ALMANAC

Notes by George Gladfelter

10/08/2024 - Items in section 2 revised.

Changes may be shown in green or blue.

Meteor Shower Calendar (Best viewing after midnight looking east.  Dates vary from year to year.)

Dates (maximum)     Shower Name

Jan 1-5 (3-4)               Quadrantids

Jan 15 - Feb 8 (7-8)    Alpha Aurigids

Apr 19-24 (22)           April Lyrids

May 1-12 (5)              Eta Aquarids

June 10-21 (15)          June Lyrids

Jul 15 - Aug 15 (28)   Delta Aquarids

Aug 1-18 (12)             Perseids

Oct 17-26 (20)            Orionids

Nov 14-20 (17)           Leonids

Dec 4-16 (13-14)        Geminids

1. Click here for the data (world wide) on moon phases, solar and lunar eclipses, equinoxes and solstices, lunar perigee and apogee, lunar perihelion and aphelion, and various data for Mercury, Venus, Mars, Jupiter, and Saturn for 2024-2025.  Also available are detailed data on solar eclipses for 2024-2025. 
Note: Copies of previous editions should be discarded.

2. Ephemerides for the Sun, Moon, Earth, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune for 2024, 2025 <-- (updated 10/08/2024) and for reference 2023.  The apparent right ascension, declination, distance, and visual magnitude are listed for each day in the year  at zero  hours Terrestrial Dynamical Time (TT) .  For objects other than the Sun and the Moon, the angle of separation from the Sun is also listed.  For the planets, the visual magnitude is also listed for the planet only (not including any rings).  For access to lists of Ephemeris Transits of the Sun, Moon, and planets, see the Additional Explanations (which may be found here). 

3. Click here for revised sunrise, sunset, and twilight times at the Journey Museum and Learning Center (JMLC) for 2023-2026.  For an explanation of the table, click here.

4. Click here for times of moonrise, moonset, and transits of the moon (as seen from JMLC) and also the percentage of the moon's disk that is illuminated, and the Moon's declination, at 9 PM MST for 2020-2024.  Note: rising and setting times of any celestial object are subject to uncertainty due to topography, and especially variations in atmospheric refraction.  Also, the calculations are specific to a single location and cannot be easily adapted to locations more than a few miles away; therefore, treat the tabulated times for rising and setting as approximations.  The other times listed are not affected by refraction, but are specific to the observer's longitude or position. Only phenomena that will be visible (assuming no clouds) are listed.

5. The planets are best placed for observing from the Earth when the angle from Sun to Earth to object is greatest.  For Mercury and Venus this is the time of greatest separation or elongation (they are not exactly the same), and for the others the time called opposition (this is the time when the planet's right ascension is 180 degrees away from the Sun's).  For a table of these times for 2018-2050 click here.

6. Click here for a table showing data at dusk, the middle of the night, and dawn for the sun, moon, and the five bright planets for each night 2024-2025.  If the moon, or a planet, is within five degrees of a planet, another line of data shows the visual separation of the pair.  Click here for an explanation of the table. Also, click here for times of rising, setting, and transit (marked "r", "s", or "t") of the sun, moon, and bright planets in 2023-2025.  Included are the times for morning and evening twilight (mt and et), the four phases of the moon, and the seasons (ME = March Equinox, JS = June Solstice, SE = September Equinox, DS = December Solstice).  Note: the rising and setting times are for the center of the sun, moon, or planet without correcting to the upper limb of the object; the twilight times are for when the sun is 15 degrees below the horizon - this is intermediate between nautical and astronomical twilight. Note well - this file is over 100 pages long.

7. Click here for a table listing the transit times of twenty stars, as seen from JMLC, for 2023-2024. These data can easily be used to calculate approximate rising and setting times. Click here for an explanation of the table. 

8. Lists of bright stars with their coordinates in mid-year are available for 2023, 2024, 2025.

9. Click here for dates and times of Solar Transits of Mercury 2016-2100 (minor revisions posted 12/13/2023).

10. Click here for a list (2024-2025) of Lunar Occultations of (A) bright planets and (B) certain bright stars (magnitude 3.5 and brighter), and (C) solar eclipses.  When appropriate, data for observers at the Journey Museum in Rapid City are shown. 12/16/2023.  Click here for a listing of all solar eclipses for 2014-2040.

