Saturnus

Saturn is a favorite among everyone. The days of the week are named after celestial bodies and Saturn’s day (Saturday) is also beloved by all! You’re probably thinking about it so here are the rest: Sunday = Sun’s Day, Monday = Moon’s day, (knowing Spanish helps with the others, English took some Norse gods like Thursday=Thor's day) Tuesday = martes = Mars Day, Wednesday = miércoles = Mercury’s day, Thursday = jueves = Jupiter’s day, Friday = viernes = Venus day. Seems like Earth day got a raw deal only being one day a year...

Saturn and its rings taken over a period of three hours by the wide-angle camera on the Cassini spacecraft. (NASA)

Saturn is currently appearing in the south next to Jupiter in our evening sky it is much dimmer than Jupiter but it is brighter than the stars that surround it. It makes almost a flat straight line in the sky with Jupiter (the brightest 'star' in the Southern sky after sunset) currently at sunset and will get more angled later in the night and later in the year. This line actually goes across the whole sky surrounding the Earth and is the line of the ecliptic (the only place you find the planets, the sun, and the moon is on this line because it denotes the plane of our solar system. Late at night (currently about 10p) going along this line due east you will see a bright red 'star' rise, Mars!

Diagram showing the Celestial sphere with ecliptic and equinoxes

Saturn is currently visiting the constellation Capricorn which can be seen below it. Saturn is a true treat in binoculars or a telescope. When you first see it you might see an oval resembling a batman symbol but once you focus your eyes in to it you should see Saturn's rings resolve. Saturn never fails to get an “oh wow!” from anyone looking at it up close, the large planet suspended perfectly in the rings is a magical sight to observe with your own eyes. If you really want to test your eyes and equipment you might see ‘the Cassini Division’ which appears as a dark region that separates the bright ring in to 2 rings. The rings are made up of countless water ice particles ranging in size from the smallest speck to the size of a house.

common view of Saturn in a telescope.

Saturn like the Earth has solstices and equinoxes, and you can see them by observing the rings from year to year. Saturn takes 30 years to go around the Sun meaning 30 earth years = 1 Saturn year. every 30 earth years Saturn has 2 solstices (i.e. summer & winter) and 2 equinoxes (i.e. spring, & fall). We see Saturn's solstices by seeing the rings tip towards us and appear to open up and we see Saturn's equinoxes by observing the rings edge on, where it’s difficult to notice the rings at all. Saturn’s last solstice occurred in 2018 this means Saturn was tipped towards the Sun opening it’s rings as wide as can be seen. Over the next 5 or so earth years we will watch Saturn's rings tip away getting smaller and smaller until it reaches equinox where we will see the rings edge on.

How Saturn will look at opposition (when closest to Earth) for the next nine years

When Galileo first saw Saturn's rings he of course didn’t know what he was looking at, some of his first sketches depict it with two moons (he had already discovered the moons of Jupiter making this a reasonable guess). After he caught his first glimpse he got clouded out and wasn’t able to see Saturn again, then once the clouds left Saturn was no longer in the sky (Saturn was too close to the Sun to be observed). Galileo knew about the movements of the planets by now so he waited till he could see it again and when he did the rings were no longer visible (Saturn had gone into equinox where the rings were edge on) this lead Galileo to think he had hallucinated when he first saw the rings. Saturn’s Greek god name is Κρόνος, Krónos who was a Titan that ate his children. Galileo knew this story so when he saw the “moons” next to Saturn disappear he thought just like in the myth Kronos had ate his children. He checked back over the next few years to see them open up again he never truly realized what they really were, later calling them "arms".

After taking in the rings of Saturn if you look around just of next to Saturn somewhere you should see the moon Titan (yes this is where Thanos is from) . Titan is the second largest moon in the solar system (after Jupiter’s moon Ganymede) and slightly larger than even the planet Mercury. Titan is really exciting for planetary researchers as it is rich in geological processes that are alien to anything seen on Earth yet somewhat familiar. I’ll give you an example much like Earth Titan has clouds in its atmosphere and lakes on its surface however Titan’s lakes and clouds are not made of water but made of methane. It is thought that methane on titan acts much like water acts on Earth. Because Titan is so far from the sun it is much colder but these cooler temperatures make it possible to have methane as a solid, liquid, and gas. When heated methane lakes evaporate into clouds that when cooled then rain and/or snow methane back down to the surface.

The Huygens probe that was sent with the Cassini spacecraft landed on the surface of titan in 2005 and proposed missions want to go further some with a submarine to be deployed in a methane lake. Just imagine what a feat of engineering that could be to have a submarine in a methane lake on a moon of one of the most distant planets in our solar system.

My new Bumper stickers are in! come to a tour to pick yours up for free!

By Jove!

If you have been out at dusk lately You may be noticing the brightest star that appears over the southern horizon just after sunset. This “star” is actually the planet Jupiter!

Infrared view of Jupiter

Jupiter is the largest planet in our solar system at 11.6 times the size of Earth in diameter (86,881 miles), making it 1,322 times the size of earth in volume, you could fit over a thousand earth's inside Jupiter. Being so massive has made Jupiter a solar system within our solar system, as it's extreme gravitational pull captures lots of objects as moons of Jupiter.

Jupiter's size compared to earth, the entirety of earth could fit, with room to spare, in Jupiter's 'great red spot' (an acid hurricane that has been raging on Jupiter for centuries)

Jupiter currently has 79 known moons. This number keeps increasing as recently as July of 2018, we added 10 newly discovered moons to the total. 26 of the moons are so new they are still awaiting official names. We are not done adding to the number of known moons of Jupiter. Astronomers are discovering new moons of Jupiter so frequently the main trick has become making sure the newly observed moons are not the same as a moon we have previously counted.

