Astronomical instrumentation

Abstract:

As the only two optical instruments appearing in its first fleet of instrumentation, the GEMINI MultiObject Spectrograph (GMOS) are indeed being developed as workhorse instruments. One GMOS will be located at each of the GEMINI telescopes to perform: a) exquisite direct imaging, b) 5.5 arcminute longslit spectroscopy, c) up to 600 object multislit spectroscopy, and d) about 2000 element integral field spectroscopy. The GMOSs are the only GEMINI instrumentation duplicated at both telescopes. The UK and Canadian GMOS team successfully completed their critical design review in February 1997. They are now well into the fabrication phase, and will soon approach integration of the first instrument. The first GMOS is scheduled to be delivered to Mauna Kea in the fall of'99 and the second to Cerro Pachon one year later. In this paper, we will look at how a few of the more interesting details of the final GMOS design help meet its demanding scientific requirements. These include its transmissive optical design and mask handling mechanisms. We will also discuss our plans for the mask handling process in GEMINI'S queue scheduled environment, from the taking of direct images through to the use of masks on the telescope. Finally, we present the status of fabrication and integration work to date.

Abstract:

Science workshops were held throughout the Gemini partnership during the second half of 1997 with the aims of identifying and quantifying the supporting capabilities required to enhance the utility and efficiency of the Gemini 8m telescopes. These workshops, held separately in the US, UK, Canada and South America, ensured representation programs were considered in detail sufficient to understand the requirements for their execution on Gemini as well as for any preparatory observations. The desire for wide-field optical and near-IR imaging was frequently identified with an average of one-half to one night of these survey observations per night of Gemini follow-up. Two other common themes were high angular resolution imaging and rapid response to target-of-opportunity events. ©2003 Copyright SPIE - The International Society for Optical Engineering.

Abstract:

We present near-infrared broad-band and H2 images of the quadrupolar source IRAS 04302+2247. High-resolution data at 3.8 μm show that the circumstellar envelope has a high degree of axisymmetry: the asymmetry at shorter wavelengths is almost certainly the result of extinction by dust in the cavity. Photometry of the flux peaks confirms that the source is variable but little change in appearance is observed between 1995 November and 1997 September. We report the first clear detection of the molecular outflow in H2 at 2.1 μm, revealing discrete streams which are inclined to the axis of the cavity. The motion of knots in the outflow remains the most likely cause of the variability.