11. Posted here is a text file giving the coefficients for apparent Right Ascension, Declination, Distance, and Horizontal Parallax of the Moon for 2024-2101. The distance is the apparent distance (light time factored in) in kilometers.  The angular coordinates are in degrees (divide the right ascension by 15 to obtain ascension in hours).  Each quantity is to be computed as:

                quantity = A₀ + A₁x + A₂x² + ... + A₅x⁵

Also, see the notes section at the bottom of this page.

12. Posted here is a text file listing DUT1 (DUT1 = TT - UT1) and DUTC (DUTC = TT-UTC) for the first of each month, starting with 1972.  The table extends 12 months beyond the table's production date using predictions by IERS, and a few years beyond that by extrapolation.  Observable events whose timing depends on  the observer's location (such as eclipses of the Sun, stars, and planets) typically also depend on the Earth's rotational angle, and therefore on DUTC and/or DUT1.

2024 

01/14 - Year 2777 Ab Urbe Condita starts (Roman/Julian calendar)

07/07 evening - Year 1446 Anno Hegira starts (Islamic)

07/13 - As seen from JMLC, Spica will be eclipsed by the Moon from before Spica rises until 22:04:25.9 MDT

07/22 01h MDT - Mercury (magnitude 0.9) at greatest elongation 26.9° E.

10/02 evening - Year 5785 Anno Mundi starts (Jewish)

2025

01/02 - 07:27:54 MST - Latest sunrise at JMLC

01/04 – 06:28 MST - Earth closest to the Sun (0.9833 au)

01/09 22h – Venus (mag. -4.6) greatest elongation, 47.2° E.

01/13 - The Moon will occult Mars.  For observers at JMLC, the first contact will be at 19:04:19.7,  and take 31.0 seconds to completely obscure Mars.  Mars will emerge from behind the moon from 19:59:32.3 to 20:00:05.6 MST.

01/14 - Year 2778 Ab Urbe Condita starts (Roman/Julian calendar)

01/29 (Wednesday) - Chinese New Year (year of the Snake) - see notes

02/28 evening - Ramadan begins

03/05 - Ash Wednesday

03/07 23h - Mercury (mag. -0.4) greatest elongation, 18.2° E.

03/09 - MDT in effect

03/13  23:09 MDT (Thursday) – Total Lunar Eclipse - umbral phase starts. Totality starts at 00:25 Friday, reaches  mid-point at 00:59, ends at 01:32, and the umbral phase ends at 02:53.

03/20 03:01 MDT - Spring Equinox

03/29 - A partial solar eclipse will last from 02:51 to 06:43 MDT but will not be visible from Rapid City. 
Note: the next five solar eclipses viewable from JMLC will be partial eclipses on 1/26/2028, 1/14/2029, 3/30/2033, 6/21/2039, and 11/4/2040.

03/30 evening - Eid ul-Fitr

04/12 evening - Passover

04/20 - Easter Sunday

04/21 13h - Mercury (mag. 0.4) greatest elongation, 27.4° W.

05/31 21h – Venus (mag. -4.4) greatest elongation, 45.9° W.

06/08 - Pentecost Sunday

06/15 - 05:09:03 MDT - Earliest sunrise at JMLC

06/20 20:42:16 MDT – June Solstice

06/26 - 20:40:14 MDT - Latest sunset at JMLC

06/26 evening - Year 1447 Anno Hegira starts (Islamic)

07/03 14h MDT - Earth farthest from the Sun (1.0166 au)

07/03 23h MDT - Mercury (magnitude 0.4) at greatest elongation 25.9° E.

08/19 04h MDT - Mercury (magnitude -0.2) at greatest elongation 18.6° W.

09/04 21h MDT - Mercury (mag. -0.4) at greatest elongation 18.1° W.

09/07 09:28 to 14:55 - Total Lunar Eclipse - not visible here.

09/21 11:30 MDT– A partial eclipse of the Sun starts, but will not be visible from the United States; maximum obscuration will be 79.7% at 13:41:59 visible from 150.975 E, 61.092 S.  The eclipse ends at 15:53:45.
Note: the next five solar eclipses viewable from JMLC will be partial eclipses on 1/26/2028, 1/14/2029, 3/30/2033, 6/21/2039, and 11/4/2040.

