An old Standby

 

In these days of Covid-19, getting together with others to have a look at the night sky is an exercise of don'ts: don't get too close to each other, don't touch or look through the telescope, don't come without a mask, etc. On-line meetings are substituting for the in-person ones. My wife and I are practicing voluntary self-isolation (we are old enough to make this necessary). That means that I'm confined to observing the sky from our home. 

 

We live in a highly light-polluted and horizon-limited area. The smoke from the wildfires in the U.S. has added to the lack of visibility of the stars. There were just a couple of acceptable evenings which led me to look for one of my favorite objects in the sky: The Whirlpool Galaxy not far from the end of the Big Dipper's handle. In a dark sky, M51 can be seen in larger binoculars as a small, diffuse patch of light.

I used my 15x50 Canon stabilized binoculars to try and see it. I did not detect it at all. The gray sky here made it an impossibility.  In earlier years M51 was easy to see from our house; high-rises, new and under construction, now limit our horizon and add much light pollution.

I decided to get my "M51 fix" by posting an image I took a couple of years ago by connecting my computer to Slooh.com to use one of their remotely accessible telescopes and take a picture; below is the result:

 

 Messier 51 

Image taken through the wide-field, 17 inch remote-control Slooh.com telescope located at the Institute of Astrophysics of the Canary Islands. 

 Some history (from Wikipedia):

"What later became known as the Whirlpool Galaxy was discovered on October 13, 1773, by Charles Messier while hunting for objects that could confuse comet hunters, and was designated in Messier's catalogue as M51. Its companion galaxy, NGC 5195, was discovered in 1781 by Pierre Méchain, although it was not known whether it was interacting or merely another galaxy passing at a distance. In 1845, William Parsons, 3rd Earl of Rosse, employing a 72-inch (1.8 m) reflecting telescope at Birr Castle, Ireland, found that the Whirlpool possessed a spiral structure, the first "nebula" to be known to have one. These "spiral nebulae" were not recognized as galaxies until Edwin Hubble was able to observe Cepheid variables in some of these spiral nebulae, which provided evidence that they were so far away that they must be entirely separate galaxies even though they are seen close together. The advent of radio astronomy and subsequent radio images of M51 unequivocally demonstrated that the Whirlpool and its companion galaxy are indeed interacting."

There are still some uncertainties regarding M 51. For instance, the distance of it is variously quoted as 31 million light years (NASA), Wikipedia says about 23 million, universetoday.com states 19 to 27 million light years. A location chart is shown above. A dark sky will allow for M 51 to be seen in 10x50 binoculars as a faint patch of light. An 8" (200mm) telescope will begin to show its spiral structure.

Messier 51 is circumpolar, so it is accessible for most of the year. At this time of year, the Big Dipper skirts the northern horizon through the night. M51 is therefore moves along above the northern horizon as well. Give it a try under a dark sky anyway. Its position will improve as we progress through winter and into next year.

At last, a naked-eye comet

After a fairly lengthy time of "comet starvation" we finally had an appearance of a comet which, while not super-bright, was visible to the naked eye. Comet Hale-Bopp in 1997 was the last one to be so visible. Using binoculars brought out a pretty impressive view of this "new" comet  (NEOWISE C/2020 F3), even in the light-polluted sky in our part of the city. Without the coved-19 pandemic in progress, the RASC would have held many public astronomy meetings; now this can only be approximated virtually (i.e. Zoom, and similar applications).

NEOWISE C/2020 F3 was discovered on March 27, 2020 by NASA's "Wide-field Infrared Survey Explorer" space telescope, which has been in orbit for about 11 years. You can see the source of the comet's name. This is a very productive telescope, which has discovered thousands of astronomical objects. Look up details in WIKIPEDIA under its name. 

At the time of discovery Neowise was a faint blob of magnitude 18, at twice the Earth's distance away from the sun. From position measurements made of Neowise C/2020 F3's orbital positions as it moved towards the Sun, a 4,400 year long orbit was calculated. By now, Neowise has been moving away from the Sun for some time, and is well past its closest approach to Earth on July 22. That means that its brightness is diminishing. The close approach to the Sun resulted in a change in the comet's orbital shape. The orbit is now longer and the comet has been recalculated to return in about 6700 years, or so (I won't wait for it).

