Champaign-Urbana Astronomical Society
December already . . .where did the year go? The holidays and chillier temperatures mean people may not be
out looking at the sky as often but there are a few things
to look at.
Let’s start with Comet Leonard. The comet was discovered by Greg Leonard on Mount Lemmon in Arizona on
January 3, earlier this year. Comets usually get brighter
as they get closer to the Sun and the ices sublime in the
warmth of the Sun. But they do their own thing – some
fizzle. If predictions hold, the comet will reach 4th magnitude and be well within reach of binoculars during its closest approach to the Earth on December 12th. However,
near the 12th, it’ll be pretty close to the Sun from our point
of view. Prior to the 12th, the comet heads eastward
north of the star Arcturus (December 4-7). Look nearly
due east roughly 45 minutes as the comet goes through
Serpens and Ophiuchus, heading towards the Sun. On
the 14th, the comet shifts into the evening sky. Look in the
west-southwest beneath Venus. In fact, on the 17th, the
comet should be 5 degrees (half a fist held at arm’s
length) below Venus with respect to the horizon. How
bright will it be then? I guess we’ll see. Comet Leonard
will move from right to left along the horizon and be
roughly 10 degrees below Saturn on the 20th. Of note,
the comet should appear to just miss the globular cluster
M3 in Bootes on the mornings of December 2nd and 3rd
Send a note to the “members” list if you see it!
Planet-wise we start the month with three planets in the
evening sky, just about evenly spaced. Venus is of course
closest to the horizon, then Saturn and finally Jupiter.
Venus has been slowing seeming to approach Saturn but it
won’t make it. This month Venus starts to head back towards the Sun. Venus is a large, thin crescent now – see
if you can see the shape with binoculars. Venus reaches
greatest brilliancy at magnitude -4.9 early in the month.
The Moon joins the line on the 5th, spanning 50 degrees,
and is nearest Venus (2 degrees) the next night. The
Moon is closest to Saturn (4 degrees) on the 7th and near
Jupiter on the 9th
In mid-December, Mercury rises up from the glare of the
Sun to join the other planets. On the 26th, look directly
below Venus not long after sunset. Two evenings later,
the Venus and Mercury are closest at 4 degrees with Mercury below and left of Venus in the west-southwest.
In the morning sky, there’s not a lot to see. Mars makes
an appearance but it’s pretty faint, being on the other side
of the solar system. It is above and left of its namesake,
the star Antares, on December 27th but it’s pretty low in
the southeast. Mars will have an opposition late in 2022.
Two other events of note . . . .the Geminids Meteor Shower peaks near 1am on the morning of the 14th. Under a
dark, Moonless sky, one might expect nearly 150 meteors
per hour. The problem will be the Moon as it’s a waxing
gibbous (77% lit), not setting until 3am. So there’s a little
time with dark skies. The shower seems to result, not
from a comet like most showers, but the asteroid Phaethon.
On the evening of the 23rd, look for the waning gibbous
Moon to rise in the east about 8:50pm. The star Al
Jabhah (or Eta Leonis) is behind the Moon as it rises. It
will emerge from the unlit side of the Moon at about
9:45pm. Watch as the star “blinks on” from behind the
Moon. This event is called a lunar occultation.
And the winter solstice occurs on the 21st this month at
9:59am. The Sun is above the Tropic of Capricorn but only
appears 26.5 degrees high at noon, resulting in long shadows and short days. But, hey, short days mean longer
nights for observing, right? Happy holidays!
Let’s start in the western sky after sunset (why break a habit,
eh?). Venus is now just past its greatest separation from the
Sun (October 29th) so its set time doesn’t seem to change much
this month and next. And that set time is right around 7:15pm
CST. Now Venus will appear to be up longer as the Sun sets
sooner as our days get shorter. In fact, Venus sets 2.25 hours
after the Sun on November 1st but it’s a half hour later by the
end of the month. It’s always
cool when the Moon comes
around to visit Venus; that happens on the evening of November
th. Two evenings later, you can
trace a nearly straight line from
Venus, through the Moon, and on
to Saturn and then Jupiter. Telescopically, Venus begins the
month as a half-lit sphere but, as
November proceeds, it’ll become
a thinner crescent. Look for it in
the southwest after sunset.
Saturn and Jupiter are next, appearing nearly due south as the
twilight begins to fade. The
Moon makes a nice triangle with
these two worlds on the 10th. Did
you see where an amateur astronomer caught something hitting
Jupiter? Brazilian amateur Jose
Luis Pereira caught the “impact” on September 13th as he was
shooting video (see the image above).
