Category: Urban Astronomy

Urban Astronomy – Mars/Jupiter Conjunction 05/29/22

Posted May 18, 2022

The night sky is pretty much a mystery to most City Dwellers.  The glare of city light drowns out all but the brightest stars – and planets don’t do much better.  If you are interested, I can tell you where to look to see these far-off worlds.  If you were not interested, you would have stopped reading after the first sentence. 

So, at this point, I know my audience. 

See Mars and Jupiter in Close Conjunction, Sunday, May 29 – around 5:30 AM Central Daylight Time

Sky Chart from Heavens-Above.com   May 29 at 5:30 AM CDT (UTM -5)

You can print out the chart and hold it with East at the bottom while facing East – to match up the planets with the chart.  Cloudy weather is probable, so  check in the days before and after, just in case.

Hasta Luego,

Steve

Urban Astronomy – Venus/Jupiter Conjunction 04/30/22

Posted April 27, 2022

The night sky is pretty much a mystery to most City Dwellers.  The glare of city light drowns out all but the brightest stars – and planets don’t do much better.  If you are interested, I can tell you where to look to see these far-off worlds.  If you were not interested, you would have stopped reading after the first sentence. 

So, at this point, I know my audience. 

See Venus and Jupiter in Close Conjunction, Saturday, April 30 – around 6 AM

Figure 1: As Close as It Gets

Urban Astronomy  April 19, 2022

Venus is the “skymark” for a collection of planets in the morning sky. 

  Look East before dawn to find Jupiter, Venus, Mars and Saturn lined up in the Southeast.  Jupiter is the lowest in the sky and second-brightest.  A bit higher is Venus – the brightest by far with Mars next and then Saturn.  See the sky chart below for reference.  If you print it out, the best way to use it is to hold it with “East” at the bottom and face East. 

Figure 1:  Skychart for April 19th from Heavens-Above.com

Don’t imagine that these planets are actually anywhere near each other. The diagram below should give the reader the “Big Picture”. The positions of the planets (including the one you are standing on). Figure

Figure 2: Yellow lines depict the “lines of sight” from an observer on Earth to the four planets. To give scale: The line from you to Saturn is almost a billion miles long.

Skymaps from Heavens-Above.com  

Solar System diagram from NASA Small Body Database Lookup

Ex Scientia, Trivia!

Steve

Urban Astronomy  April 19, 2022

Urban Astronomy – Comet Leonard 12/20/21

Posted December 20, 2021

The night sky is pretty much a mystery to most City Dwellers.  The glare of city light drowns out all but the brightest stars – and planets don’t do much better.  If you are interested, I can tell you where to look to see these far-off worlds.  If you were not interested, you would have stopped reading after the first sentence. 

So, at this point, I know my audience. 

Comet 2021 A1 – Leonard Dec 20, 2021

Leonard is even brighter – in fact much brighter – tonight. The current magnitude of Leonard is +2.3 (the smaller the number, the brighter – the comet was +4.6 yesterday and Saturn is +0.23 – VERY bright by comparison) so in the city, the Comet is visible and would be still better seen with binoculars. 

You may have heard the expression “by an order of magnitude”  – well this is over two orders of magnitude – OK?

Once again, do not use telescopes or binoculars to view the Sun – blindness will result!  I said “after sunset” so you should be OK if you listen to me. 😉

As is usual in these cases, the comet gets brighter not only because it gets close to the Earth.  It also gets brighter because it gets closer to the Sun.  The third brightening influence is the material that the closer sun vaporizes.  That stuff makes a cloud around the comet and is it also partially blown away by what is called the Solar Wind – in a comet’s tail.

Figure 1, above shows the location to view, which is conveniently close to Venus, which is the brightest thing in the sky.  If you can see the Planet, you should be able to see the comet – although you may need those binoculars to do so. 

The sky is currently “mostly clear” (look-out-window method) in Houston at 3:22 PM.   Sunset is at 5:26 PM.  These next few days are literally the last chance to see Leonard, as it is on a hyperbolic orbit – which is a nerdy way to say that it will never return to the Solar System.  (Please see figure 2 below)

For readers not in the Houston area, just look for Venus (and Jupiter for orientation) and use the chart in Figure one above to find the comet.  We are lucky to be able to have the two brightest objects in the sky (now that the moon is not around in the early evening) as our reference points.

