A personal blog by George Gladfelter

Occultations
01/10/2019
Occultations January 10th - 31st visible from Rapid City
A faint star and a nearly full moon - ugh
All dates and times are MST
Elevation above the horizon (and azimuth) in degrees.

Occultation of 54 chi^1 Ori 4.39 by moon 93% illuminated
at phase= 150 degrees
01/18/2019 18:54:48.9 Geocentric minimum angle 0.7 degrees
Global start/end: 01/18/2019 17:08:06.8 and 01/18/2019 20:41:25.9
Mid-occultation observing point (lat., long.) 62.336 -65.306

---For observations at the Journey Museum:
01/18/2019 17:28:28.0 Start 30.5 (az91)
01/18/2019 17:57:15.2 OCCULTATION MID-POINT
01/18/2019 18:27:13.3 End 40.9 (az101)

Notes about occultations:  The timing is very specific to your exact location.  Few clocks can be relied on to be accurate at the sub-second level, including the cheap radio-controlled clocks which are typically corrected once per day around midnight.  Also, it is very difficult to visually determine the exact time when a star appears or disappears at the illuminated limb of the moon.  Photography, therefore, is very helpful.  No lunar occultations of a bright star will be visible this year from Rapid City.

 

Junk Science
01/07/2019

We might think that astronomy reports on the web could be relied on, but then counter examples do show up. Here are a couple of them.

https://www.livescience.com/64433-milky-way-large-magellanic-cloud-collision-imminent.html

No, the universe isn't going to kill us tomorrow - although some of the information in this article is based on computer simulations, the theory on black holes seems to be speculative. The article also seems to have barely hidden humor in it with the suggestion that we should set our doomsday clocks for 2 or 3 billion years in the future.

From http://www.spaceweather.com on 01/07/2019:

WEEKEND SOLAR ECLIPSE: On Sunday, Jan. 6th, the Moon passed in front of the sun, off center, producing a partial solar eclipse visible from coastal China to the Aleutian Islands of Alaska. During the event, as much as 71% of the solar disk was covered. Browse the solar eclipse gallery for photos.

The eclipse covered up to 71% of the sun's diameter, but only up to 62% of the sun's disk by area. The "71%" figure relates to the "magnitude" of the eclipse, not the obscuration. Shame on Spaceweather.com for going in for hype, or using sloppy terminology.