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07/15/17 – Ephemeris Extra – Possible Auroras to be visible this weekend

July 15, 2017 1 comment

The National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center has issued a Geomagnetic Storm Watch for 16-17 July 2017 UT (Universal Time).  The watch period starts tonight for the US.  The 16th UT starts at 8 p.m. tonight, the 15th EDT.  What it means, among other things, is that the Aurora Borealis (Northern Lights) may be visible from the northern tier of states in the United States and Canada, Scotland, Scandinavia, and Russia.  And maybe even farther south.  See the map below:

Geomagnetic storm map

From the NOAA website. Click on the image to enlarge. Click here for the link mentioned in the image: http://www.swpc.noaa.gov/products/aurora-30-minute-forecast.

This alert was issued due to a Coronal Mass Ejection (CME) from the large, but decaying, sunspot group AR2665 at 2:09 UT on the 14th (10:09 p.m. on the 13th EDT).  The CME is expected to encounter the Earth’s magnetosphere on the 16th.

A tip of the old observer’s hat to spaceweather.com for the heads up email.

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02/23/2015 – Ephemeris – The Launch of the DSCOVR satellite

February 23, 2015 Comments off

Ephemeris for Monday, February 23rd.  The sun will rise at 7:30.  It’ll be up for 10 hours and 51 minutes, setting at 6:22.   The moon, 2 days before first quarter, will set at 12:24 tomorrow morning.

On Wednesday the 11th the DSCOVR satellite was launched to a special point between the Earth and the Sun called the Lagrangian point 1 or the Earth-Sun L1 point.  It’s a point of gravitational equilibrium between the Earth and the Sun, about a million miles sun-ward of the Earth, or four times the distance of the Moon.  It will take the craft over 100 days to get there, which it will slowly orbit.  It will act as an early warning sentinel, replacing the aging ACE spacecraft.  It will give us about an hour’s warning of incoming coronal mass ejections or CMEs erupting from the Sun.  It also has an earth pointing camera with various filters pointed to the full earth and occasionally the far side of the new Moon.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

Launch!

SpaceX Falcon 9 V1.1 first stage burns to launch DSCOVR to the Earth-Sun L1 point. Credit: NASA.  Click to enlarge.

Click to enlarge

Earth-Sun Lagrangian Points

Earth-Sun Lagrangian Points. Source: Wikimedia Commons, Xander89. Click to enlarge.