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Monday, December 27, 2010

A Beautiful Day in the Observing Neighborhood

With so much snow and cold throughout Europe and the US, I wanted to tell you about the beautiful day we just had here. With temperatures that required short sleeves, a beautiful blue sky and yellow sun, I decided to spend part of the afternoon at our observing site on a high plateau above Mitzpe Ramon.

When I arrived the weather was perfect and the wind was calm, resulting in an eerie quiet. I looked over the rim of the machtesh, where we take visitors at night when the moon is full, and contemplated the vast wonder of the world's largest erosion crater.

Machtesh Ramon from our observing site. (Click for full size image.)

The machtesh is a geological wonder land with all sorts of geological formations that reveal themselves under different lighting conditions and angles. I saw this black hill for the first time by the light of the low winter sun's rays.

A black hill reveals itself (below center) by the winter sun's light.

I hiked a short distance along the plateau until I came to this view through a notch in the walls of the machtesh.

Machtesh Ramon from our observing site.

The other side of our observing site is lined by pine trees from a JNF forest, their trunks bent by the prevailing winds. One of the things I like the best is the quiet at our site. I thought, perhaps, I heard the whirring sound of a generator in the distance. But perhaps not. At night, there is usually no sound to be heard. Sometimes a passing military aircraft; sometimes music from Mitzpe Ramon. But usually nothing; nothing at all.

A JNF forest borders our observing site.

On the way home I found the Ibex out enjoying a day in the sun.






Ibex Picnic

Keep on looking up!

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Sunday, December 26, 2010

The Cold Returns

On Thursday we hosted the Madar family from France. Both parents and older daughter spoke excellent English and translated my talks into French for their young daughter. The cold and wind returned to sweep the high plateau where we were observing, but all managed to stay out for a good two hours before capitulating to the cold.

The moon was still mostly full but that didn't interfere with my showing the major constellations and their bright stars. We also got in good views of several open star clusters, The Great Orion Nebula (M42), Jupiter (always a favorite) and its 4 Galilean moons, and, of course, the moon itself.

The Madar family from France.

Keep on looking up!



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We Catch a Brief Warm Spell

Pleiades Star ClusterPleiades (Image via Wikipedia)A brief warming trend helped us welcome our guests from Chicago this week, the Cohans. It was during the full moon of December, so the sky and surrounding desert were still quite bright. But we still managed to get a "Wow" for the Pleiades star cluster, which is a winner any time of the month, and some good views of the Double Cluster and Jupiter. The brightest of all lunar craters, Archimedes, is my favorite during full moon, since it is an interesting shape and so much brighter than any other area through a telescope during full moon.

We were out long enough to watch the Big Dipper rise out of the horizon muck, it is not circumpolar from latitude 30 degrees N, and we got a good telescopic view of the triple star Alcor and Mizar at the bend of the handle.

The Cohans from Chicago


Keep looking up!

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Wednesday, December 22, 2010

A Re-Run of Yesterday's Total Lunar Eclipse

In case weather or continent or sleep prevented you from watching yesterday's total lunar eclipse, here is a time lapse re-run done by William Castelman. Beautiful photography, but I could live without the sound track.


William Castleman's time lapse video of the total lunar eclipse of December 20-21, 2010


Notice especially the circular shape of the earth's shadow on the moon. I believe a total lunar eclipse is the only natural phenomenon where the circular shape of the earth can be directly perceived by the eye, rather than inferred from observations. This shape is especially well captured in this video. Flat Earth Society members beware!

Keep on looking up!
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The Blood Red Moon of December 20-21, 2010

The colors of the eclipsed moon yesterday were generally reported as "blood red", and Jewish tradition considers the color of an eclipsed moon to be a part of its "omen" value. What causes these colors which can range from very dark and barely visible to red or copper?

The earth's shadow is considerably larger than the diameter of the moon, so when the moon passes into that shadow (called the "umbra") becoming eclipsed, it can pass through the center of the shadow or on various paths above or below the center. Generally speaking, the more centrally the moon passes through the earth's shadow, the darker and less colorful the eclipse. The various paths the moon can take through the earth's shadow also account for variations in brightness seen across the disk of the moon.