Comet Neowise C2020 F3

This picture was taken on July 19, around 10:30 PDT with a Canon 60Da camera from our lawn next to the house. It's a 10-second exposure (f8, ISO 800). A slightly enhanced image, it is meant to show the comet better from our severely light-polluted area. It was easy to see with the naked eye. 

As the comet gets fainter, more and more telescope power will be needed to view it directly; photography, and the Hubble space telescope will be able to follow it for a longer time. By the third of August, the comet had faded to about magnitude 7, it was a faint hazy patch in my 10x50 binoculars, and I could not discern a tail. It was definitely no longer a naked-eye object. The Moon was almost full, and, in addition, the sky was somewhat hazy. Added to the light pollution in our area, this made viewing the comet less than ideal. 

 

Under similar conditions, Neowise was still visible in my 15x50 Canon stabilized binoculars in the evening (around 11pm PDT) of Aug. 9, between stars 70Virginis and 71Virginis. Directly looking at it showed a very faint, fuzzy, barely noticeable patch. Averted vision made it more readily perceived. The difficulty seeing it made for more fun to search for and trying to find it. Neowises's apparent motion is now relatively small, due to the relationship of the Earth's and the comet's respective orbits. It's like we were passed by a train, and we can see it down the track, getting smaller and smaller, but not moving sideways much.

Is the sun getting more active?

Lunt H-alpha telescope

(Click on picture for a larger image)

Recently (Jun 28), I set up my Lunt solar-observations-only telescope (above - it contains the proper Hydrogen-alpha light filters to cut the sunlight to the correct, safe level). I was hoping to see some activity. In the last couple of years there has been very little of that. We may just have gone through a minimum of the eleven year sun cycle. The state of the solar cycle is determined by solar observatories world-wide, counting the number of sun spots over the years.

Looking through my solar telescope, the sun did show a number of prominences which had also been absent for a lengthy period. I did not see any sunspots, though. There were a few dark streaks; these are prominences which we see "from above". They are just like the ones we see at the sun's edge, but they originate on the surface away from the edge. They look darker because, as they move away from the surface, they cool down and therefore emit a little less light. This is obvious when looking at prominences at the edge of the sun, which are also fainter than the sun's surface. Here is a picture I took of the sun some years ago; it is similar to what I saw on Jun 28.

The Sun in H-alpha light

(Click on picture for a larger image)

The diameter of the sun is 104 times that of earth. If you mentally string 104 earths across the sun and compare the size of the prominences in the picture, it becomes obvious that the prominences easily exceed the size of the earth. The hydrogen gas and plasma of which the prominences are composed follow magnetic lines of force. Magnetism and its constant changes are a major part of the sun's activity. I think of the sun as a magnetized cauldron. Solar material is constantly being stirred and ejected and, if the force of the ejections are strong enough, this material will disperse into space. The earth is often in the path of such material; northern and southern lights are one effect. There are also interferences with wireless communications and power grids. Astronauts in space have to be protected as much as possible from this powerful radiation.

I think that we are finally entering the next solar cycle. The cycle should actually have a 22 year length. When sunspots appear as a pair, for instance, the leading spot (in the direction of the sun's rotation) could be magnetic north polarity. The following spot in the pair then has the south polarity. After the next minimum occurs, sunspots in the next eleven year period reverse their paired relationship polarity (south leading, north following). Nobody has a good explanation for the cause this characteristic. The next eleven-year period after the preceding two then exhibits sunspot pairs with leading north and following south polarities again. Many other solar phenomena, such as solar flares, coronal loops, solar radiation, etc. are all synchronized in some way with these magnetic changes. There are many reasonable theories, but we have limited factual knowledge about what happens inside the sun. The eleven-year cycle has been observed for many centuries (the last 400 years are quite well documented).

Over the last 10 years, NASA's Solar Dynamics Observatory, in a geostationary orbit around earth, has collected around 425 million gigabytes of data (one image every three quarters of a second, according to NASA). This effort has contributed much to an increased knowledge of how the sun interacts with earth, and the solar system.