09/22 12:19:21 MDT - Fall Equinox

09/22 evening - Year 5786 Anno Mundi starts (Jewish)

10/01 evening - Yom Kippur (Jewish)

10/29 16h MDT - Mercury (mag. -0.2) at greatest elongation 23.9° E.

11/02 - MST returns

11/27 - As seen from JMLC the Moon will block the light from Spica before the star rises, but the emergence of the star from behind the Moon at 04:27:24.7 should be visible.

12/07 10h MST - Mercury (mag. -0.6) at greatest elongation 20.7° W.

12/09 – 16:14:24 MST - Earliest sunset at JMLC

12/14 evening - Hanukkah (Jewish)

12/21 08:03:05 MST - Winter Solstice - Shortest day of the year at JMLC: 8h 52m 45s. 

Planets: Also see notes, below. Dates, in this section, mostly refer to the date on which the night begins, "midnight" means the middle of the night, not always 12:00 A.M.  For events at "midnight" the date refers to the start of the night in question. Dates associated with dawn or morning only are not referenced to the previous night. The data given here are valid for observers in western South Dakota.

Full Moon Nights: 01/13, 02/11, 03/13, 04/12, 05/11, 06/10, 07/10, 08/08, 09/07, 10/06, 11/04, 12/04.

Also see notes below.

Planet apparitions: shown are the starting date (if not before January first), maximum elevation above the horizon, ending date (if before year’s end).  “Twilight,” here, points to the time when the upper limb of the Sun is six degrees below the horizon.  Elevations above the horizon are in degrees, visual magnitudes are shown in parentheses.   “Evening” or “dusk” refer to the end of twilight, and “morning” or “dawn” refer to the start of twilight.  “Midnight” refers to the middle of the night, which is a function of date and longitude, and not to a particular local civil time. 

Mercury or Venus, if visible after dusk, are somewhere above the Western horizon, or before dawn they are somewhere above the Eastern horizon.

Mercury – begins the year as a (-0.3) object in the dawn sky, but sinks lower each day until it disappears around 01/12 or so.

Its next apparition starts in the evening of 02/21 (-1.3) with peak elevation of 11.5° at dusk on 03/07 (-0.5), and thereafter loses brightness, sinking out of sight about 03/19 (3.6).

Again, Mercury reappears at dusk on 06/08 (-1.1) but loses brightness while climbing higher to 8.6° on 06/23-26 (0.), and sinks out of sight about 7/13 (1.2).

Another apparition starts about 8/10 at dawn (2.1) reaching maximum altitude of 10° on 08/21-22 (-0.6), with an end at (-1.4) about 09/03.

Its last apparition of the year will start at dawn on 11/25 (1.8), peak on 12/05-06 at 11.4° (-0.5), and conclude about 12/27 (-0.5)

Venus, at the start of the year, is an evening object at 27.7° above the eastern horizon, and bright (-4.5).  Venus is less than 3° above the Sun from 03/20 until dawn on 03/25 when it appears again (-4.2) and slowly climbs to 23.9° (-4.0) on 08/07-11 (-4.0).  Venus is lost to view  after 11/24 (-3.9).

Mars starts the year as a bright object (-1.2) rising after dusk, and high in the sky at 63.1° by midnight.  On the nights of 01/09-18 it is at its brightest (-1.4) and visible all night until 01/25 (-1.2). Thereafter, Mars loses brightness and sets after midnight – but before dawn until the night of 05/26 (1.2) when it continues to shine in the evening sky (1.3) until the night of 10/23 when it shines (1.5) briefly at dusk. 

Jupiter begins the year as a bright (-2.7) evening object that sets after midnight until 03/22 (-2.2) when it sets before midnight.  On 06/05 Jupiter (-1.9) makes a brief appearance at dusk and thereafter disappears until dawn on 07/12 (-1.9).  Starting on 09/29 (-2.1) Jupiter rises before midnight, and is 60.6° high at dawn.  On the mornings of 10/18-21, Jupiter (-2.3) is at its maximum height at dawn 67.2°.  It continues to grow in brightness and ends the year (-2.7) when it rises after dusk, but before midnight.

Saturn starts the year (1.0) as an evening object 36.9° in the southern sky that sets before midnight.  By 02/27 (1.1) Saturn is ending this apparition.  A new  apparition begins at dawn on 04/14 (1.2).  On the night of 06/28 Saturn (1.0) rises before midnight and is 37.6° high at dawn on the 29^th.  On the night of 09/18-19 Saturn (0.7) becomes an all-night object for five nights in a row. Thereafter, Saturn sets before dawn until 12/11 when it also sets before midnight (1.0).   At year’s end Saturn has faded to (1.1).

