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01/09/2020 – Ephemeris – What is Ephemeris about?

January 9, 2020 2 comments

Ephemeris for Thursday, January 9th. Today the Sun will be up for 9 hours and 1 minute, setting at 5:20, and it will rise tomorrow at 8:18. The Moon, 1 day before full, will set at 8:15 tomorrow morning.

The Ephemeris program has been a labor of love of mine for going on 45 orbits of the Sun this June. The topics are astronomy and space. What can be seen with the naked eye, binoculars or a small telescope. We look at constellations visible in the evening, their stories, both of western civilization and of the native peoples of our land. We look at the planets, especially the naked-eye planets on Wednesday, and whenever the Moon appears close to one to point it out. We also give heads up on upcoming events like eclipses and meteor showers, plus local events like viewing opportunities we call star parties. I have a companion blog, often illustrated: It’s at bobmoler dot wordpress dot com.

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

Addendum

When the Moon is in the evening sky I will talk about what can be seen on its surface that night, usually near the terminator, which in the evening is the sunrise line, where the shadows are longest. I don’t cover the Moon every month.  Search “Moon” to find all the posts that I do.  I just might have a post on the phase you are interested in. Otherwise when the bright Moon overpowers the constellations, I talk about what we know about the bright stars visible, astronomical news or concepts, whatever can be explained in 45 seconds. Sometimes I can only whet your appetite.  Click the about button above for more information about the Ephemeris program and me.

01/07/2020 – Ephemeris – What the heck is an ephemeris? Plus my Betelgeuse update

January 7, 2020 Comments off

Ephemeris for Tuesday, January 7th. Today the Sun will be up for 8 hours and 58 minutes, setting at 5:18, and it will rise tomorrow at 8:19. The Moon, 3 days before full, will set at 6:09 tomorrow morning.

What the heck is an ephemeris? According to Wikipedia: “In astronomy and celestial navigation, an ephemeris (plural: ephemerides; from Latin ephemeris, meaning ‘diary’, from the Greek,… meaning ‘diary, <or> journal’) gives the positions of… astronomical objects… at a given time or times. Historically, positions were given as printed tables of values, given at regular intervals of date and time.” My tables are now databases which I generate for the year during the prior December from published algorithms. I will show all on my blog today: It’s at bobmoler<dot>wordpress<dot>com. (You are already here) I used to have to interpolate values from printed ephemerides for the first 5 or so years.

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

Addenda

An Ephemeris Example

Ephemeris for 2I/Borisov

Here’s an ephemeris for the Interstellar comet for 2I/Borisov AKA C/2019 Q4 (Borisov) from the Jet Propulsion Laboratory’s (JPL) Horizons system.

R.A. is right ascension – East-west position in the sky, like longitude on the Earth, only it’s in hours, minutes and seconds.  One hour = 15 degrees.

DEC is declination – North-south position, in the sky, exactly like latitude on the Earth in degrees, minutes and seconds.

J2000.0 means that the above coordinates are based on where the vernal equinox point in the sky was on January 1, 12:00 Terrestrial Time, 2000.  Or January 1, 2000, 11:58:55.816 UTC as reported in Wikipedia.

APmag – Apparent visual magnitude.  Magnitudes are like golf scores.  The higher magnitude the dimmer the object.  It’s really, really dim.

delta – Distance from the Earth in terms of Astronomical Units (AU).  1 AU is Earth’s mean distance from the Sun.

deldot – The change in delta.  It’s in kilometers per second.  If positive, it’s going away.

For more information on how I produce ephemerides for this program go here: https://bobmoler.wordpress.com/2019/01/22/

The dimming of Betelgeuse

I finally got a clear evening.  However snow and freezing rain the rest of the week.

Orion at 7:07 p.m. January 6, 2020

Betelgeuse in Orion at 7:07 p.m. January 6, 2020. Taken with my Samsung Galaxy S10+ in the moonlight. Compare the brightness of Betelgeuse with Rigel, Bellatrix and the belt stars.

