From: Larry CochraneTo: psnlist Sent: Wed, 16 Jan 2013 3:21 Subject: Fwd: Optical siesmometer Subject: Optical seismometer Date: Tue, 15 Jan 2013 15:33:51 -0600 Larry, I thought you might find this interesting: http://www.ctbto.org/fileadmin/user_upload/SandT_2011/presentations/T3-O5%2= 0J_Berger%20Optical%20Seismometer.pdf -Charlie Hi Charlie,=20 It looks as if Mark & Co have done quite a bit more development work.= =20 But amateurs would likely to have difficulty measuring optical fringes to= =20 1/2 ppm / Root Hz and Michaelson Interferometers are not cheap.=20 Amateurs can get about 10 nano metres resolution over 10 Hz using large are= a=20 photocells and a stabilised light source, but this is likely to be adequate= -=20 unless you can 'lay your hands' on a couple of redundant Streckheisens ! Regards, Chris Chapman =20 From: Larry Cochrane <lcochrane@..............>
To: psnlist <psnlist@..............>
Sent: Wed, 16 Jan 2013 3:21
Subject: Fwd: Optical siesmometer
Subject: Optical seismometer Date: Tue, 15 Jan 2013 15:33:51 -= 0600 Larry, I thought you might find this = interesting: http://= www.ctbto.org/fileadmin/user_upload/SandT_2011/presentations/T3-O5%20J_Berg= er%20Optical%20Seismometer.pdf -Charlie Hi Charlie,It looks as if Mark & Co have done quite a = bit more development work.But amateurs would likely to have difficulty measurin= g optical fringes to<= font size=3D"2">1/2 ppm / Root Hz and Michaelson Interferometers are not ch= eap.= Amateurs can get about 10 nano metres resolution over 10 Hz using large are= apho= tocells and a stabilised light source, but this is likely to be adequate - =unles= s you can 'lay your hands' on a couple of redundant Streckheisens !<= /tt>Regards,Chris Chap= man