Volume XVII No. 10 July 2006 gggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg THE NEW RED SPOT ON JUPITER By Clif Ashcraft One of the most prominent visible features on the planet Jupiter since the dawn of telescopic astronomy has been the Great Red Spot, or GRS. It has been known since the invention of the telescope and is a favorite of amateur astronomers. The GRS is a large oval anticyclone. This means that the clouds circulate clockwise for a southern hemisphere object. It is so big that both Earth and Mars could fit side by side within its boundaries. The GRS lies between the South Equatorial Belt (SEB) and the South Temperate Zone (STZ). The time between meridian transits of the GRS has recently been 9h56m, but this has varied in an unpredictable way over the years, The GRS is quickly overtaken by objects in the SEB (the period of Home of Amateur Astronomers, Inc. Photo courtesy Hank Adams Sperry Observatory began as a $150,000 endowment to what was then Union Junior College by Mrs. Frederick W. Beinecke and son William, and was dedicated on May 21, 1967 in honor of William Miller Sperry, Mrs. Beinecke's father. Mr. Sperry was a local philanthropist, president of Sperry & Hutchinson Co., and an avid amateur astronomer. ______________________________________ the SEB is that of Longitude System I, 9 h 50m30s) and is also overtaken, but much more slowly, by objects in the STB (the period of the STB is that of Longitude System II, 9h55m4s). The color has varied from a dark brick red to considerably paler shades over the years, but has always been reddish in color. The color is thought to be the result of the deep circulation dredging up dark organics from lower layers in the atmosphere1. There had been no other red anticyclones on Jupiter, but there were numerous smaller white oval storms that are also anticyclones. Three prominent white ovals appeared in 1939 following a disturbance in the South Temperate Zone2. They were named white ovals FA, DE and BC because they had first appeared as elongated dark streaks between cyclonic storms F and A, D and E, and B and C. The streaks shortened, lightened in color, and developed anticyclonic circulation to become the white ovals. They have been tracked by Jupiter observers ever since, and have been the subject of study by the Galileo spacecraft3. As they drifted about in the STZ, the ovals have had numerous close encounters with each other, however, in 1998, ovals DE and BC merged into a single spot that was designated BE4. In late March of 2000, ovals FA and BE also merged into a single large white oval designated BA5,6. Over the next few years, amateur observers followed BA. Some excellent color webcam images were obtained by Damian Peach between December 2003 and May 20047. In his images, the color of oval BA remained white. It was still white when observed by Christopher Go in November of 2005 but had turned brown by December 2005, and was definitely red in an image he obtained on February 27, 20068. This is the image shown on the NASA web site announcing the discovery of the new red spot9. Fig.1 Feb. 15, 2006 (annotated) taken at Sperry Observatory by Clif Ashcraft and Ray Shapp. It was coincidental that Ray Shapp and I were at Sperry Observatory on the morning of February 15, 2006. We were testing the newly aligned objective of the 10-inch refractor by doing webcam imaging of Jupiter. (Ed. Note: Thanks for the credit, Dr. Ashcraft, but all my dad did was hold your coat.) The same image of Jupiter is in figures 1 and 2. The only difference is that figure 1 is annotated. This image was obtained from a video taken through the 10-inch f/15 refractor using a Philips ToUcam coupled to the telescope with a 2x Barlow lens (effectively f/30) at 5:30 on the morning of February 15, 2006. In this image which was processed from the video using Registax3 and Photoshop, the GRS has rotated past the limb on Fig. 2 Feb. 15, 2006 Same image (no annotation). the left (south is up) and the still distant Oval BA has just crossed the meridian and is indicated by the line in the annotated image in Figure 1. A distinct pink shade is evident in Oval BA just 12 days before the discovery of the new red spot was announced. I only recently noticed that we had a pre-discovery image. (Continued page 3 RED JUNIOR) CALLING ALL SCI-FI BUFFS By Leticia Shapp Mr. Salimbene begins his article on page 5 about mounting the Margaret Salter Genesis refractor on the 24-inch reflector and the upgrading