A new NASA spacecraft was successfully launched on October 25, 2006 from Cape Canaveral in Florida atop a Delta II rocket. This features a twin Sun-orbiting spacecraft called STEREO (Solar Terrestrial Relations Observatory). One STEREO spacecraft will orbit at slightly further from the Sun than the Earth and will lag behind the Earth at a rate of 22 degrees per year. The other one will orbit at slightly closer to the Sun than the Earth and will advance ahead of the Earth at a rate of 22 degrees per year respectively.Each STEREO spacecraft carries the instrument called Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI). SECCHI includes the COR1 and COR2 coronagraphs. Just similar to the C2 and C3 coronagraphs respectively but with much higher resolution and more frequently imaging.
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Instruments mounted onto STEREO spacecraft |
Some information about the instruments are listed below (taken from Karl Battams):
COR1: Internally occulted coronagraph (similar to LASCO C2) will image from 1.1 - 3.0 Rsun with 2048x2048 pixel CCDs, and a resolution of 7.5 arcsec/pixel (C2 has a 23.8 arcsec/pixel resolution and 1024x1024 CCDs). Bandpass is 650-660 nm.
COR2: Externally occulted coronagraph (like C3, except you won't see the pylon for COR2 like you do for C3) will image from 2.0 - 15Rsun with 2048x2048 pixel CCDs, and a resolution of 15 arcsec/pixel. (LASCO C3 has 1024x1024 CCDs with 56arcsec resolution). Bandpass is 650-750 nm.
HELIOSPHERIC IMAGER ("HI"): Two externally occulted coronagraphs with the occulter at the edge of the field (not the center, like COR1/2, C1/2). These will allow us to follow CME's as they head out from the Sun, towards the Earth. They are as follows: HI-1: 2048x2048 CCDs, 35 arcsec/pix resolution. Will image along the ecliptic from 3.28-23.28 degrees (that's roughly 12 - 92 Rsun) HI-2: 2048x2048 CCDs, 240 arcsec/pix resolution. Will image along the ecliptic from 18.36-88.36 degrees (roughly 73 - 318 Rsun)
Things to note are as follows. 1) COR1/2 images will be polarized on-board and will usually be taken as +90/0/-90 -degree triplets. 2) There will be *very little* full-resolution realtime data as there is with SOHO now. Most data will be dumped in one large load, once per day. 3) No one is sure on limiting magnitudes yet, but I think the COR's are hoped to be m10 - m12, and the HI's m10 - m14. We really don't know until we start imaging in space (and I'm not certain I have remembered the numbers correctly...). 4) There will NOT be a SWAN-like instrument on STEREO. 5) STEREO has a larger bandwidth available to it than SOHO... this means LOTS more data...
Latest Update: 2007/07/23
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