Digging deep in the Edmund artifact box.
Posted 18 March 2013 - 03:35 PM
Posted 18 March 2013 - 03:37 PM
Posted 18 March 2013 - 03:40 PM
Posted 18 March 2013 - 07:08 PM
Posted 18 March 2013 - 07:41 PM
Posted 18 March 2013 - 07:41 PM
Here's a little something from my own Edmund vault: the Planetimer Solar System Analog - "A graphic working model of the solar system". 10 discs held by a brass rivet in the center, one for each of the planets and the Sun (sorry, Pluto will always be a planet to me!). The back contains tables of the heliocentric longitude of the planets for the years 1971 to 2001 inclusive; if one took the time to calculate the h.l. of the planets into the future, this item would still function. Since it's snowing here tonight, I just may do so later on...
Posted 19 March 2013 - 08:27 AM
BTW, for those interested in sidereal transit timing, our observatory here in Cincinnati once housed large transit refractor (meridian telescope). We have our club meetings in the room where the the transit telescope was operated. There is a large slit that is now a skylight running across the longest diameter of the room which coincides with the astronomical (and geographic) meridian. Part of the observatory's original charter was for accurate time keeping west of the Alleghenies. The very accurate pendulum clock still ticks in that room. It's very cool.
Posted 19 March 2013 - 10:20 AM
I like those old publications and tools.Amateur radio had many "slide-rule" calculators and nomographs for calculating in the days when there were no or only a half-dozen electrical computers.
Pluto's demotion is like daylight savings time ;I can't ignore the official announcements but in my mind and heart I know Pluto is a planet and it is only truly noon when the Sun crosses the meridian!
Posted 19 March 2013 - 10:42 AM
Im just sitting complacently with my Edmund Star Finder chart I bought in 1970, still using imperial units and ignoring them all.
Posted 19 March 2013 - 11:02 AM
I'm not thrilled about pictographs of turtle and rabbit replacing "FAST" and "Slow",or any of the other similar signs.26 letters are easier to learn than 4000 little pictures.
Posted 19 March 2013 - 01:00 PM
I used to say that when I retired I'd set all the clocks in the house to Civil (Local) Mean Time for my longitude and leave them at that from then on. Then I realized I had to live in the rest of the world so there I am, changing clocks. I do hate it though!
Posted 19 March 2013 - 01:03 PM
Posted 19 March 2013 - 01:08 PM
Posted 19 March 2013 - 04:15 PM
I have one of those slide rules, and also my Edmund planisphere from the mid 60's. Got these when I ordered my "Mounting Your Telescope" booklet.
Posted 19 March 2013 - 10:29 PM
I can't agree with you on the Imperial units. I hate them. I love the metric system. Its so much easier and it's Earth based. (1 meter ~/= 10,000,000 of the meridian between the pole and the equator.)
Ive often heard that Metric is the better, more logical system and how unfortunate it is that everyone is not using Metric units Terra. I beleive this misperception is based on the fact that metric is a tens based system while imperial is a twelves base system. I do feely admit that I myself often practice counting by tens, and when I run out of toes, have to resort to higher math and count fingers as well.
Unfortunately, Metric is not always the best system. The assumption is that since metric is decimal based, one can simply move the decimal to convert between centimeter, meter, kilometer etc.
The problem with base 10 is that it can't be cut in thirds. 1/3 of a mile is 5,280 ft/3 = 1,760 feet - an integer. 1/3 of a kilometer is 333.3333333.... Meters, that is neither an integer nor a trivially representable decimal. Metrics are really more for those who dislike adding fractions I suppose. Similarly Base 12 units are the smallest units cleanly divisible by 2, 3, and 4. I use thirds quite often.
For that matter Geometry uses a power of base 12 as it's foundation with 360 degrees, Time uses a base divisible in 12 as 60 seconds in a minute, 60 minutes in a hour, 24 hours in a day.
So I find it quite odd that a people who espouse metrics would use the familiar imperial 12 base system of min and sec and degrees to find their way about the night sky.
Now Terra, how can you say that a system based on nature and living things: Three barleycorns to the inch, three inches to the palm, three palms to the foot, three feet- well, you get the idea - isn’t Earth based ?? But never mind, I am too Confucian and old fashioned perhaps, and value old ways and things made long ago more than I should. I value my metric Unitron and Tasco just as much as I value my Imperial Edmund and Cave telescope and suchlike so who am I to talk indeed.
As to Edmund loot in my box, I have my 10” Edmund kit mirror, the Edmund focuser, diagonal and finder w brackets as well as various other Edmund scientific loot, charts and books. I think my edmund GEM is still behind the horse barn somewhere.
Posted 20 March 2013 - 08:21 AM
Anyway, there is also a metric system for arc measure, the gradian (aka grad or gon) of which there are 400 in a full circle, 100 corresponding to 90 degrees or the arc distance from equator to pole. These are then divided into increasingly smaller units of 10, which again is way more convenient than degrees, minutes, and seconds. Gradian measure is more common in Europe and the former Soviet Union than in the states. Of course, the purest unit of arc measure geometrically is the radian: 2 pi r / r which is the S.I. Unit.
There was also a metric system of time keeping devised in France as an extension of the metric system in the 19 th century whereby there are 20 metric hours in a mean solar day, 100 metric minutes in an hour, and 100 metric seconds in a metric minute. This never caught on, I guess because watches and clocks were expensive and commonplace and they would have all had to be thrown away or re-geared.
I think the metric system is the way to go. We are the only country in the world that hasn't gone that way (at least not entirely).
As far as my Edmund goodies, alas, not much remains. The sidereal calculator escaped death by hiding out at the bottom of the wooden case of my Mayflower refractor. The books, because they were flat and were touched amongst the star atlases. Gone for good is my 6inch RFT made from an Edmund mirror grinding kit, its Edmund focuser, the Edmund equatorial mount and wooden tripod it rode on, and various and sundry lenses, filters, and prisms which long ago went by the wayside.
Posted 20 March 2013 - 09:57 AM
Oh Well, I suppose you’re right, it is much like Hip-Hop music, here to stay and one just must deal with it.
I’ve used radians in some Electrical Engineering problems as rad/s but do not recall having encountered the Gon before.