07/06/2023 – Ephemeris – Today the Earth is farther from the Sun than anytime this year
This is Ephemeris for Thursday, July 6th. Today the Sun will be up for 15 hours and 26 minutes, setting at 9:30, and it will rise tomorrow at 6:04. The Moon, halfway from full to last quarter, will rise at 12:16 tomorrow morning.
Today, the Sun is at its farthest distance from the Earth. It’s called aphelion. The exact time actually occurred at 4:59 this morning at a distance of 94 and a half million miles away. Because of the gravitational pull of the Moon and planets on the Earth, especially Jupiter and Venus and gravitational pull of the planets, especially Jupiter on the Sun, the aphelion and perihelion, the closest date in January don’t occur on the same date or same distance every year. The date wanders by a day or two each year. The entire distance variation of the Earth from the Sun is plus or minus 1.5 million miles (2.4 million kilometers) over the year, makes summer the longest season by a few days because the Earth moves slower when farther from the Sun, than when it is nearer.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Note: Apoapsis and Periapsis are generic terms for the farthest and nearest points in an orbit to the central body. For a body orbiting the Sun, it’s aphelion and perihelion. For a satellite of the Earth, it’s apogee and perigee.
06/27/2023 – Ephemeris – Preparing to view the upcoming solar eclipses safely
This is Ephemeris for Tuesday, June 27th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32, and it will rise tomorrow at 5:59. The Moon, 1 day past first quarter, will set at 2:21 tomorrow morning.
In preparation for the two solar eclipses that will be visible in North America in the next 10 months, I’m going to spend some time describing what the Sun is, and how it appears to us. First point: Never look at the Sun without proper and approved filters. Inexpensive eclipse glasses work fine for the partial phase of a solar eclipse. However, most features, like sunspots, are generally too small to be seen with them. Do not use these glasses with binoculars or a telescope. The plastic filters will melt through in a fraction of a second. Glass filters can shatter from the heat. The only safe solar filter for telescopes is one placed in front of the telescope tube, so it’s only exposed to ambient light and heat. If confused, just ask your local amateur astronomer.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
01/17/2023 – Ephemeris – The Sun is getting active again
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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 spaceweather.com. 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.
Addendum
09/30/2022 – Ephemeris – View the Sun and Moon tomorrow in the Grand Traverse Area!
This is Ephemeris for Friday, September 30th. Today the Sun will be up for 11 hours and 45 minutes, setting at 7:25, and it will rise tomorrow at 7:40. The Moon, 2 days before first quarter, will set at 9:57 this evening.
There are two observing sessions tomorrow in the Traverse City area with the assistance of the Grand Traverse Astronomical Society. First at the Dennos Museum Center grounds, from 2 to 4 pm, there will be telescopes to safely view the Sun. The Sun’s eleven-year sunspot cycle is getting active again. There will be telescopes to see those sunspots, and special solar hydrogen alpha telescopes to view the Sun’s chromosphere and any prominences above the Sun that day. From 8 to 10 pm, Northwestern Michigan College’s Rogers Observatory will be open for International Observe The Moon Night. There will also be a telescope on the 200 Block of East Front Street to observe the Moon during this time. Of course, all this is contingent on clear or mostly clear skies.
Update: It’s supposed to be nice this weekend, after a week of cold and rain.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
Later today I’ll add a Moon Map for tomorrow evening and what the Sun looks like today, which should give a clue to what’s happening on the Sun now.
Sun in white light (How we normally see it with a solar filter)
Sun in the light of the Hydrogen Alpha wavelength. Light absorbed and emitted by the hydrogen atom.
The Moon for Saturday evening during the International Observe the Moon Night
Download page of maps from the Official 2022 International Observe the Moon Night website.
Images in astronomical telescopes produce images of various orientations. They may be right side up or upside down, mirror reversed or both. Telescopes with an odd number of mirrors produce mirror images. Astronomers are used to it, though they have a preferred orientation… The one their favorable telescope produces.
Come on out!
04/07/2022 – Ephemeris – The Sun is getting active again
This is Ephemeris for Thursday, April 7th. Today the Sun will be up for 13 hours and 5 minutes, setting at 8:17, and it will rise tomorrow at 7:10. The Moon, 2 days before first quarter, will set at 3:11 tomorrow morning.
