Although the primary purpose of the Centennial Observatory is to provide visitors with opportunities to experience the universe visually through telescopes, the facility is also used for astronomical research. The main research program determines asteroids' sizes and orbits via stellar occultation. The method is straightforward: Timing how long a passing asteroid blocks (occults) the light of a distant star, together with the asteroid's previously-determined distance and speed, allows its diameter to be calculated (by distance = rate x time). With multiple observers at various locations around the globe, the size and shape of the asteroid's shadow (identical to that of the asteroid itself) may be mapped out.
Due to the inherent uncertainty in asteroids' orbits, the paths of their shadows on Earth, cast by starlight, are imperfectly known. While many observers utilize small, portable instruments which allow them to travel to locations where a given asteroid's shadow is likely to pass, this option is not available for the Centennial Observatory's permanently-mounted 24" (0.6m) telescope. Therefore, many occultations, including ones with a low probability of being seen by our telescope, are observed to increase the frequency of success.
The Centennial Observatory's first asteroid occultation observation was conducted on 24 August 2012, when asteroid (1585) Union cast its shadow from the star TYC 5777-010444-1 onto the Earth. No occultation was seen (i.e. the shadow missed Twin Falls). All subsequent "positives" (timings performed when the Centennial Observatory was in an asteroid's stellar shadow) are listed below, in reverse chronological order.
Click on the date for a map of the asteroid's predicted shadow path. Click on the asteroid name for a profile of the asteroid showing all observers' chords (star tracks relative to the asteroid as seen from different locations). Click on the star name for a graph of the photometric data. Click on the observers' names for a map of all observers' locations. (Use the "back" button to return to this page.)
|06 Oct 2017||(1936) Lugano||TYC 1358-00407-1||31.1%||C. Anderson|
|28 Sep 2017||(69) Hesperia||4U 380-139928||99.9%||C. Anderson
|26 Sep 2017||(372) Palma||UCAC4 697-043370||100.0%||C. Anderson|
|09 Aug 2017||(903) Nealley||TYC 5788-00046-1||66.8%||C. Anderson|
|16 Apr 2017||(838) Seraphina||4U 475-43580||31.8%||C. Anderson
|11 Apr 2017||(105) Artemis||HIP 62736||26.3%||C. Anderson
|18 Jan 2017||(52) Europa||2UCAC 28031948||99.9%||C. Anderson|
|22 Oct 2015||(247) Eukrate||TYC 3413-01493-1||57.3%||C. Anderson
|23 Aug 2015||(107) Camilla||TYC 5595-00982-1||88.0%||C. Anderson
|Cited in Astronomy & Astrophysics, 7 Feb 2017|
|27 Jul 2015||(8823) 1987 WS3||HIP 90382||2.2%||C. Anderson
|Only occ. of this asteroid ever recorded.|
|12 Feb 2015||(931) Whittemora||TYC 652-01042-1u||14.2%||C. Anderson
|09 Oct 2014||(54) Alexandra||TYC 6308-00865-1||Not rec.||C. Anderson|