Longitude book

There is now a new 'illustrated' version of Longitude by Dava Sobel, published, I think, in cooperation with the Harvard University collection of historic scientific instruments.

book sources

Two good sources (in the US at least) for books on astronomy and celestial navigation are: Sky Publishing 49 Bay State Road Cambridge, MA 02138 617-864-7360www.skypub.com Willmann-Bell, Inc. P.O. Box 35025 Richmond, VA 23235 804-320-7016www.will

Stereographic projection circle proof

http://www.geom.umn.edu/docs/doyle/mpls/handouts/node33.html has a proof that circles on the sphere project as circles on the stereographic projection.

does this work

Take a look at this sundial: http://www.angelsandearthlythings.com/hp4500.html I think it has problems. Am I correct?

Re: The analemma

> There is an article in the most recent edition of Sky and Telescope magazine > about "photographing the analemma". > > It describes how photos have been taken which show the movement of the sun. > They rely on time lapse (either 365 or 12 exposures over the course of a > year), with each exposu

NASA eclipse info page

There's a great web site for eclipse info, both solar and lunar at: http://sunearth.gsfc.nasa.gov/eclipse/eclipse.html

lunar perigee vs phase

The synodic month (full moon to full moon) averages 29.53 days, while the anomalistic month (perigee to perigee) is 27.55 days, so the phases drift with respect to perigee. see: http://www.treasure-troves.com/astro/AnomalisticMonth.html

bad sundial illustration

The cover of the June 2000 issue of Embedded Systems programming has a sundial with the gnomon pointing in the wrong direction. I've already emailed them about it. It's on my web page at: http://linux.bbn.com/~koolish with the full scan in: http://linux.bbn.co

Re: The Swensen Dial WebCam is going again.

> Isn't Beltane the other side of Candlemas? > I am looking forward to an authoritative answer based on solar declination. > > Roger Bailey Beltane explanation (and other cross-quarter days): http://www.isleofavalon.co.uk/edu/g-bank/articles/beltane.html

outdoor decor sundial question

http://www.shopoutdoordecor.com I was looking at the Outdoor Decor web page and saw the Marble Sun Sundial. It's the second one down on the Historical and Disc sundials page. Is this a working sundial?

suns angular diameter

>From the web page: >http://sunearth.gsfc.nasa.gov/eclipse/SEhelp/SEgeometry.html "Eclipse geometry is complicated by the fact that Earth's orbit around the Sun is elliptical. As a result, the Sun's apparent semi-diameter varies from 944 arc-seconds at aphelion to 976 arc-seconds at perihelion.

Re: no mail ? Is it normal ?

> Actually it is dark, but the lights are on. See the amazing photo at > > http://antwrp.gsfc.nasa.gov/apod/image/0011/earthlights_dmsp_big.jpg > > Daniel Wenger We amateur astronomers call that 'Light Pollution'. http://www.darksky.org/ida/index.html

Scientific Instruments Auction

Don Yeier, ex Vernonscope owner is having a scientific instruments auction on Saturday, May 19, 2001, in Candor, New York (near Binghamton). In addition to antique telescopes, binoculars, clocks, etc. the flyer says there is an Augsberg equitorial dial and other sundials. Catalog is $20.00 ($25.

pinhole photo of Portland sundial

There's a pinhole camera photo of the Portland Oregon Union Station sundial at: http://web.pdx.edu/%7Eharveyt/C1.html

an item on eBay

Item 1498358081 Up for Auction. More Stuff from a Prominent Eastern Shore Collection. Here is a Wonderful Antique Helio-Chronometer or Sundial. We are by no means experts in this type of Time Piece or Astronomical Instrument & we will do our best to describe it and let our pix speak for themselve

Re: Star finder (astrolabe) for sale

> I'd like to draw your attention to a star finder for sale on the > Internet auction house eBay. See > > > I own one of these, though I have to confess I haven't looked after it > well and it is now missing some of the transpa

safe solar filters

See: http://www.mreclipse.com/Totality/TotalityCh11.html This is from Fred Espenak at NASA. http://www.mreclipse.com/Totality/TotalityCh11.html -

Re: Moon rise/set on the equinox

On March 20, the declination of the sun is 0, so it rises due east and sets due west. The moons declination on that day is almost -26 degrees so it rises south of east. The full moon rise this past Tuesday was almost due east. Unlike the sun, whose declination changes just a bit every day, the de

Re: Moon rise/set on the equinox

> > > day, the declination of the moon changes a lot every day, > > since it goes through the cycle from maximum to minimum > > declination every month, while the sun takes a whole year > > to go through that cycle. > > Yes, I knew that. And I heard as well that the moon's > extreme declinations

Sky Pointer

I put some pictures of the Kennedal Sky Pointer on a web page at http://www.dickkoolish.com/rmk_page/pictures_032306.html. Sky Publishing used to sell them. You can set the RA and Dec of an object and the date and time and it will point to the position in the sky. Or you can set the Dec and rotat

Re: Moon Calendar DeltaCad macro

Two moon phase calculators that do exist are at: http://www.lunawheel.com/ http://www.moonstick.com/ > > Dear sundial friends, > To celebrate the solar eclipse tomorrow, I prepared a DeltaCad macro for > finding the MEAN MOON PHASES. > All callendar constructions use somehow corrections

A list of sundials with GPS positions

I found a web page for www.waymarking.com, which is evidently a place for people to record the location of interesting things. There is a sundial catagory with 65 sundials listed. --- https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Using "Google Patent" to find Sundial Patents.

Here is a sundial at Mt. Auburn Cemetery in Cambridge MA, USA. It's probably not a cremation container, but certainly could be. http://www.dickkoolish.com/rmk_page/sundials/payson_mtauburn.html > > Hi all, > > Was having a look at Google Patents using the key word "sundial" and = > found a nu

Re: Russell Porter sundial

An original Porter Garden Telescope recently sold at the Skinner auction in Boston. http://www.dickkoolish.com/rmk_page/pictures_032207.html There a couple of Porter sundials in the telescope making museum at the Hartness House in Springfield VT. http://www.dickkoolish.com/rmk_page/pictures_073

Glynne replica dial

I have been given a sundial that may be a Glynne replica drawn by Fer deVries. I found it at a friends house in the suburbs of Boston, Massachusetts USA. The gnomon was mounted backwards. There are some pictures at: http://www.dickkoolish.com/rmk_page/pictures_060407.html The screws were steel

Great circle calculation

There are a lot of navigation calculations at: http://williams.best.vwh.net/avform.htm It includes the distance and course between points. --- https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Plastic Fake Stained Glass

Theater lighting gels are plastic sheets that come in a large variety of colors and are inexpensive. I don't know if they will stick to windows or would work in a computer printer. Rosco is one of the major brands. --- https://lists.uni-koeln.de/mai

Re: Does Refraction Affect Azimuth? / Re: sundial Digest, Vol 24,

There is a Java applet showing the effects of refraction and flattening at: http://www.jgiesen.de/refract/index.html If it came from this list originally, I apologize in advance. --- https://lists.uni-koeln.de/mailman/listinfo/sundial

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