For the last year and a half, the Sun has entered a new sunspot cycle, solar cycle 25. It had been predicted to be a rather mild cycle with an average peak in sunspot numbers of around 120 in 2025, three years from now. Last Sunday’s daily sunspot number was 118. Sunspot numbers are not just the numbers of individual sunspots on the Sun. Groups of spots count for 10 before the individual spots are counted. These counts are averaged, from many observatories, over a month to chart the progress of the approximately 11 year sunspot cycle. The more sunspots, the more solar flares. The more flares, the more CMEs or coronal mass ejections. If CMEs are aimed toward the Earth, we get northern lights, and headaches for satellite operators and electric power companies.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
Go to spaceweather.com to keep up with what’s happening between the Sun and the Earth.
05/21/2021 – Ephemeris – For everything there is a season… even eclipses
This is Ephemeris for Friday, May 21st. Today the Sun will be up for 15 hours and 3 minutes, setting at 9:11, and it will rise tomorrow at 6:07. The Moon, 2 days past first quarter, will set at 4:14 tomorrow morning.
There are seasons for everything: baseball season, football season, spring, summer, what have you. There are also eclipse seasons. The Moon’s orbit is tilted by about 5 degrees to the ecliptic, the path of the Sun in the sky. The points where they cross are called nodes, 180 degrees apart. When the Sun is near one of those nodes we are in an eclipse season, where a solar eclipse can occur at new moon, and a lunar eclipse can occur at full moon. We are guaranteed one of each per eclipse season, and on rare occasions a third eclipse. Of course one has to be at the right place to see an eclipse. This eclipse season we will be at a marginal place to see both eclipses. Both are at sunrise, so we’ll see just a part of each of them.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
For a more extensive treatment of this subject check out: https://earthsky.org/astronomy-essentials/definition-what-is-an-eclipse-season
09/28/2020 – Ephemeris – A new sunspot cycle has started
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.
Addendum
* 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.
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.
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.
03/02/2020 – Ephemeris – Greek use of the first quarter Moon
Ephemeris for Monday, March 2nd. Today the Sun will be up for 11 hours and 14 minutes, setting at 6:32, and it will rise tomorrow at 7:15. The Moon, at first quarter today, will set at 2:39 tomorrow morning.
The Moon is at first quarter at 2:57 this afternoon. The ancient Greek philosopher/astronomer Aristarchus* tried to determine the distance to the Sun by observing the Moon at exactly first quarter and measuring the angle between it and the Sun. If we see the Moon at exactly first quarter when the sunrise line called the terminator cuts the Moon exactly in half then the angle at the Moon between the Sun and the Earth is a right or 90 degree angle. If we, on the Earth at that same instant were able to measure the angular distance between the Moon and the Sun. we could theoretically calculate the distance to the Sun. He was correct about the Moon’s distance, but calculated the Sun was at only about 10% of its actual distance.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
* In the actual broadcast program I erroneously credited the later Greek astronomer Hipparchus.
Addendum
08/21/2018 – Ephemeris – How will the Parker Solar Probe get near to the Sun?
Ephemeris for Tuesday, August 21st. The Sun rises at 6:52. It’ll be up for 13 hours and 46 minutes, setting at 8:38. The Moon, 3 days past first quarter, will set at 3:09 tomorrow morning.
I introduced the Parker Solar Probe yesterday. It’s on its way to Venus to have some of its velocity stolen by that planet as to drop to nearly 15 million miles (24 million km) of the Sun at its first perihelion, before heading almost all the way out to the Earth’s orbit. Its next encounter with Venus will steal even more velocity from the probe to drop even closer to the Sun. It will take nearly 7 years to reach as close as 3.9 million miles (6.2 million km) from he center of the Sun of 3.8 million miles (6.1 million km) from what looks like its surface, the photosphere, the bright ball we see of the Sun. The probe has a huge heat shield that will handle the over two thousand degree heat from the Sun. Even though the corona is several million degrees in temperature, it’s not dense enough to heat the probe.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
A close look at the Sun
08/20/2018 – Ephemeris – The Parker Solar probe is on its way to skim through the Sun’s corona
Ephemeris for Monday, August 20th. The Sun rises at 6:51. It’ll be up for 13 hours and 49 minutes, setting at 8:40. The Moon, 2 days past first quarter, will set at 2:22 tomorrow morning.
Eight days ago the Parker Solar Probe was launched toward the Sun. It is the first NASA spacecraft named after a living person, Eugene Parker, a Michigander, born in Houghton in 1927, graduated from Michigan State, before moving on to Caltech. He eventually landed at the University of Chicago. In the 1950’s he put forth the theory of the supersonic solar wind of charged particles pervading the solar system. The theory was not initially accepted, but has been verified by satellites. The Parker Solar Probe will make multiple passes of Venus, giving up its velocity to fall closer to the Sun on each pass, taking almost 7 years to inch closer to the Sun at its perihelion until it gets down to about 3.8 million miles of our star.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.