Category Archives: Solar System

General Astronomy, Solar System

Planets of the Month: MAY

by Erich Karkoschka

planet-of-the-month-mercuryMercury becomes visible below Venus after May 12th. It rapidly moves past venus on the 21st and will be easily observable well into June. May 21st, Venus (-4.4 magnitude) & Mercury (-.6 magnitude) have a conjunction (very close together), visible about 1 hour after sunset. On May 24th a two-day old Moon join the pair.

planet-of-the-month-venusVenus is maximum brightness at the beginning of the month and becomes visible before sunset about 45 degrees high. It can even be seen during the afternoon if you know where to look. For example just before 3 pm, look 86 degrees high, essentially overhead. It reverses its prograde motion on the 13th near Elnath and then moves rapidly toward the Sun until it becomes invisible on the 30th. This month is ideal to watch its large, thin crescent in binoculars. By the end of May, it is only 1 percent illuminated. Venus/Mercury conjunction May 21 (see Mercury).

planet-of-the-month-moonThe Moon passes the morning planets from May 12 to the 14th. It will be most impressive on the 23rd and 24th as a thin crescent during dusk near Mercury and Venus. The Moon is full May 7, Last Quarter May 14, New May 22, and First Quarter May 29.

planet-of-the-month-marsMars brightens to zero magnitude, even brighter than Saturn. It is 15 degrees east of Saturn in early May, rising to 40 degrees by the end of May. Visible in the early morning sky all month.

 

planet-of-the-month-jupiterJupiter rises around midnight, dominating the morning sky. Jupiter & Saturn are close all month. A waning Gibbous Moon joins the pair the morning of May 12th.

 

planet-of-the-month-saturnSaturn follows 5 degrees east of Jupiter all month. This is the closest distance since 2000. They will separate until September and then approach again to .1 degree separation in December. A waning Gibbous Moon joins the pair the morning of May 12th.

planet-of-the-month-cometComet PanSTARRS (C/2017 T2) should peak mid May to maybe magnitude 8 or 9.  It will be within 1/2 degree of the Cigar Galaxy (M82) May 23/24 in the northern sky.

Solar System

Planets of the Month: APRIL

by Erich Karkoschka

planet-of-the-month-venusVenus is 40 degrees high at sunset and close to its brightest possible (Magnitude -4.5). After its passage through the Pleiades on the 3rd and 4th, it moves toward Alnath in Taurus. It is visible late into the evening and sets around 10:30 pm. By the end of the month, it is relatively large (39 arch seconds) and 25 % illuminated.

planet-of-the-month-moonOn April 15, the Last Quarter Moon joins the three morning planets in the predawn sky. On April 26, it is closest to brilliant Venus in the evening sky. First Quarter Moon is April 1 and 30, Full Moon April 7, Last Quarter April 14, and New Moon April 22.

planet-of-the-month-marsMars is the third planet to rise in the morning sky, following very close to Saturn at the beginning of April but sepertated by about 20 degrees by the end of the month. Mars is at Magnitude +1.

planet-of-the-month-jupiterJupiter rises at 2 am, dominating the morning sky at a magnitude of -2.

 

planet-of-the-month-saturnSaturn follows Jupiter and is 5 degrees to the east in the morning sky abut the same brightness as Mars at a magnitude of +1.

General Astronomy, Solar System

Planets of the Month: MARCH

by Erich Karkoschka

planet-of-the-month-mercury  Mercury is just visible at dawn. Its greatest western elongation is the 23rd.

planet-of-the-month-venus  Venus is 45 degrees high at sunset, its best once every eight years. Greatest elongation from the sun is on the 24th, when it is half illuminated. On April 3 it will be inside the Pleiades (M45). At magnitude -4.5, it can be seen during the day if one can find it. The Moon visits Venus on March 26 & 27. Uranus is only 2 degrees from Venus on March 8 (within a binocular view).

planet-of-the-month-moon

Moon. First Quarter: March 2. Full: 9. Last Quarter: 16. New: 24. The Moon will visit Venus March 26 & 27.

 

planet-of-the-month-marsMars.  Rises around 4 am at magnitude +1. Mars rises first early in the month, Jupiter is 5 degrees behind, and Saturn another 8 degrees behind. By the 18th Mars has almost caught up with Jupiter and the Moon is very close to both of them. Between the 20th & 31st, Mars will be between Jupiter and Saturn and within 7 degrees of each other. A Mars/Jupiter conjunction is on the 20th and a Mars/Saturn conjunction is on the 31st. After the 31st, Mars will have passed Saturn and will move on while Jupiter and Saturn stay within 6 degrees of each other.

planet-of-the-month-jupiter  Jupiter.  Rises around 4 am at magnitude -2. See Mars write-up for positioning.

planet-of-the-month-saturn  Saturn.  Rises around 4 am at magnitude +1. See Mars write-up for positioning.

planet-of-the-month-uranus  Uranus.   Only 2 degrees from Venus on the 8th.

planet-of-the-month-neptune  Neptune.  Not visible. Solar Conjunction (in the glare of the Sun) is March 8.

planet-of-the-month-sunrise  The Vernal (Spring) Equinox is March 19 at 9 pm MST. This is when the Sun crosses the celestial equator (an imaginary line in the sky above the Earth’s equator). This happens on March 19, 20, or 21 every year in the Northern Hemisphere.

