Aperçu du fichier PDF ea2803.pdf

Page 1 2 3 456119

Aperçu texte


Authors Suppressed Due to Excessive Length

the way that their data are used and they are often frustrated.
Add some bibliometry considerations showing that amateurs are highly cited (B.
Carry input)...

2 Requirements for observations
The choice of digital cameras and the set-up of motorized telescopes play a key role
in the achievement of professional scientific goals. In addition, the development and
use of dedicated software is of major importance concerning standard data processing procedures. In a first step, an appropriate matching of the telescope and the camera is required in order to fit the goals of a given scientific program, since a universal
setup does not exist. The couple telescope and camera constitutes the basement of
an astronomical setup, but some additional instruments might be added according
the projected scientific goal: a filter wheel (with the appropriate filters), an adaptive
optics corrector, or in some cases a spectrometer. Table 1 summarizes the appropriate equipment for each proposed research topic in this article. This chapter helps to
perform the right instrument selection.

2.1 Telescope requirements
In many cases planetary studies do require high angular resolution. Different factors act on the resolution: diffraction (diameter, obstruction), optical quality (aberrations, glass composition), mechanics (flexures, dilatations, focusing, equilibrium),
environmental conditions (turbulences due to the tube, the dome, the building, and
the weather). All of these factors must be respected, and the failure of only one of
them directly degrades the finally achieved resolution.
The telescope mount is also an important choice. Mechanics for amateur mounts
are generally equatorials and based on a worm drive that have the inconvenient to
generate periodic oscillations. The quality of the worm must be measured before
buying the mount (see http://demeautis.christophe.free.fr/ep/pe.htm). Some motor
controllers can correct the periodic error allowing the use of a not perfect equatorial mount. The next generation will be based on direct drive motors and/or absolute
encoders on both axes. These technologies avoid periodic errors and should be common in premium amateur telescope mounts in the next years. Note that the direct
drive technology is more sensitive than the worm drive to the equilibrium of the
instruments placed on the mount1 .
All parts of the telescope (tube, mount and pier) must be qualified concerning the
damping of vibrations. Even with perfect optics and telescope drive, some factors

http://www.dfmengineering.com/news telescope gearing.html#chart