Accession No
0810
Brief Description
moveable celestial planisphere, by Johnson and Company, English, late 19th - early 20th Century
Origin
England; Holborn; 10 Brooke Street [Johnson and Company]; Fitzroy Square; 19 Howland Street [Miss Wilson]
Maker
Johnson and Company [printer] Wilson, Miss
Class
astronomy; demonstration; ephemera
Earliest Date
1850
Latest Date
1950
Inscription Date
Material
paper (cardboard, card, pasteboard); metal; thread; plastic or wax
Dimensions
height 360mm; breadth 361mm; diameter of planisphere 295mm
Special Collection
Robert Whipple collection
Provenance
Inscription
‘I will consider thy Heavens, even the works of Thy finger.’ (top middle)
‘The Heavens declare the glory of God, and the Firmament sheweth His handy work.’ (bottom middle)
Description Notes
Moveable celestial planisphere of paper and card. Printed by Johnson & Co., English, late 19th - early 20th century.
Titled on instruction booklet ‘Drawing-Room Planisphere’. Planisphere mounted on to a square card board coloured green with gold trim. At the base of the back board are two pockets holding the instructions booklet and a separate booklet titles ‘A Few Words on Fixed Stars to my Young Friends’. British star system. Planisphere consists of an outer ring representing the 24 hours of the day (am/pm), using roman numerals. Starting at the top of the board at XII is ‘Noon’ ‘Evening’ ‘Midnight’ and then ‘Morning’. This is painted directly onto the back board. Inner ring is of the calendar months and the hours of the day (again). On the same piece of card are drawn the stars on a blue background, use of metal to represent the stars.
‘Bring the day of the month to 12 o’clock at noon, which is on the outer circle; then fix the Pointer or Meridional Line to the hour required. All Stars that have sunk beneath the horison will be covered over, while those that are seen above the horizon at that time will be displayed on the Planisphere. All the constellations on the eastern side of the Heavens are rising; those on the western side setting: while the Meridional are vertical or culminating.’
References
Events
Description
A planisphere is a device that shows the groups of stars (constellations) that can be seen in the sky at any time of the year in a particular location. Different stars are visible in the sky depending on where you are on the earth’s surface. A planisphere is therefore designed for a certain area, showing the stars visible in that particular latitude zone (the position above/below the equator).
A planisphere consists of a star chart, i.e. a map of the sky, with the days of the year around the edge. The star chart is attached at its centre to a circular overlay with the hours of the day around the edge. The overlay has a window or hole so that only a portion of the sky will be visible in the window at any given time. Both parts are mounted so that they are free to rotate about a common pivot point at their centres. By lining up the correct date with the time of day you will get a map of what you can see in the sky at that time.
Since the planisphere shows the three-dimensional night sky on a flat surface, there is some distortion of distances and/or area, depending on what ‘projection’ is used to map the celestial sphere onto the plane surface.
15/04/2008
Created by: Ruth Horry, edited by Allison Ksiazkiewicz on 15/04/2008
FM:41679
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