CFHT / IRTF Venus observing - First CFHT day
January 19th, 2016
06:30 – In our 4WD vehicles, we leave the dormitories at 2800 m where we have been sleeping. The early start is to allow the film crew who is accompanying us to obtain shots of us climbing the mountain road.
07:30 – We arrive at the CFHT building and move our equipment up to the control room. The telescope has been in use all night, but in remote observer mode: the telescope operators have been operating the telescope from CFHT HQ, located in Waimea. The telescope operator prepares the telescope for our observations: The dome is swivelled to position; the telescope is pointed at Venus; the telescope’s petal-like primary mirror covers are opened; the spectrograph is readied.
08:30 – We start acquisition! The spectrograph is pointed in turn at different locations on Venus. We start by scanning the spectrograph along the equator of Venus, and then repeating at low latitudes. This will help get a good measure of the zonal (East-to-West) wind speeds.
10:30 – We’ve moved on to focussing on higher latitude regions, and regions near the terminator. A complication of this observation type is that we do not measure a two-dimensional wind vector, i.e N-S and E-W components; the Doppler shift measurement at any given point is only a 1-dimensional velocity measurement. If you want to see more about how the wind maps are created, see publications by Pedro Machado and Thomas Widemann!
11:30 – The sun is higher in the sky now; image quality has become worse due to increased convection in the atmosphere (Earth’s atmosphere, not Venus' atmoshere!). The control room screens tell us that the wind speed has increased to 32 mph, gusting to 41 mph (apologies for the imperial units, that’s how the data are delivered to us!). The high winds are swirling around the dome but have not, as of now, stopped us from performing our observations.
12:48 – we stop observations for the day. Atmospheric turbulence is getting stronger, degrading the observations; also, sunlight entering the CFHT dome is getting critically close to sensitive equipment and we have to stop. We have over 4 hours of observations, though, with clear skies, so it’s been a successful observing run! Now we’ll descend the mountain, have a look at the data, and prepare to run again tomorrow.
07:30 – We arrive at the CFHT building and move our equipment up to the control room. The telescope has been in use all night, but in remote observer mode: the telescope operators have been operating the telescope from CFHT HQ, located in Waimea. The telescope operator prepares the telescope for our observations: The dome is swivelled to position; the telescope is pointed at Venus; the telescope’s petal-like primary mirror covers are opened; the spectrograph is readied.
08:30 – We start acquisition! The spectrograph is pointed in turn at different locations on Venus. We start by scanning the spectrograph along the equator of Venus, and then repeating at low latitudes. This will help get a good measure of the zonal (East-to-West) wind speeds.
10:30 – We’ve moved on to focussing on higher latitude regions, and regions near the terminator. A complication of this observation type is that we do not measure a two-dimensional wind vector, i.e N-S and E-W components; the Doppler shift measurement at any given point is only a 1-dimensional velocity measurement. If you want to see more about how the wind maps are created, see publications by Pedro Machado and Thomas Widemann!
11:30 – The sun is higher in the sky now; image quality has become worse due to increased convection in the atmosphere (Earth’s atmosphere, not Venus' atmoshere!). The control room screens tell us that the wind speed has increased to 32 mph, gusting to 41 mph (apologies for the imperial units, that’s how the data are delivered to us!). The high winds are swirling around the dome but have not, as of now, stopped us from performing our observations.
12:48 – we stop observations for the day. Atmospheric turbulence is getting stronger, degrading the observations; also, sunlight entering the CFHT dome is getting critically close to sensitive equipment and we have to stop. We have over 4 hours of observations, though, with clear skies, so it’s been a successful observing run! Now we’ll descend the mountain, have a look at the data, and prepare to run again tomorrow.