Orion's brightest stars

Orion’s brightest stars with their names for 9 p.m. January 7, 2019. Click on the image to make Orion a giant hunter. Created using Stellarium.

See last Thursday’s post on the dimming of Betelgeuse: https://bobmoler.wordpress.com/2020/01/02/

06/03/2019 – Ephemeris – We’re starting Ephemeris’ 45th journey around the Sun

June 3, 2019 Comments off

Ephemeris for Monday, June 3rd. Today the Sun will be up for 15 hours and 23 minutes, setting at 9:22, and it will rise tomorrow at 5:59. The Moon is new today, and won’t be visible.

With this program Ephemeris begins its 45th journey around the Sun. While this short program mostly covers the wonders visible in the heavens with the naked eye, binoculars or small telescope, as last week has shown we also cover news developments, hopefully whetting your appetite to dig deeper. Over the last 44 years we’ve seen the rise and demise of the Space Shuttle program, the fantastic images and data brought back by the Hubble Space Telescope, the planetary probes Viking, Voyager, Galileo, Cassini, MESSENGER, New Horizons, Rosetta, Dawn and others to visit all the planets in the solar system plus asteroids, dwarf planets, and comets. Discoveries beyond the solar system boggle the mind. Let’s go for another orbit around the Sun on spaceship Earth.

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

 

01/22/2019 – Ephemeris – What the heck is an ephemeris?

January 22, 2019 Comments off

Ephemeris for Tuesday, January 22nd. Today the Sun will be up for 9 hours and 25 minutes, setting at 5:37, and it will rise tomorrow at 8:11. The Moon, 1 day past full, will rise at 7:41 this evening.

What the heck is an ephemeris? According to Wikipedia: “In astronomy and celestial navigation, an ephemeris (plural: ephemerides; from Latin ephemeris, meaning ‘diary’, from the Greek,… meaning ‘diary, <or> journal’) gives the positions of… astronomical objects… at a given time or times. Historically, positions were given as printed tables of values, given at regular intervals of date and time.” My tables are now databases which I generate for the year during the prior December from published algorithms. I will show all on my blog today: It’s at bobmoler.wordpress.com. (You are already here)  I used to have to interpolate values from printed ephemerides.

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

Addendum

An ephemeris

Here are sections of an ephemeris of the positions of 2014 MU69, Ultima Thule that the New Horizons flew past on New Years day. Created by JPL’s Horizons web site.

R.A. is right ascension – East-west position in the sky, like longitude on the Earth, only it’s in hours, minutes and seconds.  One hour = 15 degrees.

DEC is declination – North-south position, in the sky, exactly like latitude on the Earth in degrees, minutes and seconds.

J2000.0 means that the above coordinates are based on where the vernal equinox point in the sky was on January 1, 12:00 Terrestrial Time, 2000.  Or January 1, 2000, 11:58:55.816 UTC as reported in Wikipedia.

APmag – Apparent visual magnitude.  Magnitudes are like golf scores.  The higher magnitude the dimmer the object.  It’s really, really, really dim.

delta – Distance from the Earth in terms of Astronomical Units (AU).  1 AU is Earth’s mean distance from the Sun.

deldot – The change in delta.  Note that is negative.  5 days after New Horizons passed Ultima Thule that spacecraft and Ultima Thule passed behind the Sun.  Now the Earth in its orbit is approaching Ultima as we are coming around the Sun.

How my data is created

LU for DOS

I use my LookingUp for DOS program to generate sunrise/sunset, moonrise/moonset tables for the year.  I also create planetary ephemeris tables here.

Almanac Master

My Ephemeris Helper program massages the raw data from the above program to create this Almanac Master table.

Intro creation

The first 15 or so seconds of the Ephemeris program is created by the Ephemeris Helper program from the Almanac Master, a Holiday Table, A One Time Event Table created from NASA’s SKYCAL Calendar Table, and Reoccurring Events Table.