In the morning sky, Mercury is coming off its best morning view
of the year. You can still catch if it you look just before sunrise
in the east-southeast. On the morning of November 3rd, a thin
crescent Moon is just above Mercury. Look about a half hour
before sunrise. As Mercury sinks closer to the morning glow of
the Sun, Mars rises up to meet it. The closest approach occurs
on the morning of November 10th, though you’ll have to have a
very low horizon and Mercury will be the brighter of the two.
And we won’t go through all the “Uranus” jokes, but this planet
comes to opposition on November 3rd in the constellation of
Aries. It is really between Aries and the head of Cetus. At magnitude 5.7 you should be able to spot it in binoculars as long as
you know where to look. Skyandtelescope.com has a finder
Another object prime for observation is the asteroid . . .oh, excuse me . . dwarf planet Ceres. Ceres was the first asteroid
discovered back in 1801 and it’s a nearly spherical rock the size
of Texas. It gained dwarf planet status in 2006 when Pluto was
demoted. But it’s by far the easiest dwarf planet to see since
it’s in the main belt of asteroids.
Opposition is November 27th at
magnitude 7, but start looking earlier! Ceres goes from left to right
across the V-shaped star cluster,
the Hyades, which mark the face of
Taurus, the Bull. In fact, on the
evenings of November 2nd and 3rd
it is just below the eye of our bull,
the bright star Aldebaran.
“Asteroid” means “star-like” and
that’s what it will look like, but the
key is to look more than once, making a mental note (or a drawing is
better) of the area. The “star” the
moves is Ceres.
And we’ll save what could be considered the best for last. We’ll have
a “partial” lunar eclipse on the
morning of the 19th. Note “partial
is in quotes as, at maximum, 97% of
the Moon will be in the Earth’s umbral shadow. The event begins at 1:18am, maximum eclipse occurs at 3:04am and we’ll
have a full Moon
the hour, there is
no CUAS viewing
session being held
for the eclipse but
we hope you’ll go
out and look anyway.
Have you noticed the position of Venus in the evening sky? On August 1st, Venus was nearly due west as the evening twilight faded. Now it’s in the southwest – quite the change! Venus reaches it’s greatest separation from the Sun on the 29th of this month at 47 degrees – nearly five fists. It sets about over two hours after sunset and about 45 minutes after the end of evening twilight. IF you have an unobstructed horizon, watch this month as Venus appears to approach the star Antares. The pair begin in the month about 15 degrees apart and they are closest on the 16th at 1.4 degree separation (see the image). Binoculars will help, given the twilight. They won’t be this close again until 2029! The crescent Moon is below and right of Venus on the 8th and just above Venus (2.5 degrees) on the 9 th . Jupiter and Saturn are wellplaced in the sky this month, each crossing the meridian either at or near the end of evening twilight. On the 14th the two planets are 15 degrees apart, with Jupiter the brighter of the two. And, on the 14th, a waxing gibbous Moon is between and below the two planets (see the image). At mid -October, Saturn sets at about 1am CDT with Jupiter a little over an hour behind. There’s not too much more happening planet-wise until the morning hours. Mercury has its best morning view of the year this month. Around October 12 or so, you should be able to find Mercury just a bit south of east – look around 6:30am. Greatest separation from the Sun occurs on Sunday, the 24th at 18 degrees west of the Sun. It’ll be a magnitude -0.57 dot among the stars of Virgo. You should be able to find Mercury pretty easily until the second week of November. We’ll give Mars a quick mention but not for its visibility. Actually it finally passes behind the Sun on the 8th. Soon you’ll be able to find it in the morning sky. We have two meteor showers this month. The Draconids peak on the 7th and 8th of October. Unlike other showers, the evening hours are favored for this one and, since the Moon is “new” on the Wednesday before, the skies will be dark. The radiant point is near the head of Draco, which isn’t far from the star Vega. Even under great conditions, you may only see a handful of meteors each hour, but there were outbursts in 1933, 1946 and 2011. In 2011 the hourly rate was estimated at 600! Keep an eye on it! The Orionids peak during the morning hours of the 21st . The problem here is that a full Moon (which occurs the day before) will brighten the sky. Still you might see a few before dawn when the Moon is low. The dwarf planet Eris – yeah, the one that started the discussion which lead to the demotion of Pluto – reaches opposition on the 17th. Sitting among the stars of Cetus, its apparent magnitude of +18.7, you are most probably not seeing it, but we thought we’d send it some love anyway.
