Technical specifications

Every instrument, in detail

The figures below come from the exact model’s own data sheet. An instrument from a neighbouring range has neither the same focal length nor the same obstruction.

The dome

Four metres across, and self-tracking

The dome is built by Gambato, in Italy. It is automated and slaved to the instruments: it follows their pointing on its own, with no operator input.

  • Dome diameter: 4 m

  • Shutter: 1.5 m

  • Motorised and slaved to pointing

The mount

10Micron GM4000 HPS QCI

An observatory’s precision starts with its mount. This one slews fast and needs no periodic error correction.

  • Made in: Italy

  • Slew speed: 4°/s maximum

  • Pointing accuracy: under 30 arcseconds, on a 25-star model

  • Tracking: ±3 to 4 arcseconds, without periodic error correction

  • Payload: 150 kg maximum, 125 kg for optimal use

  • Mass: 120 kg

T51 · the main telescope

PlaneWave CDK 20 inch

A 508 millimetre Corrected Dall-Kirkham, the observatory’s main instrument. It carries most of the scientific programme.

  • Made in: United States

  • Optical design: Corrected Dall-Kirkham

  • Aperture: 508 mm

  • Native focal length: 3,454 mm (f/6.80)

  • With 0.66× reducer: 2,279.64 mm (f/4.49)

  • Resolution: 0.27 arcsecond

  • Central obstruction: 39 %

  • Mass: 63.5 kg

Photometry and deep sky

SLOAN and Baader filters, Moravian camera.

Planetary imaging

Baader and Optolong filters, ZWO colour and monochrome cameras.

Spectroscopy

Shelyak spectroscope, Atik cameras.

L13 · the wide-field refractor

TS Optics CF-APO 130 mm

An FPL55 apochromatic triplet, for everything that calls for field rather than magnification.

  • Optical design: FPL55 triplet, apochromatic

  • Aperture: 130 mm

  • Native focal length: 910 mm (f/7.00)

  • With 0.8× reducer: 728 mm (f/5.60)

  • Resolution: 0.55 arcsecond

  • Mass: 11 kg

Deep-sky imaging

Baader filters, ZWO monochrome camera.

TS28 · the solar telescope

Baader Triband-SCT 11 inch

A Schmidt-Cassegrain dedicated to the Sun, able to reach f/30 with its telecentric amplifier.

  • Made in: United States and Germany

  • Optical design: Schmidt-Cassegrain

  • Aperture: 279.4 mm

  • Native focal length: 2,794 mm (f/10.00)

  • With 3× telecentric: 8,382 mm (f/30.00)

  • Resolution: 0.42 arcsecond

  • Central obstruction: 34 %

  • Mass: 13.1 kg

Planetary and solar imaging

Baader filters, ZWO cameras.

T28 · at the pic du Midi

Celestron RASA 11 inch

A very fast wide-field telescope, installed at the pic du Midi. Its f/2.2 suits wide fields and short exposures.

  • Made in: United States

  • Aperture: 279.4 mm

  • Focal length: 620 mm (f/2.2)

  • Resolution: 0.49 arcsecond

  • Spectral range: 400 to 700 nm

  • Mass: 19.5 kg

The mount at the pic

Celestron CGX-L

A motorised German equatorial mount, carrying the wide-field telescope at the summit.

  • Made in: United States

  • Type: motorised German equatorial

  • Payload: 34 kg

  • Slew speed: 3°/s maximum

  • Mass: 23.8 kg, head only

  • Tripod: 21 kg, 70 mm steel

Tracking

Periodic error correction, sidereal, solar and lunar tracking.

The DIMM dome

At the summit of the pic du Midi

It houses the wide-field telescope and its mount at the summit. Its specifications are still to be supplied by the association.

  • Diameter: to be supplied

  • Manufacturer: to be supplied

  • Automation: to be supplied