David Somach

UROP Report – Wallace Astrophysical Observatory

This summer, I worked for Tim Brothers on engineering projects out at Wallace. Together with Rachel Bowens-Rubin, I worked on:

- re-assembling, re-balancing, and collimating the 24 inch telescope,

-fixing the rain sensor for the weather monitor,

-researching automated dome rotation and contacting companies with dome rotation systems,

-finding heating wire to prevent ice buildup on the tracks of the shed,

-re-installing the grip tape on the shed roof,

-fixing the shed roof so that it will slide closed over the gable,

-troubleshooting the KVM for the 24 inch telescope control (and sending in for repairs),

-putting drivers on one of the old computers (for 16 inch telescope control),

-installing Windows XP on a new Mac Mini for the 24 inch, and

-finding the possibilities for upgrading the hand controller for the 11 inch in the shed.

During my first few days out at Wallace, I helped Tim and John assemble the primary mirror with the other UROPs. Once the primary was in place, we assembled the secondary mirror, attached it to the spider, and installed the secondary setup on the telescope. Later, we collimated the telescope and aligned the finderscope connected to the TV screen.

Rachel and I worked on fixing the rain collector sensor for the Davis Weather Monitor. We took apart the sensor according to the manual to see if there were any apparent problems (disconnected cables, corroded electronics, etc.). The sensor consists of a tipping bucket which swings a magnet over a reed switch. The frequency of the swinging is proportional to the amount of water which pours into the bucket, so the switch is able to measure how much water is pouring in (how much rain is falling). We initially thought that we would need to replace the magnet since we were only getting readouts when we swung a different magnet over the switch, but it turns out that the problem is with the reed switch. We are currently waiting for a new reed switch in the mail.

We researched an automated dome rotation setup for both of the domes. The dome automation will not be installed until later (January is a likely time) so that the installation will not interfere with the fall classes. As of now, the favored system is “Dome Works” by Technical Innovations. This is the only system we considered which would not require interfacing with the computer. We decided that this type of system would be favorable to one which would require connecting to the computer since it would be helpful not to have to worry about compatibility with any future computer systems. Below is a picture of the hardware:

The system uses infrared sensors to keep the shutter where the telescope is pointing. Jerry Smith of Technical Innovations said that “Dome Works” will interface with our existing motors on the domes.

One of the biggest problems we had observing over IAP was that the shed roof would either get stuck closed or open. We noticed that there was snow and ice buildup along the tracks for the shed roof. One of the summer projects was to come up with a solution to this problem. We decided to get heating wire to put along the tracks to melt snow before it can cause a blockage. Below is a picture of the tracks:

The wheels of the shed roof roll along the triangular wedge. The heating wire will go along the trenches. The wire will melt the snow but will not interfere with the wheels when the shed opens or closes since the wheels do not come in contact with the bottom of the trenches. This should solve the shed’s winter problem. We will see this coming winter the effectiveness of the heating wire.