32 inch Cassegrain Project, Solar System

Planets of the Month: FEBRUARY 2020

by Erich Karkoschka

planet-of-the-month-mercury
Mercury is easily visible in the first half of the month during dust in the west. It disappears after the 18th.

 

planet-of-the-month-venus
Venus is 40 degrees high at sunset and even 44 degrees by the end of the month. This is close to the maximum possible. It sets after 9 pm. The Moon will visit Venus on the 27th, a beautiful sight.

planet-of-the-month-mars
MAIN EVENT. Occultation of Mars by the Moon on the morning of February 18, well visible from Tucson before dawn in the southeast. It starts about an hour after Mars rises and lasts for another hour. Mars disappears behind the bright side of the Moon at 4:38 am and will reappear at 5:40 am along the dark side. The disappearance will be visible in binoculars as Mars slowly becomes invisible planet-of-the-month-moonat the bright limb of the Moon. The reappearance will also take about 20 seconds. Since it occurs at the dark limb, it can be observed with the naked eye.

 

planet-of-the-month-uranus
Uranus is 60 degrees high after dusk, visible in binoculars or a telescope.

 

planet-of-the-month-sunrise
Morning Sky. Mars rises at 4 am. Jupiter follows at 5 am, and Saturn at 6 am. These three planets will get closer to each other as the month progresses.

General Astronomy, Solar System

Planets of the Month: JANUARY, 2020

by Erich Karkoschka

planet-of-the-month-mercury Mercury starts to be visible far below Venus in the West on the 26th. It will be well visible in early February.
planet-of-the-month-venus Venus is extending its visibility in the West from 2 to 3 hours and sets after 9 pm by the end of the month.
planet-of-the-month-moon The thin lunar crescent after New Moon in the West will be near Mercury on the 26th and near Venus on the 27th & 28th.
planet-of-the-month-mars Mars rises at 4 am. On the 18th & 19th, it will be 5 degrees north of Antares. Two red objects near each other.
 planet-of-the-month-jupiter  Jupiter will slowly appear in the morning sky starting the 11th.
 planet-of-the-month-saturn Saturn is not visible. It get occulted by the Sun on the 13th.
 planet-of-the-month-uranus Uranus is 70 degrees high after dusk in the SW.
 planet-of-the-month-neptune Neptune in Aquarius gets visited by Venus on the 27th with a separation of only 10 arc minutes, makiong it possible to fit two planets in the filed of view even at high magnification.
 pluto Minor planet #4, Vesta, is further near Uranus in Cetus and still brighter than 8th magnitude.
Astronomical Events, General Astronomy, Solar System

Planets of the Month: DECEMBER, 2019

by Erich Karkoschka
Planets for December 2019

planet-of-the-month-mercury Mercury will be visible until December 19th, rising just after Mars (15 degrees below) before dawn.
planet-of-the-month-venus Venus is in the evening sky, getting higher and more obvious.
planet-of-the-month-moon New Moon will be at Christmas, last visible in the morning of the 24th and coming back in the evening sky on the 27th below Venus and the 28th right next to Venus, a beautiful pair.
planet-of-the-month-mars Mars rises before dawn in Libra, followed by Mercury 15 degrees below.
 planet-of-the-month-saturn Saturn is to the upper left of Venus in the evening sky until December 10 & 11, when Venus passes two degrees south of Saturn. At that time, Pluto is right next to both planets, but 15 million times fainter than Venus and not an easy target. After Christmas, Saturn will be too close to the Sun to be visible.
 planet-of-the-month-uranus Uranus is well placed in the evening for observers with binoculars or a telescope.
 planet-of-the-month-neptune Neptune is well placed in the evening for observers with binoculars or a telescope.
pluto Pluto is next to Venus & Saturn December 10 & 11 but is 15 million times fianter and not an easy target. The brightest minor planet, Vesta, is not too far from Uranus and only slightly fainter.
General Astronomy, Solar System, Star Parties

