Aiming Parker Solar Probe at the Sun with Simulink GNC Software
On Monday, November 5, 2018, Parker Solar Probe reached its first perihelion, passing closer to the Sun's surface than any spacecraft had done before. Even at a top speed of about 213,200 miles per hour, it would take the spacecraft several days to pass behind the Sun and emerge on the other side. During this time, researchers and engineers at NASA and at Johns Hopkins University Applied Physics Laboratory (JHU APL) waited anxiously for the first status beacon. On Wednesday, November 7, the signal was received: Parker Solar Probe was operating at status “A,” with all scientific instruments running and gathering data.
Watching Comet NEOWISE
On July 20 and 21, I was able to take the telescope out and try catching Comet NEOWISE. Weather has been a challenge in Boston Metro West, but it cleared out enough to let the comet be naked-eye.
The coma and tail looked clearly visible through binoculars and the telescope. I was especially surprised to notice the greenish color of the coma through the telescope on July 20. Before heading out on July 21, I setup the 12mm eyepiece with the camera adapter to try capturing a glimpse of the comet with an Android phone. And it worked!
The image shown in this slice is one of the photos I took. You can see the star HIP49576 on the left at apparent magnitude 9.28 (flipped horizontally by diagonal mirror). The comet looks way brighter than the star at about 3.5 or 4th magnitude. And what I keep finding most interesting is how easy it is to distinguish the green color of the coma, visually and on the photo.
The green color is said to be caused by light emissions in high concentrations of cyanide (C-N) and diatomic carbon (C-C) molecules present in the sublimating gases, which are being energized (excited) by the ultraviolet radiation of the Sun.
Cheers to that! because it looks beautiful.
It seems like it has been a long while since we've had a bright comet in the sky. As usual, we are cautious about publicizing too much about new comets and we should do similarly in this case, because we never know if they will simply disappoint. But it sounds like we might want to continue keeping an eye on a comet that is going through perihelion recently and is already showing off during July. Would you like to learn more? Check out the stargazing pages. Below is the local path from August 20 (top right) to September 12 (bottom left) as seen at 8PM Eastern Daylight-saving Time (EDT) from New England. (Notation = DD:HH Universal Time).