Here is an excerpt from Wikipedia:

Solar cycle

The solar cycle or solar magnetic activity cycle is a nearly periodic 11-year change in the Sun's activity measured in terms of variations in the number of observed sunspots on the solar surface. Sunspots have been observed since the early 17th century and the sunspot time series is the longest, continuously observed time series of any natural phenomenon. Accompanying the 11 year quasi-periodicity in sunspots, the large-scale dipolar magnetic field component of the Sun also flips every 11 years, however, the peak in the dipolar field lags the peak in the sunspot number, with the former occurring at the minimum between two cycles. Levels of solar radiation and ejection of solar material, the number and size of sunspots, solar flares, and coronal loops all exhibit a synchronized fluctuation, from active to quiet to active again, with a period of 11 years. This cycle has been observed for centuries by changes in the Sun's appearance and by terrestrial phenomena such as auroras.Wikipedia

If you have appropriate equipment - proper solar filters for your general-purpose telescopes - or if you follow the rules of projecting the sun onto a screen, you may want to check for the visible state of sunspots over the next years. WARNING: Never look at the sun directly without correct filters through telescopes, binoculars, or even the naked eye. Damage to the eye, possibly including blindness, can be a result, either instantly or as vision problems later in life. 

Solar observations and photography are a great way to do astronomy - you can have your regular sleep hours; no need to stay awake for much of the night. There is much information about the sun (and its effects on the earth) in the RASC's Observer's Handbook (starting on page 184 of the 2020 edition). Try it, you might like it.

A close, unheralded neighbour

Not very far in the night sky from the Andromeda Galaxy (our sister galaxy) you can find M33. It is about 2.9 million light years distant from our galaxy, but not often a target at public astronomy nights (i.e. SFU's Starry Nights). Under the best observing conditions - no light pollution and a really dark sky - this galaxy, the third largest in our local group, is visible to keen, dark adapted eyes without optical help. A pair of binoculars is a great help because M33 is a diffuse object - the amount of light it produces is distributed over an area about four times the apparent area of the Moon in the sky (see pages 317 and 333 in the Royal Astronomical Society's Observers' Handbook for the year 2020). You can understand that the sky conditions required for its visibility are unlikely to be met in a light polluted city night sky. Below is a photo I took via remote access to a Slooh.com telescope

Some on-line star applications call it the Pinwheel Galaxy. That is not generally accepted, because the name is normally given to M101, a galaxy in the constellation of the "Big Dipper", about 21 million light years away.

M33

M33 seems to be a satellite galaxy of the Andromeda galaxy (M31). It may perhaps be on a rebound into that galaxy. The velocities, proximity, and indications of gravitational interactions make that a possibility. A very detailed entry regarding M33 and M31 and the interactions between them can be found in Wikipedia by searching for the "Triangulum Galaxy".

Here's an excerpt from Wikipedia regarding the relationships between these two galaxies:

Relationship with the Andromeda Galaxy               

   (illustration from Wikipedia)

Triangulum on the collision paths of Milky Way and the Andromeda Galaxy. M33 appears to be linked to M31 by several streams of neutral hydrogen and stars, which suggests that a past interaction between these two galaxies took place from 2 to 8 billion years ago, and a more violent encounter will occur 2.5 billion years in the future. 

The fate of M33 was sketchy in 2009 beyond seeming to be linked to its larger neighbor M31. Suggested scenarios include being torn apart and absorbed by the greater companion, fuelling the latter with hydrogen to form new stars; eventually exhausting all of its gas, and thus the ability to form new stars; or participating in the collision between the Milky Way and M31, likely ending up orbiting the merger product and fusing with it much later. Two other possibilities are a collision with the Milky Way before the Andromeda Galaxy arrives or an ejection out of the Local Group. Astrometric data from Gaia appears to rule out the possibility that M33 and M31 are in orbit. If correct, M33 is on its first infall proper into the Andromeda Galaxy (M31).

Here is an an excerpt from a (highly recommended) Stellarium Mobile planetarium map of the sky showing the relative positions of the Triangulum and Andromeda galaxies.

Stellarium Mobile app star map.

The above excerpt shows that several different scientific opinions are stated about M33. It's obviously an object about which a number of uncertainties exit. And yet, it is less likely to be shown as an object of interest at public astronomy nights (placed best in the sky in the autumn of the year). The reason is likely because public astronomy nights are usually set in or near a city, with light pollution making M33 hard to see. Usually, the planets, the Moon, and even the Andromeda Galaxy are the showpieces.

Are the weather gods mad at us?

