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Astronomical Hypothesis for the Illinois UFO

Eric W. Davis, Ph.D.
Aerospace & Astrophysics - NIDS
Fellow of the British Interplanetary Society
Member of the American Astronomical Society
Senior Member of the American Inst. for Aeronautics & Astronautics
February 29, 2000

Many people have suggested that a parsimonious explanation for the Illinois UFO case of Jan. 5, 2000 is that the UFO "might be" Venus. Others have faulted the NIDS analysis because they perceived that NIDS investigators did not consider this a possibility. NIDS considered but rejected stars or planets as possible explanations for this case on the grounds that the majority testimony identified the UFO as a large (200-600 feet linear, 40-60 feet thick) triangular-shaped object possessing (on its underside) downward pointing white lights arranged at the corners, a red light near the center, possible additional red lights spaced at intervals across the underside and near the perimeter, and a row of multicolored lights along one side between two corner white lights. There also appeared to be large windows with light emanating through them, but these could have possibly been openings or light sources. The bright white lights on the corners were described as blinding to the eye and lighting up the area below the craft. A witness estimate of the brightness of the white lights was that they were much brighter than a police cruiser spotlight. Witnesses observed the UFO to be hovering, slowly rotating about a vertical axis, a combination of the first two followed by slow linear motion, and slow linear motion or hovering followed by sudden linear accelerations sending the object across the sky to the witness’s apparent horizon. The UFO was flying at low altitude, described by witnesses as being tree top or 1000-2000 feet above ground. The object flew northeast to southwest from Highland at 4 a.m., later observed at Lebanon and Shiloh in Illinois, changed its course to northwest and then changed course again heading southwest. At 4:30 a.m. it was sighted at 10,000 feet altitude near Dupo, changing direction from southwest to north then to east while maintaining that altitude (knowing that this altitude is very approximate), yet at this time Venus was still less than a degree above the horizon and very difficult to see. The object hung around the Dupo area for about two more hours.

These facts together do not argue in favor of a planet or star explanation for the UFO. They argue in favor of an aerial object, a craft, possessing extended physical dimension, shape, complex array of lights along with slight sound. The present data is insufficient to determine whether this object was a special access (black) program vehicle or something of unknown origin. The planet Venus was not above the horizon until it rose at 4:25 a.m. on January 5 in Illinois/Missouri and it was -4.07 visual magnitude. At 4:30 a.m. Venus was 0° 45’ (corrected for refraction) above the horizon when it could first become visible to local observers, but generally difficult to see because of the surrounding trees, rolling hills and structures known within the localities of the UFO sighting. Venus was at 4° 38’ (corrected for refraction) below the horizon at 110° 52’ azimuth (between E and SE) when the UFO was first sighted near Highland, Ill. in the northeast part of the sky by the first witness at approximately 4 a.m. At this altitude below the horizon, Venus will not be seen any earlier in this time frame due to refraction. (The refraction angle correction for visible star/planet altitude above/below the horizon is measured in arc minutes, 1/60th of a degree, which decreases in value as objects approach zenith, and 30 arc minutes is the maximum refraction correction at the horizon.) The second witness saw the UFO in Lebanon approximately ten minutes later when Venus was still 2° 49’ (corrected for refraction) below the horizon (112° 23’ azimuth). The police log in Lebanon also noted that witness one’s report was recorded at 4:10 a.m. ten minutes after he sighted the object in Highland. Jupiter (-2.51 visual mag.) rose at 12:11 p.m. on January 4 and set at 1:15 a.m. on January 5 so it was not in the sky during the January 5th event. Mercury (-0.77 visual mag.) was well below the horizon near the sun until it rose at 7:02 a.m. that morning. Vega (visual mag. 0.10, NE), Arcturus (visual mag. 0.02, E), Sirius (visual mag. –1.6, SW), Procyon (visual mag. 0.5, SW), Rigel (visual mag. 0.3, W), Betelgeuse (visual mag. 0.6, W) and Capella (visual mag. 0.2, NW) are the only relatively bright stars at or above the horizon after 4 a.m. January 5. But again, they (visual magnitudes and sky positions) do not fit the facts as described by the eight witnesses as an explanation for the UFO.

A thorough forensic investigation requires consideration of all facts and details gathered from complete eyewitness testimony, and not just from selected excerpts from same such testimony. The testimony transcripts were put on the internet to make clear to interested readers the evolution of events as described by the witnesses interviewed by NIDS. It is erroneous to extract selected excerpts from witness testimony out of context so as to frame a simple explanation for the Illinois UFO.

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