The Toppo Telescope #1 (TT1) is an 1.54m altazimuth telescope with a Ritchey-Chretien optical configuration.
It is equipped with an active secondary mirror, designed specifically for optimal image quality.
The TT1 is the first Alt-Az telescope in Italy.
The following tables show the main TT1 optical parameters:
|M1 - Diameter/focus
|| 1.537 m / 8.9
|M2 - Diameter
|Free vignetting area
|Resolution (optics + detector)
|Nashmit foci (not avaiable)
|Trapped focus (not avaiable)
|Pointing velocity AZ
|Pointing velocity ALT
|Max AZ traking error
|AZ traking error (rms)
|Max ALT traking error
|ALT traking error (rms)
The telescope enclosure is ventilated
by a system of flaps which optimize the air flow minimizing the dome and
mirror seeing. All motors in the telescope environment and the hydraulic
system are cooled to prevent heat input to the building. The volume under
the floor is overpressurized and cooled with respect to the ambient.
Motors, switchboards and any heat source are contained in this cooled
interface/ambient. The upper surface of the telescope pillar is also
contained in this volume. The building outside is insulated by means of a
5 cm thick insulation. The telescope floor and the telescope ambient are
so insulated from the rest of the building.
The main feature of the TT1 is the presence of an Active Optics (AO) system:
M2 is mounted on an exapod system (six expandable arms) used to keep the
mirror in the correct position and tilt with respect to M1.
Both the thermal control and the active optics will contribute to the
excellent image quality foreseen for the TT1. They will allow the TT1
optical quality to reach the ambient seeing.
The TT1 has a rigid construction due to the reduced
mass of the primary mirror and telescope structure compared with classical
telescopes. The goal is a very accurate pointing of 1.5" r.m.s. over
most of the sky. Degradation occurs close to the zenith and at zenith
angles larger than 70°.
Tracking accuracy at 0.1" will match the overall image quality of 80%
energy in 0.23" diameter.