of the big telescope's focuser by citing scenes from the movie, "Forbidden Planet". It is really good imagery and I hope it heightens your interest in the rest of his article. That leads me to wonder whether there are any sci-fi buffs among us who can write an article for the August ASE in which story tellers or screen writers of years past imagined devices or processes or discoveries in space sciences or applied physics that are only recently becoming a reality. Certainly our many robotic space missions have their parallel in the Class I and Class II probes in the Star Trek series. The origin of this idea undoubtedly goes back much farther. A survey of less obvious ideas might be more instructive and entertaining. If you can speak Klingon, and you have some familiarity with modern science, please send me your article (but render it in English). Original illustration of Columbiad from Jules Verne's "From the Earth to the Moon" published in 1866 http://jv.gilead.org.il/pg/moon/ Also in this issue, on page seven, is what we hope is a faithful reproduction of the text of an obituary of Mrs. Salter. The original was found wrapped around the Genesis. The document was stained and nearly illegible in part. It contains many details of Mrs. Salter's professional career(s). Except for the actual date of death, it almost seems that the obituary might have been written by Mrs. Salter herself. My genuine thanks go out to all the contributors whose creative efforts are making my first editing job a real joy. RED JUNIOR (Continued. from page 2) Since its discovery, the new Red Spot has gotten much closer to the GRS. The image below was obtained on June 13, 2006 at 9:44 pm EDT using my home observatory 12.5-inch f/6 Newtonian coupled to my Philips ToUcam with a 5x Powermate. The new red spot is just above and to the right of the GRS and is essentially the same color as the GRS. It is expected to pass the GRS early in July. A close pass to the GRS has occasionally disrupted cloud belt features, however Junior is expected to survive. In any event, weather permitting, I am planning to image the event and its aftermath. Stay tuned… Perrineville, NJ. 1 http://www.physics.uq.edu.au/people/ross/phys2081/planet/jupiter.htm 2 http://www.windows.ucar.edu/tour/link=/jupiter/atmosphere/J_white_ovals_birth.html 3 http://www.webs.wichita.edu/lapo/amb/jup.htm 4 Reported in paper [30P.15] at the meeting of the American Astronomical Society meeting of Oct. 14, 1998 by BM Fisher et al. 5 Icarus, Volume 149, 491-495 (2001) Sanchez-Lavenga et al. 6 http://www.popastro.com/sections/planet/plannews.htm 7 http;//www.damianpeach.com/jup_0304.htm 8 http;// www.christone.net/astro/9 http;//science.nasa.gov/headlines/y2006/02mar_redjr.htm Fig. 3 June 13, 2006 Red Jr. now much closer to GRS. ___________________________________________________________________________ STEWART'S SKYBOX By Stewart Meyers Sorry about missing the first edition of the ASE (Asterism, Summer Edition). This was due to some misunderstanding about when the ASE would actually start. I was told that it would be for the summer of 2007. But, that has all been cleared up, so on to the article. Back in the November 2005 issue of the Asterism, I had written an article about 99924 Apophis and Near-Earth Objects (NEOs) in general where I discussed how much of a threat they actually pose, possible defenses, and even how the Earth itself is well protected. But there has been some news on the NEO issue recently and it turns out that the threat of these objects is literally much less substantial than previously thought. NOW THIS STORY IS TURNING JAPANESE This recent news actually started in Japan back in 2003, when the Japanese space agency launched a probe called Hayabusa (named after the peregrine falcon, not the World War II fighter plane). The mission of the probe was to go to an asteroid and, after detailed imaging and other studies, almost touch down on it and use a novel sampling device to capture small pieces of surface material for later return to Earth. The sampler consisted of a gun that would fire a small pellet at the asteroid. Tiny pieces of the asteroid would be broken off, and go into a funnel that would take them to a sample chamber. That was the plan and it looked good on paper. But this is the Japanese space program we're dealing with. While Japan is one of the world leaders in robotics (in some areas of the field they are way ahead of the United States), they seem to have