This Month August 2021
Lets start off talking about the Perseid Meteor Shower, one
of the most potent of the year. You can see Perseids throughout the month of
August but the peak occurs during the second week or, more specifically, the
evening of the 11th into the morning of the 12th. The good news this year is
that Moon is out of the sky, for the most part, leaving dark skies for meteor
watching. Lets hope the soot from the western wildfires will have been cleansed
from the atmosphere to reduce hazy skies. The good news about meteor watching
is that you need no equipment, save for maybe a lawn chair. At the max, you
might see an average of two meteors per minute. Set-up that lawn chair so you
can pretty much see straight-up. See the “Club News” section about an observing
opportunity. The Perseids result from the Earth plunging through the debris
trail of Comet Swift-Tuttle. Starting with the evening planets, technically Mercury is in the
evening sky, but the view isn’t favorable. We have had two pretty good evening
views of this elusive planet so maybe we’re spoiled. Greatest separation occurs in midSeptember but, even
at the end of this month, Mercury is setting in the evening twilight just under
an hour after sunset. Look really low,
just after sunset, in the westnorthwest if you want
to give it a shot. On the evening of the 18th, Mercury
passes Mars, missing it by 0.1
degrees, but the pair will be tough to see. On the other hand, Venus is more
recognizable due to its brightness. All month Venus
sets about 90 minutes after the Sun or about the time full twilight ends. It
does appear to move further to the left,
along the horizon, appearing due west near August
8th. The crescent Moon is to the right of Venus on the evening of the 10th.
Watch each night as Venus appears to head for Spica; the two will unite next
month. Both Saturn and Jupiter reach “opposition” this month, on August 2nd and 19th
respectively. Of course, opposition is when an outer planet is opposite the Sun
from our point of view. So think about being in your backyard. If the planet is
opposite the Sun, it must rise as the Sun sets and be visible all night. Given
the Earth and the planet are on the same side of the Sun, it means the planet
is relatively close to us so it appears bright and large through a telescope.
Look for both Saturn and Jupiter in the southeast. Jupiter rises about an hour
after Saturn and is much brighter. The Moon scurries just south of both planets
on the 20th and 21st of August. Given the Moon’s orbit is off the ecliptic by 5
degrees, you can see this difference given
the Moon will be about 4 degrees below these planets. August 22nd brings the
full Moon. This month it happens to be a
“seasonal blue Moon.” The definition of “blue Moon” was altered long ago. Think
about this. Normally we have one full Moon a month. There are four seasons in a
year, three months each. So normally we’d expect to have three full Moons in a
season. But sometimes there are four. When that happens, the THIRD full Moon of
the four is called a “blue Moon.” In 1946, an article in Sky & Telescope
magazine talked about the “blue Moon” being the second full Moon in a month’s
time and that erroneous definition stuck. So, to be clear, August’s full Moon
Is a “blue Moon” by the traditional definition.
The Moon won’t look blue and, in fact, there will be nothing special about it.
But go look anyway!
Looking Up This Month July2021
Have you seen Venus in the west-northwest yet? It’ll appear like an airplane coming in for a landing but it never reaches the airport. Venus’s set time is right around 10pm CDT all month, about 90 minutes after sunset. Things get interesting starting the evening of July 9th. Venus and Mars will approach each oth-er with Venus being much brighter (magnitude -3.8 compared to +1.8 for Mars). Venus is getting hither while Mars is sinking towards the Sun. On the evening of the 11th, a thin crescent Moon joins the pair with the Moon being five degrees to the right (see the image). On the 12th, Venus and Mars are closest at 0.5 degrees. Venus seems to not get too much higher but heads southward, near-ly parallel to the horizon. The planet comes to within a degree of Regulus on the evening of the 21st. Mars is close to Regulus on the 29th, but this pair is really low after the sun sets. By the end of July, Venus is nearly due west. And you can pretty much say “see ya” to Mars for a while as it appears to pass behind the Sun. Officially this doesn’t happen until early October but Mars is low enough that it won’t command much attention.
You don’t need to wait too long to see another planet. As July begins, Saturn rises in the southeast right about the time the evening twilight leaves us. By the end of the month, Saturn is rising right about the time of sunset. In fact, Saturn’s opposition occurs on August 2. Of course you’ll have to wait a little while for the ringed planet to get high enough to train a telescope on her. Saturn sits in the star-poor constellation of Capricornus, so, at magnitude +0.37, it will be the brightest thing in the southeast, at least until Jupiter rises an hour later. The Full Moon is near Sat-urn on the 23rd and makes a triangle with Jupiter and Saturn the next evening.
