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Episode 6 - Transits and
Caldwell Objects

(Pawling Public Radio 103.7 FM)

Welcome to The Astronomical Almanac.
I am your host - Bob Antol. I am a local astronomer in the Pawling area (Poughquag specifically), with a passion for all things astronomical.

Astronomy is the branch of science that deals with celestial objects, space, and the physical universe as a whole. This show, The Astronomical Almanac, will make you more comfortable with these concepts so you will be able to recognize, grasp and appreciate the universe around us.

This is the The Astronomical Almanac on WPWL - Pawling Public Radio - 103.7 FM - Pawling, New York.
And today's episode is entitled Transits and Caldwell Objects.

Old Business

  >   The first segment of the program is something I call Old Business. This will be devoted to answering any questions from the previous episodes or to correct anything I may have said in error.

The Astronomical Almanac can be found on the web at http://www.stargate4173.com/wpwl/.

  <   This concludes the Old Business portion of the program. Next up ... Expanding Your Astronomical Vocabulary ...

Expanding Your Astronomical Vocabulary


  >   Each week, a term (or two) will be defined laying the groundwork for a more general understanding of astronomy. This week, in Expanding Your Astronomical Vocabulary, I will be discussing ...

Past and future transits of Mercury and Venus (next transit is highlighted):

  • Transits of Mercury: 1901-2100
    Date Universal
    Separation (*)
    (Sun and Mercury)
    (*) distance (arc-seconds) between the centers of the Sun and Mercury.

    Transits of Mercury are separated by either 3.5, 7, 9.5, 10 or 13 years.

    1907 Nov 14 12:06 759"
    1914 Nov 07 12:02 631"
    1924 May 08 01:41 85"
    1927 Nov 10 05:44 129"
    1937 May 11 09:00 955"
    1940 Nov 11 23:20 368"
    1953 Nov 14 16:54 862"
    1957 May 06 01:14 907"
    1960 Nov 07 16:53 528"
    1970 May 09 08:16 114"
    1973 Nov 10 10:32 26"
    1986 Nov 13 04:07 471"
    1993 Nov 06 03:57 927"
    1999 Nov 15 21:41 963" (graze)
    2003 May 07 07:52 708"
    2006 Nov 08 21:41 423"
    2016 May 09 14:57 319" (my images are here)
    2019 Nov 11 15:20 76"
    2032 Nov 13 08:54 572"
    2039 Nov 07 08:46 822"
    2049 May 07 14:24 512"
    2052 Nov 09 02:30 319"
    2062 May 10 21:37 521"
    2065 Nov 11 20:07 181"
    2078 Nov 14 13:42 674"
    2085 Nov 07 13:36 718"
    2095 May 08 21:08 310"
    2098 Nov 10 07:18 215"

  • Transits of Venus: 1601-2400
    Date Universal
    (Sun and Venus)
    Transits of Venus are separated by 8, 121.5, 8, 105.5 (243 cyclical) years.
    1631 Dec 07 05:19 940"
    1639 Dec 04 18:25 522"
    1761 Jun 06 05:19 573"
    1769 Jun 03 22:25 608"
    1874 Dec 09 04:05 832"
    1882 Dec 06 17:06 634"
    2004 Jun 08 08:19 627" (my images are here)
    2012 Jun 06 01:28 553"
    2117 Dec 11 02:48 724"
    2125 Dec 08 16:01 733"
    2247 Jun 11 11:30 693"
    2255 Jun 09 04:36 492"
    2360 Dec 13 01:40 628"
    2368 Dec 10 14:43 835"

Will Mercury and Venus ever transit the Sun simultaneously?

    Yes, but this will not happen until AD 69,163.

    Mercury near the Sun's limb

    A transit can take place only when Mercury or Venus is near an ascending or descending node, meaning a crossing point of its orbit on the plane of the ecliptic. For this reason, transits of Mercury currently occur only in early May or mid-November, and those of Venus in early June or early December. Astronomers have long known that the longitudes of the nodes of both planets are slowly increasing and that Mercury's nodes will catch up to and pass those of Venus in about 11,000 years. But until quite recently no one knew whether a simultaneous transit would ever occur.

    The question has finally been answered by Jean Meeus and Aldo Vitagliano in the June 2004 Journal of the British Astronomical Association. Their calculation involved a numerical integration of the motions of all major bodies of the solar system. In addition to the Mercury-Venus transit of July 26, 69,163, they find that a total eclipse of the Sun will take place during the Venus transit of April 5, 15,232. (These dates are expressed in Dynamical Time; exact dates will depend on the changing length of Earth's day,which we can't know in advance, and on whatever calendar adjustments our descendants might make.)

    Roger W. Sinnott (Sky & Telescope)

  <   This concludes the Expanding Your Astronomical Vocabulary portion of the program. Next up ... What's Up in the Sky This Week ...

What's Up in the Sky This Week

  >   In this next segment of the program (What's Up in the Sky This Week), I will highlight events in the sky that are of interest to the average person. First up ...

