W29X BALLOON TEST + SDS (Solar Disk Sextant)

The Solar Disk Sextant (SDS) is a balloon-borne instrument whose objective is to measure the solar diameter, at different orientations, as a function of time. Results include the solar oblateness, the oscillation spectrum for use in helioseismology, and the rate of the secular variation of the solar diameter. The required instrumentation precision (a few milliarcsec) is attained by means of an objective beam splitting wedge which produces multiples solar images through consecutive reflections.

Balloon launched on: 10/17/2009 at 14:30 utc
Launch site: Scientific Flight Balloon Facility, Fort Sumner, (NM), US  
Balloon launched by: Columbia Scientific Balloon Facility (CSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon  
Flight identification number: 604NT
End of flight (L for landing time, W for last contact, otherwise termination time): 10/18/2009 at 0:30 utc
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): ~ 10 h
Landing site: West of Olton, Texas, US

• Variation of the Diameter of the Sun as Measured by the Solar Disk Sextant (SDS) Monthly Notices of the Royal Astronomical Society, Volume 436, Issue 3, 11 December 2013, Pages 2151-2169