nothing but trouble when it comes to spacecraft. Hayabusa was no exception. Despite the achievement of actually making it to its destination in 2005, Hayabusa still had trouble and soon started breaking down. A drop probe failed and is thought to have missed the asteroid (now named Itokawa after a noted Japanese astronomer) completely. Then the "landing" attempts failed except for the last one, which may or may not have succeeded in obtaining some samples. And as a final(?) insult, the fuel system developed a leak which rendered Hayabusa almost uncontrollable. Control was eventually restored, but Hayabusa missed the window for an Earth return. Japanese scientists hope to have it return in 2010, about three years late, but no one is terribly optimistic about the likelihood of success. PLENTY OF NOTHING While the Hayabusa mission was largely a failure, some useful science did come out of it. Numerous images of Itokawa were taken revealing that it is an irregularly shaped asteroid about 535 meters (1783 feet) long and the width varies from 294 meters (980 feet) to 209 meters (697 feet). Itokawa's surface is quite varied with large smooth areas as well as rather rocky ones. But the really astounding discovery was soon to come. As Hayabusa was maneuvering around Itokawa, the asteroid's miniscule gravity was affecting the motion of the probe. This gave a very good idea of the mass of the asteroid. Coupled with the volume and likely composition of Itokawa, this gives the bulk density of the asteroid. The result, just announced recently, is unbelievable. Itokawa has an incredibly low density. It is so low that the only credible explanation is that it is made up of about 40% empty space. That's right, empty space. Absolutely nothing. To give some idea of that level of porosity (the technical term), consider that a pile of loose sand is about 20% empty space. Now, one shouldn't get the idea (though some nuts might have already done so) that Itokawa is hollow with just a solid outer layer. The truth is more interesting and significant. Itokawa most likely is a number of small space rocks (the components are probably too tiny to deserve the term asteroid) of varying sizes stuck together by their own gravity. The reason Itokawa looks like a solid single object is that even smaller debris and dust cover the whole assemblage, rendering the seams invisible. And it appears that Itokawa may not be alone in this regard. Quite a few, if not most, NEOs may be of a similar nature. True, there are some like Eros, which the NEAR mission confirmed was a single conventional rocky object, but Itokawa appears to represent the majority of NEOs, a conclusion based on a study of asteroid rotation rates made by Petr Pravec of the Ondrejov Astronomy Institute in the Czech Republic and supported by later work from Bill Bottke, currently at Southwestern Research Institute. What does this mean in terms of the threat of cosmic impact? Read on. THE INCREDIBLE SHRINKING THREAT One fact that puzzles scientists about Itokawa's density and composite composition is how it has managed to stay together. Anything that porous would likely be rather fragile. While the scientists are still figuring that one out, this information does have an effect on the impact threat. Due to its porous nature, the "conventional" means of deflecting NEOs will be quite ineffective on such an asteroid. Any impact or even a nuclear blast would merely crush part of the asteroid like the crumple zone of a car with minimal effect on the asteroid's motion. Of course, the "tractor" method Dr. Lew Thomas mentioned in his February 2006 Asterism article would still work. But, such methods would probably be unnecessary. In my November 2005 article, I mentioned how tides are caused by the difference in gravitational pull on one side of an object versus that felt on the opposite side. For solid single objects, the forces holding them together are able to hold up against the tidal stress that Earth's gravity could induce in them. However, for an object like Itokawa, that is not the case. Such a fragile object would easily be torn apart. And the resulting chunks would likely be small enough to burn up in the atmosphere with very few even surviving to become meteorites. And since many, if not most, NEOs are probably this kind of object, the threat is a lot less than has been previously thought. IMPLICATIONS One effect of the revelation of how insubstantial rubble-pile asteroids are would be asteroid