 drift align routine and aligned with my wide angle guide scope. Although I was widely off at startup, this did not take too much time, and I was decently aligned in about 35 minutes. At that point the clouds rolled in and that was it for the night.

Computer set up:

The following day, I came back and proceeded with installing the remote computer (all operations from the previous night were done from my laptop), the Switched PDU, flat panel and took some flats consistent with the new collimation. I was a little afraid of the configuration of the Switched PDU (because all remote operations depends on it) but it turned out to be super easy and uneventful -maybe because P. did all the work for me on that one.

After that, the weather turned to rain and it was clear I would not be able to refine my collimation nor my alignment that night. So I went back to fort Davis and tested my remote set up from my hotel room, confirming that everything was OK.

I finally drove back home the following day, without the possibility to fully check collimation and alignment on stars.


Once back home, I ran a very complete drift align remotly, and determined alignment was 1.6 arc minutes off. I also built a pointing model, to confirm the value, and know in which direction I needed to correct. Note: I should have taken notes during the initial drift align procedure on site to record, for each side of the pier, the correspondence between a positive or negative drift and an East or West correction -but I did not, and use the pointing model estimate instead. On the AP1100, the azimuth knob has 18 divisions, and each division is 2 arcminutes. So I called P. who was still at DSO and asked him to unlock my azimuth axis and turn the azimuth knob a little less than 1 division. I knew the direction (East or West) though the pointing model error result, and next time I should get it from my notes. He did the correction and I was basically aligned in Azimuth. Regarding the error in elevation, the pointing model tells me I have a positive error on one side of the pier and a negative error on the other side. I will at some point fiddle with it, so the errors are equal in magnitude and opposite in sign. But for now I have let go, and the pointing model takes care of it.