Our Great Grandparent's Astronomy

Discussion in 'Other Skills' started by charlesmc2, Oct 8, 2018.

  1. charlesmc2

    charlesmc2 Scout

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    After derailing myself on the compass discussion, I thought it might be interesting to discuss some skills we are likely losing. I know I did not learn much basic astronomy in school. I always loved science and graduated with a BS degree in physics. I think I was too much into what made the stars hot, neutron stars, black holes and the like.

    For starters, how many times does the earth rotate on its axis each year? Hint: it's not approximately 365.25 days.

    I'm thinking in terms of identifying the planets visible to the naked eye. Watching for an opportunity to catch mercury just after sunset or before sunrise on those odd occasions it is visible. Or learning that venus has phases like the moon, but we never get to see a "full" venus. How about seeing how tiny a crescent moon you can catch just after a new moon. Or learning Orion, the Big Dipper, Polaris and Cassiopeia. Learning when noon is where you live. (Both our adult kids live in Lubbock, TX. There are a few days when their noon occurs after 2:00 pm, thanks to Daylight Saving Time and a location far west in the Central time zone. Another, why does the latest sunrise in the northern hemisphere occur about January 10, almost three weeks after the solstice.

    Incidentally, the answer to the rotation question is 366. The earth turns on its axis in about 23 hours, 56 minutes. The other four minutes are required to "catch up" to the sun since we are moving about it, just like you have to turn your head to catch up to something you are passing by in your car. Another way to see this is to consider that if the earth did not rotate at all we would still have one night and one day a year. We "lose" that one day every year.

    I've chosen some of the more puzzling things to consider, but most are simpler. My own grandmother, born in the 1880's and only educated through the 7th grade taught me a few. One I remember is to tell whether it would be wet weather or dry was to look at the phase of the moon. If the "cup" was relatively level, expect rain. The cup could hold water. (This happens in spring and fall, our wettest seasons where we live.) In summer when it is dry the "cup" is tilted over and is thus empty--no rain.

    What are some observations you think are worth passing along to following generations?
     
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  2. charlesmc2

    charlesmc2 Scout

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    Also, plant cucumbers early Easter Sunday morning. (And this from parents who observed a day's rest on Sunday.)

    OK, now how do they decide when Easter is?
     
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  3. NattyBo

    NattyBo Guide

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    We in the northern hemisphere for the past couple millennia have been in a great era for celestial navigation using the pole star Polaris. Because of the earth's axis wobble this has not and will not always be the case. Around 4100 AD the pole star will have drifted to Gamma Cephei (Errai).

    https://stardate.org/radio/program/future-north-star
     
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  4. Beach Hiker

    Beach Hiker LB #42 Bushcraft Friend

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    Easter is the first Sunday following the first full moon of the spring equinox.
    As a result its date can vary widely.
     
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  5. charlesmc2

    charlesmc2 Scout

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    The latest sunrise occurs almost three weeks after solstice because earth is closest to sun in winter (northern hemisphere) and thus moving fastest. It is easier to think in terms of when noon is. Solar noon occurs later and sunrise is a little later. Most of us live where the earliest sunset is in early December. Day length changes very little around either solstice and most rapidly around either equinox.

    A good source for this sort of stuff is www.sunrisesunset.com. You can look up data for your location. I'm goofy enough to like this stuff.
     
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  6. Yknpdlr

    Yknpdlr Scout

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    To find cardinal directions on earth using the moon, observe it before "first quarter" or after "3rd quarter" when cusps are visible ( the pointy looking lit top and bottom). Draw an imaginary line from top cusp to the bottom, extend it to the horizon, and that point will be very close to true south (in the northern hemisphere). It works even when the moon is visible in the daytime. Of course having a general knowledge of position of the moon in the sky and its track will tell you directions as well.
     
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  7. Yknpdlr

    Yknpdlr Scout

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    Knowledge of the mathematics of orbital mechanics and geometry was so accurate in the 1600's that by measuring differences in observed time of eclipses of Jupiter's moon Io, one could calculate the speed of light due to differences in observed vs predicted eclipse event time as the distance from earth to Jupiter varies throughout the year. In 1676 Danish astronomer Roemer estimated that light would take about 22 minutes to travel a distance equal to the diameter of Earth's orbit around the Sun. This would give light a velocity of about 220,000 km/s, about 26% lower than the true value of 299,792 km/st.
     
    Last edited: Oct 10, 2018
  8. charlesmc2

    charlesmc2 Scout

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    I think we greatly underestimate the intelligence of people in ages past. Archimedes developed a way to calculate pi to great accuracy (although doing so by hand was extremely laborious.) He was on the leading edge of what would eventually be calculus. Tycho Brahe and Johannes Kepler established the orbits by observing the motions of the planets. Considering there was no fixed platform from which to observe that was pretty amazing.

    And then there was Newton. A man of first order both in physics and mathematics.

    Nature, and Nature's Laws lay hid in Night,
    God said, Let Newton be! and All was Light.

    Alexander Pope
     
    Last edited: Oct 11, 2018
  9. ExAF1N1

    ExAF1N1 LB-42 Purveyor of sharps and savory burnables. Supporter

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    @CowboyJesus , some of this may be of use for the navigation section of the course you'll be teaching.
     
  10. CowboyJesus

    CowboyJesus Supporter Supporter Bushcraft Friend Bushclass I

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    thanks for mentioning it-i have been watching and following!
     
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  11. Kacie

    Kacie Guide

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    My Grandpa said
    "When there's a ring around the moon,
    count the number of stars inside of the ring...
    expect rain in that same number of days."
     
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  12. Foulwind

    Foulwind Guide

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    What kind of drugs were they using back then to even think up the #$%^ they did then? I can spell algebra buts that's about as far I go with it!
     
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  13. charlesmc2

    charlesmc2 Scout

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    Newton, Beethoven, Bach and a handful of others were not human. But seriously, they were capable of thought and concentration we cannot imagine. I wonder if there will be another like them. Too many distractions. We can progress by group work and collaboration, but the fundamental advances are different.

    I love the statements like "our knowledge is doubling every 10 (now 5) years." I'm sorry, but sheer volume does not equate to quality any more than someones's dissertation equates to Newton's Principia. Einstein just might have been the last. Only time will tell.
     
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  14. Kenneth

    Kenneth Hobbyist Hobbyist

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    I was told by my dad that when I see a pecan tree start to bud the danger of frost is over. Sure enough over the years I watched the neighbors pecan tree in the his front yard and year after year it was true.

    I saw the north star last week on October 13th in Alaska, we went on a northern lights viewing and the guide showed me the big dipper and leading to the north star.

    The funny thing that I was told, the better you see the Aurora Borealis with your eye, the worse the pictures will be, however the better the pictures turn out the worse it is see what your eye. They got a good picture of me with their professional camera and I did see part of the lights dance for about a minute.
    DSC01630-1.jpg

    GOD Bless you and your families

    Kenneth
     
  15. charlesmc2

    charlesmc2 Scout

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    I don't remember the exact year, but it was the late 90's. I was visiting my sister out in West Texas near Midland. My wife called me, it was late, sort of frightened me because we just don't call late. One of my friends at work had called the house to tell me to go outside. The aurora was putting on quite a show. I knew the northern lights were visible in Texas at times. My mother had watched them one early morning some 40 years previously. (Why she didn't wake me to see it I never knew.)

    Incidentally, rural West Texas is one of the very best spots for night time star viewing. Those of you familiar with that part of the world know the air is clear and dry. And none of those pesky trees to spoil the horizon.
     
  16. Yknpdlr

    Yknpdlr Scout

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    A severe geomagnetic storm struck Earth on March 13, 1989. It occurred during solar cycle 22 and caused a nine-hour outage of Hydro-Qu├ębec's electricity transmission system. (from Wikipedia)

    From the Adirondack region of NY State I remember this event well. I occasionally see the aurora from my location, though it is rather rare. Usually just a a low glow on the northern horizon, so I'm surprised that it is ever visible as far south as TX. But this 1989 event was something spectacular. It was like simultaneous bomb bursts happening every second at random locations all over the sky, even toward the far south horizon. Mostly red colors, some white. I kept waiting for the boom sound that never arrived. But in the span of 30 minutes it all ended.
     
  17. charlesmc2

    charlesmc2 Scout

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    If I recall correctly, during the 90's we were seeing high sunspot activity. I've seen a map of frequency and as far south as I am in Texas it is only once or twice a century and probably never unless you are in a rural area. I wish people would take it upon themselves to direct lights downward so as to minimize the so called light pollution that keeps so many of us from seeing the milky way, most comets, Andromeda Nebula and so on. I guess there are more important things people are concerned about. As best I can tell, the light that escapes upward is wasted so it is in our own self interest to save those $$ and make sure the light is directed downward. I know some communities have adopted ordinances that fight light pollution, but I also hate to see still more regulations for something a lot of people do not understand or value.
     
  18. Yknpdlr

    Yknpdlr Scout

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    I grew up in a very rural dark sky area of northern NY State, in the Adirondack Mountain region. I learned to love astronomy from my back yard and owned a couple of telescopes which taught me the location of many favorite deep sky objects. I went to college on very light polluted Long Island (majoring in astrophysics by the way). My trips to home from college usually occurred at night. I can remember every time I got out of the car at home on a clear night that my jaw dropped at the beauty of the black sky background with thousands of bright stars that are never visible from Long Island.

    Later, flying as an Air Force navigator (mastering navigating by celestial means with a sextant before GPS existed- easy since I already knew and could locate the navigation stars by name), it bothered me to look down and see the vast proliferation of street lights when flying virtually everywhere over CONUS even when far from cities. Closer to home, I could never understand why so many people want to move out of the city into the country, only to demand that the city lights come with them in the form of multiple mercury vapor lamps with so much light going skyward.
     
    Last edited: Nov 17, 2018
  19. riverjoe

    riverjoe Supporter Supporter

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    Drives me crazy . Those chickenship towneys need to get a Teddy Bear if they feel so insecure in the dark .
     
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  20. MountainWanderer

    MountainWanderer Scout

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    As a kid I was into astronomy. Asked for and got s telescope one birthday. I spent many hours watching the ink black sky in rural farm country where the view was clear & unmarred by city light. - - Now my cellphone has an app that quickly and easily locates all sorts of night sky objects- constellations, planets, stars, galaxies, and even man made satellites. It provides background information & you can check out more links that will go into as much depth as you can handle. I would have been amazed & delighted if we had that when I was a kid.
     
  21. Yknpdlr

    Yknpdlr Scout

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    I now have a couple of telescopes only slightly larger than the ones I had as a kid. The new ones have a computer that will automatically point to any desired object in the sky that is programmed in that I select by pushing a button. But that process makes me feel lost and unfamiliar with the sky.

    In the old days I learned to find the direction of viewable objects by studying star maps, relating them to the actual sky, and locating objects of interest by using the alignment of certain guide stars or pointer star configurations to aim my telescope in the right direction, I also learned to identify those guide stars by name and their characteristics. I manually pointed the telescope by placing my cheek along side the tube, until I could see a guide star with one open eye and the other looking through the finder scope, moving the telescope to coincide the images of both eyes. I can still find things that way if I pay attention to the old method of visual astronomy. However, somehow, in using the new computerized pointing technology, that old skill feels distant and has become nearly lost.
     
    Last edited: Nov 18, 2018
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  22. charlesmc2

    charlesmc2 Scout

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    Yknpdlr, I agree with you. It does take some of the frustration from beginners, but what have YOU really done? With a scope you lose the astronomical context due to the narrow field of view. I think there is a balance to be achieved between naked eye, binocular and telescopic viewing. And, it is a real joy, even with my old eyes, to get to view the stars where the sky is dark, where you can see the Milky Way, and achieve the sense there are a LOT of stars out there! Years ago, I recall going outside at a friend's house out in a rural area to look for Andromeda. When I finally saw it, wow. And maybe my favorite, Pleaides. Even when you cannot completely see the other stars in there, it catches your eye and seems to say "keep looking, there is more to me than meets the eye." Well, maybe not that exactly, but you get the point.
     
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  23. Yknpdlr

    Yknpdlr Scout

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    Yeah, I always look to viewing the fuzzy smudge of M81 (the Andromeda galaxy) as a test of clear skies, or clear eyes, or maybe both. There are several other clear sky and vision test objects too, but M81 is my favorite with a certain pattern of guide stars that easily lead me to it (or at least to where it should be visible), even when conditions are marginal. Luckily I still live in a fairly dark sky area, although this fall season in the northeastern U.S. has been unusually cloudy each day and night.
     
    Last edited: Nov 27, 2018
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  24. ExAF1N1

    ExAF1N1 LB-42 Purveyor of sharps and savory burnables. Supporter

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    I would love to learn celestial navigation besides Polaris. Almost bought a nocturn a couple of times.

    I'd like to make my own someday, and navigate at night between that and a compass. Knowing constellations and major stars, where the ecliptic is and what planets are visible does a lot, but I'd surely like to learn more.

    It's on the list with a lot of things lol.

    I have much respect for someone that can do it, have a buddy that was a Navy SWO, and he was one of the last ones to go through training with sextant and an ephemeris to a great extent alongside GPS
     
  25. Yknpdlr

    Yknpdlr Scout

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    I guess I 'm somewhat of a dinosaur, with my Air Force senior navigator wings. I leaned air navigation in the 1970's, when navigators were still flying on most large AF aircraft. GPS was not available then, so most navigation was done by accurate dead reckoning (DR is always required) backed up by air to ground radar and celestial. Every training flight had at least 2 hours devoted to a celestial navigation leg exercise.

    Later, palletized inertial navigation systems (PINS) came into being. It was a footlocker size box that was bolted in place for some certain flights going over polar or wide oceanic regions. No guarantee of getting one. I did not much like it because it was yet another system that required babysitting, and was often wrong, even with a manufacturer guarantee of less than 1.9mph error each hour. When it worked it was a good cross check on dead reckoning, but when it drifted it was worthless. I once led a 6 aircraft refueling flight with trailing reconnaissance planes out of Alaska over the pole with my plane having the only INS. but it failed on the way out. So I had only celestial to get us out and back. Using radar I plotted distinctive ice ridges on my map on the outbound leg so I could recognize them on the return way home. Eight hours later I brought us all back to within a couple miles of our assigned entry point. I could almost always do better than INS with celestial and DR, especially on long flights of 8-10 hours. I was gone from flying duties before GPS was a technology option. Today, air navigators are practically extinct.

    Sadly, being a real navigator is now a lost art and those skills are no longer taught or practiced. All navigation, air or ground, is what we call a "perishable skill", in that if you don't use and practice it, you lose it.
     
    Last edited: Dec 1, 2018
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