Hasta Luego,

Steve

Urban Astronomy – Comet Leonard

Unmasked and Unafraid

Posted December 19, 2021

The night sky is pretty much a mystery to most City Dwellers.  The glare of city light drowns out all but the brightest stars – and planets don’t do much better.  If you are interested, I can tell you where to look to see these far-off worlds.  If you were not interested, you would have stopped reading after the first sentence. 

So, at this point, I know my audience. 

Comet 2021 A1 – Leonard

There is another “Eyes Only Visible” comet to be seen in the Southwestern sky, just after sunset. The current magnitude of Leonard is +4.6, so in the city, it is only just visible and would be better seen with binoculars.  Once again, do not use telescopes or binoculars to view the Sun – blindness will result!  I said “after sunset” so you should be OK if you listen to me. 😉

As is usual in these cases, the comet gets brighter not only because it gets close to the Earth.  It also gets brighter because it gets closer to the Sun.  The third brightening influence is the material that the closer sun vaporizes.  That stuff makes a cloud around the comet and is it also partially blown away by what is called the Solar Wind – in a comet’s tail.

Figure 1, above shows the location to view, which is conveniently close to Venus, which is the brightest thing in the sky.  If you can see the Planet, you should be able to see the comet – although you may need those binoculars to do so.  

We have had very cloudy weather here in Houston (today, Dec 19) is “Mostly Cloudy” at 4 PM, changing to “Cloudy” around Sunset at 5:26 PM.  Tommorow at Sundown the prediction is “Mostly Cloudy” and the comet will have moved slightly relative to Venus.  These next few days are literally the last chance to see Leonard, as it is on a hyperbolic orbit – which is a nerdy way to say that it will never return to the Solar System.  (Please see figure 2 below)

Figure 2. Comet Leonard is diving through the Solar System, never to return.

For readers not in the Houston area, just look for Venus (and Jupiter for orientation) and use the chart above to find the comet.  We are lucky to be able to have the two brightest objects in the sky (now that the moon is not around in the early evening) as our reference points.

Hasta Luego,

Steve

Urban Astronomy April 6, 2021 (about 0630)

Published April 5, 2021

The Earth has gone around the Sun again and Jupiter is in the morning sky once more.  The Urban Astronomy Cursor (AKA, The Moon) is again indicating that planet around 6 to 7 AM.  Shortly thereafter the Sun rises.  Readers will remember that the “last time around” Jupiter and Saturn were close neighbors.  Now more distant, they are. You will find Saturn at a 45 degree angle up and to the right from Jupiter.

The waning crescent Moon points out Jupiter and Saturn.

Urban Astronomy – The Scale of the Solar System

Posted Dec. 29, 2020

I read regularly at AmericanThinker.com (AT) and they have published a few of my articles and blog posts. (that last one is not mine, but from some other author with a similar name)  In a recent AT article What I Learned from the Christmas Star by Mark Deutschle that author wrote:

“…we were looking at Jupiter and Saturn, which are over 700 million miles from Earth.”  That is an oversimplification that implies that those planets are actually near to each other.  They are not.  They only happen to be in the same part of our sky.

Also, in a conversation with my Number-One Son about science fiction, and actual astronomy, he asked me how the batteries were charged on the probe that landed on Titan (the large moon of Saturn).  The answer (They were not charged, they died after a few hours.) surprised him.  Why not solar panels?  Because Saturn is (on average) about ten times as far from the sun as Earth.  (You might have read this in my article called A Nice Place to Visit, But…)*.   That means that the sunlight received at Saturn is only one percent as intense as we get here on Earth.  Add the cloudy atmosphere of Titan and less than 1/10th of one percent (1/1000th) makes it to the surface of Titan. 

You might think that the son of an Astronomy Nerd would know all this.  It might surprise you to learn that my son does not listen in fascination to my every word.  If you, indeed are surprised, I have a premonition that you are, as yet, childless – or at least “teenagerless”.

*I have written another article, along those lines – meant for actual profitable publication.  If you are an editor and have any interest, let me know through the “contact” tab in this website and I can send a link and a password for you to read same.

I wrote all that so I could tell about the Scale of the Solar System.  Since distances of other planets vary due to their orbits and the Earth’s orbit, the way to keep this clear in your mind is summed up with one distance – 93 million miles (close enough) which is called one astronomical unit (AU).

Then remember these numbers:   0.4, 0.7, 1, 1.5, 5, 10, 20, 30 and 40 – which are the distances from the Sun to each of the planets in Astronomical Units.

