Cassini Death Plunge

Goodbye Cassini and WELL DONE!
by John Hlynialuk

Intentionally crashing a 5600 kg spacecraft into a planet does not sound like a good thing, but controllers at the NASA Jet Propulsion Lab in Pasadena, California will do just that to end a multi-billion (that “b” is not a typo) dollar mission that has been studying Saturn for the last 13 years. It happens on Sep 15 and it is, in fact, the smart thing to do. One of the discoveries made by Cassini, the vehicle in question (think fully-loaded, over-sized SUV), is that one of the moons of Saturn probably has an ocean under its ice layer that could harbour some form of life. If the spacecraft contaminated that moon with earthly bacteria (spacecraft are routinely sterilized but you can’t keep a hardy bug down), it would not be a good thing. It is much wiser to vapourize the vehicle intentionally in Saturn’s atmosphere where the incineration would reduce everything to sterile atoms.

PIA21438 2

But even to the very end Cassini’s instruments will be wringing out information about Saturn.

To quote Linda Spilker, Cassini project scientist from NASA’s Jet Propulsion Laboratory:

The Cassini mission has been packed full of scientific firsts, and our unique planetary revelations will continue to the very end of the mission as Cassini becomes Saturn’s first planetary probe, sampling Saturn’s atmosphere up until the last second. We’ll be sending data in near real time as we rush headlong into the atmosphere – it’s truly a first-of-its-kind event at Saturn.

The data about the composition of Saturn’s atmosphere will be added to the wealth of other data and terabytes of images sent back by the spacecraft over the last 13 years. The discoveries have increased our knowledge about the planet immensely; where we had a single chapter in astronomy texts on Saturn, now there are literally dozens of volumes of information about the planet. As of December 2016, there were 3700 papers published in scientific journals using the data from this mission and it is not over just yet.

Cassini has clearly transformed our knowledge of the planet. Starting with the beautiful feature visible in telescopes from Earth, Saturn’s rings, Cassini found a highly dynamic system of particles constantly changing over time. Another surprise were the small moons embedded in the rings; these carve out gaps leaving behind beautiful sinuous patterns in their wakes. The dynamics of the rings of Saturn have revealed secrets about how planets form around stars and give insights into how our own planet may have coalesced from the dust circling our Sun in our early solar system.

8423_20181_1saturn2016-1

As some discoveries have solved mysteries about Saturn, other mysteries have arisen as scientists scramble to analyze the data coming in. This includes giant hurricanes at Saturn’s poles, one with bizarre hexagonal sides unlike anything ever seen. How can this pattern be maintained over time? The number of scientific papers will continue to grow as planetary meteorologists propose theories to explain this unusual structure and other weather patterns in Saturn’s immense atmosphere.

Cassini also studied the dozens of moons circling Saturn and discoveries of wonderful things have involved them as well. Plumes of water vapour stream up from Saturn’s moon Enceladus, indicating a sub-surface ocean that is a possible abode for living organisms perhaps like those near Earth’s own deep ocean vents, the “black smokers”. The Cassini mission to Saturn also involved a smaller spacecraft called Huygens, which piggy-backed on Cassini from Earth and was released to parachute into the atmosphere of Titan, Saturn’s most enigmatic moon. There it found hydrocarbon lakes and rivers containing organic compounds, -a world where the chemistry may resemble our early Earth giving us a possible look back at our own evolution.

I highly recommend a look at the NASA Cassini website for more about the spacecraft and its discoveries, including some of the most spectacular images of Saturn, its rings and moons that I have ever seen. The link is provided here: https://saturn.jpl.nasa.gov

Goodbye Cassini, you have served us well!


SOLAR ECLIPSE VIEW FROM OWEN SOUND

by John Hlynialuk
As a satellite in our solar system, Earth’s Moon is actually one of the larger ones, ranking 5th biggest in diameter. Only three moons of Jupiter and one of Saturn, appropriately called Titan, are larger. Ganymede, circling Jupiter, holds the number one spot at 5262 km across, half again as big as our Moon which is 3475 km in diameter. Six of the several hundred planetary satellites in our solar system are actually bigger than the former planet, Pluto, now a “dwarf planet”, which I think puts it in its proper place.

The four large moons of Jupiter are interesting to watch in a telescope as they circle the giant planet especially when one (or more) cast shadows onto Jupiter’s disk. Through our telescopes, we can actually see the shadows produced by these moons during their eclipses and can follow the dark blots as they pass across the face of the planet.

Our own Moon also casts a shadow, and being on the surface of the Earth, we have the opportunity to put ourselves inside the shadow where it appears. All this comes together during a total solar eclipse.

