This is the Solar Dynamics Observatory Mission blog. It will consist of mission status, news, and event updates.
Once again, a lunar transit shows how complicated the motions of objects can appear even as they move along simple orbits.
SDO data is the basis of accurate models of the solar corona. Machine Learning algorithms are being used to squeeze even more information out of our 12 PB of data. We are looking forward to another lengthy lunar transit next month and the Mercury transit in November.
Happy Anniversary SDO!
The Moon moves from left to right during this transit. That makes it an SDO-overtake transit.
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 (2018) and the day of year (311). The six numbers after the period are the hour, minutes, and second of UTC (2 numbers each).
The next SDO lLunar Transit will be on March 6, 2019. That one will also be a double transit similar to the one in September 2018.
For example, the coatings on the HMI instrument housings and optical surfaces have been degrading slowly but steadily, causing the instrument to absorb more solar radiation and heat up. The front surface of HMI’s telescope is now hot enough that the HMI team is having difficulty maintaining proper focus. Without some adjustments, this problem will only get worse as the instrument continues to age.
For this reason, the HMI team is going to increase the operating temperatures of the front of the telescope and adjust the internal focus mechanism. This should give the instrument many more years of precise control and excellent data. The process of increasing the operating temperatures is a slow one — the team will begin heating the front telescope tube up at 1000 UTC on Tuesday, October 16, and will then wait six hours for the temperature to stabilize. The next step is to fine-tune the temperatures. These smaller changes will need about an hour for the temperature to become constant. Science data will not be available during the time it takes to bring the instrument back into focus. That also means there will be no magnetic field, continuum, or Doppler NRT data products.
HMI resumed taking science data before 2130 UTC, October 16. Fine tuning of the focus will occur Wednesday, October 17, but science data will not be interrupted.