Stellar occultations

Triton, November 29, 2003


Triton occultation yellow alert On 2003 November 29, there is a possibility of a Triton occultation observable from Hawaii and California. The event is described at the MIT occultation page, with maps at Bruno Sicardy's 2003 occultation page As usual with occultations by small, outer-solar system bodies, the maps only show the current predicted location of the shadow. This can change dramatically depending on refinements to the star's position.

If the event is observed from Hawaii and California, we can continue to track the changes in Triton's atmosphere. But this event may be difficult to observe; it occurs just after sunset in Hawaii, and at high airmass in California (3.2 at Lick, 2.3 at Palomar).

Star= GSC 6348-476, or USNO-A2.0 0675-35937787 DATE & TIME = 2003 November 29 3:45:59.36 (UT)
RA: 20 52 45.9017 Dec: -17 33 34.365 (Ron Stone)
V = 13.4 (V) (Ron Stone)


This star is not in 2MASS, and no accurate colors are found in Vizier for spectral typing.
The star is in the USNO-A2.0 (0675-35937787) with B=13.5, R=12.7, but USNA-A2.0 magnitudes are often poor.
Leslie Young and Will Grundy measured J = 12.1 K = 11.6 with an accuracy of probably about 0.2 mag, so this star is somewhere between a G8 (V-K=1.63, T=5490) and K0 (V-K=1.83, T=5240). This doesn't jibe well with the USNO mags though, since USNO gives B-R = 0.8 (cf. B-R=1.3 for G8, 1.5 for K0).
For Hawaii, it is also important to concider sky backgorund. This report from Gemini estimates a brightness of 9.9 mag/square arcsec at zenith with the sun 1 deg above the horizon, or 14.5 mag/pix on SpeX/Guidedog (0.12 arcsec pixels).


Leslie Young and Jim Elliot have proposed to IRTF for this event, and were awarded time. Other possible sites include Haleakala or Palomar.
Observers and other interested parties: Jim Elliot (, Michael Person (mjperson@MIT.EDU), Cathy Olkin (, Kurt Retherford (, Lewis Roberts (Lewis.Roberts@Maui.AFMC.AF.MIL), Scott Severson (, Bruno Sicardy ( , Rem Stone (, Ron Stone (, Thomas Widemann (, Leslie Young (
Send mail to 2003 Nov 29 Triton list
A list of potential sites is:
Location     Observers              Instrument  
--------     ---------              ----------   ----------------------------------------
Lick Nickel  Olkin/Rem Stone        Guide camera Cancelled due to altitude limits
IRTF         Young/Retherford       SpeX        
CFHT         Widemann               Megacam

Last updated 2003 Nov 25 by Leslie Young, ,