Asteroids of 2017

I’ve won a battle with the asteroids, and so am able to start adding them to “Astronomical Calendar 2017” – see the tab above.  That is, as with the comets, I’ve worked out my way to use data from the Minor Planet Center, which you can see at

(That file consists of orbital elements for thousands of minor planets, but I’m extracting only the first 999.  You may notice that the first in the list is still Ceres, the first to be discovered.  Including Ceres among the asteroids still makes sense, even though it also, because of its size, ranks in the new class of dwarf planets.)

I find that in 2017 these are the six asteroids that become brightest:

Asteroid number 4 Vesta (reaching magnitude 6.3)
7 Iris (6.9)
1 Ceres (7.5)
2 Pallas (8.3)
8 Flora (8.3)
20 Massalia (8.4).

Of the classic First Four (the ones discovered 1801-1807), Ceres is not at opposition (the most observable time) in 2017, so it is brightest at the end of the year as it approaches a January 2018 opposition.  2 Pallas with its strange orbit has an unfavorable opposition in October (it can be as bright as 6.5 at opposition or as dim as 10.6).  3 Juno, dimmest of the Four, ranges between opposition magnitudes of 7.6 and 10.3; this time, on July 2, it reaches only 9.9.  4 Vesta with its whitish surface becomes, as almost always, the year’s brightest asteroid, the only one to touch naked-eye findability, around its opposition in January.

Among those lower down the list (discovered from 1845 onward):  7 Iris is at one of its best oppositions, in October, because this is close to its perihelion on November 18.  8 Flora is at perihelion in July, so that it is brightening at the end of the year, only just before a January 2018 opposition.  20 Massalia has a favorable opposition in December because its perihelion is in February 2018.

So I have added to the “Astronomical Calendar 2017” timetable of events some asteroid dates: the oppositions and perihelia of the brightest ones, also the opposition of Juno and the brightening of Ceres at the end of the year.  With time I’ll add an asteroid page with more detail and charts.

You have an Astronomical Calendar 2016 (I hope) to keep you abreast of sky events, and don’t need me to remind you that tomorrow, Monday Nov. 28, Mars is at its winter solstice.


Part of a diagram in the Mars section of Astronomical Calenda 2016.  In late November, Mars’s north pole is leaning maximally away from the Sun, as happens for Earth in late December.  The two planets’ north-hemisphere winters do not always happen close together.


10 thoughts on “Asteroids of 2017”

  1. This one’s not quite as bright (8.7) as the others, it’s just that it comes very close (relatively) to earth (0.047 AU). Here’s an ephemeris from the Minor Planet Center, sorry about the column alignment…
    (3122) Florence
    Date UT R.A. (J2000) Decl. Delta r El. Ph. V Sky Motion
    h m s “/min P.A.
    2017 08 27 000000 21.8088 -38.203 0.064 1.067 150.9 27.4 9.5 12.79 340.9
    2017 08 28 000000 21.6649 -32.914 0.059 1.064 154.6 24.1 9.2 15.12 342.3
    2017 08 29 000000 21.5173 -26.649 0.055 1.061 157.9 21.0 8.9 17.67 343.6
    2017 08 30 000000 21.3666 -19.359 0.051 1.058 159.9 19.1 8.7 20.20 344.6
    2017 08 31 000000 21.2133 -11.123 0.049 1.055 159.1 19.9 8.7 22.33 345.3
    2017 09 01 000000 21.0581 -02.205 0.047 1.052 155.1 23.8 8.7 23.55 345.6
    2017 09 02 000000 20.9017 +06.960 0.047 1.050 148.7 29.9 8.9 23.53 345.6
    2017 09 03 000000 20.7448 +15.863 0.049 1.047 141.5 36.8 9.1 22.27 345.3
    2017 09 04 000000 20.5879 +24.073 0.051 1.045 134.3 43.7 9.4 20.14 344.6
    2017 09 05 000000 20.4317 +31.339 0.055 1.043 127.7 49.9 9.7 17.61 343.6
    2017 09 06 000000 20.2769 +37.589 0.059 1.040 121.9 55.3 10.0 15.09 342.3
    2017 09 07 000000 20.1239 +42.876 0.064 1.038 117.0 59.9 10.4 12.80 341.0

  2. Thanks for the post. A ‘slight’ correction: not all of Mars is at winter solstice, of course. Only its northern hemisphere is, as you point out in the caption to Fig. 1.

  3. Guy,there’s a new theory floating around that as the Universe expands a new Now is added per rate of expansion.Hopefully,it might take a merciful pause-barring any catastrophic effects of course !.

  4. The paragraph after the list refers to “4 Pallas”. I’m sure you meant 2 Pallas.

    Also, did you write the poem? After a long holiday weekend for which I had ambitious plans but during which my greatest accomplishments were several long naps, I can relate.

    Thanks for Astronomical Calendar 2017.

    1. Thanks for the correction (now made).
      Yes, the protest against Time is mine. I didn’t exactly spill it out just now, but recalled it (getting only one word wrong) from my “Language” (
      I could say a lot more (but won’t) about how my mind is space-oriented and time-disoriented.

    1. I wish I had time too.

      I am outargued by the clock,
      The dialogue of tick with tock.

      I say that I’m an optimist;
      It tells me of the train I’ve missed.

      I state my optimistic creed,
      The minutes pass with no less speed.

      There’s time! – but no, the clock has stopped.
      With timist am I, pess or opt?

      I’d rather wake to a crowing cockerel
      Than to the clock’s so-logical doggerel.

      I’ll rise and fight a frantical battle
      To tame the pendulum’s practical prattle!

      I’ve tilted at the windmill hands,
      I’ve tried to choke the running sands–

      In vain! “Engagements for today,”
      They say… “Your hair is turning gray.”

      Who with the clock can hold his own?
      The calendar and he alone.

      He can in merciless debate
      Match tripping time with tolling date.

      Rip every calendar from the wall,
      Wrap clocks with them and bury time all!

      1. We have, in the end, only this moment now; and every moment spent on your site is such a joy. Thank you.

      2. I love the poem Guy! One of my favorite time pieces has always been Pink Floyd’s song “Time,” one of the lyrics of which is:

        “And you run and you run to catch up with the sun but it’s sinking,
        Racing around to come up behind you again”

        A lifetime of enjoying astronomy allows one to put life events into astronomical context. For example, when I left home to go out in the world and start my own adult life, Saturn was almost exactly one orbit around the Sun ago, amid the stars of Libra and Scorpius and Ophiuchus. I will over 80 years old the next time it’s there!

  5. Hi Guy,

    The Astronomical League is creating an activity for Global Astronomy Month sponsored by Astronomers Without Borders that will feature asteroid identification and tracking. Its working title is “In the footsteps of the Celestial Police” and should be ready by mid winter. I hope.

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