Subject: Scoop: Earlier MIThenge predictions for November! Date: Sat, 05 Nov 2005 02:07:53 -0700 From: Alan Eliasen It's just about time for the annual November MIThenge phenomenon! This is the time that the sun align's with MIT's Infinite Corridor and shines all the way down its length. Over the past year, several of us have been involved in trying to find a more correct figure for the azimuth of the Infinite Corridor. Published values for the azimuth seem to be significantly in error, and don't explain some historical sightings. Keith Winstein, Ken Olum, Matthias Huerlemann, Gary Boyack and I have performed several measurements and analyses of the corridor using GPS and sun observations, but the exact azimuth is still somewhat uncertain. We think we have much better figures, though. Ken Olum made observations of the sun's position during the last crossing on 2005-01-31. He later returned to MIT to measure and sketch out the geometry of the corridor, including intervening obstacles and doorways to help with the geometrical interpretation. We came to the conclusion that the azimuth of the corridor was somewhere between 245.79 and 245.89 degrees, with our best guess at 245.85 degrees. For reference, the published azimuth of the corridor and the basis for previous predictions (such as those on MIT's website) was 245.47391075. Using this 245.85 figure, and projected temperatures for this week of 59 degrees F, (to take atmospheric refraction into account,) I've run the numbers to see what the revised predictions should be. Based on this new azimuth, the predictions for days where the phenomenon will be visible differ from past predictions. Here are my predictions: Alt (deg) JD Date 1.85 2453682.3863279 2005-11-07 04:16:18 PM EST 1.48 2453683.3872094 2005-11-08 04:17:34 PM EST 1.12 2453684.3880908 2005-11-09 04:18:51 PM EST * 0.77 2453685.3889717 2005-11-10 04:20:07 PM EST * 0.44 2453686.3898516 2005-11-11 04:21:23 PM EST * 0.11 2453687.3907302 2005-11-12 04:22:39 PM EST * -0.20 2453688.3916070 2005-11-13 04:23:54 PM EST * -0.51 2453689.3924814 2005-11-14 04:25:10 PM EST -0.82 2453690.3933529 2005-11-15 04:26:25 PM EST The rows marked with (*) indicate days of possible visibility--November 9-13. These dates are in fact 2 days before the dates predicted at: http://web.mit.edu/mithenge/mithenge-data.text which only predicts visibility the 11th through the 13th. The crossing on 2005-11-09 will be quite high. As the azimuth of the top of the doorway is 0.91 degrees or less, (as seen from the back of the corridor,_ only part of the sun will be visible, and this will probably only be seen slightly later, and viewing from the bottom left corner (looking toward the sun) of the hallway. The later crossings on the 12th and 13th will very likely be blocked by intervening objects, but it may be possible to see the top of the sun slightly earlier and looking from the right-hand-side of the corridor, or farther sunward (west) in the corridor. If you're only expecting to observe once, I don't recommend the 12th or 13th. In fact, all of the "sketchy" crossings will possibly be visible from farther forward in the corridor. If you observe, please note your position and time! If our new azimuth figures are correct, the sun will almost certainly be visible on the 10th. This may, in fact, be the best day for viewing. Now, my dilemma! Since I live in Colorado, I need others to be my spotters. If anyone in the Boston area could provide accurate observations, that would help me significantly, especially on November 9 or 10! Accurate timings are very helpful. Even knowing if the sun was visible on the 9th would be useful. If other GPS-surveyed figures of mine (with larger error terms) were correct, it might even be possible to see a sliver of the sun in a corner of the hallway on November 8. Even knowing that the sun couldn't be seen on this date would be a very useful data point. Please forward this information to anyone in the MIT area who may be able to observe on any of these dates. Also, feel free to publish these predictions (with attribution (unless I'm wrong. :) ) to your blogs, prediction pages, etc. Besides, this may be your only chance to see MIThenge without hundreds of intervening gawkers! If you have any questions, please contact me. I have many, many more details and analyses of past photographs, etc. I also have predictions of when the *moon* will be visible down the corridor, but there's not a favorable crossing for several months. Improved corridor azimuth figures will help me refine the moon predictions. Please contact me if you're interested in these. --------- For reference, my programs to calculate the sun's position are available. These are written in a programming language I've developed, called "Frink": Frink documentation: http://futureboy.us/frinkdocs/ The Frink programs necessary for calculation of the Sun's position are: http://futureboy.us/fsp/colorize.fsp?fileName=mithengecorridor.frink http://futureboy.us/fsp/colorize.fsp?fileName=mithengesun.frink http://futureboy.us/fsp/colorize.fsp?fileName=mithengemoon.frink http://futureboy.us/fsp/colorize.fsp?fileName=sun.frink More discussion, from my Frink presentation at MIT in December, 2004: http://futureboy.us/frinkdocs/LL4.html#MIThengePredictions (note that the predictions above use different azimuth figures. The azimuth figures and predictions in this e-mail should probably be considered to be more accurate.)