mining, which would no doubt be a bit more difficult since these asteroids could fall to pieces at the slightest strain. But, since nobody has any idea how to mine asteroids in the first place, this would be a concern for the future. For now, we can pretty much scratch NEOs (except for the solid ones) off the list of things to worry about this summer. *** UPGRADING THE 24-INCH REFLECTOR By Phil Salimbene I'm sure that many of you have seen the classic science fiction movie Forbidden Planet. That's the one with Walter Pidgeon as Dr. Morbius, Anne Francis as his daughter, Altaira, Leslie Nielsen (in a non-humorous role) as Commander Adams of the United Planets Cruiser C-57-D (space ship) and, of course Robby, the robot. As you may remember from the movie, Dr. Morbius and his daughter Altaira are the last surviving members of the Belerephon exhibition; which was sent to Altair 4 from Earth twenty years earlier. While marooned on Altair IV, Dr. Morbius discovers the ruins of a race of extinct, super beings called the Krell. Forced to explain how he and his daughter have survived alone for twenty years, Dr. Morbius gives Captain Adams (Leslie Nielsen) a tour of the still functioning Krell machinery which fills a cube twenty miles on each side. In one scene, Dr. Morbius explains that the Krell machinery has been "self maintained for over 2,000 centuries". Dr. Morbius goes on to further explain that "approximately sixteen years ago an automatic upgrade of the equipment took place". Well the 24-inch reflector at Sperry has not been around for 2,000 centuries and, unlike the Krell machinery, no "automatic" upgrade has taken place. However, I'm pleased to inform you that the Executive Committee and a team of dedicated members (non-Krell) have "quietly" upgraded our 24-inch. From a Trustees' point of view, I thought that the membership would be interested in knowing some of the details of our work. In November, 2005 the Executive Committee approved funding for upgrades to our 24-inch telescope. Approximately $1,200 was approved for a new state-of-the-art, 9:1 ratio focuser from Astro-Physics and for the attachment of our TeleVue Genesis, donated by the estate of Margaret Salter. Each upgrade posed its own set of problems. THE FOCUSER: Purchasing the focuser was the easy part. All it took was one phone call and, $586.00 later, it's on its way. Attaching the focuser was another issue. We were attempting to attach a 2005 piece of technology to a 1970's era telescope. A spare bayonet mount, left over from the initial Astro-Physics telescope construction project was located by Al Witzgall. A 6-inch thick, round piece of aircraft-grade aluminum was sourced, purchased, and milled by Tom Koscica to fit the bayonet mount on one side and the state-of-the-art, 9:1 ratio "Feather Touch" focuser from Astro- Physics on the other. The parts were then permanently bolted together to form one very solid unit. In less than five weeks, all the parts were ready to be tested. Astro-Physics Feather Touch focuser Thanks to the skill and technical ability of several of the members, things worked out fine. To give you a sense of how well, in the initial proposal, money was allocated to have all the parts anodized. But as soon as the focuser was mounted to the 24-inch no one would allow it to be removed to be anodized. The improvement was that dramatic. Vince Henderson and Ed Carlos were in the dome that night and both said that the 24-inch was "brought back to life". The team was having so much fun being able to focus and "see" objects that were very difficult to spot before the focuser upgrade, that the Instrument Qualification Committee paid for a new 1/10-wave diagonal. THE TELEVUE GENESIS: This 101mm refractor was donated by the estate of Margaret Salter to AAI (circa June 1999). The proposal, which was approved by the Executive Committee, was to replace the 7x50mm finder 'scope on the 24-inch with the Genesis. The thought was that the Genesis was a tool that was ours but currently unused. Mounting the Genesis on the 24-inch would open up a wide range of opportunities in the such as: " Visual Observing, as spotting instrument, guide 'scope, providing a second 'scope for visual observation during public nights, and potentially for solar observing (through the addition of a $90 filter) during "special" solar events or parties " Astrophotography, via web cam, or through member-owned Sony, Canon, or Nikon CCD cameras (image projection or field stop