The GOLD gif animations are organized by year, and within each year, by month. Click on the desired year to go to that page.
Overview of NI1 Scan Sequences
At the beginning of the GOLD mission, the standard NI1 scan sequence was hybrid:
- Single Channel Mode: From 2010 UTC until 2310 UTC, Channel B alternated between the northern and southern hemisphere, so the effective cadence for a full hemisphere scans was 30 minutes.
- Dual Channel Mode: From 2310 until the end of the night scan Channel A and Channel B each scanned one hemisphere simultaneously at a 15 minute cadence.
Beginning 2022.018 (January 18), the each nighttime scan was only Dual Channel. The metadata visible in the gif animations is explained below. Note that the scans are outlined, no data is shown. [As with all the gifs displayed on this site, a click will display a full size gif, and a right click will download the gif.]
The meta data that appears in the header of each gif animation can be confusing, especially during the single channel phase of the scan sequence. In the gif at right, the geomagnetic equator is plotted in magenta, while the terminator at the start of the current scan is plotted in cyan.
Because the slit can only access one hemisphere at a time, during single channel mode the slit alternates between hemispheres every 15 minutes. The gif maintains a 15 minute cadence by combining the most recent scan with the previous scan. The most recent scan is designated B2, the prior scan is labeled B1. In the gif, the B1 scan (the previous scan) is always red, the B2 scan (the current scan) is always blue.
The first scan of the night is always a northern hemisphere scan, designated B2. B1 is listed in the header but is actually non-existent.
Once the scan sequence switches to Dual Channel, the Channel A scan is outlined in red, and the Channel B scan is outlined in blue.
Throughout the GOLD Mission, it has been found necessary to modify the NI1 (Nighttime Ionosphere) scan sequence. Some of these modifications are due to the seasonal configurations of the terminator, but others have to do with changing objectives. The main page for each year contains descriptions and illustrative graphic examples of the changes that occurred during that year. A summary is presented here:
