Date: Sat, 24 Dec 2005 13:12:53 -0700 From: Neal Galt Subject: Seeing crescent Venus At lunch on 12/23/2005 While visiting in Tucson. AZ, I drew a circle, a half circle, and a crescent on a piece of paper and showed the symbols to my 5 and 7 year old grandsons. We discussed the shapes and the moon for about 15 minutes, until they were compfortable describing the phases. That night, about 6 PM, the 5 year old was standing with me in a line for a horse pulled trailor ride through a highly decorated residential area. I pointed out Venus to him and asked what the shape was. He answered immediately upon gazing at it....."That's a crescent"! Ten minutes later, when the 7 year old arrived with Moma, I asked him the same thing and got the same immediate reply. I'm not surprised that young eyes can see the crescent shape, but I am surprise that I have never heard of any reference to the phases of Venus prior to the invention of the telescope, considering that it is that easy for those with good eyesight. Has anyone seen or heard of any historical references to this? Merry Christmas, Happy New Year, Merry anything else and have fun and be loved. Neal ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- Neal, et al; I was observing at a pretty good spot with clear, pretty stable skies. This observation is from Sept 25, 1984 when there was a conjunction of Mars, Mercury and Venus before sunrise. It is from Four Peaks Road, which is 40 miles to the east of Phoenix, Az. Using my 17.5 inch stopped to 5 inches between the spider vanes and a 20mm Erfle eyepiece the phases of Mercury and Venus were identical at about 20 percent illuminated. I took some notes on the conjunction and looked at the almost full Moon overhead and then it started to get a little lighter toward the eastern horizon. I decided to take one more peek at the planets while it was dark enough to see them easily. As I lined up Venus naked eye to get it into the 8X50 finder, I saw that it was a crescent. I was NOT looking to see that naked eye. My notes say that I could not hold it steady, only in brief moments and that the crescent was most prominent with averted vision, that is how I saw it the first time--out of the corner of my eye as I moved the old Dobsonian toward the field of view of Venus. I was 34 years old and had about 5 years experience observing the sky at the time. I have only been able to repeat that observation once, and that was about 2 years after this in the evening sky. I can't find the notes from that night. I am now 56 and those eyeballs are not available to me anymore;-( Thanks for reminding me of a fun observation; Steve Coe ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- Date: Sat, 24 Dec 2005 15:39:05 -0500 From: Tom Kunsitis Subject: Re: Seeing crescent Venus At 03:12 PM 12/24/2005, you wrote: >I am surprise that I have never heard of any reference to the phases of >Venus prior to the invention of the telescope Actually, I have read that there have been some ancient records of Venus presenting a crescent phase. They are mostly from Mesopotamia which describe the horns of Venus. However, they say some similar things about Mars. It is a matter of text interpretation and there is no one around from then to ask for clarification. Merry Christmas and clear skies to all. Tom Kunsitis - Richmond, Virginia USA ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- Date: Sat, 24 Dec 2005 17:42:57 -0700 (MST) From: Brian Skiff Subject: RE: Seeing crescent Venus >> He answered immediately upon gazing at it....."That's a crescent"! I wish you'd asked the second question: which way is it oriented? What's astigmatism and what's seeing the Venus crescent? I just had a look at Venus about 5 minutes after sunset, with the sky bright enough that there were no stigmatic flares/spikes in the image visually. About the best I would say is that it was maybe not quite stellar, but it was too small to see any shape. The best I could do, in fact, was an elongation such that if there was a crescent, it appeared to be opening southward (i.e. to the lower-left in the alt-az sense), which is nonsense. A moment later I used 7x35 binoculars to see the crescent, but it's very small even at 7x. So I guess I want to be skeptical about kids' resolving the crescent. It looks as though the coming week or ten days is especially favorable for trying this again as Venus approaches inferior conjunction. \Brian ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- Date: Sat, 24 Dec 2005 23:19:18 -0700 From: Neal Galt Subject: Re: Seeing crescent Venus Brian...shame on you. The kids had NO advanced information that Venus even went through phases like the moon. Two kids....five minutes apart...same answer. Without thinking, kids just tell the truth........good or bad. Now's the time, that's why I brought it up. Lots of posters in this group have young children or young