Last night I saw Neptune...

... and thought about horizons.

("Last night" was actually last Saturday, but I did start to write this on Sunday.)

I grew up in Arizona in the 1950s and 60s. I took for granted that the horizon was 30, maybe 40 miles off, and the sky overhead was an infinite expanse of blue, blue, blue. I have vivid memories of topping a rise on one of my many family trips "up north" (to Payson or Flagstaff) and seeing revealed to my eyes range after range of mountains receding into the distance, each one 30 to 40 miles further away that the one in front of it.

How different it is here "back East" (as we used to say). Here the horizon is seldom more than one or two hundred yards away. On rare occasion (usually on a highway when you're paying no attention to such things) you might actually see a mile or more in front of you, but that's not so often and you're almost always distracted from enjoying the view by the need to watch the traffic right next to you.

I remember (when I was old enough to see the humor in such things) laughing whenever the weatherman said that "visibility is 10 miles at BWI" when I could plainly see the Moon overhead. I wanted desperately to shout at the radio, "No! Visibility is one quarter million miles!"

Neptune, as seen from Voyager II

Neptune is not the easiest target to find in the night sky, especially for someone like me who resolutely (some would say fanatically) eschews any and all electronic or mechanical aids to observing. My "finder scope" is a pair of 8X56 binoculars hanging round my neck. And, no matter how faint the objective, I stick with starhopping as my one and only method of navigation. Last night, it was find the Water Jar in Aquarius. From there, it was a fairly easy slide down to Lambda Aquarii, a star on the ragged edge of naked eye visibility in light polluted suburban Maryland. Then scan westward until I have a kite shaped asterism centered in my field of view. Neptune (in my mirror imaged view) hung off the left side - a tiny blue dot with just a hint of a disk. Switch to a higher powered eyepiece and the non-stellar nature of the dot became more apparent.

A quick check with the ephemeris and one finds that Neptune is currently two and three quarter billion miles from the Earth. Knowing full well that I will never see Pluto or any other Trans-Neptunian object with even my largest telescope (a 102mm refractor), I acknowledge that this electric blue dot in my eyepiece is the furthest thing I will ever see within our Solar System with my own eye. And I cannot tear myself away from it. I care not that there are hundreds of DSOs clamoring for my attention on this rare evening of perfect conditions. I can't get enough of this sight, this "dot".

I don't care how silly this sounds, but 2.75 billion miles I can understand. But interstellar distances? They defeat me. Oh, it's easy enough to say the words, "This star is 840 light years away," but we all know that such words don't really mean anything to us. The distance is simply too great to comprehend. And don't get me started on intergalactic distances!

I think I spent maybe all of 20 minutes drinking in the view and pondering what I was seeing. Then it was on to some double stars that I really wanted to observe that evening. But it was Neptune that haunted my thoughts all the way home, and Neptune that first came to mind the following morning.

We don't think much about horizons in suburban Maryland - not when houses, buildings, and trees restrict our view to a few yards around us. Stargazing can be a useful corrective to our everyday perspective on things.

Bring it on Home

Considering the appalling events of the past few days in our country, I cannot in good conscience continue to exist as though I am not part and parcel of the world around me. I cannot pretend that it is possible to isolate myself from what is happening to us. If our "hobby" of amateur astronomy has nothing to say to the terror and pain around us, then to hell with it! But... it has a lot to say, a lot to teach us, a lot to teach the world.

The following is a reposting of something I wrote several years ago for my now defunct blog, Celestial Pilgrimage. It is more relevant now than when I first posted it:

Everywhere I look in the sky, no matter what the direction nor how distant the object, whatever I see is either acting on or being acted upon by something else. It is either orbiting something else, or is itself being orbited. It is either attracting something else, or is in turn being attracted. It is either illuminating its surroundings, or is itself being illuminated. Nothing is alone; nothing exists in isolation. There is a bedrock fundamental something to be discovered here, and double stars are perhaps the clearest visible illustrations of whatever this is to the amateur astronomer.

Albereo

But allow me to digress a bit. I am forever amazed by how much the whole of my subsequent life has been influenced by the relatively short time I spent in the Army (1975-1979). I truly believe that I learned and grew more in those four years than in any other comparable length of time. From insignificant mannerisms (how I stand, what I do with my hands while walking, the fact that I always start off on the left foot) to fundamental ways I view the world, I keep finding bits and pieces of my Army experience down there in my subconscious, nudging (or pushing) me in one direction or another.

One really good example is foxholes. One of the first things we learned in Basic Training at good old Fort Ord, California, was the correct (that is, the Army’s) way to dig one. And if you have some picture in your mind taken from a host of cheesy WWII movies (hole in the ground, head and rifle sticking out) – get rid of it now. What we were taught was the DuPuy foxhole, named after the general who invented it. DuPuy had studied the carnage of Vietnam (remember, I enlisted only about 3 months after the fall of Saigon), and realized that everyone had been doing it all wrong ever since, well… ever since ever. The problem with firing out of a hole in the ground was that an advancing foe could fire right back at you. Thus the high casualty rate on both sides in a defensive battle.

General DuPuy (right) with Westmoreland in Vietnam

What DuPuy came up with was a system of mutually supporting two-man foxholes. “Buddy Teams” of two soldiers would each dig their own pit, piling all the excavated dirt directly in front of the hole, completely blocking one’s view straight ahead. When you were finished, you could fire diagonally to the left or to the right, but immediately in front of you was this great earthen berm, higher than your head. The end result was that, in a line of these DuPuy “Defensive Fire Pits” (to use the official term), each buddy team was responsible for protecting the team to either side of them, while their own defense was left in turn to those teams. To work, the system required complete trust between the teams. You yourself could do absolutely nothing to protect yourself, and concentrated all your attention and efforts on defending your neighbors.