The number of moons of Jupiter will also be changing further as new moons are likely about to be made and destroyed. Of the known objects going around Jupiter most are going the same direction but, some are going the opposite direction and just like if you go the opposite direction of traffic in a traffic circle collision is likely.

If you look at Jupiter with even just a halfway decent pair of binoculars you will be able to see 4 of Jupiter's moons Io, Europa, Ganymede, and Callisto. These are called the Galilean Moons as they were first observed by Galileo in his small telescope. They are very easy to make out even in small telescopes/binoculars but, telling which one is which takes several observations over a long period of time as they are circling Jupiter and you can only see this movement edge on from Earth. To determine a moon’s true distance from Jupiter you must watch the moons to see when they stop getting further from Jupiter, turn around and get closer. (or you can just cheat and use this web tool)

how Jupiter and it's 4 Galilean Moons appear in a telescope or binoculars (the stripes/spot can be much harder to see than it might look from this picture)to

All of the Galilean Moons are interesting places and studied extensively. Io (the closest) is the most volcanic body in our solar system, Eropa is the smoothest body in our solar system it’s believed to have liquid water and therefore possibly life beneath it’s ice surface. Ganymede is bigger than the planet Mercury, and Callisto (the furthest out) is the most cratered body in our solar system.

Jupiter’s moons served as one of the first standardized clocks. Jupiter’s moons movement is regular and predictable so the Royal Observatory in Greenwich calculated and published their future locations and local time (as would be shown on a sundial or pendulum clock) at Greenwich, forming the foundations for our time zones based around Greenwich Mean Time.

With a good pair of binoculars you can also see red stripes contrasted with white stripes this is Jupiter’s atmosphere. The change in coloration is caused by different compounds in the atmosphere that change color when exposed to the light of the Sun.

A really good set of binoculars or a decent telescope you can see the red spot which is an acid hurricane more than twice the size of earth that has been observed since at least 350 years ago. This has been the only silver lining of stargazing in Colorado thru the smog/haze from the wild fires in the mountains is that the haze has been increasing the contrast on Jupiter making the stripes and spot easier to see (I've actually been able to make out a personal record number of stripes this year seeing 7). A day on Jupiter last about 10 hrs so over the course of a long winter night you can watch Jupiter do a full rotation by watching the great red spot do a lap around the planet.

close up of the spot on Jupiter

Jupiter is currently “in Capricorn ”. Capricorn doesn't look like much unless you have really dark sky, but you will see Sagittarius to the right, right next to it! If you have decently dark skies and some imagination you might see a constellation that resembles a teapot just to the right of Jupiter. A triangular lid atop a trapezoidal body with a trapezoidal handle on the east side and a triangular spout on the west side. Even better if you are in a particularly dark area you can see the milky way appearing as steam coming out of the spout. This “teapot” was originally seen as an archer, and named Sagittarius. The tip of the spout to the two stars that make the top of the handle are the arrow and the top of the lid and the two stars to the right of the base make the bow for the archer.

The archer's arrow is drawn pointing to the west towards a bright star with a red/orange hue. This star is Antares. Antares is not to be confused with mars which is currently rising in the eastern sky around 10pm ~ish (this is such a common mistake it is where Antares name came from, it's Arabic for 'rival of mars'). The star Antares is the heart of the scorpion or Scorpio. and Sagittarius is protecting others from Scorpio by keeping his bow drawn towards it's heart.

Capricorn, Sagittarius, and Scorpio you might be familiar with from the zodiac over the course of 12 years we can watch Jupiter move across every sign in the zodiac. If you read my post on Jupiter two years ago you have been able to watch Jupiter move from the constellation Scorpio to the next constellation in the zodiac Sagittarius and now to Capricorn! Jupiter takes just a little less than 12 years to go around the Sun, there are 12 signs in the zodiac, therefore Jupiter spends a year in each one! so next year we can be sure to find Jupiter in Aquarius!

Come get a closer look at Jupiter seeing it's stripes (this year better than ever with the haze), moons, red spot and more! On an astronomy tour! Book now for an out of this world experience!

Black Lives Matter

AstroTours.org is committed to becoming an anti-racist organization. We mourn the murder of George Floyd and all victims of racial injustice and police brutality. Black Lives Matter. We stand in solidarity with protests across the nation and globally calling for justice and accountability.

Juneteenth parade Denver

The Night Sky is a common heritage of all cultures and peoples. The stars have played an integral part throughout history in both guiding oppressors to the lands of peaceful peoples (from Columbus to Cook) and in guiding oppressed peoples to liberation (from the underground railroad to the Jews of Egypt). We try to include these stories but In all sincerity, the current situation made us take a hard look at the voices within our organization and we realized that we have a lot of work to do.

We are a white-led organization with a white staff, and have a majority-white audience. We conduct tours upon the occupied lands of the Southern Arapaho people. We are a part of the scientific community that has been and continues to be exploitative of people of color. We're also part of an education system that has centered and valued the contributions and expertise of white people above those of Black people and people of color. Beyond this, we are living through a global pandemic that is having an outsized impact on people of color.

AstroTours.org has not been exempt from these patterns of injustice, and in fact we have benefited from our position of privilege. We acknowledge this, and know that we have much work to do. We also acknowledge that this statement itself is late in coming, and is insufficient on its own.

We are learning and listening, with particular attention to Black, Indigenous, People of Color voices in our community. We are working on creating pathways forward to further center and uplift these voices as we work towards becoming an anti-racist organization.