The solar eclipse on Aug 21 is the most spectacular astronomical event of the year and will probably be seen by millions of people. For about an hour and a half, the Moon’s 110 km wide shadow will travel diagonally across the USA from Oregon to South Carolina. Two dozen BAS members will be watching near Grand Island, Nebraska where we reserved campsites a year and a half ago. Many more casual observers in the 11 states the path crosses will likely clog up the highways to the shadow path on that date, -one estimate predicts up to 7 million people may try to get to the narrow track at eclipse time.

The Moon may be large, but it’s shadow dwindles to a tiny dot by the time it reaches the Earth and only in that very narrow path, can one say that they have “caught” the Moon’s shadow. (it’s more like letting it pass over you for the few minutes of totality). I “caught” my first Moon shadow in the clear, cold sky above Gimli, Manitoba on Feb 26, 1979, over 38 years ago, and I still get goose-bumps on the back of my neck when I think about it. The shadow could be seen moving our way and then it swept over the group creating a 360* sunset. I could not help but shiver, not from the Manitoba cold but from the experience itself. And up in the sky an incredible sight! The corona, the outer atmosphere of the Sun appeared, wispy streamers like white, irregular flower petals, surrounding a black hole, the silhouette of the Moon. More shivers!

In the Bruce-Grey area on Monday, Aug 21, only a partial eclipse will be seen since the Moon misses crossing the centre point of the Sun. The maximum is at 2:30 pm DST, when 70% of the Sun will be covered.
The partially eclipsed Sun will NOT BE SAFE TO VIEW without solar eclipse glasses like those available from FotoArt or from suppliers like Rainbow Symphony or American Paper Optics online. SkyNews magazine July/Aug issue came with a pair as an insert and it may still be available at local outlets. Also a #14 (not #12) arc welders filter will provide safe viewing. Please note, none of these filters are to be used with binoculars or telescopes, they are for naked eye viewing and only for short intervals. Please be careful with your eyesight!
First contact last contact

From Owen Sound, some part of the Moon’s silhouette will be visible on the Sun from 1:08 pm DST to 3:45 pm DST. If you are further north or south, times may vary by several minutes, -first contact occurs later if you are north of Owen Sound’s latitude and earlier if you are south.

mid-eclipse

So if you are stuck on this local part of Earth on Monday Aug 21, at least have a quick look at the Sun with solar eclipse glasses around 2:30 pm or so. And on Sep 6 at 7 pm, you are welcome to join BAS at the Fox Observatory as we recap the event from the path of totality.
Here’s hoping for cloud-free skies (all over North America) on Aug 21!

Dark Skies -Bright Stars, PLEASE!

By: John Hlynialuk

Amateur stargazers, cottagers and nocturnal animals are really lucky to be living in Bruce and Grey counties. Stargazers have dark skies and bright stars to observe. Cottagers (away from overly-lit urban areas) have dark skies and a beautiful swath of summer Milky Way overhead when the family is out cooking weenies over a campfire. Nocturnal animals that live near or in the Bruce Peninsula Biosphere Reserve have nighttime darkness to which they have adapted over the millennia -no pesky streetlights making them well-lit targets for predators.

The common theme here is, of course, dark skies and a natural environment. Many places like the Bruce Peninsula Fathom Five National Park and the Bluewater Outdoor Education Centre are still mostly pristine environments and from a stargazing perspective, protected from unnecessary nighttime lighting, be it incandescent, florescent, or the most recent abomination, LEDs.

Keeping a dark nighttime environment is crucial for human health. Just google “Dark skies human health” for dozens of medical studies that support this contention. Fortunately, in the Bruce/Grey area of Ontario, nighttime over-illumination is only a problem in a few localities. Furthermore, efforts to preserve the dark nighttime environment locally have borne fruit. There are 17 Dark Sky Preserves in Canada, and four of them are within a 160 km radius of Wiarton. The four include Bruce Peninsula National Park near Tobermory, the Bluewater Outdoor Education Centre near Wiarton, Gordon’s Park on Manitoulin Island, and Torrence Barrens near Gravenhurst. Yes, locally we are optimistic about controlling light pollution, but the planet-wide scene is decidedly much the opposite.

Not to mince words, overall, we are losing the battle to control nighttime illumination. You just have to look at an image of the Earth at night from space to see how bright it is at night. Satellite cameras detect the totally wasted light sent upwards. Much light reflects back down from dust particles and water vapour and brightens the sky generally. The effect is visible even in rural areas as the visibility of faint objects is reduced. Even from 100’s of kilometres away, the light domes over our cities cast an orange glow into the sky. Anywhere near or within a large city, the glare from overhead lights is extreme, allowing only light from the Moon and bright planets to get through. Fainter objects are totally invisible.