Take a moment to ponder this. There is a really profound principle at work here. One that I think goes to the very core and fundament of our being - of the universe itself. It is the indispensable principle behind How We Must Live. As the poet Charles Williams so beautifully put it:

This abides – that the everlasting house the soul discovers is always another's; we must lose our own ends; we must always live in the habitation of our lovers, my friend’s shelter for me, mine for him.

The consequence of ignoring this is not just selfishness. It is not just missed opportunity or a life sadly lacking in color or meaning – it is a violation of the very nature of reality. To attempt to live for one’s self is an exercise in futility – you will fail.

One of the most awesome passages in the New Testament (for me, at least) occurs near the end of the Gospel according to Mark. Christ has been crucified, and various passersby taunt Him, asking why He doesn’t “save yourself and come down from the cross”. They conclude with the scoffing remark, “He saved others, Himself He cannot save”.

Wow. Read that again. What was meant as a contemptuous dismissal, as a cynical comment on apparent failure, turns out to be the very key to The Meaning of Life itself. We cannot save ourselves – we must rely on others. And it is up to us in turn to save them. This is what it means to be a Human Being. When we fall short of this principle, we fall short of and even deny altogether, our very Humanity.

Think about that, the next time you are admiring a particularly beautiful double star... or the next time someone shoots up a House of Worship out of fear of the "other".

Queen of the Gods!

Our best image of Juno, showing its highly irregular shape. 

Juno is 145 miles across at its widest.

Exactly 2 weeks from today will be your best chance to observe the third asteroid to be discovered (although by far not the 3rd largest) - Juno, named for the mythical wife of Jupiter.

Bottom line on top: This will be Juno's most favorable opposition since 2005, and will not be this close to the Earth again until 2031 (by which date I will either be 79 years old, or dead). This is due to Juno's highly eccentric orbit, worse than Mars, which makes for some oppositions being far more favorable than others. (See illustration below.)

Although assigned the number 3 due to its order of discovery, Juno is actually only the 11th largest asteroid (exceeded by Ceres, Vesta, Pallas, Hygeia, Interamnia, Europa, Davida, Sylvia, Cybele, and Eunomia). Where it does excel, however, is in its high surface reflectivity, which with an apparent magnitude of 7.5 makes Juno (at opposition) brighter than Neptune. No wonder it was one of the first asteroids to be discovered! Juno was even listed amongst the planets for 38 years before being demoted from that lofty status to mere asteroid in 1845.

Although opposition does not occur until the 17th of November, the 11th will be your best chance of actually seeing Juno, due to its near miss of naked eye star 32 Eridani (magnitude 4.46) on that night. Try to spot it on the 10th (weather permitting, of course), and take a second look on the 11th. See which star in 32 Eridani's vicinity has moved since the night before - that's Juno! And if conditions permit, go for the 12th as well. After that, Juno will increasingly blend in with the anonymous mass of similarly looking points of light which are, of course, the background stars.

Useful hint: Sketch the stars near to 32 Eridani each night as accurately as you can. That will aid you immeasurably in positively identifying Juno, since it will be the only "dot" that moves night to night.

Juno will be bright enough to observe this opposition uning only binoculars - no telescope required. In fact, that is my intention - to spot Juno using only my 8X56 binos. If that does not work, then and only then will I resort to a telescopic search.

The Truth, the Whole Truth, and Nothing But the Truth

Science fiction writer Arthur C. Clarke once had a character in one of his stories (I wish I could remember which one, but I cannot - believe me, I've tried.) looking in awe at an ultraviolet (or maybe it was an X-ray) view of the Earth as seen from the Moon. Staring back and forth between the image and the actual Earth in the lunar sky above him, he finds himself lost in a philosophical reverie. Which is the Earth's "true" appearance, he wonders.

The fact is, they both would be. What we see with our eyes is indeed a valid picture of reality, but not the only one. Notice I did not say there were two realities - there is only One Truth - but rather there are two (in fact, many) ways of looking at that one reality.

Here is an image of Pluto taken by the New Horizons spacecraft, as seen in "natural color, that is, as it would appear to a hypothetical astronaut reproducing New Horizon's flight plan.

So. That's pretty much what you or I would see, were we ever lucky enough to travel so far. But here is the same image with "enhanced color". That is, the colors are true, but somewhat exaggerated to bring out fine detail.

Is that less real than the first image? Not really. All the person processing the image did was to compensate for the limitations of human eyesight. He hasn't added or subtracted any data - just enhanced it. All those colors were present in the first image. They were just too subtle for the eye to pick up without assistance.

But there are other wavelengths that human eyesight is totally incapable of ever seeing. We're just not constructed for it. But that does not mean those wavelengths are any less real. Below we have a view of Pluto in the infrared. The imager has selected colors that can be seen by us humans to represent those we cannot, and here is the product thereof.

And next is an image where the color scheme is completely arbitrary, each one representing a different type of surface mineral. Scientists use such "false color" images to see patterns which would otherwise be invisible to us.

And how about this image, showing the unlit, night side of Pluto, surrounded by its atmosphere?

But are such global images really the "truth"? Do we need to be close up to see what Pluto really looks like? After all, imagine you were looking at a picture of a person taken from a distance of one mile away. You might be able to make out that it was indeed a person (and not, say, a tree), but could you really say you knew what the person looked like?

Here is a relatively close up image of Pluto, showing its rugged terrain and mountains made of pure ice water.

