They Told The Story
A Neptune Chronology
Adams Dated Computations
The Forgotten Diary
Within One Degree
The Crown Jewels Document
Announcing The Discovery
Challis' Unseen Testimony
A Retrospective History
A Cantab. Clique
Adam's July Ephemeris
Mapless In Cambridge
Airy Tells the Truth
The Radius Vector: A Trivial Question?
Airy Blows His Top
Eggen Takes the Papers
Selected Correspondence
Primary Sources
Related Links.

 

ADAMS’ JULY EPHEMERIS

Professor Challis emphasized his use of a certain one-page document, in his report to the RAS. This appears as being the first clearly dateable (within a month) document that Adams gave to another concerning the position of the new planet. It defines the planet’s likely positions in RA and Declination, for the purpose of directing Challis’ sky-search. This document has never been described or reproduced in the history books -only Challis’ selective and partial account of it is reiterated, as if the document itself did not need to be viewed.35_1_sm.jpg (16586 bytes)

Its page divides into two sections from two different calculations. Both are based on circular, Bode’s law orbits of the kind that Adams is supposed to have left behind in early 1845, and neither draw upon his perturbation-calculations. Its top section is based upon two anomalous star-position records, where the objects found were later lost. Perhaps, Adams reasoned, these were the new planet, its motion explaining why they could not later be found. He gives a node position and therefore an inclination to the circular orbit which he infers. Its position for August 29th, 1846 he concluded was ‘336 .4 nearly.' He chose that date as being its heliocentric opposition (the Sun was then at 156 : at helio opposition each year a planet appears brightest in the sky).

Of the two ‘missing stars’ used by Adams, one was that seen by Flamsteed in 1690 (recorded in the British Star-Catalogue as no. 1007), and the other was that published in Comptes Rendus by the Belgian Joseph Wartmann in 1836. From these Adams computed an orbital motion some ten degrees away from that of Neptune.

 

The Chimera of ‘Wartman’s Star’

Louis Wartmann made certain observations at Geneva in 1831 which were published in 1836 (Comptes Rendues Paris, 1836, 2, 307-11). He claimed to have seen a new planet, at the Bodean distance of 38.8 AU from the Sun; and, noting it had not moved for a while, he claimed this showed its retrograde station! He then lost his star – or whatever it was - in 1832. Few took him seriously. Wartman positioned it at co-ordinates equivalent to 314 for September 6th, 1831 (14 Aquarius), while Uranus was then at 313 . Fumbling with his telescope, he had just seen Uranus. This was the reasonable view of Sheehan and Baum:
'in fact, Wartman had simply "discovered" Uranus.’
(In Search of Planet Vulcan p.120).

There was a mere one-degree difference between these positions. Thus Adams was, in July of 1846, mistaking Uranus for Neptune. Contrary to obfuscating comments that Challis made in his presentation to the RAS, Adams appears as the sole British astronomer on record as taking seriously Wartmann's claim to have observed the new planet.

Wartmann's 'observations' were made a decade after the Uranus-Neptune conjunction, when the two spheres were nine degrees apart. As the Harvard mathematician Benjamin Pearce reported to the American Academy of Arts and Sciences in Boston on 12th November, Wartmann's planet could not have been more than eight or ten degrees from Leverrier's computed orbit for Neptune (Hubbell & Smith, JHA 1992 23, p266).

The second and lower half of Adams’ July ephemeris gives five possible positions for the planet over a twenty-degree interval, the middle one being that specified in Leverrier’s June 1st paper. For each of these positions, its RA and Declination values are specified over two-wekly intervals from July 20th to October 8th. This section appears as a mere transcript from Leverrier's June 1st paper in five respects:

  • use of a circular orbit and
  • its adoption of the Bode's-law radius of 38 AU; 31_sm.jpg (3217 bytes)
  • the orbit used had no inclination i.e. was in the ecliptic plane;
  • the longitude on the 29th August 1846 was given as 325 , the same degree as Leverrier's,
  • and lastly, its five columns span plus or minus ten degrees, the same confidence limit as in Leverrier's paper.

That 325 position which it advocated (cited by Challis at the RAS presentation) was three degrees away in helio longitude from the position he was later to claim had been given to Airy in the previous October and is not a solution present in his manuscripts.

Adams was invited to produce a document to guide the Cambridge sky-search, beginning in July. What he came up with began and ended with references to ‘Wartmann’s star’, its final conclusion being:

‘If the star obsd. by Wartmann be the supposed planet, q = 336 .4 nearly’

followed by his signature. Seeking for a planet that was perturbing Uranus, he had used some delusive readings as had derived from that same planet a decade earlier. Thereby he recommended a value in error by ten degrees.