Friday, September 13, 2019

Lunar Transit on September 28, 2019

SDO will experience a lunar transit on September 28, 2019. Here is a movie from the Flight Operations Team that shows SDO, the Sun, and the Moon during the transit. This transit lasts from 2044-2115 UTC (4:24-5:16 pm ET) and covers at most about 7% of SDO's view of the Sun.
The Moon moves from left to right during this transit. That makes it an SDO-overtake transit.

During the transit SDO will be in inertial mode with the fine-guidance system turned off. Images may jiggle around a little bit, but will continue to be observed and recorded.
Although you can see the Moon throughout the movie SDO's instruments cannot see the Moon when it is not covering the Sun. The little white flash seen in the Moon is the word "Moon" being written by the software and then quickly covered. The boxes drawn around and on the Sun help the FOT run the spacecraft. The time is displayed in the lower left corner of the movie. The first seven numbers are the year (2019) and the day of year (271). The six numbers after the period are the hour, minutes, and second of UTC (2 numbers each).
The next SDO Transit will be the Mercury Transit on November 11, 2019. We will have a webpage dedicated to the transit.