During the summer of 1998 Phoenix is undergoing an upgrade of the mechanism controls. The motions of the slit and viewer wheels have been too slow to provide the quick slit centering capability that was envisaged for the instrument. This upgrade will make these two wheels, as well as the other mechanisms, turn faster. Furthermore, jams of the viewer wheel and incorrect computer read back of the mechanism positions will be corrected by this effort. To implement these changes, the grating drive mechanism had to be rebuilt. A desirable additional outcome of this work is that the precision for setting the grating angle has been increased as has the stability of the grating after a change in grating angle.
The 1998B semester was the last semester that Phoenix will be available as a Kitt Peak instrument for the next few years. As announced in the NOAO Newsletter No. 53, Phoenix is being redeployed to CTIO in 1999. Future use is also planned on Gemini South. There will be a period of roughly six months when Phoenix will not be available to the user community. This time will be devoted initially to understanding and improving the collimator image quality. The collimator currently has large astigmatism, which is both limiting the spectral resolution and reducing the sensitivity by spreading the image over an excessive number of pixels. Phoenix will also be tested under operating conditions for Gemini where the instrument can be operated in nearly any orientation (including upside down) from the normal Cassegrain position. The instrument will be shipped to CTIO and interfaced to the 4-m Blanco Telescope. At that point, it will again be available for user programs.
An aggressive campaign is already underway to correct the collimator imaging. This could result in changes to the details of the deployment plan during the next few months. Prospective Phoenix users who want an update on the availability in 1999 should check the Phoenix Web page (http://www.noao.edu/kpno/phoenix/) or send e-mail to the undersigned.