If you want to know the distance in miles, multiply each of the nine numbers by 93 million.

So:

The Earth is right now on the opposite side of the Sun from both Jupiter and Saturn.  The distance from Earth to Jupiter is 6 AU’s and to Saturn is 11 AUs.  The distances in miles are 465 Million and 1023 Million.  The average of those two is 744 Million.  So, Mr. Deutschle rounded that average down to 700 million and said “Both were farther”.  In fact, Saturn is over twice as far as Jupiter and the maximum distance involved with those three planets is over a billion miles

Below is a Solar System diagram (from JPL Small body dataset browser) of the sun and planets that helps to visualize the Christmas day configuration of these three planets.  In this oblique view, you can see the actual situation

Deutschle’s  point in his article was that the Universe is large and majestic.  So, to appreciate the Solar System even more, we can say (since Neptune is 30 AUs from the sun) that it is 60 AUs in diameter – or Five and a Half Billion Miles. You might think that the popularity of the word “billion” started recently – with the National Debt.  Not so, neighbors!  Astronomy Nerds were in “billions” territory more than a century ago!  In fact, we knew the distances to some stars were in light years early on and the very nearest is Proxima Centauri at 4.24 light years or 1.31 Parsecs or 268,400 AU’s or 25 Trillion miles.  We got to Trillions long before any of those corrupt, big-spending politicians!


Hasta Luego,

Steve

Urban Astronomy – Orion

Posted December 21, 2020

The night sky is pretty much a mystery to most City Dwellers.  The glare of city light drowns out all but the brightest stars – and planets don’t do much better.  If you are interested, I can tell you where to look to see these far-off worlds.  If you were not interested, you would have stopped reading after the first sentence.  So, at this point, I know my audience. 

By the way on the date of this post, you should go out shortly before sunset and look for the Jupiter/Saturn Conjunction in the Southwest sky. Don’t look at the Sun, OK?

By the way, on the date of this post, go out shortly before sunset and look for the Jupiter/Saturn Conjunction.

UrbanAstronomy-all posts

So far, I have used the moon as a cursor to point out the planets Venus, Mars, Jupiter and Saturn.  This is four of the five “eyes only” planets and since Mercury is so elusive, we have pretty much run out of subjects.  There is other stuff in the sky, of course and we might just as well look at those.   

As stated in my prolog for this series, the night sky is a mystery to city dwellers and they might find stars interesting.  Why – you may ask – would I be interested in points of white light that never change?  Long ago, people were interested in stars because they clearly documented the progress of the seasons.  If you are a subsistence farmer (and most people were) you had a vested interest in knowing when to plant and when to harvest your crops. 

As these farmers – and later astronomers – studied the stars, they came to know that they are not all the same color and they actually do change – at least some do.  Furthermore, a few of the stars are not actually single points of light, but are surrounded by luminous gas and dust.  Some look like single stars but – under closer observation – are actually double or triple stars.  Some are clusters of stars with likewise interesting traits.

So, this time I’ll send you out to look at the moon and then direct your attention at the constellation of Orion.  The date is December 28, 2020 and time is 2100 (nine PM).  This is Houston and US Central Standard Time, but around this date, if you can find the moon, after sunset, you should be able to find the constellation.  Orion is known for its three bright stars in “Orion’s Belt”, as well as its two brightest stars, Betelgeuse* and Rigel.  You will see them labeled on the skymap, below.

*You may wonder how to pronounce this.  As a young elementary school student, I did too.  Nobody around the elementary school knew either and I called it, “bet” (wager) “tel” (as in telephone) “geeze” (as in geezer).  With accent on the wager.

Nobody had the knowledge to say otherwise until a college Astronomy professor corrected me.  The word sounds just like “Beetle Juice”.

Steve:  Sorry, I didn’t know!

Prof:     It’s OK Mr. Campbell, nobody does at first.”

Obviously, I was not the first ten-year old Astronomy Nerd.

As you see, I have marked Orion with an arrow from the moon to Orion (that I have apparently drawn with a blue crayon).  Also, please note the “A” that I have placed to point out an object to be discussed later.

I will also post a time-lapse photo I made of this region of the sky.  It shows about half of Orion.  I could show you the whole constellation, but this picture was photobombed by a passing helicopter.  You can see that the aircraft had a constant white light and a flashing red one.  I could probably take pictures every night for a year and not capture something like this – that happened by accident alone.