And here is one of the closest, most detailed images taken by New Horizons, showing features as small as what would be individual buildings on the Earth. (As always, click on the image to get full resolution.)

At this point, you can either throw up your hands and say there is no "true" view of the planet Pluto, or...

... or, you can realize that Reality is damned complex, and the best we can ever do is tug at the edges of it. Now please don't get the totally false impression that somehow what we see with our own two eyes is somehow "not true". Far from it! It is as true as any of the other images we just perused. It's just not the Whole Truth.

Averted Imagination

One of the oldest jokes in amateur astronomy is to (laughingly) accuse someone of using "averted imagination" while observing some really difficult object, such as a super faint galaxy or an impossible to split double star. Heck, I've on occasion accused myself of doing so. But truth to tell, it's often hard to delineate the line between desperately trying to see something and just plain imaging that you are successful at doing so.

Sirius and Sirius B (off to the lower left)

Case in point: last winter I was convinced I had finally, after numerous attempts, seen Sirius B (the white dwarf companion to Sirius) through the eyepiece. It didn't stay in view, dang it, but kind of "popped" in and out - the tiniest imaginable point of light nestled right up against the overpowering glare of Sirius. I even stepped away from the telescope and returned to see whether it was still there. And it was... But alas, when I did some calculations at home later that evening (science ruins everything!), I had to admit that whatever I was seeing could not possibly have been Sirius B - it was on the wrong side! (And yes, I did take into account my telescope's mirror imaged view.) So I sadly had to conclude that I was not only using averted vision to see my mystery object, but averted imagination as well.

So yes, an overactive imagination can be a real problem. It is likely a major component of why Percival Lowell and his contemporaries kept seeing all those canals on Mars. (I myself have seen them twice, despite knowing full well that they do not exist!)

But there may be an equal and opposite error possible.

A City on Mars, as imagined by artist Leslie Carr (1951)

Take a good look at the illustration right above this paragraph. I found this in a most remarkable book by science popularist and science fiction writer Arthur C. Clarke, The Exploration of Space (published in 1951, the year before I was born). It supposedly depicts a future settlement on Mars, but when you think about it, what it actually depicts is a quite unremarkable 1950s midwestern American city. Just look at that architecture! In fact, why is there architecture at all? You're under a dome - what need for buildings? And the cars! The dome looks to be all of 400 yards across. Just where are you going to drive? Plus, it would be sheer insanity to waste so much valuable (and limited) real estate on something as useless as roads. Finally, I wish I could see the pedestrians up close. I am sure they would fit in unnoticed in any random crowd of shoppers in downtown Indianapolis.

Now I am not pointing these things out to make fun of the illustrator - far from it! But what I am saying is there was a Failure of Imagination when designing the image. The implications of colonizing Mars were not thought through, and there was a (likely) unconscious assumption that the styles and norms of 1950 would not be out of place in 2150 (or whenever this future city was supposed to be built).

Another and far more glaring example of such a failure of imagination is when the news media inevitably announce every new discovery of an Earth-sized exoplanet as a "Second Earth", neglecting the too numerous to count differences (or possible differences) between said exoplanet and our home body. It seems that all that counts in such reporting is the mass of the planet and the distance from its sun. But there are a myriad of other qualifiers that must be met before we can even begin to speak of an "Earth 2", among them being age, atmosphere and water content, plate tectonics, possession of a moon, a rotating iron core (to create a magnetic field), prevalence of asteroids and comets in the system, distance from gas giants (if any), axial tilt and rotation rate... failure to match in even one of these traits  means we might as easily be looking at a second Venus as a second Earth.

Do we do the same thing when seeing some Deep Sky Object for the first time? Do we assume without thinking about it that "You've seen one globular cluster, you've seen 'em all!" and fail to see that M13 doesn't look at all like neighboring M92?

So we really ought to approach each new object with a mental clean slate - no preconceptions, no assumptions. These are the bad habits that prevent us from seeing subtle differences that ultimately make the difference between one genus and species and another.

Don't Hate the Moon!

Some years back, a fellow HAL member (who shall remain nameless - he knows who he is) quite calmly stated at a Carrs Mill impromptu star party, "You know, if I could shoot down the Moon, I would." It brought to mind the old Looney Tune character, Marvin the Martian, who was always saying, "I'm going to blow up the Earth! It obstructs my view of Venus."

And yes, truth be told, the Moon does "obstruct" our view of deep sky objects - especially the fainter ones. In some ways, it's the ultimate in light pollution. All those moonlight sonatas and syrupy old love songs about walking in the moonlight... "Bah, humbug!" is the reaction of all too many amateur astronomers. I especially hear this reaction when one of our all-too-rare clear nights coincides with a full or near-full Moon. (There almost seems to be an inverse correlation between how much Moon is up there and the percentage of cloud cover.)

But, please. Let's not throw out the baby with the bathwater. In and of itself, the Moon is one of the most rewarding objects up there to observe (see my postings on this subject from Nov. 30th and Dec. 2nd, 1017, entitled "Explorers!").

Now this very upcoming weekend is a case in point. It appears that we're going to be presented by the weather gods with at least 5 clear nights in a row (Wednesday through Sunday), with a Full Moon on Saturday. So you have a choice. You can either stay indoors and mope, crossing your fingers that the skies will be clear for the next New Moon, or you can use this opportunity to take a look at some sadly overlooked lunar features over on the seldom observed "left side" of the Moon's Earth-facing hemisphere. They are far too many to list outside of a textbook, but allow me to highlight 1 or 2 per evening.