grandchildren. Make sure they have the vocabulary to describe the sight, or draw it, and let's see what we get. I gave the introduction. We have about a week or so. For those of us who write articles, this may be some fodder for the masses! Young eyes may be more perceptive than previously thought. Neal ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- Date: Sat, 24 Dec 2005 23:46:25 -0700 (MST) From: Brian Skiff Subject: Re: Seeing crescent Venus >> Brian...shame on you. The kids had NO advanced information.... But you did prime them a bit with the circle/crescent chat. I'm no psychologist, but a crescent shape is more interesting than a circle. Back in the Comet Halley days I often asked little kids about the color of the comet through the Lowell Clark. Below a certain age, and to the extent they knew what words went with which color, the response could be just about anything, including "orange" and "purple". If this opportunity arises again, have the kids make a 'C' (with left or right hand...) with their curved thumb-and-forefinger and have them show which way the crescent is oriented. ...preferably without the crescent Moon in the sky, since the orientation will be the same. \Brian ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- Date: Sun, 25 Dec 2005 08:04:21 -0700 From: Neal Galt Subject: Re: Seeing crescent Venus Brian...fair enough...hopefully some more on the group will check it out. I'll be seeing the same two grandchildren tonight in Tucson. I'll set up a drawing independantly, and see what we get. Might even be a few neighbor kids around, who havn't heard the word crescent. I'll just see if they can draw that "star" and see if we get a five pointed star or something else. Or would that be priming them in the wrong direction? Maybe I'll just use draw the shape " of the bright light". Cheers....Neal ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- Date: Sun, 25 Dec 2005 13:51:33 -0500 From: "Sue French" Subject: Re: Seeing crescent Venus Brian, I did ask that question once. In my old neighborhood, I had a 4-inch Unitron set up at the end of my driveway to look down the road at Venus. The guy from across the street came out and asked what star I was looking at. I said that it wasn't a star, it was a planet. He asked what the difference was, so we are not talking about an astronomically knowledgeable person here. So I explained the difference and pointed down the street at Venus. I told him that Venus was interesting right then because it had a pretty crescent phase like you sometimes see with the Moon. I asked if he'd like to see it, and still staring down the road he said he could. Expressing astonishment that that would be possible, I asked him how the crescent was orientented. Without pause he described it exactly. This man was in his 20s and color blind - not that I know if color blindness is pertinent, but I thought I'd mention it. Clear skies, Sue ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- Date: Sun, 25 Dec 2005 11:35:09 -0800 From: Peter Abrahams Subject: seeing crescent Venus Here are some texts on this subject. I have also heard other anecdotal accounts of children seeing the crescent. I believe that kid's eyes are superior in this respect because of lower interocular scatter & glare. -------- US Astronomical Expedition to Chile, 1849-1852, vol. 1, p38, J.M. Gillis, good seeing conditions in Santiago, "Venus...its crescent was more than once seen with the naked eye." (cited in J.R.A.S.C. 25 (1931) 269, Notes & Queries. ref. J.R.A.S.C. March, p131.) -------- Hostetter, Clyde. The Naked-Eye Crescent of Venus. Sky & Telescope 79:1 (Jan. 1990) 74. 'Several [naked eye] sightings of the crescent are listed by Patrick Moore in his book 'The Planet Venus' (revised edition, 1982). One is an account of a 12-year-old boy who reported seeing the crescent before he knew that Venus had phases. In another instance, a distinguished member of the Royal Astronomical Society, W.S. Franks, informed the Society that his son had seen the crescent frequently between 1890 and 1900. In 1852 Sir John Herschel received a letter from Rev. D.T. Stoddard, an American missionary living above 5,000 feet near Lake Urmia in Persia. Stoddard reported seeing both the Venus crescent and the moons of Jupiter without using his telescope. Charles Doughty, a 19th-century traveler in the Arabian desert, recorded a Bedouin's comment that Venus was "hanging like a scimitar in the sky." The Bedouin also described small "stars" that surrounded Jupiter and were presumably its moons. I asked readers of Sky & Telescope in May, 1988, to look for the crescent as Venus approached inferior conjunction that June. One response came from Douglas Muenzer, a Texas amateur. "My vision is 20/10 in my left eye and 20/20 in my right eye," Muenzer wrote. "I looked at Venus until after sunset and had no problem at all seeing the