Technical Notes | RCOS 14.5" RC
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RCOS 14.5" RC

The Dual 14.5" Ritchey-Chrétien telescope shown above was manufactured by RCOS (Flagstaff - Arizona www.rcopticalsystems.com ) using ion-milled optics by Aries (Ukraine).  The special feature is the exchangeable f/9 and f/15 secondary mirrors.  Apart from swapping the secondaries, the exchange involves repositioning the spider assembly and recollimation.  Although simple and fairly quick - the operation is best done on a mission-specific basis, i.e. from f/9 to f/15 for a favourable planetary opposition.

The instrument was installed end of August 2003.  The mount is an Astro-Physics AP1200GTO  www.astro-physics.com on a combination 10" steel pedestal and concrete pier.  Primary mirror installation, system check-out and initial operation were straightforward. Collimation, both by daylight using a Takahashi collimating scope and on a star by night was easy, repeatable and accurate. A few minor issues with secondary temperature control and instrument rotator backlash remain but should be solved soon.

Visual performance was nothing short of stunning, especially deep sky objects at around 100x magnification and Mars at opposition with a 10mm ZAO and neutral density filter.

Below is the very first light image taken while 'commissioning' the RC at f/9: checking guiding performance, on-chip collimation, temperature behaviour, etc... No special care was taken to use good bias, dark and flat field frames. Seeing conditions were regular to poor: the rare "Terral" was running, a warm, dry land wind from across the Cordillera that kept the focusing FWHM values well above the 2 arcsecond mark.

Update on 09.09.03:

The secondary temperature control problem was solved by installing the latest firmware version into the TCC (Telescope Control Center). The TCC now flawlessly controls secondary focuser position, cooling fans for the primary, heater element for the secondary and the instrument rotator. 

See the first real images taken with the 14.5" RCOS here:  NGC 1365Mars, NGC 1398, NGC 7582, NGC 1097

M16 - Pillars of Creation   H-Alpha  3x 10min  ST-10XE 4.5nm Ha filter
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Antilhue 2008 Š Daniel Verschatse