The crater Aristarchus and surrounding terrain, as seen by Apollo 15 astronauts

Wednesday: The brilliant crater Aristarchus (brightest spot on the nearside hemisphere) will just be coming into view, around about 10 o'clock (2 o'clock in a mirror-imaged view). If you're patient enough, you can actually watch the endlessly fascinating surrounding terrain emerge into the sunlight, as dawn sweeps over it over the course of the evening.

Schiller

Meanwhile, down in the southern hemisphere, the dramatically misshapen crater Schiller is close to the terminator. This bizarre feature was created by a object striking the Moon at an extreme angle - almost missing it altogether.

Thursday: Go back once more to Aristarchus. The entire region will be in sunlight by this time, and the crater itself will be almost too bright to look at.

The Marius Hills, as imaged by the Lunar Reconnaissance Orbiter
(Click on image to see full resolution.)

Further south at approximately 9 o'clock (3 o'clock in a mirror-imaged view) and not far from the terminator, you'll come upon one of my personal favorite areas of the Moon to observe - the Marius Hills. This is a region of literally hundreds of volcanic domes and related features such as collapsed lava tubes. I remember well the first time I laid eyes on this feature, not knowing what I was looking at. Through the 80mm scope I was then using, it appeared that the Moon had either a bad case of acne or else goosebumps! The low elevation domes naturally show up best when they're smack on the terminator. They rapidly fade into invisibility as the shadows disappear just hours after dawn. So take a look while you have the chance!

Reiner Gamma, as imaged by Lunar Orbiter 4

Friday: For lovers of mystery and enigma, the Moon on Friday presents Reiner Gamma, one of the strangest features anywhere on its surface. Astronomers still do not completely understand how this feature originated, but they have some pretty good guesses. First of all, it is not a topographic feature. If you were standing right on top of it, you'd never know it was there. There is not an inch of elevation difference between its light and dark swirls, it being entirely an albedo feature. But orbiting lunar probes have detected a powerful, localized magnetic field directly under Reiner Gamma. It is believed that this field has charged fine dust particles in the regolith with static electricity, which has caused them to line up like iron filings around a magnet, like we used to do in high school science classes. (Do they still do that?) Reiner Gamma is found to the southwest of the Marius Hills.

No one knows why the magnetic field is there, making Reiner Gamma all the more intriguing.

Mare Orientale, as imaged by Lunar Orbiter 4

Saturday: To top things off, if you look over at the lunar horizon at about 8 o'clock (4 o'clock if your scope gives you a mirror-imaged view) you can catch a glimpse of the edge of what is possibly the most spectacular feature on the entire surface of the Moon, both near and far sides - the Mare Orientale. This is a truly gigantic impact basin (nearly 600 miles in diameter) although from the Earth we can only see its extreme eastern parts. Sometimes, you just have to take what you can get!

Recharging my Batteries

This year's Stellafane was a landmark for me, in that this was the first year when I truly could not remember for certain how many of these I've attended. I have to admit that I'm an addict. I started going up to Stellafane several years ago when I was fully intending to move to New England, and thought it would be the perfect way to get acquainted with the local astronomy clubs. Well, here I am still in Maryland, and seemingly here to stay. But every summer, I feel the draw of the Vermont mountains, with their dark skies and quaint little towns filled with wonderful restaurants and totally unique art galleries and local crafts shops. I'm always done for the year with my Christmas shopping after a week in Vermont - and this year was no exception. I think I contributed about 700 dollars to the state's economy.

As for Stellafane itself, it's an opportunity to hobnob with hundreds and hundreds (there were as many as 1000 in attendance this year) of like-minded astronomy fanatics. Some of my favorite moments at various Stellafanes have occurred not on the observing field, but in the food tent or up at the Clubhouse, meeting perfect strangers and talking literally for hours about viewing conditions back home, our local clubs, our own and others' equipment, our observing triumphs (and failures), our children and/or grandchildren, the Drake Equation, plate tectonics, hot Jupiters, red dwarfs, meteorite hunting in New Hampshire, World War II, global warming, how amateur astronomy is going to hell in a handbasket, and ten million other topics.

But the meat and potatoes of any star party, whether it be a Carrs Mill Impromptu or a major regional like Stellafane, is what did you see. We had one superb night this year (Thursday), one so-so (Friday), and one cloud out (Saturday). So Thursday was the "Make or Break" evening, as far as observation went. And in my books, it all by itself was worth the 8 and 1/2 hour car ride north.

On Thursday night, I observed:

Venus
Jupiter
Saturn (saw 5 moons)
Mars (could make out the polar cap and Syrtis Major)
The Lagoon Nebula
The Trifid Nebula
The Small Sagittarius Star Cloud (M24) - came back to this again and again!
The Swan Nebula
The Eagle Nebula
The Wild Duck Cluster (M11)
The Dumbbell Nebula
M71 (globular cluster in Sagitta)
The Coathanger
61 Cygni (double star in Cygnus)
Albireo (double star in Cygnus)
Omicron Cygni (triple star in Cygnus)
Barnard's Star
B111 (dark nebula in Scutum)
M22 (globular cluster in Sagittarius)
M4 (with binoculars)
HD 162826 (with binoculars)
Several Perseid meteors (2 of them spectacular!)
The star fields of Cygnus (it spoils it if you look for anything in particular - just look!)
M6 (open cluster in Scorpius) - the last thing I looked at, just before tearing down
The Milky Way (just looked away from the eyepiece and drank it all in)
6 or 7 satellites
The International Space Station

The scope I used that night was my 102mm Stellarvue refractor with a variety of eyepieces.

