Monday, August 20, 2018

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.


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!

Sunday, August 12, 2018

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:

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!

Thursday, August 2, 2018

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?