Mainstream Science and Observational Data

Request for observational data:

1. Micrometer separation distance, vs. time, for nearest-approaches of pairs of Jupiter's Galilean moons (or Uranus' moons - see below). Much has been published about eclipses by Jupiter but little about near-miss approaches of the moons themselves. I can use this data for a new test of Newton's laws and Special Relativity.

This coming Sunday, Jan 28, 2007, at about 05:57 AM Mountain Standard Time, about an hour before sunrise in the Mountain Time Zone, Io & Europa will achieve such a minimum distance (not very close, because one is in front & one behind Jupiter). (I got this from the Sky&Telescope "chasing Jupiter's moons" site, and confirmed it, to within a few minutes of time, two different ways by measuring on a chart in the Astronomical Almanac.) This conjunction also should be observable in most of the Pacific Time Zone because Jupiter is high enough as a morning star now.

For those with more powerful telescopes, who may wish to view an evening star instead of a morning star: the equator of Uranus is nearly edge-on to Earth during all of 2007. I would be able to use separation vs. time data for conjunctions of pairs of Uranus' moons also.

Please mail your reports to:

Joseph C. Keller, M. D.
POB 9122
Ames, Iowa 50014 USA


2. Observation of stellar occultations by Saturn's rings will require a bigger telescope, maybe 18" (the size with which possibly the most important professional ring-occultation observation ever, was made in 1960 - it was a 9th magnitude star). The rings are getting more edge-on (i.e., the occultation phenomena pass more quickly) and Saturn is wandering toward sparser star fields. So unless one wants to wait until Saturn approaches Sagittarius a decade from now, the next four months give the best chance of a good occultation.

Saturn is stationary at about April 18 or 19. According to the Millenium Star Atlas (one million stars to magnitude +11.5), Saturn will be passing within roughly an arcminute of each of three candidate stars of magnitude +10, 9 & 11 (east to west), near stationarity. The brightest is about 300 arcsec closer to the ecliptic than is the 6th magnitude reference star HD81361/SAO98561 (which is shown in Leo east of 8Leonis in both the Norton & Tirion atlases); the other two stars are about 200 arcsec closer to the ecliptic than is the reference star. The Sky Catalogue 2000.0 gives the reference star at RA 9h25m32.4s, Dec +16deg35'08" for 2000AD; its proper motion is negligible. It is type K0, 170pc distant. The candidate stars are almost collinear, ranging from about 30arcminutes "SE by E", to 5 arcminutes "W by SW", of the reference star.

I had to determine the positions of the candidate stars by measuring on the page with a millimeter ruler and using trigonometry to avoid the need for measuring any angles. At best, the error of this is about 5 arcseconds (0.05 mm on the page). It is insufficiently accurate, to assume that Saturn's path is parallel to the ecliptic.

I found these positions (epoch 2000.0):

Star #1 (10th mag) RA 9h27m19.8s Dec +16deg24.06'

#2 (9th mag) RA 9h26m06.8s Dec +16deg28.54'

#3 (11th mag) RA 9h25m11.7s Dec +16deg34.08'

I found that Star #1 will be occulted (*see correction below based on SIMBAD data*) by Saturn's rings March 20, 2007; conjunction with Saturn (i.e., same RA; closest approach on center is about 25 minutes later) at about 06:46 UT (no better than +/- one hour because of at least 5 arcsec uncertainty of star position); Saturn will cross the star's RA, at +16deg23.98', 0.08' below the star (the north endpoint of the rings' major axis will be 0.160' higher than Saturn's center). The view will likely be best from the western U. S.

I found that Star #3 will have a near miss April 2, 2007; conjunction with Saturn (i.e., same RA) at about 03:34 UT (again no better than +/- one hour); Saturn will cross the star's RA, at +16deg33.73', 0.35' below the star (the north endpoint of the rings' major axis will be 0.157' higher than Saturn's center). The accuracy of the star positions is such that either of these could be an occultation or a miss. The view will likely be good all over the U.S.

Star #2 will pass above Saturn by 1.5 arcminute (measured along the longitude line) on May 14. The other three conjunctions of these stars with Saturn are much farther yet.

I found all three of these candidate stars using a SIMBAD search by coordinates in their 300,000-star catalog. My position for Star #3 (TYC 1402-742-1) erred only 0.05', negligible for these purposes. My position for Star #2 erred 0.21', which doesn't affect the outcome.

The on-center distance at closest approach (true conjunction) of Saturn to [my "Star #1"], as seen from an ideal position in the Bering Sea about 62N 177E on Earth (45 degrees higher above the plane of the ecliptic than the sub-Saturn point at 16.5N 168E near Wake Island), is 13.69" = 0.23' with Saturn north of the star. This includes proper motion (negligible) and aberration of the starlight due to Earth's orbital motion. Saturn's polar radius will be 8.98" so it will miss planetary occultation by 4.71". The time is 09:39 UT for Saturn crossing the star's longitude line; the time of closest approach by Saturn's globe, is 10:16 UT, March 20, 2007.

Assuming Saturn's axial tilt is 27 degrees, the nearest part of the outer edge of the "A" ring will pass 10.34" closer than Saturn's center, for a net miss of 3.35" = 0.056'. I estimate that the brightest part of the narrow, sparse, outer "G" ring will miss the star by only 0.90" = 0.015' from an ideal observation point in Siberia. This slow tangential occultation by the G ring could provide phenomena never before observed. At 15:40 UT (when the sub-Saturn point is 16.5N 96E and the ideal observation position about 62N 105E) the endpoint of the major axis of the apparent A-ring outer ellipse will be at its closest to the star; the actual closest approach of the A-ring edge will be roughly two hrs. sooner.

The star, TYC 1403-307-1, also appears multiple times in the VizieR search of all databases. Its V & P magnitudes are +10.5, and its B magnitude +11.6 (error? 10.6?).

Occultations are least likely near the time when the planet is stationary (April 2007) but such occultations proceed more slowly and are likelier to yield new information. For the four occultation reports I've seen, the closer to stationary Saturn was, the more interesting the observations. I made a rough estimate that there should be 10 occultations of stars of magnitude +11.5 or brighter between now and stationarity in April, 4 of which should be in the Millenium Star Atlas.

The anomalous occultation findings that I found in my literature search, are in my post under the name "Joe Keller" in the Special Relativity section of Dr. Van Flandern's www.metaresearch.org messageboard, Jan 21, 2007. Anyone making any ring-occultation observations is invited to mail me a report to:

Joseph C. Keller, M. D.
POB 9122
Ames, Iowa 50014 USA


Thank you.