Here is the path the moon took through the earth's shadow yesterday:

Path of the moon through the earth's shadow on December 20-21, 2010

The moon passed well north of the earth's umbra, the central and darkest part of its shadow, causing the moon's northern limb to appear much brighter than the southern. 

The moon at mid-eclipse. (Tony Sharfman, Cranford, NJ)

Once the moon is in the umbra, the earth's atmosphere acts as a giant lens, bending the light of the sun around the earth and focusing it on the moon. Just as at sunset the long, red rays of the sun become enhanced because the thicker atmosphere scatters all of the shorter wavelengths, most of the light striking the moon is reddened by this atmospheric scattering and lensing. This effect can be enhanced or diminished by global weather effects along the rim of the earth, so the actual colors and brightness of an eclipsed moon are impossible to predict.


And that is why we had a "blood red" eclipse yesterday.

Keep on looking up!

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Does Jewish Tradition Consider Eclipses to be a Bad Omen?

It would seem from the Midrashic and Talmudic texts below that Jewish tradition considers eclipses of various kinds to be a bad omen, both for the world at large and Jews in particular, caused by our sinful behaviors and warning us to repent. Given the fact that eclipses are caused by the invariant laws of celestial mechanics, it seems rather hard to understand how our actions can influence them. Perhaps our tradition is teaching us that these events are reminders of our sinful behavior and a reminder to repair our defects. On a deeper level, perhaps in the times of Mosiach when "...the land shall be filled with the knowledge of the Lord as the waters cover the sea" (Isaiah 11) eclipses will cease or the universal light of G-dliness will blind us to them.

The eclipsed moon as seen from Teaneck, NJ on Dec. 21, 2010. (Photo credit: Yitzy Glicksman)

There is no bracha or blessing to be said upon seeing an eclipse, although it is a wonder on a par with seeing a rainbow or shooting star, for both of which there are blessings to be said. Perhaps this is because the Hebrew word for eclipse is Likui - defect. The Talmud states, as we read below, that a Likui of the sun is a bad sign for the world; a lunar Likui is a bad sign for Israel. Being associated with bad signs, the eclipse was not assigned a bracha. May one say a bracha if moved by the beauty and wonder of an eclipse? Consult with your Rav, I don't know.


I guess it's a good thing that yesterday's lunar eclipse was not visible from Israel. We dodged another bullet!


Succah 29a Our Rabbis taught, When the sun is in eclipse, it is a bad omen for the whole world. This may be illustrated by a parable. To what can this be compared? To a human being who made a banquet for his servants and put up for them a lamp. When he became wroth with them he said to his servant, ‘Take away the lamp from them, and let them sit in the dark’. It was taught: R. Meir said, Whenever the luminaries are in eclipse, it is a bad omen for Israel since they are inured to blows. This may be compared to a school teacher who comes to school with a strap in his hand. Who becomes apprehensive? He who is accustomed to be daily punished. Our Rabbis taught, When the sun is in eclipse it is a bad omen for idolaters; when the moon is in eclipse, it is a bad omen for Israel, since Israel reckons by the moon and idolaters by the sun. If it is in eclipse in the east, it is a bad omen for those who dwell in the east; if in the west, it is a bad omen for those who dwell in the west; if in the midst of heaven it is bad omen for the whole world. If its face is red as blood, [it is a sign that] the sword is coming to the world; if it is like sack-cloth, the arrows of famine are coming to the world; if it resembles both, the sword and the arrows of famine are coming to the world. If the eclipse is at sunset calamity will tarry in its coming; if at dawn, it hastens on its way: but some say the order is to be reversed. And there is no nation which is smitten that its gods are not smitten together with it, as it is said, And against all the gods of Egypt I will execute judgments. But when Israel fulfill the will of the Omnipresent, they need have no fear of all these [omens] as it is said, Thus saith the HaShem,' Learn not the way of the nations, and be not dismayed at the signs of heaven, for the nations are dismayed at them, the idolaters will be dismayed, but Israel will not be dismayed. Our Rabbis taught, On account of four things is the sun in eclipse: On account of an Ab Beth din who died and was not mourned fittingly; on account of a betrothed maiden who cried out aloud in the city and there was none to save her; on account of sodomy, and on account of two brothers whose blood was shed at the same time. And on account of four things are the luminaries in eclipse: On account of those who perpetrate forgeries, on account of those who give false witness; on account of those who rear small cattle in the land of Israel; and on account of those who cut down good trees. 
Midrash Rabbah - Leviticus XXXI:9 R. Levi said: Every day the Holy One, blessed be He, sits in judgment on the globes of the sun and the moon which are reluctant to go forth to shine upon the world. What reason do they give? People burn incense to us, people worship us. R. Justa b. Shunem said: What does the Holy One, blessed be He, do to them? He sits in judgment on them and they go forth and shine upon the world against their will. Hence it is written, Every morning doth He bring His right to light--lo ne'dar {Zeph. III, 5). What is the meaning of ’lo ne'dar’? 'It does not cease.’ But the unrighteous knoweth no shame (ib.). People are not ashamed but worship them. They see them being punished but are not ashamed. 
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Monday, December 20, 2010