Pairings (center-to-center angle of 5° or less) of two planets, or the Moon and a planet.

Dusk 01/03 – Moon and Venus 3.9°

Dusk 01/04 – Moon and Saturn 3.7°

01/13 – Moon and Mars 1.3° at dusk, 2.0° at midnight

Dusk 01/18 – Venus and Saturn 2.2°, next five nights: 2.4°, 2.9°, 3.5°, 4.2°, 4.9°

Dusk 01/31 – Moon and Saturn 2.9°

Dusk 02/01 – Moon and Venus 2.5°

Dusk 02/09 – Moon and Mars 3.5°

Dusk 02/24 – Mercury and Mars 1.6°

Dusk 02/28 – Moon and Mercury 2.7°

03/08 – Moon and Mars 1.5° at dusk, 3.0° at midnight

Dusk 04/05 – Moon and Mars 3.7°

Dawn 04/28 – Venus and Saturn 3.7°

05/03 – Moon and Mars 1.8° at dusk, 3.1° at midnight

Dawn 05/22 – Moon and Saturn 3.2°

Dusk 05/31 – Moon and Mars 4.4°

Dusk 06/26 – Moon and Mercury 3.3°

Dusk 06/29 – Moon and Mars 1.0°

07/15-16 – Moon and Saturn 2.5° at midnight, 3.3° at dawn

Dusk 07/28 – Moon and Mars 4.4°

Dawn 08/07 – Venus and Jupiter 4.7°, next five dawns: 3.8°, 2.9°, 1.95°, 1.2°, 0.9°

08/11-12 – Moon and Saturn 4.0° at midnight, 3.3° at dawn

Dawn 08/20 – Moon and Venus 4.4°

Dawn 08/21 – Moon and Mercury 4.2°

Dawn 09/16 – Moon and Jupiter 4.2°

Dawn 09/19 – Moon and Venus 0.8°

10/05 – Moon and Saturn 2.5° at dusk, 4.6° at midnight

Dawn 10/19 – Moon and Venus 3.8°

Midnight 11/01 – Moon and Saturn 3.3°

Midnight 11/09 – Moon and Jupiter 3.6°

Dawn 12/07 – Moon and Jupiter 4.00°

Dusk 12/26 – Moon and Saturn 2.95°

NOTES:

Observing The Sun -- WARNING  --  WARNING  --  WARNING !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Extreme caution must be used by anyone trying to view the sun.  You must block most of the visible light, and virtually all of the UV and infra-red coming from the sun.  Viewing the sun is inherently dangerous to your eyes and equipment.  Dark photographic materials are NOT designed to reduce sunlight to a safe level, especially UV and IR!  If a filter slips off your telescope, or your binoculars, your eye can be permanently damaged before you can react. Sunlight concentrated by a lens or telescope can overheat a filter causing it to melt or crack, and then you or your equipment will be at severe risk; therefore, sunlight must be filtered BEFORE entering any optical instrument or camera.

Prolonged viewing of the sun requires great care and knowledge.  Viewing the sun safely requires previous study and setting up the equipment well in advance. Last minute preparation is likely to lead to disaster!  Please be sure you know what you are doing, and that you have the proper equipment with secure attachments if you wish to view or record solar phenomena. Do not hesitate to seek help from an experienced observer.  Also, Wikipedia has a good article titled "Solar Viewer" with good information. Wikipedia article link.

About the precision and accuracy of the listed times for specific events: Where times are listed to a precision of one second, or better, it should be understood that the calculation process has yielded a result to that precision, but several caveats apply:  (1) even though the calculation in question might depend only on TT, the quantities DUTC = TT-UTC, and DUT1 = TT-UT1, for future dates can only be estimated.  For events that directly depend on DUT1, even TT becomes an estimate. (2) For most events, observational precision is difficult and expensive - if not impossible.  The chief exception to this is a lunar occultation of a bright star; but even in this case there are difficulties requiring great care in recording the event, determining accurately the observer's position, and establishing the time with high accuracy (in general, battery operated clocks are rated as good only to one-second accuracy at best) and clocks that use GPS, or frequent NTP updates, are required for errors no more than one tenth of a second.

