Archive for January 18, 2022

01/18/2022 – Ephemeris – James Webb Telescope Status

January 18, 2022 Comments off

This is Ephemeris for Tuesday, January 18th. Today the Sun will be up for 9 hours and 17 minutes, setting at 5:32, and it will rise tomorrow at 8:13. The Moon, 1 day past full, will rise at 6:07 this evening.

Let’s take a look at what’s happening with the Webb Space Telescope as of Sunday night when I’m recording this program, the technicians are moving the 18 mirror segments of the primary mirror away from their stowed position for liftoff to near their final position. That’s moving each of them forward about a half inch by tiny increments. Then each will be tilted to concentrate each mirror into a single image and focus it. The mirrors can be tilted and also change the curvature of the mirror segment a bit. This is what takes the time, about 5 months. All the teeny tiny adjustments take time, especially with a nearly eight and a half second two-way light-time between the Earth and the telescope.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.


MirrorAlignmentTracker for 1/17/22

Mirror Alignment Tracker for January 17, 2022. It looks like most mirrors are about 3 millimeters from their final position. Shown are 19 mirrors, the center on, labeled SM is the secondary mirror, out in front of the primary mirror segments. Mirrors A3 and A6 have not moved forward very much. From their position, I assume that’s intentional. Credit: NASA.

As of yesterday (January 17, 2022) the James Webb Space Telescope has journeyed to 91% of the distance to L2 (Lagrange point 2), and its speed has dropped to 577 miles per hour (929 kilometers per hour). They do not want to overshoot the velocity to drop into a halo orbit of L2. By next week’s report, the telescope should have entered its halo orbit of L2.