techniques) or by use of the club's research-grade SBIG ST-8 CCD camera. " Training or providing handicap access via wireless transmission of imagery to the first floor classroom of what's taking place at the 24-inch. Here again, finding the component parts was the relatively easy part. Yes, some incorrect items had to be returned. And, yes the attachment plate required more milling than had been expected. In the end, however, things came together thanks to Tom Koscica, Clif Ashcraft, Al Witzgall, Ed Carlos, and Steve Clark, TeleVue Genesis is a 101mm, 540mm focal length, f/5 Apochromatic with a 4-1/2º field in a 31mm eyepiece at 17 power. We are still rebalancing the 24-inch to compensate for the added weight of the new focuser and the Genesis, however, both the 24-inch and the Genesis are available and functional. The Forbidden Planet story ends in the classic way: boy (Commander Adams) gets girl (Altaira). Evil beings (monsters from the ID) are destroyed, and Robbie, the robot, flies space ship home to Earth. All is well with the Universe as can now be seen through our 24-inch instrument. Below is the budget and summary of expenses. Both projects were completed under budget. *** CLUB EMAIL ADDRESSES editor@asterism.org Editor of The Asterism membership@asterism.org AAI Membership Chair trustees@asterism.org All three Trustees of AAI exec@asterism.org Executive Committee ray@asterism.org Ray Shapp for the website *** DOME DUTY FOR JULY 7 July Team E 14 July Team A 21 July Team B 28 July Team C ______________________________________________________________________________________ MEMBERSHIP DUES Regular Membership: $21 Sustaining Membership: $31 Sponsoring Membership: $46 Family Membership: $5 Sky & Telescope subscription: $32.95 Astronomy subscription: $34 First Time Application Fee: $3 Dues can be paid to the Club Treasurer or Membership Chairperson at the Observatory. DR. LEW'S SEMINARS Some of the topics for upcoming seminars include: " Planets beyond Pluto. " Rotation of the Milky Way. " How close must we be to Venus to witness it eclipsing the Sun? " Measuring the diameter of a lunar crater from Sperry Observatory. " Measuring the mass of the Sun. " Measuring the mass of the Earth *** All schedules above and on page 8 were accurate at time of publication. Please check www.asterism.org for latest information (click on "Club Activities") Margaret Salter, 1919-1999 Margaret Salter, 80, daughter of Malcolm Miller, died June 9, 1999 of lung and liver cancer and recurring and serial lung infections (including TB), possibly aggravated by dust, fungus, and cigarette smoking. A Springfield Telescope Maker, in her last years, she helped build the McGregor observatory, at Stellafane in Springfield, Vermont. Assistant Professor of Speech and Theater, Monmouth University, succeeding her husband, John, (disabled MS; died 1977). She taught one year as lecturer 1967-8, and 5 years (Asst. Prof. 1968-73) with colleague Lauren Woods and others, directing GB Shaw's Androcles, and one other. Born in Pittsburgh, raised in Knoxville, acted with a professional stock company at age 4. Auditioned on her own rather than take a referral, she played a season at Barter Theater (1941) under family friend, Bob Porterfield, where she met Greg Peck and friend Charles Korvin. Acquaintance, Patricia Neal, came out of Knoxville High School shortly before, and friend, Jimmy Dobson (film actor, University of Tennessee), put her up in his New York City apartment, and introduced her there. Margaret's mother was an opera singer, Elizabeth Putnam, repeatedly retired to a sanitarium in poor health. Her father was a lumberman, impresario, theater critic for the Knoxville Journal, and producer, (died 1963). As a young girl, Margaret met the luminaries of the era backstage: Galli Cunci, Heifetz, etc. Sister, Betty Moore (Mrs. Ralph Moore), died mid-1970s in Florida. Margaret received her BA 1941 and MA in French (1942) at UT Knoxville, translating Marius for the stage. Pauline Capell Walker Prize for scholarship, 1941. Teacher and Director of Drama, Canton, High School, Georgia. During WWII (1942-3), became an air traffic controller at Atlanta. Later became the first woman Controller in the tower at LaGuardia Field, NYC (she believed she was the second woman in US control towers). Tower certificate 1943, weather observer, 1943, Junior rating, 1946. She had transferred from Atlanta to New York City to look for acting jobs on the side, and acted in a few TV