Mercury Transit Across the Sun (November 11, 2019)

by Jim Knoll

Monday November 11, 2019 (Veterans Day). This is a school holiday and a work holiday for many. Don’t pass up this “seldom-in-a-lifetime event”. A Mercury Transit (passing in front of) will NOT be visible again in the U.S. until May 7, 2049. Transits occur only 13-14 times per century. A Mercury Transit is too small to see without a properly filtered solar telescope. When you observe a transit, you see a small black circle (the planet Mercury) moving across the Sun. This event is visible throughout the U.S. TAAA will have several solar telescopes to safely view the Transit at Brandi Fenton Memorial Park (3482 E River Rd, River & Alvernon) on November 11 from 7:30 – 11 am (Mercury mid-transit when it is crossing the middle of the Sun is at 8:20 am Tucson time).  Sunrise November 11 is 6:49 am and the Transit will already be underway. You can follow the Mercury Transit event on our Facebook page (facebook.com/tucsonastronomy) for real-time weather updates. This event requires a clear view of the Sun (no cloud cover). CAUTION: Never look at the Sun without a proper solar filter or you can damage your eyes.

For more information, email: astronomy-events@tucsonastronomy.org.

Visible light image of sun, with Venus transiting. The sun is a type yellow type G star approximately 4.5 billions years old with a life cycle of 10 billion years. NASA Image
Visible light image of sun, with Venus transiting. The sun is a type yellow type G star approximately 4.5 billions years old with a life cycle of 10 billion years.
NASA Image
32 inch Cassegrain Project, Astronomical Events, General Astronomy, Solar System

Planets of the Month: Summer 2019

by Erich Karkoschka

Planets for Summer 2019 (June – September)

planet-of-the-month-mercury Mercury is visible all June until July 3 in the evening to the WNW just after sunset. In mid-June, it is the most obvious object in the western sky. August 3 -24 it is visible during dawn in the east.
planet-of-the-month-venus Venus is a difficult dawn object until July 18. It will reappear September 18 low at dusk.
planet-of-the-month-moon The Moon is New on June 3, July 2, July 31, August 30, and September 28. First Quarter Moon is June 10, July 9, August 7, September 5. Full Moon is June 17, July 16, August 15, and September 13. There is a partial Lunar Eclipse on July 16, visible in South America and further east.
planet-of-the-month-mars Mars is above Mercury in early June. On June 18, Mercury passes close to Mars. Then, Mars slowly gets lower during dusk until it disappears in the glow of the Sun at the end of June for the rest of the summer.
planet-of-the-month-jupiter Jupiter comes in opposition to the Sun on June 10 and is a great evening object all summer. It is moving toward Antares.
 planet-of-the-month-saturn  Saturn is just 30 degrees east of Jupiter. It is in opposition July 9 and will be a great evening object most of the summer as well. The brightest parts of the Milky Way are between Jupiter and Saturn in the night sky.
 planet-of-the-month-neptune  The distant, faint planets come in opposition September 8 (Neptune) and October 28 (Uranus).
 There are two eclipses in July. A Total Solar Eclipse July 2, visible in South America, and a Partial Lunar Eclipse on July 16, visible in South America and further east.
General Astronomy, Solar System

Planets of the Month: March 2019

by Erich Karkoschka

planet-of-the-month-mars Mars is still magnitude 1, 40 degrees high at dusk, sets at 11 pm. It is moving toward Taurus with Aldebaran of similar brightness and color.  The last week of March it is 3 degrees south of the Pleiades.
Uranus is visible in binoculars below Mars.
Jupiter transits at dawn.
Venus is further east and stays low at dawn.
Saturn is 26 degrees east of Jupiter, the closest since 2001.
Mercury is visible at dusk till the 5th and at dawn starting on the 30th.
The moon is close to Venus on the morings of March 2 and 3. The moon will be back in the evening sky on the 7th as a very thin crescent low in the west.
General Astronomy, Solar System

Planets of the Month: February 2019

by Erich Karkoschka

Mercury has the best evening apparition of 2019, visible after the 12th in the west at dusk, best around the 24th.
planet-of-the-month-mars Mars is still magnitude 1, 50 degrees high at dusk, sets after 11 pm. It is moving toward Aries and Taurus with Aldebaran of similar brightness and color.
Uranus is 1 degree south of Mars on February 12. Although Mars is 100 times as bright as Uranus, both are of similar sizes, 6 arcsec versus 4 arcsec, but very different colors.
Jupiter rises at 3 am and is 30 degrees high at dawn.
Venus rises 4:30 am and is 20 degrees high at dawn.  Venus and Jupiter are only separated by 10 degrees at the beginning of the month.
Saturn rises after Venus in early February.  On the 18th, it is within 1 degree of Venus.  Saturn and Jupiter are separated by 30 degrees, the closest since 2001.
The moon will be back in the evening sky on the 6th, possibly on the 5th, very low in the WSW in bright twilight.  Binoculars may be needed to spot it depending on the atmospheric conditions.