Techniques d'observation spectroscopique d'astéroïdes

58 CHAPTER 3. OBSERVING TECHNIQUES
(a)
(b)
Figure 3.1: a) The 3m NASA InfraRed Telescope Facility at the Mauna Kea Observatory on Hawaii. b) SpeX
instrument mounted to IRTF telescope. As scale, SpeX is 1.4m tall and weighs 478kg.
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cross-disperser [Rayner et al., 2003]. Single order long slit modes are also available. A high
throughput prism mode is provided for 0.8 - 2.5 µm spectroscopy at R≈100.
SpeX employs a 1024x1024 Aladdin3 InSBb CCD array for acquiring the spectra, while
image acquisition could be made with a 512x512 Alladin2 CCD InSb array.
Two interfaces are used to manage the instrument and the spectrograph, GuideDog interface
(Fig. A.1) is dedicated to pointing and tracking the object and BigDog (Fig. A.2) interface is
used for spectrograph setup and spectra acquisition.
Observations on IRTF can be performed from anywhere in the world using an internet connection
via VNC (Virtual Network Connection) protocol. The observing runs for this work
were conducted remotely from Meudon-Paris (France), more than 12 000 Km away from
Hawai [Birlan et al., 2004b, Bus et al., 2002]. Due to different time zones, for the observers
in Meudon, the observing time occurred during daylight hours: a full hawaiian night session
started at 5 a.m. and ended at 5 p.m. - Paris local time.
Using the equipment provided at Centre d’Observation à Distance en Astronomie à Meudon
(CODAM), team had the control remotely of both the instrument/guider system and the spectrograph
set-up and spectra acquisition [Birlan et al., 2004a, 2006]. A permanent and constant
audio/video link with the telescope operator was essential in order to administrate possible
service interruptions, thus another interface was used to keep the audio-video link open (via
Polycom ViewStation video-conference system both on Meudon and Mauna Kea). All software
was re-initialized at the beginning of each night.
3.2 Planning the observations
The typical cycle of astronomical observations on world-class telescopes imply the following
steps: 1) issue received with the call of proposal for observers; 2) targets selection; 3) proposal
submission and evaluation; 4) observations; 5) data reductions and analysis; 6) publications