Monthly Report: 2004 January

Also located here.

Murison continued work on the adaptive optics (AO) front end for the FTS project.  He and Brad Behr revised the optical design several times.  The optical fiber is now imaged onto the same CCD camera as the starlight from the telescope, which makes calibration of the AO corrections much easier.  The new design can be found here (click on “config 4” and on “hardware drawing 2").  Murison added refraction by ideal thin lenses into his computer algebra ray tracing package (AESOP) in order to trace the new AO design with misalignments.  He wrote a memo describing how to ray trace an ideal thin lens in the paraxial approximation.

Behr, Hajian, and Murison redesigned the interferometer of the FTS.  The new design has two major changes.  First, the metrology laser light (red beam in the drawing) is injected directly into the starlight path via the first beam splitter cube, rather than via the notch filters of the previous design.  This simplifies the system, improves throughput by about 25 percent, makes alignment easier, and is a “sweet” design.  Second, the half of the starlight beam that used to get thrown away at the first beam splitter cube (required to polarize the starlight signal) has been fully recovered and sent through the system to wind up as a second signal on the CCD detector (yellow beam in the drawing), thereby effectively doubling our throughput.  This was accomplished by clever use of transmitted and reflected polarized beam components, thus refuting the conventional wisdom that it is not possible to recover both halves of the starlight beam.

In response to several requests from colleagues of FTS members, Murison designed and implemented a web site for the FTS project.  It is currently only a skeleton and not at all ready for public use.  Content will be added by the FTS group as time allows, and it will “go public” when sufficiently ready.  For now it serves as a useful repository for documentation of recent FTS work.

Murison and Efroimsky have decided on dynamics projects for presentation to the AAS Division on Dynamical Astronomy at its annual meeting in April.  Their topics are on the dynamical stability of objects orbiting oblate, precessing planets, using the dynamical gauge formalism recently discovered by Efroimsky.  Murison may, if time allows, also present recent results on calculation of orbit-orbit distances.

Murison’s student, Andrei Munteanu, has been announced as a Finalist in the Intel Science Talent Search.  Andrei submitted a paper to the Intel STS describing his work (in collaboration with Murison) on orbit-orbit distances.