Mark Dow

Projects

Stereo pairs

Stereo pairs of the moon

    The earliest high quality photographs of the moon are due to Warren de la Rue in the 1850's. His stereo pair of the moon, using the moon's libration for the differing perspective of the two views, is a spectacular example of early scientific photography, astrophotography and stereo photography. Modern methods have made some improvements to the quality and ease of acquisition of the imagery, but capturing a good stereo pair of the moon is still technically challenging.

(stereo pairs, cross-view)
The Moon, Lunar Stereo Photograph, 1858/59, by Warren de la Rue.
The originals were made with the wet plate collodion process. The contrast of this low resolution reproduction has been stretched to highlight detail. See below for history and references.


Laurent Laveder lunar stereo pair, link to
Laurent Laveder, November 2006 and January 2007. (Source: pixheaven.net.)


Lunar eclipses stereo pair, by Tom Matheson, link toTom_Matheson_lunar_eclipse_cross_stereo_pair.jpg
Lunar eclipses stereo pair, by Tom Matheson.



    Note that the libration axis, and there for the orientation of the moon in the images lined up for stereo viewing, is not the same for the different pairs.

    Also note that these examples all show the moon at its full phase. While using libration would apply at any phase, the number of suitable opportunities is reduced because the axis of libration is not in general aligned with the inclination of the solar illumination.

    Also see Stereoscopic Pictures of the Moon (Thomas B. Greenslade, Jr., "The First Stereoscopic Pictures of the Moon", Am. J. Phys., 40, 536-540 (1972) ), with examples of partial moon phases.

    Stereo pairs of the moon could be acquired simultaneously from the earth. If the photographers were separated by a large fraction of the earth's diameter, say the 10,000 km between [Hawaii and New York states], the parallax would be about 1/40 radian (10,000 km divided by the 400,000 km distance to the moon), or a bit more than 1 degree. This is somewhat smaller than the libration angles used in these stereo pairs.

Libration of the moon

    While we see primarily only one part of the moon's surface because its rotation is tidally locked to earth, its libration. As the moon orbits the earth, it apparently rocks, about more than one axis. This allows more than one perspective of the moon at different parts of it's phase. If the phase is matched in two photographs at different times (orbits), the libration angles are not necessarily matched. The stereo photographs (above) use these different perpectives, lining up the axis of the libration angle with vertical, to mimic a stereo view of the moon.

  This animation of photographs over a single orbit of the moon shows both libration of the moon and a change in the moon's  apparent size, due to its varying distance from earth.


Source: libration animation

Warren de la Rue photography and stereo photography


Warren de la Rue lunar mounted stereograph


From Warren de la Rue (Wikipedia, accessed 3/20/10)

Warren de la Rue was the Son of Thomas De la Rue, the founder of the large firm of stationers of that name in London, Warren was born in Guernsey. Having completed his education in Paris, he entered his father's business, but devoted his leisure hours to chemical and electrical researches, and between 1836 and 1848 published several papers on these subjects.

In 1840, Warren De la Rue enclosed a platinum coil in a vacuum tube and passed an electric current through it, thus creating the world's first light bulb. The design was based on the concept that the high melting point of platinum would allow it to operate at high temperatures and that the evacuated chamber would contain less gas molecules to react with the platinum, improving its longevity. Although it was an efficient design, the cost of the platinum made it impractical for commercial use.[citation needed]

Attracted to astronomy by the influence of James Nasmyth, he constructed in 1850 a 13-inch reflecting telescope, mounted first at Canonbury, later at Cranford, Middlesex, and with its aid executed many drawings of the celestial bodies of singular beauty and fidelity.

His chief title to fame, however, is his pioneering work in the application of the art of photography to astronomical research. In 1851 his attention was drawn to a daguerreotype of the Moon by G. P. Bond, shown at the great exhibition of that year. Excited to emulation and employing the more rapid wet-collodion process, he succeeded before long in obtaining exquisitely defined lunar pictures, which remained unsurpassed until the appearance of the Lewis Morris Rutherfurd photographs in 1865.

In 1854 he turned his attention to solar physics, and for the purpose of obtaining a daily photographic representation of the state of the solar surface he devised the photoheliograph, described in his report to the British Association, On Celestial Photography in England (1859), and in his Bakerian Lecture (Phil. Trans. vol. clii. pp. 333–416). Regular work with this instrument, inaugurated at Kew by De la Rue in 1858, was carried on there for fourteen years; and was continued at the Royal Observatory, Greenwich, from 1873 to 1882. The results obtained in. the years 1862–1866 were discussed in two memoirs, entitled Researches on Solar Physics, published by De la Rue, in conjunction with Professor Balfour Stewart and Mr B Loewy, in the Phil. Trans. (vol. clix. pp. 1–110, and vol. clx. pp. 389–496).

In 1860 De la Rue took the photoheliograph to Spain for the purpose of photographing the total solar eclipse which occurred on 18 July of that year. This expedition formed the subject of the Bakerian Lecture already referred to. The photographs obtained on that occasion proved beyond doubt the solar character of the prominences or red flames, seen around the limb of the moon during a solar eclipse. In 1873 De la Rue gave up active work in astronomy, and presented most of his astronomical instruments to the university observatory, Oxford. Subsequently, in the year 1887, he provided the same observatory with a 13-inch refractor to enable it to take part in the International Photographic Survey of the Heavens.


Description of a New Optical Instrument Called the Stereotrope
Proceedings of the Royal Society of London, Vol. 11, (1860 - 1862), pp. 70-73
[To Do: Transcribe.]

Eclipse of the sun, the first images
[To Do: Transcribe a few of the good bits, description.]

Laurent Laveder photography and stereo photography


Laurent Laveder, November 2006 and January 2007. (Source: pixheaven.net.):

Canon 350D + Barlow 2x + WO Megrez 960/80 (F/D 12.0) refractor, composite of 2 pictures
1/200 s on
 
November 2006 and January 2007, Quimper, France

Also see Laurent Laveder's analglyph of this lunar stereo pair.

Other stereo pairs by Laurent Laveder:
Saturn
Mars
Jupiter
This Jupiter stereo pair, using the planet's rotation, is extraordinary for showing atmospheric changes that are manifested by anomolous disparity features.

Tom Matheson astrophotography

   
From Ton Matheson's description (accessed 3/20/10):

"During the partial phases of a lunar eclipse, part of the Moon is inside the darkest portion of the Earth's shadow (the Umbra) and part is outside it. The part in the Umbra is about 1000 times dimmer than the part outside it. While our eyes can deal with that kind of brightness range, computer monitors and prints can't display it. In order to produce an image that approximates what the eye sees, I combined eight exposures ranging from 1/2 second to 1/320 second. The eight images were taken over the course of a few seconds at 11:11 p.m. EST while the Moon was emerging from the Earth's shadow.

Partial phase: 2008-02-20 11:11 p.m. EST from northern New Jersey. Composite of 1/320, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, and 1/2 second exposures at 800 ASA with Canon 40D through Astro-Physics 155 at f7."


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Comments are welcome (dow[at]uoregon.edu).