The conditions were far less promising on Friday evening, so all I set up was my 60mm refractor, because I wanted to be able to tear down at lightning speed if I decided it wasn't worth hanging around. Besides, I could always look through other folks' monster Dobs if I felt like it! That night I had my best eyepiece view this opposition of Mars. Absolutely amazing how big it appeared. I know it wasn't, but damn if it didn't seem bigger than Jupiter. But Mars looked best of all naked eye, like a baleful red eye rising over the tree line. I couldn't get enough of it.

On Saturday, I woke up to wall-to-wall cloud cover and off-and-on rain. But it didn't bother me. I hiked up to the Stellafane Clubhouse and had some great conversations with the people who had entered their scopes into competition. Met one gentleman who had attended every Stellafane since the year I was born (1952)! He talked to me for half an hour about how one tested a newly ground mirror for accuracy, and showed off some equipment used in the process which he had designed and built himself. I admired the work of Sara Schechner who makes astonishingly beautiful astronomically themed quilts (her day job is the David P. Wheatland Curator of the Harvard University Collection of Historical Scientific Instruments). I ran across two young women from Roland Park in Baltimore, attending their very first Stellafane, and discussed the pros and cons of urban astronomy. I spent a good hour with a 77 year old man (whose name I never did get - he wasn't wearing his name tag) who told me his life story, occasionally with tears in his eyes. He was so interesting, I wish I could have taken notes, but that would probably have been rude. I saw (but did not speak to) Al Nagler as he walked by my telescope on the observing field. I hope he noticed my 9mm Nagler eyepiece!

(True Story: A couple of years ago, I was sitting right next to Al for a good 30 minutes during lunch at the food tent, and had no idea who he was. In my defense, I hadn't the slightest idea at the time what Al Nagler looked like. It wasn't until I was getting up to leave that two other people walked over and said hello to him, thus enlightening me to my now totally wasted opportunity to speak with one of my heroes.)

All in all, a great star party, and definitely not my last Stellafane. I look forward to the day when I can bring my now 5 year old granddaughter along with me. (Of everyone in my extended family, she is the most interested in (dare I say obsessed with?) astronomy.)

So here I am, back in light-polluted suburban Maryland, batteries recharged and ready for another year of stargazing!

Things To Come

I know 2019 might seem like a long time away still, but it's not too early to plan for two major astronomical events which will be visible in their entirety from Maryland.

Total Lunar Eclipse

All the world's sunsets seen at once,

as reflected by the Moon

First: A Total Lunar Eclipse beginning at 9:36 PM on Sunday, January 20th, and ending at 2:48 AM on Monday morning. For once, we'll be able to see the entire thing - from the moment the Moon enters the Earth's penumbral shadow (9:36 PM) to when totality begins (11:41 PM) to when totality ends (12:43 AM) to the last hurrah (2:48 AM).

So there's a good reason to brave the cold of a mid-winter's night!

A Transit of Mercury

Second: A Transit of Mercury. Maybe not as rare or dramatic as 2012's Transit of Venus, but since I won't be around for the next one of those (on December 10th, 2117), I'll take what I can get! Mercury will make first contact with the Sun at 7:36 AM (exactly 50 minutes after sunrise) on November 11th, 2019 and be fully between us and the Sun approximately one minute later. The elusive planet will have left the Sun's disk completely by 1:04 PM, after a transit time of 5 hours 25 minutes. So once again, weather permitting, we'll be able to see the entire event - and this time in daylight!

Now just about everyone in HAL knows that I am a huge fan of Mercury, and that we're lucky to get just a passing glimpse of him in the evening twilight before the planet slips below the horizon. But here we'll get to observe him for a full five and one half hours! How cool is that?

Triangulation

Every stargazer knows the Summer Triangle. Heck, it's like the Big Dipper or Orion. Just one of those things up there that we all take for granted, not really thinking about them. "Oh, there's the Triangle. Must be summer." And on we go.

But let's take a moment to really explore the obvious. What exactly are those stars which make up the Summer Triangle? First off, what are their names? From north to south, they are Deneb (Arabic for "tail"), Vega (Arabic for "falling") and Altair (Arabic for "flying eagle"). They are, respectively, the 19th, the 5th, and the 12th brightest stars in the entire sky. That is, at least as seen from the Earth. In and of themselves, their order in descending brightness would be Deneb, Vega, and Altair. In fact, although Deneb appears to from our vantage point to be the dimmest of the three, it is one of the brightest stars in the entire Milky Way Galaxy, shining with a luminosity of 200,000 Suns (yes, you read that correctly). Only its enormous distance from us makes it appear less bright than otherwise. Vega, which boasts a luminosity of 40 Suns, is but 25 light years distant, making it appear to be the most brilliant member of the triangle. And bringing up the rear, Altair shines out with a radiance of a mere 10 Suns, but at 16.75 light years, it is the nearest of the three.

So let's start with Deneb. "Tail" is certainly an apt name for this star, as it marks the tail feathers of the celestial swan Cygnus (Albireo being the beak). In addition to its fantastic brilliance, this star is HUGE. Were it our own star, our poor Earth would be just grazing its surface in its present orbit. Ouch! Deneb weighs in at a little less than 20 solar masses, but is spewing out into interstellar space roughly the equivalent of one Earth mass every 500 years. Currently a blue-white supergiant, astronomers believe that Deneb with ultimately expand even further, evolving into a red supergiant before collapsing in on itself and going supernova. But that's a few million years into the future, so there's no immediate threat to our lovely summertime asterism.

