Archive for the ‘Space weather’ Category

01/17/2023 – Ephemeris – The Sun is getting active again

January 17, 2023 Comments off


This is Ephemeris for Tuesday, January 17th. Today the Sun will be up for 9 hours and 15 minutes, setting at 5:30, and it will rise tomorrow at 8:14. The Moon, 3 days past last quarter, will rise at 5:11 tomorrow morning.

The Sun is getting active again, there are a lot of sunspots on the sun today. The sunspot number which isn’t really a count of the sunspots on the face of the Sun, but it’s sort of a weighted average was 177 yesterday, which is a really high number even for the last few sunspot cycle peaks, and we haven’t reached the peak yet. You can find this number on the website called These sunspots cannot be seen with solar eclipse glasses that we had for the last eclipse back in 2017 because they are too small, even though they are much larger than the Earth. For the most part it would require a telescope with an approved solar filter in front to see them or go to that aforementioned website to see a daily picture from them.

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.


Sunspots on the Sun the evening of January 17, 2023.

This image, from NOAA’s Solar Dynamics Observatory (SDO) downloaded last night, shows a many spotted Sun. The sunspot number by this time was up to 186. Sunspot groups are numbered as active regions. The most active region is AR 3190. Click on the image to enlarge it. Credit: NOAA’s SDO via

09/28/2020 – Ephemeris – A new sunspot cycle has started

September 28, 2020 Comments off

This is Bob Moler with Ephemeris for Monday, September 28th. Today the Sun will be up for 11 hours and 50 minutes, setting at 7:27, and it will rise tomorrow at 7:38. The Moon, 3 days before full, will set at 5:06 tomorrow morning.

Word has come down from NOAA, the National Oceanic and Atmospheric Administration that the new solar or sunspot cycle has definitely started as of last December. The length of a sunspot cycle is about 11 years and may vary in length from one cycle to the next. The peak in sunspot numbers isn’t expected until 2025. The intensity of the cycle, that is numbers of sunspots around peak are expected to be about the same as the last cycle, about 150 observed daily. Each cycle is different and not really wholly predictable. Fewer spots means fewer solar flares and coronal mass ejections and less worry for satellite owners and power companies, and fewer displays of the northern lights for us.*

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


* I didn’t have time to add that we will have more cosmic rays penetrate the heliosphere, the magnetic bubble that protects us from damaging particles produced by high energy events in the universe. We’re at a solar minimum now, so cosmic ray flux is high. With a weak sunspot or solar activity cycle cosmic ray flux will not dip too much.

Sunspot numbers from solar cycle 19 to the prospective cycle 25. Credit: NOAA NWS Space Weather Prediction Center

I came of age, astronomically speaking, during cycle 19, the most active peak since the 1779. I saw quite a few displays of the aurora borealis (northern lights) from Grand Rapids, MI 140 miles south from where I now live.

Sunspot butterfly diagram

Sunspot butterfly diagram for solar cycles 23 and 24. Sunspots of a new cycle begin to appear at a relatively high latitude on the Sun. Sunspots of the old cycle form close to the equator. There is some overlap of spots from the old cycle seen at the same time as spots from the new cycle.

At one of 2019 summer’s Sun party at Sleeping Bear Dunes National Lakeshore we saw a high latitude sunspot popping up as a precursor to cycle 25. We watched two solar flares from the spot in our hydrogen alpha solar telescopes that afternoon, ejecting short term filaments of hydrogen. It was cool watching it in real time.

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:

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 for the heads up email.

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.



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.