Watching the Total Lunar Eclipse of December 21, 2010 from Israel

Although this eclipse is not visible from Israel, it can be watched online from a large number of sites contributed by individuals and NASA. And the good news is that the eclipse is at a much more reasonable hour in Israel than in the US, starting at 8:33AM on Tuesday morning and ending at 12:01 PM. Below are links to the sites that will be webcasting real time video of the eclipse. With much of the US covered by clouds your best bets are stations on the Atlantic coast and the south.

Times of the December 21, 2010 total lunar eclipse in Israel (Israel Standard Time)
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Watching the Total Lunar Eclipse of Dec. 20-21 Live Online

(Apologies: I mistakenly wrote Dec. 21-22. The correct date is above, early Tuesday morning on East Coast of the US, late Monday night on the West Coast.)

For those of us not fortunate enough to be able to see this winter's solstice lunar eclipse live, whether because of location, weather or other circumstances, the Internet offers the opportunity to watch it in real time online. The Astronomer's Without Borders site keeps an updated list of sites that will webcast the eclipse in real time, together with their locations and equipment used. This should be an interesting supplement even for those who are able to watch live.

Web sites showing the lunar eclipse in real time
NASA's live coverage of the lunar eclipse

To "Clear skies and fair viewing" we must now add "and good Internet connections"!
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Sunday, December 19, 2010

North America to be Treated to Total Lunar Eclipse on Dec. 20-21, 2010

Total eclipseImage via Wikipedia
(Apologies: I mistakenly wrote Dec. 21-22. The correct date is above, early Tuesday morning on East Coast of the US, late Monday night on the West Coast.)

Observers in North America, Central America, and Hawaii will be treated to a total lunar eclipse on the night of the winter solstice, December 20 - December 21. Unfortunately, the eclipse will not be visible in Israel or the Middle East. Totality begins at 2:41AM EST and ends at 3:53AM EST on December 21, so observers on the West Coast will be able to see it at a much more reasonable hour. Partial phases of the eclipse begin about 1 hour before and after totality.

The last time a total eclipse of the moon occurred during the winter solstice was December 21, 1638AD, the year John Harvard died and left his library to the two year old university that would be named after him. So, if you are into rare, coincidental astronomical events, you won't want to miss this one. The next one won't be until December 21, 2094, not so long to wait but an event you can't bet you'll see.

Here are the circumstances of the eclipse:

Source: Sky and Telescope Magazine

This should be a beautiful event, with the moon high overhead on a frosty winter night. The eclipse is entirely visible by the naked eye, so just go outside and enjoy, although any optical aid, such as binoculars, will enhance your enjoyment. Since it is cold in many places at this time, you may be able to view from indoors, if you have a window from which the moon is visible. The moon will be nearly overhead, so perhaps a skylight would work best.

Clear skies and fair viewing.

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Thursday, December 16, 2010

Our Winter Clouds

Fair weather winter clouds in the Negev are almost always thin cirrus. These thin clouds are white to light grey ice crystal clouds that cross but do not cover the sky. These clouds form when there is moisture at high levels and the temperature there is colder than freezing.

Thin cirrus over Mitzpe Ramon

In the evening these clouds, however thin, can always be noted by the circular rainbow they create around the moon, the result of the ice crystals refracting the moon's light. These clouds can also be quite deceptive, since they leave large portions of the sky uncovered and when very thin are invisible at night except for the dimming of the stars they cause. But once you get into a dark zone, you can immediately see they are trouble. A number of times I have gone out to my dark sky location, only to notice high, thin cirrus after arriving. But it's a small price to pay for the mostly clear, clean skies we have here in general.