Next on our list is Vega, the brightest (to us) of the three. Vega has quite a history to it. It used to be the Earth's North Star (14,000 years ago), and will be again in about another 13,000 years. (It will be so much easier then to do polar alignment, with such a bright North Star.) It was the first star (other than the Sun) to be photographed, and the very first to have its spectrograph taken. At about 500 million years old, Vega is quite the youngster. But due to its mass (about twice that of the Sun), it is racing through its time on the Main Sequence. In another half billion years, it will begin to swell into a red giant before losing much of its mass in the form of a lovely planetary nebula. (So stick around!)

Vega and the Sun to scale. Note the enormous equatorial bulge on Vega.

Vega rotates so quickly (once every 12.5 hours) that it is very near the point where it would tear itself apart from centrifugal force. This was hidden from astronomers until recently, since we are looking down directly onto one of Vega's poles, and cannot observe its squashed shape directly.

Vega is surrounded by what appear to be multiple discrete disks of dust and small bodies, possibly in the process of coalescing into planets. So we may actually be observing a solar system in the very act of creation!

Last but not least on our list is Altair. Those of you who are my age, or are fans of 1950s B-grade science fiction movies, will recall that Altair was the parent sun of the "Forbidden Planet" in the movie of that name - home to the mad scientist Morbius and his beautiful daughter Alta, Robby the Robot, and the Monsters from the Id.

A Monster from the Id

In our far more boring reality, Altair is a fairly typical main sequence star. It is somewhat less than twice the mass of our Sun and shines at 11 times its brightness. Like Vega, it has an extreme rotation rate, spinning on its axis once every 9 hours. This results in an equatorial diameter a full 20% greater than its polar measurement.

Only 17 stars other than our own Sun have ever been imaged as anything other than a point source of light. Below is a 2007 image of Altair taken in the infrared. Note the oblateness. And unlike Vega, we are not looking down on one of the poles.

So now summer's most prominent asterism ought to be more than just a triangle. Its component stars are fascinating individuals, which are worth getting acquainted with.

Pure Magic

We all have as observers different reasons why we track down different objects. Sometimes it's because this or that star is intrinsically interesting, or because it possesses one or more superlative (the biggest, the closest, the oldest, the furthest, etc.). Sometimes it's because the object is bright and splashy, and fills one's field of view with all sorts of complexities.

30 Cygni off to the upper left - 31 Cygni A and B off to the lower right

But every now and then we check out this or that deep sky object because.. well, darn it, because it's beautiful! Such is the case for Omicron Cygni. It's not just that their arrangement is aesthetically pleasing - their brilliant colors (bright gold and electric blue) rival those of the more famous (and nearby) Albereo.

Another view of 30/31 Cygni, showing off their colors

Now Omicron Cygni isone of the more confusing appellations up there, because several stars in Cygnus all go by that  label. Much better to use the Flamsteed designations 30, 31, and 32 Cygni, all of which make up "Omicron Cygni". Confused? So am I.

But there's more to Omicron Cygni than a pretty picture (although that's quite enough). The stars are interesting in their own right. 30 Cygni is a blue-white giant star, 610 light years distant, shining with the radiance of 324 Suns, making it a magnitude 4.83 star to our view. Nearby (visually, at least) 31 Cygni is an easily splittable binary. Despite its apparent nearness to 30 Cygni, the 31 Cygni system is 880 light years from our Solar System, so the 2 are actually separated by 270 light years. 31 Cygni's A component is an orange supergiant, 4,300 times brighter and 200 times the size of our Sun. Its dimmer B companion appears to different observers as either bright blue or "dirty" white. The three stars, although in actuality quite distant from each other, make up an attractive apparent triple star due to a chance line of sight alignment.

32 Cygni at upper left, 30 and 31 at bottom right

Meanwhile, 32 Cygni sits off about 1 degree to the north, completing the view through any eyepiece with a moderately wide field of view. At 1,100 light years away, it is the most distant of the "Omicron" stars in Cygnus. 32 Cygni is a spectrographic binary. (Its components cannot be separated visually.) The A component of this system shines with a luminosity of 6,600 Suns and is bright orange. Meanwhile, its poor B companion star has to make do with only 300 times the Sun's luminosity, and by itself would be a blue-white main sequence star. The 2 components make up an eclipsing binary, similar to Algol over in Perseus. Because the plane of the stars' orbits is precisely aligned with our line of sight, we can spectrographically study the solar wind of the primary star during each eclipse. From these observations, astronomers have concluded that 32 Cygni A is losing an incredible full stellar mass every 77 million years. Wow.

By the way, the colors in the above image do not do justice to the glorious view one gets through the eyepiece. I never fail to spend a minute or three just drinking in the view whenever Cygnus is high in the sky. Don't miss it this summer!

Mirror, Mirror...

Ever wonder what our Sun would look like, if you were observing it from outside the Solar System? Well, take a gander at HIP 569498, over in Draco.

This magnitude 8.7 star, at 208 light years away, is the closest analog to the Sun that we know of in the entire sky. Its mass is practically identical to the Sun, the difference being basically a rounding error (1.02  ± .02 solar masses). Its surface temperature is only 17° Centigrade higher that the Sun's (5521° vs 5504°). Its radius is a mere 9,000 km less than the Sun's (687,000 vs 696,000). Most importantly, its lithium content is identical to that of the Sun to within observational parameters. Lithium content is one of the markers that varies most widely from star to star, so an identical measurement is amongst the rarest of the rare. The two stars share many other close similarities as well.

But it is no solar birthmate. HIP 569498 is approximately one billion years younger than the Sun and shares no common orbital parameters (about the galactic center) with the Solar System.

HIP 569498 also apparently possesses no "hot Jupiters", so it is entirely possible that one or more Earthlike worlds exist within the star's habitable zone.