ads, one on WPIX under the direction of Freddie Bartholomew, sang Gilbert & Sullivan with Chartock Co., chorus, (music director and friend Frank Miller, first cellist, NBC/Chicago), studied dance under Jean Erdman, (Bill Campbell's wife), friend of artist J. Ziltzer. Married John Salter, 1948, acquainting with in-law Leone, and Frederick Minassian, John Xeron (artist), Ajemians (Anahid, Vn, Maro, Pf, A's husband G. Avakian, Columbia Records), and C. Thompson, and C. James, Hercule, and Theodore Nicholson (restaurateurs). Agitated for school crossing light and play reading club. With friends, became leading woman and director at Pavilion Theater, 1951, stock company, E. Almstead, NH, directed one, played staring leads. Learned play production informally from Milton Smith, Columbia, worked Monmouth College (later U.Y). Lived in Long Branch, New Jersey, acted with the Navesink players, older leads, "Separate Tables" and "The Pleasure of his Company", assisted backstage briefly at Center Drama Group, Long Branch. Attended several years, meeting G. Gordon Liddy and Ted Mack, and listening to presentations by Ralph Nader, Danny Kaye, Glenn Seaborg, and Jack Anderson. Failing to get tenure as part of a personal dispute, she left Monmouth and worked a year at Ranney School, putting on "The Magistrate" and negotiating for the US rights to the London musical "Jack The Ripper" which she had seen on her second London trip. Adjunct Faculty Kean College (NJ) 1974-77, Bergen Community College, 1978. Worked ten years at Warwick Group (Insurance), Morris Twp., NJ, first as telephone receptionist, then editorial assistant, and retiring as feature writer. In 1990, moved to Freehold, NJ. She joined Amateur Astronomers, Inc., Cranford, in 1973, Qualified Observer, 1974, became a Life member (1985) and Board member. Ten years Recording Secretary, Trustee three years, Chair of Nominating Committee one year, first woman senior QO, and, for the past several years of her life, Chairperson of the Observatory Committee. Associate member, Springfield Telescope Makers, (Vermont) 1989, constructing a 6-inch Newtonian reflector (first light 7/21/94) for her full membership. Listed in Marquis Who's Who of American Women, The World Who's Who of Women, the Dictionary of International Biography, 0- 900332-75-1, 41-7,..322-54-9. Notable Americans of the Bicentennial Era 1976, American Biographical Institute. Memberships AAUP, IPA, AAI, STM. Died at peace, Morristown Memorial Hospital. Survived by a son, Jeremy. Services at Sperry Observatory, Cranford, at Stellafane, Springfield, Vermont, and Shoreland Cemetery, Hazlet, New Jersey. *** ORIGIN OF THE NAMES OF THE DAYS OF THE WEEK By Dr. Lew Thomas Our days of the week are named for ancient Roman or Teutonic gods and the rule for naming days goes back even farther in time. It was thought that each hour of a day was ruled by a particular god. The day, in turn, was named for the god who ruled the first hour. The planets were also named after the gods and can be listed in terms of the speed of their observed motions through the sky: Saturn being the slowest and the Moon, the fastest. Such a list, with their corresponding days, is given in the following table. Planet Anglo-Saxon Italian 1 Saturn Saturday Sabato 2 Jupiter Thursday Giovedi 3 Mars Tuesday Martedi 4 Sun Sunday Domenica 5 Venus Friday Venerdi 6 Mercury Wednesday Mercoledi 7 Moon Monday Lunedi In the above table, we give the equivalent Italian names for the days of the week so that the correspondence between the planets and the days may be complete. Teutonic gods have been used in the Anglo-Saxon notation for Thursday, Tuesday, and Friday, but the Italian retains the planetary correspondence. In the case of Jupiter, the Italian Giovedi comes from the Greek Zeus. We see this when we refer to the Jovian planet. Our Thursday was named for the chief Teutonic god, Thor. (Ed. note: Wikipedia gives an alternate spelling of "Tiw" from the Old English for the god of single combat and heroic glory from which we get the name "Tuesday". See http://en.wikipedia.org/wiki/Tyr The "Calendars through the Ages" website at http://webexhibits.org/calendars/week.html cites Frya as the source for our "Friday". In Norse mythology, Frya is a goddess of love and fertility. She shares some of the atributes of Venus.) The Anglo-Saxon god Tyr from an 18th century Icelandic manuscript gave us the name "Tuesday". Now to use this table, let us start with Saturday for which Saturn