It's been raining here for all of January, one day of no rain. February was not much better. From my astronomical point of view, it was the pits. I haven't taken part in one of SFU's Starry Night events since well before Christmas; Since October, most of the time the event had to be cancelled, mostly because of bad weather.

click on image for a larger view

Every now-and-then, there was a break in the clouds, allowing for a short glimpse of the evening and night sky. A few nights ago, the Moon and Venus appeared very close to each other. The picture shows a similar situation exactly 4 years ago today. At that time, Mars was also near the Moon, but not this time. I looked at the recent event a couple of nights ago, through some holes in the clouds, but before I could get my camera ready, the Moon and Venus were covered up again. Let me emphasize that the apparent closeness of these two planets to the Moon is strictly a perspective effect, caused by the particular position of our Earth in its orbit around the Sun. The actual distances are in the millions of kilometres.

Another way to do some "armchair" astronomy is to take some pictures of the sky, preferably as seen from other latitudes. To this end I use one of the remote-controlled telescopes at Slooh.com, with locations on the Canary Islands and Chile. Here's a black-and-white image of the Tarantula Nebula.

The Tarantula Nebula

I quote an excerpt from Wikipedia:

"The Tarantula Nebula has an apparent magnitude of 8. Considering its distance of about 49 kiloparsec (160,000 light-years), this is an extremely luminous non-stellar object. Its luminosity is so great that if it were as close to Earth as the Orion Nebula, the Tarantula Nebula would cast visible shadows. In fact it is the most active starburst region known in the Local Group of galaxies. It is also one of the largest H II regions in the Local Group with an estimated diameter around 200 to 570 pc, and also because of its very large size, it is sometimes described as the largest although other H II regions such as NGC 604 which is in the Triangulum Galaxy could be larger. "

One parsec is the distance at which the radius of the Earth's orbit around the sun is seen at an angle of one arc second, that distance is 3.26 light years. That means that even from the nearest star (4 light years away) the Earths orbital radius has an angle of less than one arc second. 

Let the weather gods do their thing - if you have a roof over your head, and a safe place to live, you can evade them anyway.

My start in Astronomy

This article begins with a part of my life which is germane to this story. I was born in Berlin about three months before the start of World War II. My father was conscripted into the war effort; military duty was mandatory. As a result, I saw very little of him and I have only sporadic memories of the occasions when he was on furlough. I remember the end of the war more clearly - being subject to the evacuations and bombings tend to sharpens one's mind. My father was taken prisoner of war in Russia at that time and I did not see him for about two years. When he came home in 1947, he was a very sick man and went straight into the hospital. I visited him many times during his stay there. On one of these visits he showed me a book he was reading. It was the German translation of a book about the Moon and the craters on it. The English title is: The Moon, Considered as a Planet, a World, and a Satellite. The authors are James Nasmyth and James Carpenter. The book was published in 1876.

At that time, the origin of lunar craters was still a subject of contention: either by volcanic activity or by meteor impacts (this question was finally resolved in the 1960's and, except for a few volcanic features, impact is the answer). My father showed me a picture of a lunar crater in that book; the picture actually showed a plaster of Paris model, made by the authors to show the lunar craters' volcanic nature. That picture has been in my memory ever since, as well as the title of the book, and its authors. The picture (see below) was the start of my interest in Astronomy; I don't know why it made such an impression on me. The book is actually my last memory of my father - he died a couple of months later. Nowadays, antibiotics would have saved his life, but they were non-existent at that time, especially not in war-torn Berlin.

I subscribe to the Sky and Telescope magazine. The December 2019 issue includes an article by Klaus Brasch, professor at California State University in San Bernadino. The article is entitled "Just Over a Century Ago"; in it, the book about the Moon I described above is mentioned, including the picture of the lunar crater that caught my original attention in 1947. I looked up Nasmyth and Carpenter on the internet, and immediately found a link to lynx-open-ed.org, which showed a dissertation on the two authors and their firm conviction of the volcanic origin of lunar craters, in the German version of their book. The book's title page and the lunar crater picture are shown below. Published in 1876, the original information in the translated text was already about 70 years old by the time I saw it.

Still an active member of the Vancouver centre of the RASC, involved in public astronomy days, using my telescopes, I never get tired of what the sky has to offer. Our current technologies have made astronomy into a science with connections to most other sciences, witness astrophysics, astrobiology, astrochemistry, quantum physics, computer science, geography and geoscience, space travel, etc. These connections often lead to interesting conversations with some of the people attending our star parties.

Professor Brasch's article certainly invoked a lot of nostalgia and makes me recount the many years I've enjoyed this hobby called Astronomy.