So take a few moments to contemplate this "dot" in the northern skies, and imagine some stargazer on a world 208 light years away looking in our direction. He would be seeing exactly what you are.

By the way, HIP 56948 has two very unofficial names other than its catalog listing. They are Intipa Awachan ("Sun's Twin" in Quechua), and Zilia ("Jealous" in ancient Greek). How unofficial are these monikers? They are the winners of a New York Times readers' poll conducted in 2007, so give them all the respect (that is, very little) that they're due.

HIP 56948

The Music of the Spheres

Seven poets sing of the stars:

Look thou no further, but affix thine eye 

On that bright, shiny, round, still moving mass, 

The house of blessed gods, which men call sky, 

All sow'd with glist'ring stars more thick than grass, 

Whereof each other doth in brightness pass.

(Edmund Spenser)

The infinite shining heavens rose 

and I saw in the night

Uncountable angel stars

Showering sorrow and light.

(Robert Louis Stevenson)

Look how the floor of heaven

Is thick inlaid with patens of bright gold.

There’s not the smallest orb which thou behold’st

But in his motion like an angel sings.

(Shakespeare)

The heavens declare the glory of God

And the firmament sheweth his handywork.

(King David (the Psalms), KJV Translation)

BEND low again, night of summer stars.

So near you are, sky of summer stars,

So near, a long arm man can pick off stars,

Pick off what he wants in the sky bowl,

So near you are, summer stars.

(Carl Sandburg)

Look at the stars! look, look up at the skies! 

O look at all the fire-folk sitting in the air! 

The bright boroughs, the circle-citadels there! 

Down in dim woods the diamond delves! the elves'-eyes! 

(Gerard Manley Hopkins)

As I watch the bright stars shining, 

I think a thought of the clef of the universes and of the future. 

A vast similitude interlocks all,

All spheres, grown, ungrown, small, large, suns, moons, planets,

All distances of place however wide,

All distances of time, all inanimate forms,

All souls, all living bodies though they be ever so different, or in

different worlds,

All gaseous, watery, vegetable, mineral processes, The fishes, the brutes,

All nations, colors, barbarisms, civilizations, languages,

All identities that have existed or may exist on this globe, or any globe,

All lives and deaths, all of the past, present, future,

This vast similitude spans them, and always has spann’d,

And shall forever span them and compactly hold and enclose them.

(Walt Whitman)

Magnus Frater

I'll be on the road for the next two weeks and away from my computer, so I thought I'd sign off (for now) with one more posting, this one about our own Sun's probable sibling, born out of the very same cloud of gas.

From left to right

90 Herculis, HD 162989, and HD 162826

I am speaking, of course, of HD 162826 in Hercules. This star is currently 110 light years from our Solar System, and has an apparent magnitude of 6.7. Its chance alignment with two slightly brighter stars, HD 162989 (magnitude 6.04),  and 90 Herculis (magnitude 5.16) is a huge aid in finding it. The 3-star asterism lies approximately halfway between super-bright Vega and the globular cluster M92 and just three degrees north of Theta Herculis (magnitude 3.85). It is ridiculously easy to find through binoculars. Theta Herculis is a naked eye star, to the left of the northwest corner of Hercules' "Keystone" (which contains the mighty M13 globular). Find that, and place it at the lower edge of your binocular field of view. The 3 stars shown in the above image will be near the top of that same field of view. [see footnote] The star on the far right is the one you're looking for. It's that easy!

Red arrow points to HD 162826

So why do we believe that HD 162826 was born in the same stellar litter as our own star? Three reasons:

1. It is the same age as our Sun (4.6 billion years).

2. Its chemical composition is a close match to the Sun, especially in elements that typically vary wildly between different stars, such as barium and yttrium. There are only 30 stars known in the entire Milky Way galaxy that are as close a match to our Sun as HD 162826.

3. It has been calculated (by computationally "winding back the clock" of the orbits about the galactic center of HD 162826 and the Sun) that 4.6 billion years ago (that is, when the two stars were born), they pretty much occupied the same space.

HD 162826 may indeed be the Sun's litter mate, but it is no twin. It is 15% more massive than our star and shines at an absolute magnitude of 3.92 (as compared to 4.83 for the Sun). If our Earth were circling round HD 162826, it would have be orbiting at a distance of Mars to be the same temperature.

Hmm... HD 162826 is a rather awkward moniker for so close a relative. It was a pain typing it nine times for this posting. Considering its mass, perhaps we ought to just call it "Big Brother" (or, more formally, we could use the Latin Magnus Frater).

Footnote: This assumes the top of your field of view is to the north. At the time of this posting (early July), HD 162826 will be very close to the zenith, so your own orientation may be quite different. So with that caution, let us say that the 3-star asterism will be to the north of Theta Herculis in your binocular field of view, and leave it at that.

Seeing Double Double

Epsilon Lyrae, the "Double Double"

We all of course know of the iconic Double Double (Epsilon Lyrae) next door to brilliant Vega. Many of us use this star as a test of our instrument's resolving power, or of the steadiness of a night's air. But have you ever taken a look at the other double double, over in Boötes? I am speaking of Iota and Kappa Boötis, or Asellus Secundus and Asellus Tertius (a.k.a., 2nd and 3rd Donkey Colts). Not a true "double double", since Iota Boötis is a mere 95 light years away, whilst Kappa Boötis stands off at more respectable 151 light years. A chance line of sight alignment is what allows us to see them side by side.

