Showing posts with label astronomy. Show all posts
Showing posts with label astronomy. Show all posts

Monday, August 31, 2015

FCC approves robotic lawn mower, rejects worst case analysis

On August 12, 2015 the FCC granted a waiver (pdf) of some Part 15 rules to allow iRobot to market a robotic lawn mower transmitting in the 6240-6740 MHz range (Order in Proceeding 15-30). The National Radio Astronomy Observatory (NRAO) had expressed concern that the waiver could lead to interference to radio astronomy operations.

Wednesday, July 29, 2009

Boggle: measuring how sunshine alters the moon's orbit

The July 11, 2009 issue of New Scientist ran a series of stories of why the moon still matters to astronomy, in celebration of the thirtieth anniversary of the Apollo 11 landing. One of them, by Stuart Clark, described how reflectors left on the lunar surface are helping test Einstein's theory gravity. Laser pulses bounced off these reflectors allow researchers to measure the distance between the earth and the moon to a precision of a few millimetres.

At such accuracy one has to factor in the effect of solar radiation pressure "which pushes the moon's entire orbit from its calculated path by about 4 millimetres."