Thin cirrus over the Club Ramon Hotel

Wishing you clear skies and fair viewing.

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Wednesday, December 15, 2010

We Hit the Geminids Jackpot

After being clouded out on Monday night December 13, I put my hopes on Tuesday night/Wednesday morning to get a view of the Geminids meteor shower this year. We were not disappointed. Although there was a slight haze in the early evening, by 11:00 PM, when we were heading out, the skies had completely cleared and the winter constellations shined brightly overhead.

We threw our camp pads and sleeping bags in the car, together with my 80mm Brandon wide-field telescope and eyepieces, and headed up to our dark sky site just outside of Mitzpe Ramon. I brought the telescope just in case I decided to do some deep sky viewing, but it is not at all needed to observe a meteor shower. In fact, one of the beauties of a meteor shower is that all you need to see it best are your two eyes and a dark sky location, both of which we have in ample measure in Mitzpe Ramon.

I was quite confident we would get a good show, but I was not prepared for just how good it was. Although the peak of the meteor shower was scheduled for the previous night, the actual time of the peak was 13:00 UTC on Tuesday (15:00 Local Israeli Time). So, Tuesday night around midnight was actually closer to the peak time than the night before. Also, the Geminids, unlike the other great shower of the year, the Perseids, has a very broad peak, spread out over a longish period of time.

We threw our pads on the ground, spread out our sleeping bags and hopped in, waiting for our eyes to adapt to the dark and the show to begin. Although the first quarter moon was still visible, we immediately began to count lots of meteors. Donny, my observing buddy, counted 34 meteros in the first hour, despite the moon light. After the moon went down around 12:45AM, the meteors intensified. They were mostly very bright, with medium length trails, moving at moderate to fast speed, and bright white in color. We saw one fireball, which illuminated the entire area during its brief passage, and was accompanied by a dimmer twin, that fell in parallel beside it. On a number of occasions the meteor's train was illuminated by the ionized gas it left in its path, brightening and dimming as it quickly fell through the sky.

Our Geminids meteor count, by the quarter hour, December 14-15, 2010

We were delighted with the show, which was one of the best I have seen. Other observers report it one of the best meteor showers of the last 10 years. It is still not too late to view it, as many meteors from the shower will continue to be visible through December 17, although in smaller numbers than previous nights.

Lying on the ground in our sleeping bags under a star-filled sky, watching the shooting stars, called to mind that not far from this place, G-d took Abram out under the night sky to show him these stars and demonstrate how numerous his descendants would be. Not far from this place, under a sky very much like the one we watched, Abraham began his journey to sacrifice his son Isaac, which would end the generations to come that G-d had promised him under this same night sky. Not far from this place, under a sky filled with the same stars, Jacob, Isaac's son, would flee from the wrath of his brother Esau, lie on the cold hard ground as we did, and dream of angels ascending and descending a ladder. And not far from this place, in the middle of the night (va'yehie be'chatzie ha'lahylah) under a sky filled with stars that looked like our own, Moses would take the Children Of Israel out of Egyptian bondage to the very self-same land that we were lying on.

Such are the thoughts on an astronomical evening in the Holy Land.

Clear skies and fair viewing.
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Tuesday, December 14, 2010

Geminids - Skunked by Clouds on Monday Night

The worst dust storm in many years began subsiding Monday afternoon, raising my hopes that we would have calm and clear skies for the peak of the Geminids meteor shower. However, early in the evening a slight rainbow encircling the first quarter moon did not bode well for the evening. By midnight, the sky looked like it might clear, so I dressed warmly, packed my small Brandon 80mm wide-field refractor and eyepieces, threw the sleeping bag and camping mattress in the back of the car, and headed up the hill to my favorite observing site.

By the time I arrived a thin cloud cover had moved back in, and high cirrus clouds covered a mackerel sky.  Despite the clouds which made the constellations look totally unrecognizable, I spotted 8 meteors in 20 minutes. This bodes well for a very strong showing of the Geminids this year. However, within an hour of my arrival, the cloud cover thickened and I beat a retreat to wait for tomorrow night. The Geminids have a very broad peak, so observing on Tuesday and Wednesday nights should prove rewarding as well.