The Title Page of the Book

The picture of the simulated lunar crater which started my interest in Astronomy

Incoming comet

A couple of weeks ago, I took a picture through the remote Slooh.com telescope of a comet coming in from the outer reaches of the solar system, an area called the Oort cloud. This is a theoretical cloud, thought to extend from about 2,000 AU (Astronomical unit - the distance Earth to Sun - about 150,000,000 km) to 200,000 AU. It supposedly contains icy planetesimals (Wikipedia contains some detailed information).

Because its outer reaches are so far from the Sun, the planetesimals can be affected by the gravitational influences of other objects in our galaxy, and occasionally my be deflected towards our Sun. There is a reasonable chance that this comet is one such object. Here's the picture:

The name of the comet is Comet C 2018 W2 Africano. It's the fuzzy spot to the right of the dashed line. At the time of writing, the comet is moving at 50 km/sec towards the Sun and will be at Perihelion (closest to the Sun) on Sep.5 and closest to Earth on Sep 27. It may become visible in common telescopes and possibly even binoculars. Africano is currently in the constellation Camelopardalis. Look for more current positions in TheSkylive.com as time progresses

Africano will be closest to Earth on Sept 27 at around 75 million km from Earth.

King of the sky

Right now, the planet Jupiter is visible in the sky fairly low in the south in the evening. That's a comfortable and convenient time to observe it.

Jupiter is the most massive, and the largest planet in the solar system. All the other planets would easily fit into it's volume, with room to spare for a second set of solar system planets. We have not detected a solid surface on Jupiter yet; it is one of the two gas giant planets orbiting the sun (which one is the other?). It has the mass of over 300 Earths and around 1200 times the volume. with a diameter about 11 times that of Earth. It is a gas ball with a diameter of 143,000 km and consists of Hydrogen (about 90% and 9+% Helium, with traces of Methane and other elements). That's somewhat reminiscent of the Sun's composition; some people are calling Jupiter a "failed star".  However, in order to start the necessary nuclear fusion, Jupiter would have to have about ten times more mass. None-the-less, internal pressures are huge, enough to transmute Hydrogen and Helium into a liquid metallic state. At the centre, there may be an ice/rock core.

At opposition (i.e. now, August/September 2019) it is close to Earth, since Sun, Earth, and Jupiter are positioned almost in a straight line. That means that Jupiter is somewhat more than 4 Astronomical Units away from us (1 AU = 150 million km). Therefore, the light coming to us from Jupiter takes around 35 minutes to get here. Add to that the distance of Jupiter to the sun, and you get about 45 more minutes. Since all solar planets shine by reflected sunlight, we see Jupiter illuminated by sunlight which left the sun around 80 minutes (1 hour and 20 minutes) earlier.

Even though Jupiter is 5 times as far from the sun as Earth, and receives only 1/25th (square of distance law) of Earth's sunlight,  it is, after the Sun, the Moon, Venus, and the space station in orbit around Earth, the brightest object in the sky. That is due to its large diameter and relatively high reflectivity (albedo). It appears large enough from Earth to show some details in even a small telescope, as well as the Galilean moons. Even binoculars will show the dance of the moons around Jupiter. Larger telescopes, i.e. 4", 5", 8" and larger will show many always changing details on Jupiter, including the great red spot, a local storm as large as our Earth, undergoing quite drastic changes at this time. Jupiter turns once in just under 10 hours; constantly showing new features on its surface. The prominent cloud bands (mostly methane, some ammonia, water ice, traces of hydrogen sulfide) move at hundreds of kilometers/hr., they are far more energetic than the worst storms on Earth.

The Galilean moons orbiting Jupiter show relatively fast changes in relative positions. These are easily followed even in binoculars. The moons themselves are very different from each other. In order of increasing distance from Jupiter they are Io, Europa, Ganymede, and Callisto. Io is the most volcanically active of any planets or moons in the solar system, Europa has a very smooth, icy surface, possibly about 50km thick, with a vast layer of liquid water suspected underneath; Ganymede is the largest moon in our solar system, and has a quite complex composition; Callisto is the third largest of the moons around any of the solar system planets, after Ganymede, and Saturn's moon Titan. It has a heavily cratered surface. Only the largest of Jupiter's moons' features are visible through earth-based telescopes, and a large telescope is needed even for that purpose.

Look up The RASC's Observer's Handbook; Wikipedia and other astronomical on-line sources to contain more details for Jupiter-related phenomena.

People have spent a lifetime exploring Jupiter's system, and now the latest orbiting probes have sent back very detailed data.

Jupiter is truly the King of the Solar System planets.