Iota and Kappa Boötis 

As sketched by someone calling himself "asteroid7" on Cloudy Nights

Both both components of this charming mashup are themselves doubles - and easily splittable ones at that. The A and B components of Iota Boötis are separated by 38.8 seconds of arc and 1130 AU of actual distance. (A single orbit of the two stars about a common center takes a whopping 24,000 years!) Together, they have an apparent magnitude of 4.75 making them a naked eye star. Meanwhile, the two components of more distant Kappa Boötis (known as Kappa-1 and Kappa-2) are separated by a tighter 13.5 seconds of arc and a mere 640 AU of actual distance. They orbit each other once each 8700 years, and are themselves each double stars (making Kappa Boötis a true "double double", but observable as such only spectrographically). The combined apparent magnitude of the entire Kappa Boötis system is 4.53, remarkably close to that of Iota Boötis.

As usual with double stars, different observers report different colors, so I won't "poison the well" here, and allow you to come away with your own impressions.

Iota and Kappa Boötis are the two stars at the top right of this rather simplified star chart

Zimiamvia

They sat there till the shadows crept over the lawn and up the trees, and the high rocks of the mountain shoulder beyond burned red in the evening rays. [Lessingham] said, "If you like to stroll a bit of way up the fell-side, Mercury is visible tonight. We might get a glimpse of him just after sunset.

A little later, standing on the open hillside below the hawking bats, they watched for the dim planet that showed at last low down in the west between the sunset and the dark.

He said, "It is as if Mercury had a finger on me tonight, Mary. It's no good my trying to sleep tonight except in the Lotus Room."

Her arm tightened in his. "Mercury?" she said. It is another world. It is too far."

But he laughed and said, "Nothing is too far."

E.R. Eddison, The Worm Ouroboros

Mercury and Venus as seen from Idaho, earlier this year

Image by Kris Hazelbaker

The above passage from The Worm Ouroboros is one of the most beautiful accounts of naked eye planetary observation I have ever read. It never fails to move me, especially after an evening like tonight. I had driven out to a nearby civic center that has a large open space behind it with a relatively clear western horizon. I knew that Mercury would be putting in his best evening appearance for the entire year, and despite the oppressive heat and clouds of mosquitoes, I walked out into the middle of that field and drank in the steadily darkening sky, which ran the spectrum from brilliant pink on the horizon to yellow at the tree line, up to pale blue just above the treetops to a deep blue where brilliant Venus reigned supreme, reminding me of Edmund Spenser's description of her:

Fayre childe of beauty, glorious lampe of Love
That all the host of heaven in rankes doost lead,
And guydest lovers through the nightes dread,
How chearfully thou lookest from above.

(Epithalamion, lines 588-589)

(If you have never heard Ralph Vaughan Williams' heartbreakingly beautiful setting of these words to music, you owe it to yourself to listen to it, Here: https://www.youtube.com/watch?v=QKaAtuEe_sQ Begin at 20 minutes 12 seconds in, and be sure to not miss the full chorus breaking in at 21 minutes 34 seconds.)

The sun had set at 8:30, but I couldn't see anything of Mercury, even through my 8X56 binos, until 9:04 - pretty much right where I expected to find him (a little lower, maybe). The humid atmosphere was distorting the view a bit. Mercury was a distinct yellow instead of its usual pristine white, and it actually twinkled. (Planets aren't supposed to do that!) I hadn't brought along my telescope, so both planets remained glittering points of light.

By 9:12, Mercury had brightened (or, more accurately, the sky had darkened) to the point where he could be seen naked eye, albeit only intermittently, and with averted vision. But by that time, I was being eaten alive, and decided to beat a retreat to the land of air conditioning, glancing up at Jupiter on the way to the car.

Mercury and Venus as seen from North Carolina

Image by Nicolas Holshouser

Bursting with Doubles

The constellation Boötes is pretty sparse when it comes to anything to observe. It contains only one globular cluster (NGC 5466), which by all accounts is a pretty poor example of the breed. Sky and Telescope's Pocket Sky Atlas lists only 5 galaxies within its boundaries, none of which are anything to write home about. Perhaps it is fitting that Bootes is home to the great Boötes Void, a 250 million light year diameter bubble of nothingness - no stars, no gas, no galaxies, and apparently no dark matter. Just nothing. (Obviously not a good target for observation!)

But what Boötes lacks in the splashier DSOs is more than made up for in its fine collection of double stars, several of which (such as Izar, a.k.a., Epsilon Boötes) routinely make the lists of "must see" doubles.

Struve 1835, and companions

But today I intend to focus on a lesser known example, Struve 1835. Located near the extreme southern edge of the constellation, almost due south of bright Arcturus and not far from the boundary with Virgo there lies an attractive chain of three stars, slightly curving to the northwest. The stars making up this asterism gradually increase in magnitude as you progress up the chain, making it lovelier still. The "bottom" star (HD 126271) has an apparent magnitude of 6.19. The middle star (HD 126200) shines at 5.95, while Struve 1835 has a combined magnitude of 5.12. All by itself, this beautiful trio is worth a glance or two.

Hmm... This 3-star asterism is currently unnamed. Let's see, we already have Brocchi's Cluster (the Coathanger), Herman's Cross, and Kemble's Cascade. Why not Prokop's Parade? (Alliteration is always a plus!)

But the real gem is that brightest star at the top. Pump up the magnification, and you'll split Struve 1835 into its component members. Descriptions vary enormously as to what colors different observers see. Some see no color at all, just two unevenly matched white stars. At least one observer has noted "2 yellow stars". But the most common description is of a bright blue primary with a dimmer secondary of uncertain hue, ranging from gray to purple.

I was unable to find an image of this star on the internet, but I did come across this very fine sketch (below).