UKIRT Upgrades Programme
The UKIRT Upgrades Programme
The goals of the Programme are:
- To improve the telescope optics to be diffraction
limited at a wavelength of 2.2 microns (K band), implying
inter alia intrinsic (= no seeing) image FWHM = 0.''12.
To do this we have implemented:
- Active control of the primary mirror figure
- Active alignment of the secondary mirror
Look-up tables are being developed to automate these processes.
In 1997 we hope to upgrade the system to provide active control of
telescope focus (and maybe adaptive: see below).
- To eliminate image movement from whatever source. To do
this we have:
- Installed a new, stiffer topend ring and vanes;
- Equipped it with a fast adaptive tip-tilt secondary mirror
and fast guider (up to > 100 Hz sample rate).
With a sensor sampling rate between 30 and 100 Hz (loop bandwidth
between 3 and 10 Hz) the tip-tilt secondary reduces image sizes in
good seeing from 0.''6 to 0.''3. It is now in regular use, and we
hope to be able to guide on stars down to about V = 16 mag.
- To reduce facility seeing by ventilating the dome
and cooling the primary mirror. We have:
- Enhanced the extraction system to remove 10 - 12 dome
volumes of air per hour.
- Installed a Dome Ventilation System (DVS) of sixteen
ventilation apertures (operational by April 1997).
- Installed a 5 kW primary cooling and ventilation system
(operational by mid-1997).
Funds in 1997-98 permitting, the thermal isolation of the
dome will be increased by insulating the floor.
These improvements are intended to make local seeing - excluding
layer effects - imperceptible during about 85% of observable time.
The UKIRT Upgrades Programme is a collaboration of the Joint Astronomy
Centre, Hilo, Hawaii(JAC), the
Royal Observatory, Edinburgh(ROE), the
Royal Greenwich Observatory RGOand the
Max Planck Institüt für Astronomie,
Heidelberg (MPIA) (See: