|WikiProject Astronomy / Constellations||(Rated Start-class, Mid-importance)|
I changed the reference to Orion as violating the Bayer rule of naming the stars in order of brightness into Sagittarius as Orion actually conforms rather well with Beta only being slightly brighter than Alpha and Alpha being variable and possibly brighter when Bayer named them. Sagittarius however has its two brightest stars named Epsilon and Sigma with Alpha way down in the list.--Kalsermar 17:52, 7 November 2005 (UTC)
Depth of curve of a telescope mirror.
Defined by the formula
it refers to the glass removed to yield the optical curve. I am writing a book over at Wikibooks on Telescope making and would love to link to an article here at Wikipedia that referenced this bit of knowledge.
There needs to be a reference to the geometric term "sagitta" - which does not just refer to telescopic mirrors, but more broadly, to the depth of any arc. It is used extensively in architecture when calculating the arc necessary to span a certain height and distance.
Defined by the following, where s equals sagitta (the depth of the arc), r equals the radius of the circle, and l is one half the distance across the base of the arc:
Architects, engineers, and contractors use these equations to create "flattened" arcs that are used in curved walls, arched ceilings, bridges, and numerous other applications.
- I'll try to find it. Versine is also called "sagitta", but that's a third thing. ... said: Rursus (mbork³) 15:13, 3 November 2009 (UTC)
This article name
If my creation of Sagitta (geometry) and Sagitta (optics) were correct, we should consider moving this article to Sagitta (constellation) and let this article name contain a disambiguation. ... said: Rursus (mbork³) 15:37, 3 November 2009 (UTC)
Moving here some of the myth stuff, that couldn't find their citations (yet):
- Star tales (a reliable source) tell us a story where Sagitta is sent from Eros (Cupid) towards Ganymede (representend by Aquarius) on instigation on Zeus. Star tales refers to Germanicus Caesar. ... said: Rursus (mbork³) 16:47, 3 November 2009 (UTC)
File:Sidney Hall - Urania's Mirror - Delphinus, Sagitta, Aquila, and Antinous.jpg to appear as POTD soon
Hello! This is a note to let the editors of this article know that File:Sidney Hall - Urania's Mirror - Delphinus, Sagitta, Aquila, and Antinous.jpg will be appearing as picture of the day on February 4, 2016. You can view and edit the POTD blurb at Template:POTD/2016-02-04. If this article needs any attention or maintenance, it would be preferable if that could be done before its appearance on the Main Page. — Chris Woodrich (talk) 23:57, 15 January 2016 (UTC)
|Picture of the day|
A plate from Urania's Mirror depicting the constellations Delphinus (the dolphin), Sagitta (the arrow), and Aquila (the eagle), as well as the former constellation Antinous (according to legend, a young man who saved Hadrian from drowning).