About the dates of religious observances: These dates are conceptually tied to astronomical phenomena, and cannot be simply predicted.  In the case of Christian and Jewish festivals the dates are determined by rigorous, but complicated, mathematics.  In the case of Islamic observances, many adherents believe that the calendar can only be determined from direct observation in each community; the dates shown here are determined algorithmically and should differ from direct observation by no more than a day or two.  The numbering of years in the Roman system (A.U.C.), although relatively simple, is also shown because of its historical importance.  For a table showing the dates of Ash Wednesday, Easter, and Eastern Orthodox Easter for 1900-2100 click here. For the dates of the Chinese New Year, see the note below.

About visibility of the planets: The narrative provided above on this page is specific to the latitude of the Journey Museum and Learning Center in Rapid City, South Dakota, (JMLC) and should be reasonably accurate for latitudes between 42 and 46 degrees north, but increasingly inaccurate for observers farther north or south. The dates given are for the date on which a given night begins.  The times given are for the end of evening twilight (E), the middle of the night (m), and the start of civil twilight in the morning (M); they are specific to the vicinity of the observatory.  The elevation of a planet above the horizon is given in degrees for those times - if the planet's elevation is at least 3 degrees. Click here for more detailed information.

About Full Moon Nights: On the night of a full moon, and for a few nights before and after, the brightness of the moon may hinder observation of objects other than the moon.  It occasionally happens that two nights in succession "enjoy" being about equal in moon brightness. Click here for more detailed information on visibility of the moon (corrected 10/14/2016).

About "Super Moons":  The Moon is "full" when it is 180 degrees away from the Sun (in right ascension) and thus appears fully illuminated.  However, its distance (from the Earth's center to the Moon's center) varies as the Moon moves in its orbit, and ranges from less than 357,000 km (at perigee) to more than 406,000 km (at apogee).  Naturally, it appears bigger when it is closer, and the popular press has taken to calling a full moon near a perigee that is particularly close to the Earth a "Super Moon".  In this discussion, particularly close will be defined as closer than 357,000 km.  The full moon of September 27, 2015 in the evening at a distance of 356,878 km thus qualifies as a Super Moon, and the next one was on the morning of November 14, 2016 at 356,520 km - this will be the closest Super Moon until 2034, but there will be less notable Super Moons in 2018, 2019, 2025, 2026, 2028, 2029, 2032, and 2033 also.

About Lunar Occultations:  The moon can, for a time, block an observer's view of a star or a planet.  Only occultations of bright stars and bright planets are listed on this page; and only if the event is visible for an observer at the JMLC - the Journey Museum and Learning Center.  The timing of an occultation is highly dependent on the observer's location, and is very sensitive to any inaccuracies in the computation of the coordinates of the moon and the star or planet involved.  Therefore, accurate times for actual observations are of great interest.  An extensive listing of lunar occultations is available here.

About Chinese New Year (Lunar New Year): This is determined by the date and time in China (UTC+8 hours) and is assigned to the date when a new moon first occurs on or after January 21.  The last possible date for this is February 20.  Once this date is calculated according to Chinese time, the same date is used also in the United States and the rest of the world (although, as an example, 6 PM in the evening on January 21 in San Francisco corresponds to 10 AM on the 22nd in China; moreover, it seems that celebrations outside of China may indeed start according to the time in China rather than local date-time).  No correction for the equation of time is made when computing the date of the new year, i.e. the calculations are referenced to UTC+8 hours, not local solar time on a selected meridian.  The actual time of day for the new moon is irrelevant unless it is so close to midnight as to introduce an ambiguity as to the date.  For a listing of the dates from 2015 through 2050, click here.

About daily polynomials for lunar coordinates: The Astronomical Almanac lists the apparent right ascension, apparent declination, and true distance (light time not factored in) of the moon at zero hours Terrestrial Time for each day of the year. 

The online web site at http://asa.hmnao.com/SecD/LunarPoly.html gives daily polynomials (for the years 2001-2021) for apparent right ascension, apparent declination, and horizontal parallax for any desired time during the day listed.  Note: the coefficients listed by USNO are slightly different from those I list because I adjust the coefficients to minimize the discontinuities in the coordinates for 24 hours of one day versus zero hours of the next day.

Please report corrections and suggestions to g e o r g e 0 7 @ r a p . m i d c o . n e t   (using no spaces in the address).