[M]: (M)dew heater worries
| Subject: | [M]: (M)dew heater worries |
| From: | Eric Schandall |
| Date: | Fri Apr 16 11:54:46 1999 |
Hi Bill,
Just heard an interesting talk by Andy Woodsworth, the Canadain Project
Manager for the Gemini telescopes.There has been tremendous engineering
devoted to minimizing deterioration of seeing due to temperature
differences anywhere in and around the observatory. He even said that
the support of the secondary housing was made with as little mass as
possible to minimize its being a heat sink.
The primary is cooled to about one degree cooler than the forcast for
the night air, then to make it completly ambient a current is delivered
to the coating on the mirror to fine tune it and prevent any dewing as
well! Look out Jim Kendrick. This may be old stuff but I hadnt heard of
it before, likely goes with attempting better that .05 arc second seeing
.
I also run my heater most of the time. Maybe we would do better if it
was used less and certainly at the lower settings. We could then look
forward to sub arc minute seeing.
Regards,
Eric
Just heard an interesting talk by Andy Woodsworth, the Canadain Project
Manager for the Gemini telescopes.There has been tremendous engineering
devoted to minimizing deterioration of seeing due to temperature
differences anywhere in and around the observatory. He even said that
the support of the secondary housing was made with as little mass as
possible to minimize its being a heat sink.
The primary is cooled to about one degree cooler than the forcast for
the night air, then to make it completly ambient a current is delivered
to the coating on the mirror to fine tune it and prevent any dewing as
well! Look out Jim Kendrick. This may be old stuff but I hadnt heard of
it before, likely goes with attempting better that .05 arc second seeing
.
I also run my heater most of the time. Maybe we would do better if it
was used less and certainly at the lower settings. We could then look
forward to sub arc minute seeing.
Regards,
Eric
