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- To: Ray548Ti@aol.com
- Subject: BULLETIN: First Images from the SOHO Spacecraft - Status Report
- From: Cary Oler <oler@holly.cc.ulethdot ca>
- Date: Wed, 14 Oct 1998 02:38:20 -0600 (MDT)
SOHO SPACECRAFT STATUS REPORT First Images Look GREAT !! 14 October 1998 The Solar and Heliospheric Observatory (SOHO) spacecraft is performing above expectations since control of the spacecraft was recently regained. Recommissioning activities for the numerous scientific instruments are continuing and will persist through the remainder of October. Over the weekend and today, the MDI/SOI (Michelson Doppler Imager/Solar Oscillations Investigation) instruments and the LION (Low Energy Ion and Electron Instrument) sensor on the COSTEP (Comprehensive Suprathermal and Energetic Particle Analyzer) instrument were all successfully switched on yesterday and today. Yesterdays first-light images from the MDI instrument showed a notable blotchy pattern that was assumed to be related to non-thermal equilibrium in the MDI filter. Today, the filter reached equilibrium and new imagery from MDI show practically no trace of the blotchiness observed yesterday. One of the most significant (and worrisome) events occurred today: the activation and recommissioning of the EIT (Extreme ultraviolet Imaging Telescope) instrument. EIT was successfully turned on today (13 October) and four images from each of the four extreme ultraviolet wavelengths were successfully obtained. An examination of the images revealed excellent image quality. It appears the CCD detector has actually benefited from the 3 month bakeout that occurred when the spacecraft lost control. Current FULL-RESOLUTION imagery is now being released in honour of the spacecrafts second year of operation. The imagery may be obtained at: http://umbra.nascom.nasadot gov/eit/eit_full_res.html Please note that these images are not true with respect to the Sun's north and south pole. The orientation of the spacecraft has not yet been trimmed so that these sensors see the Sun's north pole at the top of the image (as was the case prior to the spacecraft problem). In these images, the northern solar pole is more nearly toward the lower-right side of the image frames while the eastern limb is toward the upper-right and the western limb is toward the lower-left of the image frame. This oddity, which affects all of the imaging instruments, will be corrected when the spacecraft is rolled into an appropriate orientation. The LASCO (White Light And Spectrometric Coronagraph) instrument was also successfully activated today. All heaters, calibration lamps and shutters of each of the C1, C2 and C3 cameras have been tested successfully. Dark images from each of the cameras at 0 seconds and 60 seconds have been obtained. Activities currently in-progress include checking out the C2 and C3 filter wheels, mechanisms and the cameras themselves. This will be followed by checking the C1 mechanisms and camera, and then by a complete calibration sequence of the LASCO telescopes. Not until these steps have been completed will the telescope doors be opened and the solar corona be imaged. The process of recommissioning the UVCS (UltraViolet Coronagraph Spectrometer) instrument is also continuing without problems today. It has been a GREAT day for SOHO! ** End of Bulletin **
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