rules the first hour. We then count down the list for 24 hours (each time you get to the bottom of the list continue at the top again). After 24 hours have been counted, we come to the Sun and so the day following Saturday is Sunday. Again a 24 hour count will end on the Moon, or Monday. In this manner the days of the week become Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, and Saturday. _______________________________________________________________________ FRIDAYS AT SPERRY July 7, 2006 The Sloan Digital Sky Survey -- The Telescope, Its Purpose, and How It Works Clif Ashcraft July 14, 2006 Behind The Scenes At The Keck Telescopes on Mauna Kea (includes 43 minute video) Alan Midkiff July 21, 2006 How To Buy A Telescope Steve Clark July 28, 2006 TBA With rare exceptions during the past two years, the informal talks at 8:30pm on Fridays have been given by the same seven people. If you have a special interest in any astro-related topic, please consider sharing your enthusiasm with the rest of us. To schedule a talk, just send me the date and title. I would be glad to help you prepare a PowerPoint presentation. Ray Shapp ray@asterism.org *** Logo for Asterism, Summer Edition credit: Justin Shapp *** THEATER IN THE SKY by Ron Ruemmler July 2006 provides a month-long opportunity to see the planet Mars at its dimmest possible. On August 28, 2003 the Red Planet had a magnitude of -2.9; its brightest in 60,000 years. All the conditions are reversed this month. With a magnitude of +1.8, Mars is just 1 1/3 percent as bright as it was three years ago! What does it take to minimize the brightness of Mars? First, we need to maximize the distance from Mars to the Sun. This event, aphelion, occurs once every 26 months and just happened on June 25. Second, we need to maximize the distance from the Earth to the Sun. Our aphelion occurs on July 3. Finally, we want the angle that the two planets make with the Sun to be large, but not too large. Obviously, if the two planets formed a straight angle with the Sun in the middle, we couldn't see Mars at all. But there's another problem. Whenever a solid body starts to turn its illuminated face directly toward us there is an intensification of the reflected light. That's why the Full Moon is ten times as bright as the "half" Moon, instead of merely double. In fact, the calculated brightness of Mars is listed as +1.6 for its passage behind the Sun this October. Although Mars is still half a magnitude brighter than the North Star, we still need a little help to find it. For the first week of July, it is low in the west to the upper left of Saturn moving slowly toward Regulus, the heart of Leo, the Lion. On the 2nd, Regulus, Mars, Saturn and Mercury form a long, evenly spaced line to the lower right ending at the WNW horizon in twilight. On the evening of the 22nd, the orange planet is just above, and slightly dimmer than, blue-white Regulus. Probably the easiest chance to spot Mars is on the 27th when it is just 3 degrees to the lower right of the thin crescent Moon. Binoculars will help for all these events. In other business, Jupiter is still spectacular in the southwest anytime before midnight, and is particularly well placed near the Moon on Independence Day. Venus actually gains a little altitude over the rising Sun this month. Mercury jumps into the morning sky at the end of July, heading for a rendezvous with Venus in August. The waning crescent Moon passes through the southern half of the Pleiades star cluster on the morning of the 20th. This is a reverse rerun of the event of the evening of April 1st. This time the bright, leading edge of the Moon overrides the stars, so their disappearances are not so dramatic JULY SKY CALENDAR 3 MON 12:36 PM First Quarter Moon 3 MON 6:00 PM Earth at aphelion; farthest from the Sun 4 TUE 9:30 PM Moon right of Jupiter and left of Spica 5 WED 9:30 PM Moon below Jupiter 6 THU 9:30 PM Very dim Mars midway between Regulus and Saturn 7 FRI 9:30 PM Antares just left of Moon; occultation visible from Australia 10 MON 11:03 PM Full Moon 17 MON 3:13 PM Last Quarter Moon 18 TUE 3:00 AM Mercury passes between Earth and Sun into morning sky 20 THU 4:00 AM Crescent Moon occults lower half of Pleiades 20 THU 9:20 PM Mars 1.2 degrees right of Regulus 21 FRI 9:20 PM Mars 0.8 degrees upper right of Regulus 22 SAT 9:20 PM Mars 0.7 degrees above Regulus 25 TUE 12:31 AM New Moon 27 THU 9:00 PM Regulus lower right of crescent Moon with Mars midway between ***