Lastly, we should mention Mercury which inhabits the morning sky. Greatest separation from the Sun occurs on the 4th of July and Mercury is well placed for early risers the entire first full week of July. Capella will rise first in the northeast, followed by Aldebaran, and then Mercury in the east-northeast. In fact, Mercury will look like one of the bull’s horns. On the morning of the 7th, Mercury is closest to the horn star, Zeta Tauri. The waning crescent Moon is also to the left of the planet at this time, rising at the same time. Mercury then heads through the foot of Gemini and is tough to see by the last week of the month.
The Earth reaches the furthest point from the Sun in its nearly circular orbit on July 5th. If you’re keeping score, we’ll be 94,510,886 miles from our nearest star at right about dinner time.
And the Delta Aquariid meteor shower peaks on evening of July 28 and into the morning hours of the 29th. Last quarter Moon occurs on the 31st, meaning we’ll have a bright waning gibbous Moon brightening the sky during the morning hours, which isn’t good for meteor watching. Still, the shower really runs from July 12 through August 23 so you still might see a few even if the maximum isn’t ideal. At the max, 15-20 mete-ors per hours are expected. Good luck!
Did you see Mercury last month? I believe we had a clear night on May 13 and the Moon was beautiful to the left of Mercury. I hope you saw that. Mercury is no longer in the picture (well, not like it was in May) and, in fact, it will pass between the Sun and the Earth on June 10 to slip into the morning sky. Mercury will ascend in the morning sky though it’ll reach its greatest separation from the Sun early next month. Early risers may see it at the end of June but don’t mistake it for the star Aldebaran – they’ll be relative close in separation and brightness.
Back to the evening sky. Venus is still in the process of making a slow ascent from the horizon. At the beginning of June, it sets at 9:45pm CDT, a bit over an hour past sunset. That stretches to about 95 minutes at the end of June. Venus comes pretty close to passing over the rich star cluster, M35, in the foot of Gemini, but the sky will be too bright to see the cluster. Look for Venus low in the west-northwest. At magnitude -3.8, you don’t have to wait that long after sunset to start looking. A thin crescent Moon is just below and right of Venus on the evening of the 11th (pictured here) then midway between Venus and Mars on the 12th. Note this month how the separation between Venus and Mars is decreasing. By the end of June, it’s about 7.5 degrees. On the evening of the 24th Venus is in line with the stars Castor and Pollux.
Mars is pretty faint (well, for Mars, anyway) at magnitude +1.8, but Mars does something cool this month. Easily locate Mars on June 13 since the crescent Moon will be right above it. Then keep an eye on the planet with binoculars. On June 23 Mars will cross in front of the Beehive Cluster in Cancer. Granted it’s not high in the sky but if you can find a good, unobstructed horizon, you got a good shot. Mars will look like an extra “star” in the cluster but, of course, the cluster is well over 15 millions times further away!!
Jupiter and Saturn are still in the morning sky but, in mid-June, they’re both above the east-southeastern horizon by just after midnight. By sunrise, they are closed to being on the meridian. On June 1, a roughly 3rd quarter Moon is just below Jupiter but the scene repeats itself near the end of the month. The Moon is near Saturn on the morning of the 27th and then below and between the two planets the next morning.
Besides Mars in the Beehive, diligent observers might look for the brightest asteroid, Vesta, among the stars of Leo. It’ll be about magnitude +7.6 so you’ll need binoculars at minimum. It’s nice when asteroids are near stars. Start with Theta Leonis (one of the Lion’s back legs) and go past the galaxies M65 and M66 to the star 78 Leonis (magnitude 4). See the next page for a chart. Vesta is between two stars at magnitudes 5.8 and 6.5. Now the key to finding an asteroid is to watch over a couple of nights and look for movement. There’s a reason why the name “asteroid” means “starlike!”
We also have an annular eclipse coming up on June 10, though the path of the Moon’s shadow goes over both the Earth’s geographic and magnetic poles. Eastern Canada has probably the best view for a inhabited area. Will we get to see it here? Maximum eclipse occurs while it’s still dark here. You may get
to see some or the Moon exiting the Sun disk right at sunrise on the 10th. Now if you try, USE ECLIPSE GLASSES! DO NOT look at the Sun with just your eyes! The entire eclipse is over around 8am.
Oh, yeah, and happy summer, too! The summer solstice occurs on Sunday, June 20, at 10:32pm. That is when the Sun is over the Tropic of Cancer. We’ll have our longest day and the Sun will be at its highest at noon (though not straight up). I got into a bit of a “heated discussion” with a couple of meteorologists who claim summer begins June 1 and they “have the data to prove it.” I haven’t seen the data yet. The calendar is so arbitrary. Whether you like the solstice or not, it’s a definitive date and time! I suppose in the long run it really doesn’t matter, right?