Incoherent scatter radars observing the eclipse

There are two incoherent scatter radars, which will be able to directly observe the ionospheric effects of the eclipse. The Millstone Hill Radar in Boston, and the Arecibo Radar in Puerto Rico. Both of these instruments will be running during the eclipse. They will be able to directly measure the changes in ionospheric electron density and electron temperature during the eclipse. They will also be able to observe changes in photoelectron flux and ion-drift. 

Antennas for the Millstone Hill incoherent scatter radar, in Westford MA. The zenith antenna is in the background and the steerable MISA antenna is in the foreground.  
Inside the Arecibo Observatory antenna.

Millstone Hill plasma lines during a test measurement conducted in preparation of the eclipse on Monday. Image: MIT Haystack Observatory realtime plot of plasma-lines. I worked on developing this receive several years ago while still working at Haystack. The measurement will perhaps be the first observations of photoelectron enhanced plasma-lines during an eclipse. The eclipse should have a detectable effect on plasma-line power, as local photoelectron will be greatly reduced.   
One of the special features of the The Millstone Hill ISR is that it can observe at very low elevation angles. This allows a very large geographic coverage, as is apparent from the above image, which was taken this week during radar testing in preparation for the upcoming eclipse. This will allow observing large scale effects of the upcoming eclipse. Image credit: Bill Rideout, MIT Haystack Observatory.


  1. It's a shame that the first half of that plasma line plot is missing (because we just upgraded the processing computer to Digital RF 2 and needed that time to work out the bugs). It's working fine now though and should be good to go for the eclipse!

    1. That was a test run to iron out bugs. I've been looking at the start of the eclipse run, and plasma-lines work fine now. I've been using DRF2, and I must say that it was worth the trouble to go to 2.0. All the experimental external scripts and tools that were developed over the years are now standard features, and also the file access times are O(1).


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