Approach to Scanning Historic Glass Plates Yields an Astronomical Surprise. Technical details at
Precise Photometric Measurements from a 1903 Photographic Plate Using a Commercial Scanner.
Professional astrophotography used to be done on emulsion-coasted glass places. That was how astromical discoveries were made for nearly a
More than an estimated 2.4 million glass plates are out there in collections in North America alone. These were taken starting in
the 1890s right up until the 1970s, when CCD (Charged Couple Device) detectors started to come online for astronomy. Of these, only an
estimated 400,000 plates have been digitized to research quality
The team in this article has found a much cheaper way to proceed with this process, using
I found this post on Facebook: Why is it
important to know so many digits of pi?.
As someone who started computing with log tables and slide rules, the first question I ask is
how many significant digits do the other variables in your calculation have? The smallest such number tells you how
many digits of pi you need. With electronic devices there is no harm in using more in your calculation, as many as
your device has, but do not let that give you a false idea of the precision of your result.
I learned about significant figures in my high school chemistry in 1967-68. (Thank you, Mr. Wheeler!).
Use of appropriate significant figures, also from a chemistry
class, clearly explains the concept and its use in practice.
I only first saw Star Trek (TOS) after high school, in reruns. Thanks to that chemistry class I gag every
time I hear Mr. Spock reporting some calculation to an absurd number of decimal places. His input data could
not possibly be that precise!
Back in High School (1964-68) I read a lot of science fiction by Mack Reynolds. His
Joe Mauser series is set in a world where the cold war continues into
the 21st century, but, to avoid catastrophe, the West and the “Sov-world” have agreed to restrict all military forces to pre-1900 technology. There
is still lots of fighting going on at that level.
Recently I was reading about the decades old border dispute between between China and India
countries, which actually led to war in 1962. The conflict still simmers on, but a
agreement states that
Neither side shall open fire, cause bio-degradation, use hazardous chemicals, conduct blast operations or hunt with
guns or explosives within two kilometers from the line of actual control.
Neither side wants to get the blame for starting a shooting war, so both sides are following the letter of the agreement. However, nobody is backing
down. There have been reports
that “Chinese troops have used improvised edged weapons, such as nail-studded clubs, in … skirmishes with Indian forces.” and both sides
have martial artists in their border forces.
It seems that the Chinese are escalating.
We now have Chinese soldiers armed with new devices for hand-to-hand combat with Indians in Tibet.
Actually the “new device”, the guan dao, is quite old. It similar to a a western medieval halberd. It will be interesting to see how Indian army responds.
They have a rich tradition of edged weapons to draw upon.
Irish Class, January 11, 2016
Rang Gaeilge, 11ú lá mí Eanáir 2016
|Is beag an aibhleog a lasann tine mhór.
||A small coal lights a big fire
|Is doimhin é poll an amhrais.
||Deep is the hole of doubt.
Cé acu Captaen spásloinge is glice, Kirk nó Picard? Tá Picard níos glice ná Kirk./Is glice Picard ná Kirk.
Ainnmnigh fear atá níos deise ná Donald Trump? Tá Will níos deise ná Donald Trump.
Cé acu beoir is áitiúla, Summit nó Guinness?
Cé acu cathair is fairsinge, San Francisco nó Los Angeles
Cé acu cathair is ísle, Denver nó Charleston
Ainnmnigh scannán atá níos stairiúla ná Braveheart? Tá Apollo 13 ….
Nuacht ó na stáit
Tógadh níos mó ná céad mac léinn go dtí hospidéil mar réamhchúram ó scoil Horace Mann i ndiaidh fuarthas amach méideanna ard aonocsaíde carbóin. [IL]
Tá crann Nollag na priomhchatrach saorga sa bhliain seo, agus tá sé ar taispeáint i Halla Cuimhneacháin. [ND]
D’oscail arís Roinn na leabhar annamha Leabharlainne Poiblí i ndiadh ráig múscáin. [MA]
German scientists invent working teleporter, of sorts
An object at one end of the system is milled down layer-by-layer, creating a scan per layer which is then transmitted through an encrypted communication to a 3D printer. The printer then replicates the original object layer by layer, effectively teleporting an object from one place to another.
Irish Class, July 28, 2014
Rang Gaeilge, 28ú lá Mí na Iúil 2014
Le Meas …
Part of our homework was to write “… a script for a short clip … to be used at a dating site! But it isn’t about you, pick a famous person, dead or alive.”
Here is my effort:
Dia dhuit! Inseoidh mé cupla rud fúm féin:
Is mise an captaen loinge réaltaí Enterprise.</i
- Is maith liom taiscéaladh domhan aisteach nua.
- Is maith liom cuardach saol nua.
- Is maith liom dul go dána go háiteanna atá ní fhaca aon duine sula.
- Is maith liom mná ó gach cine, daonna agus thar.
- Ní maith liom an Phríomhtreoir.