crescent shape with my naked eye." This sighting was on May 4th, more than a month before inferior conjunction on June 12th. Eight days later on May 12th, during another clear evening, Muenzer reported he saw the crescent again. --------- From: Clyde Hostetter To: talk@sas.ORG Subject: Crescents of Venus While on an assignment in Saudi Arabia some years ago I acquired an artifact which appears to indicate that the crescent phase of Venus was known and observed as early as 2000 B.C. -- perhaps even earlier. This seems improbable, since persons today with average/normal vision cannot see the crescent without optical assistance. However, I have some evidence, both historical and contemporary, that persons with better than normal distance vision have seen the crescent. If true, this has importance in pushing the beginnings of careful observational astronomy back as much as 2000 years from the Babylonian period. My question: Does anyone out there have any data that would confirm naked-eye sightings of the Venus crescent? Does anyone have suggestions for obtaining such data? Clyde Hostetter, Professor Emeritus, Calif. Poly. St. Univ. (see July 1979 Griffith Observer) --------- --Peter Abrahams ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- Date: Sun, 25 Dec 2005 15:14:50 -0500 From: Bob Bunge Subject: Re: Seeing crescent Venus Ok, I'll have to try this with my 6-year old. She's somewhat astro-savy (thinks everyone has a 20-inch telescope in their backyard and looks at Mars :-) but not so much... I don't think I've ever shown her Venus in the scope, but she aware of the phases of the Moon. Bob ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- Date: Tue, 27 Dec 2005 12:39:26 -0000 From: "Andrew James" Subject: Re: Seeing the Phase of Venus Hello All Interesting discussion on the problems in seeing the phase of Venus - (which I believe also appeared in January's S&T.) I have had some experience observing Venus - especially in finding the time of dichotomy - when the phase is 50% - which deviates by an average of four days depending on the western or eastern elongation of the planet . While investigating for an article on "Johann Schröter, William Herschel and the Mountains of Venus: Overview" - which appeared in the Royal Astronomical Society of New Zealand (RASNZ) journal in March 2003 ("Southern Stars" 42, 1, March (2003), I came across a reference of simple devices to enable observers to possibly see the Venus phase or other planetary disks visually. [This mentioned article appears on my Homepage at; http://homepage.mac.com/andjames/PageVenus005.htm for those who might be interested in historical documents] (I will have to go through my records on the actual source, as I never thought it would be useful.) The device used an clever observation trick in attemping to visually seeing this phase - a trick that has been attempted I believe when observing naked-eye double stars. It involved using something like a drinking straw, that was looked through like a telescope. At the 'aperture' end was place a thin piece of paper or wire, which divided the apparent field in two. (The straw must be mounted or fixed to say a wall, and viewed through carefully.) With a bit of manipulation, this division is carefully aligned with the direction of the planetary phase. (Ie. Where the direction of the wire or edgewise paper is aligned to where the sun rises or sets on the horizon.) The opposing ends of the crescent are then placed either side of the division, and the planet diurnal motion continues in down the direction of the dividing line bisecting the field. If any phase is visible, observers should see two points of light either side of the division being the horns of the phase. (and possibly shape?) If the planet is simply occulated, then the planet's phase appears unresolved. My understanding thinks this halves the resolution limit of the naked eye. I was going to try this tonight, but my horizon was covered with clouds. Hope this idea helps. Andrew James ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- Date: Tue, 27 Dec 2005 14:29:24 -0000 From: "Andrew James" Subject: Re: Double Stars and Colour Perception Alister I am a bit confused about your point here. While the difference of black and white backgrounds certainly affect the colours seen in bright light, the effect on stars in a darkened field are certainly minor. (Unless you are only looking a bright first or second magnitude pairs - and there are not many of those!) Any "negative" afterimage is more likely to be caused by illumination from external sources. Ie. Like a red light, which makes stars appear green - an example of a complementary colour problem. If you want to try this yourself, the look at the TV for sometime then go outside and the stars will be very blue - and this afterimage will stay for some time. Another suggestion is to point the bright red source