CFHT / IRTF Venus observing - IRTF
January 20th, 2016
For today’s blog entry we visit the NASA InfraRed Telescope Facility (IRTF), where Therese Encrenaz (from the Paris observatory) is also observing Venus. The IRTF is at the summit of Mauna Kea, only a few hundred metres away from CFHT.
Attached to the back of the IRTF telescope is an instrument called TEXES - while the *telescope* is consists of the mirrors which collect the light, it is the *instrument* which analyses this collected light. The TEXES instrument observes a slit-like area of the sky; it then measures a spectrum for each point along this slit. This slit is then scanned across the target – in this case Venus – in order to build up a 2-D picture, where for each pixel in the picture one has a spectrum. Each spectrum carries information about the chemical composition of the observed target, allowing a mapping of chemical species across the target. In this case, Thérèse Encrenaz has been using this to make maps of Sulphur Dioxide (SO2) – in the upper atmosphere of Venus.
The IRTF has been busy tonight; from sunset until 23:30 it was being used to observe water-rich asteroids, and then it switched to Tommy Greathouse’s observations of Jupiter. Venus observations then started well after sunrise at 08:40, carrying on until well into the daytime at 11 am. Looking out of the telescope dome, one can clearly see Venus even in the middle of the day, a small white dot in the brilliant blue sky. At 11 am the observing run is declared over and Thérese and Tommy break out in cheers – this marks the end of their observing run with TEXES, they will now return to their home institutions and closely examine the data.
Attached to the back of the IRTF telescope is an instrument called TEXES - while the *telescope* is consists of the mirrors which collect the light, it is the *instrument* which analyses this collected light. The TEXES instrument observes a slit-like area of the sky; it then measures a spectrum for each point along this slit. This slit is then scanned across the target – in this case Venus – in order to build up a 2-D picture, where for each pixel in the picture one has a spectrum. Each spectrum carries information about the chemical composition of the observed target, allowing a mapping of chemical species across the target. In this case, Thérèse Encrenaz has been using this to make maps of Sulphur Dioxide (SO2) – in the upper atmosphere of Venus.
The IRTF has been busy tonight; from sunset until 23:30 it was being used to observe water-rich asteroids, and then it switched to Tommy Greathouse’s observations of Jupiter. Venus observations then started well after sunrise at 08:40, carrying on until well into the daytime at 11 am. Looking out of the telescope dome, one can clearly see Venus even in the middle of the day, a small white dot in the brilliant blue sky. At 11 am the observing run is declared over and Thérese and Tommy break out in cheers – this marks the end of their observing run with TEXES, they will now return to their home institutions and closely examine the data.