If you have clear skies, I hope you've been outside watching the best meteor shower of the year. No optical equipment is needed. Just your eyes and the patience to watch the night sky.

Good viewing!

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Sunday, December 12, 2010

Dust Storm Update for The Geminids Meteor Shower

Sunday
December 12, 2010

The dust storm that started on Saturday continues unabated into Sunday afternoon and evening, with temperatures dropping and the wind continuing in full force. At 1:30 PM the conditions were:

Temp: 45 F
Wind Chill: 35 F
Avg. Winds: 20 MPH
Gusts: 34 MPH

I attempted to make this report from downtown Mitzpe Ramon, but all you can hear is the wind and my muttering something about the Geminids meteor shower:



The storm is supposed to begin tapering off by Monday noon, so it will be touch and go for the weather on Monday night when the Geminids peak.

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Succah in the Desert

Not far from Mitzpe Ramon is a rustic retreat where you can stay, isolated from civilization and all modern communications. It is called Succah Ba'Midbar (Hut in the Desert). It is located in a hidden valley just below the Wise Observatory.

Panoramic view of Succah Ba'Midbar

The buildings are all very rustic, built of succah materials. There is a central hut which has a home kitchen and large eating area, where guests are treated to home made meals. It is all very cozy and conducive to reflection and introspection. You can get cell phone reception if you climb one of the nearby hills; otherwise there is no telephone, TV, or Internet access.

Kitchen, dinning room, and common room of the Succah Ba'Midbar

Inside the dining room and common area

There are no electrical lights outside. Guests get kerosene lanterns to see at night, or else can use flashlights if they bring any. All electricity is generated via an array of solar panels. I don't know if the guests huts have electricity. I didn't think to ask. But without communications, who needs it anyway? Heat is provided by way of wood burning stoves.

Guest hut at Succah Ba'Midbar

One nice thing is that the Succah Ba'Midbar is located close to the Wise Observatory and our favorite viewing location above Mitzpe Ramon.

The Wise Observatory from a location near the Succah Ba'Midbar

For a different lodging experience you should give Succah Ba'Midbar a try. And don't forget to go observing with Astronomy Israel when you do!


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Moon Phases Calendar for December 2010

Saturday, December 11, 2010

Dust Storm Pummels the South

As predicted, a huge dust storm with winds between 60-75 kph pummeled Mitzpe Ramon today. This after a beautifully clear and calm night on Friday. The dust was so thick I couldn't go outside. As of this evening there was still dust and clouds in the air, but the winds had subsided somewhat. It looks like the weather will be touch and go for the peak of the Geminids on Monday night. Stay tuned for Mitzpe Ramon weather updates here.

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Friday, December 10, 2010

December's Geminid Meteor Shower - One of the Best of the Year

The Geminid meteor shower, one of the best of the year, is scheduled to peak next week on Monday night and Tuesday morning, December 13-14. In Israel, the first quarter moon will set at 11:53PM on Monday night, and will not interfere with observations after midnight when the most meteors can be seen. Expect to see 60-80 meteors per hour after midnight under a dark sky. The Geminids tend to be quite bright, so observing even under somewhat light polluted conditions can be very rewarding. This shower is the equal of the more famous Perseids meteor shower which occurs in August. However, the colder winter conditions of December's Geminids tend to discourage people from going outside to observe. This meteor shower also has quite an extended peak, unlike most that peak sharply during a single hour, so observing on other dates before and after December 13 can still show a fine display.

Meteor showers are named for the constellation from which they appear to come or "radiate", hence the term "radiant" for the circle in the sky where the meteors would appear to come from if you were to draw a straight line so they all intersect. In the case of the Geminids, the radiant is, of course, the constellation Gemini which should be rising in the NE around 10:00 PM in Israel. As the radiant rises higher in the sky throughout the night, more meteors can be seen.

The Geminids' radiant is near Castor in the constellation Gemini.

We will be out most of the night so come down and join us. Give us a call or send an email so we can direct you to where we will be. One major caveat - Israel is expecting some quite inclement weather beginning this Shabbos and extending for a few days. This includes very high winds and rain. So there is a chance we will be weathered out. Stay tuned here for updates as we get closer.
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Wednesday, December 8, 2010

Getting a "Crikey"!