  • Evening sky highlights
    12 Nov 2017 Mercury 2 degrees north of Antares

  • Morning sky highlights
    11 Nov 2017 Regulus is 0.4 degrees south of Moon
    13 Nov 2017 Jupiter is 0.3 degrees to the right of Venus. The giant planet will emerge from the glare of the Sun and race into the pre-dawn sky for a spectacular conjunction with Venus.
    14 Nov 2017 Mars 3 degrees south of Moon

  • Upcoming meteor showers
    11 Nov 2017 Northern Taurid meteor shower

    2017 Minor Meteor Showers (Class II)

    Shower Activity Period Maximum Radiant Velocity r Max. Time Moon
    Date S. L. R.A. Dec. km/s ZHR
    Northern Taurids (NTA) Oct 25-Dec 04 Nov 11 229 03:54 +22.4 27.1 2.3 5 0000 22

  <   This concludes the What's Up in the Sky This Week portion of the program. Next up ... Astronomical Curiosities ...

Astronomical Curiosities

Caldwell Objects

  >   In this segment, called Astronomical Curiosities, I will explore a unique and different aspect of the world of astronomy. Today's curiosity is ...

This is the The Astronomical Almanac on WPWL - Pawling Public Radio - 103.7 FM - Pawling, New York ... streaming live at pawlingpublicradio.org.

The Caldwell Catalogue is an astronomical catalogue of 109 star clusters, nebulae, and galaxies for observation by amateur astronomers. The list was compiled by Patrick Moore (Sir Patrick Alfred Caldwell-Moore) (4 March 1923 - 9 December 2012) as a complement to the Messier Catalogue. Born to Capt. Charles Trachsel Caldwell-Moore and Gertrude White.

Moore was

  • President of the British Astronomical Association,
  • co-founder and president of the Society for Popular Astronomy (SPA),
  • author of over seventy books on astronomy, and
  • presenter of the world's longest-running television series with the same original presenter, the BBC's The Sky at Night.

As an amateur astronomer, he became known as a specialist in Moon observation and for creating the Caldwell catalogue. Idiosyncrasies such as his rapid diction and monocle made him a popular and instantly recognisable figure on British television.

While the Messier Catalogue is used by amateur astronomers as a list of deep-sky objects for observation, Moore noted that

  • Messier's list was not compiled for that purpose and did not include many of the sky's brightest deep-sky objects, such as the Hyades [C41], the Double Cluster (NGC 869 and NGC 884) [C14] in Perseus, and the Sculptor Galaxy (NGC 253) [C65]
  • (the Messier Catalogue was actually compiled as a list of known objects that might be confused with comets).
  • Moore also observed that since Messier compiled his list from observations in Paris, it did not include bright deep-sky objects visible in the Southern Hemisphere, such as Omega Centauri [C80], Centaurus A [C77], the Jewel Box [C94], and 47 Tucanae [C106].
  • Moore compiled a list of 109 objects - to match the commonly accepted number of Messier objects (he excluded M110) - and the list was published in Sky & Telescope in December 1995.

Moore used his other surname (Caldwell) to name the list, as the first letter of "Moore" is already used for the Messier Catalogue. Entries in the catalogue are designated with a "C" and the catalogue number (1 to 109).

Unlike objects in the Messier catalogue, which are listed roughly in the order of discovery by Messier and his colleagues,

  • the Caldwell catalogue is ordered by declination, with C1 being the most northerly and C109 being the most southerly,
  • although two objects (NGC 4244 [C26] and the Hyades [C41]) are listed out of sequence.
  • Other errors in the original list have since been corrected:
    • it incorrectly identified the S Norma Cluster (NGC 6087) [C89] as NGC 6067 and
    • incorrectly labelled the Lambda Centauri Cluster (IC 2944) [C100] as the Gamma Centauri Cluster.

Click on image to enlarge.

Click on image to enlarge.

  <   This concludes the Astronomical Curiosities portion of the program. Next up ... Did You Know? ...

Did You Know?

  >   This segment of the program will be devoted to little bits of trivia that can be shared at parties, family get-togethers, reunions. Hey, the next time you are at a bar and there is a lull in the conversation, simply yell out Did You Know ... and share the following!

Belt of Venus: Also known as Venus's Girdle, twilight wedge, or anti-twilight arch is an atmospheric phenomenon visible shortly before sunrise or after sunset, during civil twilight, when a pinkish glow extending roughly 10 - 20 degrees above the horizon surrounds the observer.

  <   This concludes the Did You Know? portion of the program. Next up ... The Buffer Zone ...

The Buffer Zone

  >   If there is still time left in the program, this segment (The Buffer Zone) will be devoted to 'personal recollections' of the things that initially got me interested in astronomy.

Leonid meteor storm (1999); an annual Leonid shower may deposit 12 or 13 tons of particles across the entire planet.

The Astronomical Almanac can be found on the web at http://www.stargate4173.com/wpwl/.

You will be able to see:

  • The format of the show
  • Links to the music from the show
  • Links to the notes for each episode
  • My bio

  <   This concludes The Buffer Zone portion of the program.

This has been The Astronomical Almanac
on WPWL - Pawling Public Radio - 103.7 FM - Pawling, New York.
I have been your host - Bob Antol.
I hope you enjoyed today's show and are a little more comfortable with the topics I discussed so you can now more easily recognize, grasp and appreciate the universe around us.
On next week's show, the episode will be entitled The Da Vinci Glow and The Moon.

Clear skies ... and don't forget ... to look up!

copyright © 2017-2018 Robert A. Antol