Stray light reflections on GOES visible imagery
GOES-12 visible images
We received the following question on 02 October 2008:
Hello: I sometimes look at the GOES-12 vis nightime images even though they are usually devoid of any light of course. The 03:15 image tonight, however, is showing a meteor-type streak with a comet-like head and tail. I wonder, though, if GOES can actually detect a rapid transient event such as a meteor – or is this some sort of internal reflection caused by another light source or process? Many thanks! Rob Jackson, Hampton, NH
Excellent question, Rob! A sequence of GOES-12 visible images every day at 03:15 UTC from 27 September through 02 October 2008 (above) revealed that an increasing amount of “stray light” was finding its way to the satellite’s instrument detectors just prior to the time when the GOES-12 satellite was entering the Fall “eclipse period” (when the satellite passes through the Earth’s shadow). During such Spring and Fall season eclipse periods, imagery from the satellite is interrupted, since the solar panels cannot generate the power needed to operate the various instrument packages.
An example of stray light affecting GOES-12 imagery during a Spring season eclipse period can be seen here.
Beginning with GOES-13, larger batteries on-board the satellite allow the instruments to operate through the eclipse periods (when the satellite is still in the Earth’s shadow). However, while imagery is available through the eclipse period, it is still vulnerable to small amounts of stray light which can affect the accuracy of any images or products. An animation of night-time GOES-13 visible imagery (below) shows the impact of stray light during the eclipse period (during that same time period, no imagery was available from GOES-12 between 03:32 UTC and 06:45 UTC).
GOES-13 visible images