We hosted a lovely pair of families from Bet Shemesh this evening, originally from Australia and England: seven boys and two sets of parents. Alot of maleness. I don't consider my job complete until I get at least one "Wow!" from everyone. Tonight I got one better with a "Kreike" from the Australians (or was it the Brits? It was too dark to tell.)!

It is a measure of how much we've lost when the first "Wow" of the evening comes from just seeing a really dark sky full of stars. It really is a "Wow" experience, now had all too rarely because of nearly ubiquitous light pollution. Even before becoming dark adapted, people looking at the sky from the dark skies around Mitzpe Ramon usually exclaim, as in "2001" (or was it "2011"?), "It's full of stars."

There was quite a bit of atmospheric scintillation, so the rising of Sirius, the brightest star in the heavens, was itself a great light show with the star twinkling almost every color of the spectrum, even green. We also saw quite a few early meteors from the Geminids, scheduled to peak on December 13-14, which may herald a good show this year, except inclement weather is being predicted for Israel then.

So, what was the "Crikey" experience of the night? It was the Double Cluster in Perseus, my favorite deep sky cluster, with literally thousands of stars filling the eyepiece of even a small telescope.

"Crikey," it's the Double Cluster in Perseus. 
Credit: Roth Ritter, Dark Atmospheres.
(Click for full-size image.)

We were cold and tired by the end of the evening, but I managed to round up a few of the group for this photo.



Emma and Yoel captured this picture of me showing the business end of the early vintage William Optics 4" refractor to the group.

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Friday, December 3, 2010

Cleaning the 40 Inch Mirror of the Wise Observatory Reflector - Part II

L1060696The 40-inch (40") main mirror of the Wise Observatory telescope in Mitzpe Ramon is cleaned about every six months. It is given a new aluminum coating about every two years, depending on conditions. The secondary mirror is cleaned much less often since its face is not directly exposed to the dust and dirt of the desert.

Technical Director Ezra's procedure for cleaning the 40-inch (40") mirror is as follows:

Rinse with distilled water -> rinse with tap water -> wash gently with detergent -> rinse with distilled water -> rinse with reagent grade ethanol -> drag dry with optical cloth -> touch up blemishes that can scatter light

Step 1:
Shai washes the surface of the mirror with distilled water as Ezra looks on.


Step 2: 
Ezra hoses down the mirror with tap water as Yevgeny and Matan look on.

Step 3:
Ezra carefully cleans the surface of the mirror with regular dish detergent and a sponge made of surgical cotton wrapped in TexWipe's TechniCloth III. Only the weight of the wet sponge itself is allowed to bear down on the mirror.

The cleaning cloth holding the surgical cotton is TexWipe's TechniCloth III

Ezra's choice of cleanser.
Step 4:
Shai rinses the mirror with distilled water while Yevgeny and Matan spin it.

Step 5:
Ezra purges the surface of the mirror with ethanol, while the team points out areas that need attention.

Step 6:
Ezra swipe dries the alcohol from the surface of the mirror.
Step 7:
Ezra touches up chips on the mirror edge with black marker to reduce scattered light.

A chip in the mirror's edge, blackened with marker to reduce scattered light. The mirror was delivered with this edge chip. It has a negligible effect on performance, but amateurs would never accept a mirror with such a large blemish on their much smaller optics. Of course an amateur mirror only costs a few thousand dollars and a few days to replace. Not so a large observatory mirror.

From left: Ezra, Matan, Yevgeny and Shai view their finished work.

The clean, 40" mirror is covered while the team takes a break before reversing the procedure to remount the mirror.

Saying goodbye, a stark desert of dust and rock, waiting to re-coat the mirror, surrounds the observatory on all sides.

L1060760
Goodbye for now to the Wise Observatory.

Thank you for allowing me to observe and photograph the cleaning of the 40" mirror.

(Cleaning the 40" Mirror - Part I)

Addendum:
Some folks on the Cloudy Nights astronomy forum wanted to know what it took to clean a really big mirror. This photo was posted in response.

Cleaning a REALLY BIG telescope mirror.

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