This 10 or 20 second exposure was taken in early 2020.  Of the three stars in Orion’s Belt, you see two, below the big yellow “2”.  I have pictures with all three, but no helicopter.  The big yellow “1” annotates Betelgeuse, the red-hued star that is the brightest of all in the constellation and referred to as “Alpha Orionis” – meaning the brightest star in Orion.  The big yellow “3” shows you Rigel, the second brightest star in Orion (Beta Orionis).

“Hold on there, Laddybuck!” you are saying, “I can clearly see that Rigel (Yellow Three) is much brighter than Betelgeuse.”

At that particular time, it was, indeed.  Betelgeuse is a variable star  and pulsates – not as extremely as that red helicopter beacon, but at least enough to make you all say, “Hold on there, Laddybuck!”

And, in fact this particular dimming of Alpha Orionis was unprecedented.  Please see chart below:

Betelgeuse Brightness 1965 – 2020

As you can see, Betelgeuse’s drop in brightness was the most severe in many decades.  There was actual serious speculation that Betelgeuse was collapsing.  When red supergiant stars (of which Betelgeuse is one) collapse, the result is a catastrophic explosion called a Supernova.  Is Betelgeuse headed that way?  If so, the “Conventional Wisdom” is that – because the star really, really big and is so close to our Solar System, a Betelgeuse Supernova might easily be visible in the daytime…perhaps for months.

I looked up some more recent data and found the answer…Maybe – but not immediately.

Betelgeuse Brightness 9/2018 – 5/2020

You see that the brightness has recovered completely. 

However, who is to say that this unprecedented drop will not be repeated?  It may take some extreme oscillations to trigger the Supernova.

Latest numbers show Betelgeuse dimming again.

I hope you find this interesting.  😉

What’s that?   The “A” on the skymap?

I’ll get back to you on that one…

Hasta Luego,

Steve

Urban Astronomy – Conjunction in December

Posted December 2, 2020

The night sky is pretty much a mystery to most City Dwellers.  The glare of city light drowns out all but the brightest stars – and planets don’t do much better.  If you are interested, I can tell you where to look to see these far-off worlds.  If you were not interested, you would have stopped reading after the first sentence.  So, at this point, I know my audience. 

Urban Astronomy

Background: Occultations

Jupiter and Saturn were already close together in November.  Now they are bound for near-occultation in December.  An occultation is when one astronomical body passes in front of another.  It happens quite frequently with the moon passing in front of stars and sometimes planets.  Occasionally planets and asteroids do so.  Long ago, before space telescopes and sophisticated image processing, these occultations were used to characterize the shape and size of asteroids by distributing observers across the planet to time the disappearance and reappearance of stars as the asteroid passed in front of same.  To understand this, imagine the shadow cast by asteroid across the face of the Earth.  The durations observed by various locations measures the shadow precisely.  This was done in the case of near-Earth asteroid Eros and its shape was determined to be something like a fat cigar.

Much later, Eros was visited by a space probe called NEAR (Near Earth Asteroid Rendevous).  You see below that the shape was confirmed.

Near Earth Asteroid Eros: (remember, I said “something like…”)

Explanation

I told you all that because it is interesting.  But that won’t happen with Jupiter and Saturn.  Rather, they will be so close in the sky that it will take near-perfect vision to see them as two objects.  Once again, I will use the moon as a sort of cursor to point out this event.

On December 16, 2020 at 6PM (this is Central Standard Time in Houston) you will see – low in the Southwestern sky –  a thin crescent moon near the pair of planets that will appear only a fraction of a degree apart.  Please remember that your thumb at arm’s length covers about one degree of sky.

Illustrations

An image of what you will see from The December 2020 Great Conjunction  By Graham Jones, appears below. 

A sky map – from Heavens-Above.com –  like those I’ve shown before, appears below:

Epilog

Keep watching over the following week – you will not have the moon as a landmark, so, remember where Jupiter and Saturn were on the 16th and look there again. On December 21, the two will be about one tenth of a degree apart.  This close an approach of the two planets last happened on July 16, 1623.

Hasta Luego,

Steve

Artist’s conception:   https://www.timeanddate.com/astronomy/planets/great-conjunction

Heavens-Above (Houston):   https://heavens-above.com/main.aspx?lat=29.7382&lng=-95.6329&loc=13811&alt=0&tz=CST

Heavens Above (Oslo):     https://heavens-above.com/main.aspx?lat=59.9133&lng=10.739&loc=Oslo&alt=0&tz=CET