The three calibrations that we wanted to do were the; silver bullet, a 1m spectrometer that looks at OH airglow, the 1/2m white and the 1m green periscope that we looked at yesterday. As this would be the only calibration these instruments would have for the entire season it was important that it was as accurate as possible. Each of the calibrations would require us to be outside for a protracted period of time meaning that someone would always have to be on Polar Bear watch, I got the joy of doing this for the first calibration of the 1m silver bullet. I half loaded the rifle and filled my pockets with extra ammo and the flare gun so that if anything happened it would all be on quick draw. I then got our very own Polar Bear early warning system Breeze and we headed outside.
Breeze was on a very long lead so that when we tied one end to the hut where I would be watching out for polar bears he had a lot of room for movement. Standing on top of the hut with the rifle on my back and flare pistol in my pocket I felt like a proper guardsman. Stu and Andrew were also on the hut with me helping Dag set up the huge Tungsten lamp that would be used in the calibration. They used a LASER to measure the distance from the lamp to the reflector screen as accurately as possible, while Frances, Nicola and Stephan were working with Margit on the roof of the observatory to set up the screen.
After a brief period inside to get the feeling back into our toes we started to prepare to do the second calibration. As Stu Andrew and I had been working with the bulb (or in my case looking out for Polar Bears) we were now going up onto the roof to set up the reflective screen for the next instrument. The ladder up onto the roof is located in the inside/outside room. This is a room that although has walls and a roof is bloody freezing and at some points has snow built up on the inside. At the top of the ladder there is an almost 1m gap between the top and the roof where you have to pull yourself up (all good fun when you have a bad back). When we got onto the roof we had to clear the surroundings of the next dome so that the screens mount lay flat and the angles were all correct for the calculations to be valid. Then it was just a case of lifting the mount from one dome to the next making sure that the screen covered the whole of the instruments field of view before the other group, now on the top of the hut with the Tungsten bulb, took the distance measurements. We once again headed inside while the readings were being taken as any outside light sources would have led to an error in the measurements.
This brief rest-bite unfortunately left time for us to get our laptops out where twitter informed us of Kepler’s latest discovery, 6 new planets around one of its observed stars. Of course this lead me to searching through Kepler’s archives and new data sets and press releases to obtain the Kepler ID number and stellar parameters so that I could download the public light curves. I am still working on writing a new IDL code to determine individual planetary orbits so that I can remove their specific frequencies to get to the stellar data.
We then removed the screen mount from the roof and transferred the screen to a different mount so that we could place it over the periscope of the 1m green spectrometer. This process took very little time so when we were done most people went back inside while I took the rifle and the signal pistol while Stu, Andrew and I stayed outside to play in the snow and look up at the stars. Unfortunately as we were calibrating the instrument at the time we were unable to take any photos as any small amount of light would have messed with the instruments. After all of the measurements were made we headed back inside to have a look at the readings before heading home for the night.
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