[Click on image below to download a copy]

F3.large
Image from study published in Science Advance magazine.


A study in 2016 authored by Fabio Falchi of the Light Pollution Science and Technology Institute in Italy and Chris Elvidge of the US National Oceanic and Atmospheric Administration (along with other international scientists) has found that in the USA, for ex., 80% of the population cannot see the Milky Way from where they live. The percentage is the same in urban Canadian areas like those along the Windsor to Montreal corridor. The darkest skies on our planet are of course, in areas like the Canada northland and in countries like Madagascar, the Central African Republic and Greenland, where everyone can see the Milky Way by just stepping outside.
[The original paper is available here:
http://advances.sciencemag.org/content/2/6/e1600377 ]

I am lucky to be able to see the Milky Way from my back yard because my house blocks the city lights to the north but there are sickly yellow-orange glows along parts of the southern and eastern horizon. Of course, like other large towns and cities, no Milky Way is visible from downtown Owen Sound. The situation locally has gotten worse in the last few years because the city recently replaced the majority of their streetlights with LEDs. These are certainly more economical and do have proper shielding to prevent upward light spill, but the overall level of lighting has increased approximately 30%, so the total light reflected from the ground upwards (especially in winter) has increased by a large fraction. Many people have commented to me that they find the lights at night overly bright. I agree and have the measurements to prove it.

On Saturday afternoon, May 27, there is an opportunity to visit a Dark Sky Preserve during the Open House at the Bluewater Outdoor Education Centre. The Bluewater Education Foundation and Ducks Unlimited Canada are co-sponsoring this event and it is open to everyone. You are welcome to come to the Outdoor Ed Centre (maps on the BAS website given below) and enjoy the wagon rides, birding, hikes, and fun kid activities like critter-dippin’ and face painting. Events start at 1 pm and will include solar observing with (safely-filtered) telescopes from the Fox Observatory. Everyone is welcome and after the Sun goes down, the observatory will be open for some dark sky viewing. Come and see what a Dark Sky Preserve is all about.

Check www.bluewaterastronomy.com for more information.

UFO's -NOT!

UFO’s -a personal experience
by John H.

Considering that I have been a stargazer most of my adult life, you might think that I have seen a lot of strange things in the sky. The answer to the question: “Seen any UFO’s?” is pretty simple: “No.” This lack of UFO sightings on my part is perhaps remarkable. After all I am out two or three times a week (weather permitting) looking at the sky with a variety of telescopes and cameras. I have taken close to 5 000 pictures on film, and more than three times that number of digital images. This is by no means unusual for a die-hard stargazer like myself and I number myself among a million or more amateur astronomers around the world. The USA has about half of those and Canada probably has close to 50 000 or so.

There are rarely reports of unusual objects (UFOs) from this large group of sky-savvy folks. The simple reason is that people who know the sky well can identify 99.99% of what they see as natural objects. These include ordinary aircraft, bright glints of sunlight from satellites or moving points of light such as the International Space Station, meteors of various brightnesses, some exploding at the end, bright planets like Venus (the single object most often mistaken for a “flying saucer") and even bright stars refracting the colours of the rainbow when their light passes through the thick air near the horizon. I have seen Sirius, for example, flashing colours across the entire spectral range from red to violet.

There is, however, one incident that had me stumped, for a little while anyway. If I had not used
all of my senses, I would be puzzled to this day. But it took only a simple observation to get an answer for the UFO that I saw. (it is now an IFO on my list, -an Identified Flying Object).

It happened in May 1980, in Thompson, Manitoba chaperoning a group of Bruce County students who had won the right to compete in the Canada-Wide Science Fair. I had a great experience with that wonderful group of young people and several came back home with Canada-Wide awards. We were housed for several nights in a college residence and at night, (after my charges were safely tucked away in their rooms...) I would go out for an hour or two of stargazing and photography. The residence parking area (within sight of our rooms) was an ideal spot to view the northern sky and I came home with some good photos of aurora and some interesting planet groupings in the western sky. I was particularly impressed with how low Polaris was compared to its 45° elevation back home.

IMG_152399_611K
Venus appeared in the sky of Thompson Manitoba in May, 1980 and no one mistook it for a UFO. Photo by John H.

