AAS 199th meeting, Washington, DC, January 2002
Session 88. Our Favorite Star
Display, Wednesday, January 9, 2002, 9:20am-6:30pm, Exhibit Hall

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[88.07] Optical Design of the MOSES Sounding Rocket Experiment

R. J. Thomas (NASA/GSFC), C. C. Kankelborg (Montana State University)

The Multi-Order Solar EUV Spectrograph (MOSES) is a sounding rocket payload now being developed by Montana State University in collaboration with the Goddard Space Flight Center, Lockheed Martin Advanced Technology Center, and Mullard Space Science Laboratory. The instrument utilizes a unique optical design to provide solar EUV measurements with true 2-pixel resolutions of 1.0 arcsec and 60 mÅ\ over a full two-dimensional field of view of 1056 \times 528~arcsec, all at a time cadence of 10~s. This unprecedented capability is achieved by means of an objective spherical grating 100~mm in diameter, ruled at 833~gr/mm. The concave grating focuses spectrally dispersed solar radiation onto three separate detectors, simultaneously recording the zero-order as well as the plus and minus first-spectral-order images. Data analysis procedures, similar to those used in X-ray tomography reconstructions, can then disentangle the mixed spatial and spectral information recorded by the multiple detectors. A flat folding mirror permits an imaging focal length of 4.74~m to be packaged within the payload's physical length of 2.82~m. Both the objective grating and folding flat have specialized, closely matched, multilayer coatings that strongly enhance their EUV reflectance while also suppressing off-band radiation that would otherwise complicate data inversion. Although the spectral bandpass is rather narrow, several candidate wavelength intervals are available to carry out truly unique scientific studies of the outer solar atmosphere. Initial flights of MOSES, scheduled to begin in 2004, will observe a 10~Å\ band that covers very strong emission lines characteristic of both the sun's corona (Si~XI 303~Å) and transition-region (He~II 304~Å).

The MOSES program is supported by a grant from NASA's Office of Space Science.

If you would like more information about this abstract, please follow the link to http://solar.physics.montana.edu. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: kankel@icarus.physics.montana.edu

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