Astronomical Spectroscopy - Physics - University of Cincinnati

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Fig. 9.— View of the focal plane of Hectospec. From Fabricant et al. (2005). Reproduced
by permission.
astronomer goes to the telescope on the scheduled night, but a “queue manager” decides on a
night-by-night basis which fields should be observed and when. The observer has discretion to
select alternative fields and vary exposure times depending upon weather conditions, seeing,
etc. The advantages of this over classical observing is that weather losses are spread amongst
all of the programs in the scheduling period (4 months). The advantages over normal queue
scheduled observations is that the astronomer is actually present for some of his/her own
observations, and there is no additional cost involved in hiring queue observers.
2.5. Extension to the UV and NIR
The general principles involved in the design of optical spectrographs extend to those
used to observe in the ultraviolet (UV) and near infrared (NIR), with some modifications.
CCDs have high efficiency in the visible region, but poor sensitivity at shorter ( 1µm) wavelengths. At very short wavelengths (x-rays, gamma-rays) and very long
wavelengths (mid-IR through radio and mm) special techniques are needed for spectroscopy,
and are beyond the scope of the present chapter.
Here we provide examples of two non-optical instruments, one whose domain is the