My UFO experience started rather simply with a moving point of light that was just like many meteors I had seen before. Then another one appeared from the same direction and split into two at the end of its path. “Wow”, I said, “a fragmenting meteor!” I went back to gazing at the stars and it happened again, but after the trail split, the two separate trails started criss-crossing each other! Meteors breaking up do not do this, so was this a UFO mother ship and scouts?. More trails appeared, even three together and some performed the same crossing pattern as before. I was stumped, but then I started actually hearing the meteors! -a faint, swish, swish sound in the quiet of the night. It sounded just like the beat of wings of low-flying birds.

In fact, these UFO’s
were birds. The faint light was reflection from feathers covered with chemicals that make them water resistant and which also fluoresce in the UV light, spilling upward from the streetlights below. The flight paths of birds often cross from our perspective on the ground.

If I had only seen and not heard the event, it would have gone down in my book as a genuine UFO.

UFO sighting statistics always have a small percentage of UFO sightings that remain “unexplained”. My contention is that if more details of the sighting were available or if an experienced sky-watcher was observing, most, even all, sightings could be explained. I know this will not satisfy those folks out there who want there to be extra-terrestrials visiting us, but my own experience and that of thousands of amateur astronomers familiar with the sky indicates otherwise.

Jupiter Viewing Starts!


If you have noticed a bright light in the eastern sky (perhaps while taking your pet for a walk) you are not alone. Venus in the west is gone (returning soon to the morning sky) and Mercury will not last long as a substitute evening star. Now we turn to the eastern sky to watch our next featured planet, Jupiter, a planet almost as bright as Venus, and in many ways much more interesting.

Jupiter is the largest planet of the 8 planets in our solar system (9 if you still pine for Pluto). Jupiter and our Sun constitute 99.99% of the total system mass and each has a gravity pull so strong that according to current theories, a major planet was prevented from forming in the space between -only jagged chunks of space debris, the asteroids, are found orbiting there. One Jove-centric pundit defined our solar system as “Sun, Jupiter and assorted debris”, and it is true that the “leftovers” don’t amount to much, mass-wise. Earth, of course, has water, an atmosphere, and conditions that allow living organisms to thrive, so it is pretty special. Jupiter is unique, too, but only because it is such an extreme contrast to our own beautiful world.

The gravity of Jupiter is over 2.5 times Earth’s so, if yours truly, at a trim 180 pounds, were on Jupiter, I would need to support 455 pounds just to stand up, -if there was any place to stand. A solid surface like that on Earth cannot be found on Jupiter, and what we see in telescopes are the tops of swirling white and brownish clouds of ammonia crystals and darker-coloured sulphur compounds. Below the clouds (about 50 km thick) is a mixture of very cold hydrogen and helium gas which gets thicker and thicker all the way to the “surface” of a strange ocean of metallic liquid hydrogen. The atmospheric pressure here would crush the strongest pressurized vessel from Earth. So if the gravity doesn’t kill you, the pressure will.

Exploration of Jupiter can only happen from orbit or floating/flying in the upper atmosphere, but even here spacecraft are severely challenged. Wind speeds reach 1600 km/h (10 times those in Earth’s jet streams), and lightning occurs in “superbolts” the equivalent of 100 of the terrestrial variety. Huge storms in the atmosphere of this huge planet are common, -one Jovian hurricane, the Great Red Spot (first seen in 1665 and raging still) is bigger than the entire Earth with wind speeds over 400 km/h (twice those of a category 4 hurricane on Earth). Even Jupiter’s magnetic field is huge, extending several million km into space, so we are lucky that we are 600 million km away, -it is a safe enough distance.

Jupiter reaches a point in our sky called opposition on Apr 7 when it is exactly opposite the Sun and highest in our sky at midnight. This is prime-time for Jupiter, when it is well above the turbulent air near the horizon. But if it is cloudy Apr 7, don’t panic. Planets at opposition are in good viewing position for a month before and several months after the opposition date. For the best views on any clear night, observe the planet when it is away from the disturbing air near the horizon. Summer star parties will obviously feature both Jupiter and Saturn, which itself reaches opposition June 15.

Jupiter Apr1 - Sep 1 2017

Jupiter is near the star Spica, the brightest star of Virgo, but Spica does not move, so use it as a reference point to watch Jupiter doing what distinguishes planets from background stars, i.e. wander. Jupiter slowly slips westward until June 8 (retrograding), then, in the summer, it starts back towards Spica. By the end of Jupiter-viewing in autumn, the pair will be setting in the west just after sunset, with Jupiter closest to Spica and right above it.

Observing nights at the Fox Observatory will certainly include views of Jupiter with its always-changing arrangement of 4 bright moons. These are even visible in binoculars, but true to its status as King of Planets, Jupiter has 63 more moons circling it, the most of any planet. By Jove, Jupiter really is an attention-getter!

John H.