directly at your eyes for a minute or two and again observe the same stars - the stars will be more green. I assume that the causes of these changes are chemical reactions that occur with the rods and cones in the retina - the cones being the receptors of the light received in the eye. Naturally, the exposure of bright coloured light excite one of the main three colour pigments and they become saturated with just one colour. Once the bright illumination is removed, this saturation continues on for sometime, taking time to dissipate. and whose colour is complementary to the original colour. This lag diminishes, likely exponentially, where the opposite colours become dimmer until the 'chemical cone balance' returns to normal. Hence the brighter the source - the longer this lag continues. Your colour example with the corona in a total eclipse might be another example of this. (I assume these colours were seen in a telescope?) Any star cannot cause such saturation. (unless it is too overwhelmingly bright). Futherrmore as a star is a near point source, the focus will wanders over the retina so that different cones are exposed over time. Simply the smaller number of photons cannot saturate the cones. Obtuse colour contrast in doubles is clearly not real. It is the mind and not the eye itself that is causing these perceptual differences. There likely is some problem with the decision on the faint colours being received, which the brain tries to differentiate - likely separating the two objects by trying enhancing differences in colour. Science in this field s4eems to be uncertain in regards this line of study, as mainly the problems of seeing colour at night are not considered important. (Just like weather prediction of the sky during the night. People are mainly interested in the weather during the daylight hours when most of the human activity occurs, Nighttime weather is of little consequence.) As for Bill's problem of colour changes in pairs under different magnifications etc. is a valid point, as I have notice these subtle differences as well. I have no explanation other than differences in the properties of the eyepiece, observer etc. Moreover, the differences might be real in other aspects - ranging from diet, mood, age or even alertness. Perhaps the only way is to elevate this is to slightly defocus the stars when looking for any real colour. At least this might lead to a slightly more realistic appraisal. Regards Andrew James [Perhaps this seemingly convoluted answer isn't completely satisfactory, but in essence it may approximate the truth.] ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- Date: Tue, 27 Dec 2005 07:54:06 -0700 From: Neal Galt Subject: Re: Re: Seeing the Phase of Venus I was unable to stay Christmas Day until it got dark to continue with my questioning relative to seeing the crescent phase of Venus by the youngsters. However, at about 11:00 AM I was outside with one of the grandson and noticed the waxing crescent moon still visible in daylight. I simply asked him if that's the way Venus looked. And he said "Yes, but backwards!" My daughter indicated that she could also see the crescent, but it seemed to have a line in it right about in the middle....a spike. I sure think there's something to this......I can't see the crescent, and never have. But, then I may not have ever looked for it at the correct time. With all of the support accounts (even historical) it seems that some can see the crescent phase. Beyond that, a true and reliable test would have to be done. Neal ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- Date: Tue, 27 Dec 2005 22:49:22 GMT From: "Wayne (aka Mr. Galaxy)" Subject: Re: Seeing crescent Venus 15480 Empire Rd. Benson, AZ 85602 hm ph: 520-586-2244 Along the same topic of Venus observation, I had a most interesting incident about two years ago involving the crescent Venus, though it _was_ through a telescope. Regrettably no notes, but the circumstances involved observing a Venus-set. I don't think it was the passage associated with the recent Venus transit, but it could have been. Just as the orb of Venus was setting below the distant, but hilly horizon the two horns of the crescent planet both showed a strong refractive apparition equivalent to a green flash. It was very interesting and something I had never heard of or realized could happen. The phase was about two weeks before solar conjunction. The seeing was very steady down to the horizon. I was using my 13-inch Dob with fairly low magnification (~75x) and was completely startled by what I saw. Anybody else ever see this effect? You may want to try for it this time around if the conditions are right. Clear skies and Happy New Year to All! Wayne (aka Mr. Galaxy) ----------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- -----------------------------------------------------------------------------------