Planet Master table

The Planet Master table in the Ephemeris Helper program which I use each Wednesday for planet positions.

LookingUp for Windows

First tab of the LookingUp for Windows program which I don’t use much for the radio program but has uses on this blog and for illustrations for the Stellar Sentinel, the newsletter for the Grand Traverse Astronomical Society, that I edit, which is sent to members and distributed free via email to educators.

Source for the algorithms that I use is Astronomical Algorithms by Jean Meeus, Willmann-Bell 1991.

 

 

 

01/22/2016 – Ephemeris – Getting sunrise and sunset times for your location

January 22, 2016 Comments off

Ephemeris for Friday, January 22nd.  The Sun will rise at 8:12.  It’ll be up for 9 hours and 24 minutes, setting at 5:36.   The Moon, 1 day before full, will set at 7:31 tomorrow morning.

With the bright moon, blocking all but the brightest stars, it’s a good time to do some housekeeping.    When I started this program 40 ½ years ago Interlochen Public Radio (IPR) had only one transmitter and a single antenna pattern. It was simply WIAA then.  The sunrise and sunset times worked well for that.  However since then with transmitters from Manistee to the Straits I cannot hope to cover it all with a single set of times.  The differences in the times also vary with the seasons.  To get help on the Internet go to my monthly site ephemeris.bjmoler.org and click on Calendars.  There are calendars for Ludington, Cadillac, Interlochen/Traverse City, Petoskey and Mackinaw City.  Select a month to view or printout a whole year, or use the email link to request a sunrise, sunset, and Moon calendar for your town.  There’s also a link to get sunrise and sunset times for anywhere in the world

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

Addendum

As an aside.  I wrote the program to compute the calendars back in the ’80s.  It produces calendars in three formats, of which I still use two: comma separated values, and HTML.  The HTML output is what is used for the calendar pages.  The comma separated value files are input into a database which is used to create for me the first paragraph of the transcript.  For the blog posting I omit “This is Bob Moler with…” as redundant.  The program also produces database tables of the planets from which I base the Wednesday planet program rise, set and sometimes transit times.

The actual Ephemeris audio programs are also found on the ephemeris.bjmoler.org under the audio link.  A whole week of programs are available.

01/05/2015 – Ephemeris – Ephemeris’ dirty little secret

January 5, 2015 Comments off

Ephemeris for Monday, January 5th.  The sun will rise at 8:19.  It’ll be up for 8 hours and 56 minutes, setting at 5:16.   The moon, 1 day past full, will rise at 6:14 this evening.

With the bright moon, blocking all but the brightest stars, it’s a good time to do some housekeeping.    When I started this program 39 ½ years ago IPR had only one transmitter and a single antenna pattern.  The sunrise and sunset times worked well for that.  However since then with transmitters from Manistee to the Straits I cannot hope to cover all that in a single program.  The differences in the times vary with the seasons.  To get help on the Internet go to my monthly site ephemeris.bjmoler.org and click on Calendars.  There are calendars for Ludington, Cadillac, Interlochen/Traverse City, Petoskey and Mackinaw City.  Select a month to view or printout a whole year.  Use the email link to request a sunrise, sunset, and Moon calendar for your town.

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

Addendum

Calendars main page

Click on Calendars in the header. and you will get this page.

Mackinaw City Header

This is the top of the Mackinaw City calendar where you can select to start at any month.

January calendar

Partial image of the January calendar for Mackinaw City.  The last column illum Fractn is the moon’s illuminated fraction.  It is set for 24h UT, which is early evening on the date listed.

Interesting note:  You can draw a straight line through Ludington, Interlochen/Traverse City, Petoskey and Mackinaw City.  The angle with that line and the meridian is about 23 1/2 degrees.  The same as the tilt of the Earth’s axis.  Therefore near the winter solstice the sunrise times are nearly the same, but the sunset times can differ greatly.  Conversely at the summer solstice the sunset times are nearly the same, but the sunrise times are the most divergent.