The Steward Observatory’s Bok 2.3m telescope sits right beside the largest telescope on Kitt Peak Mountain: the Mayall 4 meter. I’ve posted pics of it many times, like here, and here, and here. I’ve walked up to it a few times and gone inside the visitor centre there, but an up-close look at the telescope is usually only afforded to those that are using the telescope. Happily, we met the operator of the telescope and he offered us a chance to see it. This is what it looks like when astronomers geek out over astronomy-type things:
There are roughly 25 observatories atop Kitt Peak mountain, so there’s lots to see and do. I am visiting the mountain in order to use the Steward Observatory’s 2.3 meter Bok telescope (‘the 90inch’). One of the observers on our team was also scheduled to use a different telescope for part of the week; she is working with the WIYN 3.5 meter telescope, which is the 2nd largest optical reflecting telescope on the mountain (1st is the 4m Mayall). As a result, we got to take a quick peak in side:
I received this tweet* from Katrina (aka @Astro_yyz), and thank her for the kind wishes. But it got me wondering: what exactly is the difference in atmospheric pressure between sea level and the elevation of Kitt Peak Mountain? To the internet!
The Kitt Peak summit is at an elevation of 2,097 m, just over 2 kilometers above sea level. This is the sign that greets you when you hit the top
Sea level atmospheric pressure is (on average) 101.325 kPa (kilo Pascals). The atmospheric pressure reduces as altitude increases, the amount by which can be calculated based on simple physical laws. I used a short derivation of these equations by the Portland State Aerospace Society; their equation 9 gives the value of atmospheric pressure as a function of height:
where ‘height’ is in meters. So subbing in height=2097, the equation gives P=78,543 Pascals, or 78.543 kPa. Therefore, the pressure atop Kitt Peak is:
of the pressure at sea level. Cool! And this lines up nicely with a graph that Wikipedia has:
So does this affect me as Katrina alluded to? It hasn’t so far! and it really isn’t high enough for most people to experience any negative effects (such as dizziness, headache, elevated heart rate). However, walking to the cafeteria every day (up a very slight incline) does seem harder than it should be. Though that may just be because I’m horrendously out of shape.
* My own twitter account is @jesserogerson, however, for the week of 12-18 May 2014 I was tweeting as @AstroCanada. This is the official account of the Canadian Astronomical Society. Each week a different Canadian astronomer will be tweeting from it.
1. A Quick Derivation Relating Altitude to Air Pressure [PDF], Portland State Aerospace Society, 2004
2. Atmospheric Pressure, Wikipedia, accessed May 2014
3. Effect of High Altitude on Humans, Wikipedia, accessed May 2014