11.12.2022 Dew problems [again!]

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 Sunday 11th 0C. Sunny periods between cloud.

 The 150mm objective is dewed internally. As is the D-ERF. I have been using the hair drier and dew bands. Nothing reaches inside the cold glass.

 12.23 Best image of a very bad lot!

 12.40 Clouded over again. Going in for lunch and to warm up.

Wasted another hour after lunch before giving up. The sun is very low and the cloud persistent.

One of my no-name heat bands had a dangerously hot connecting lead but no heat in the band itself! It has been discarded for safety.

The rear of the objective cell is hidden inside a plywood counter-ring. The D-ERF cell clamps to the front of the cell. 

Projecting clamping knobs make it impossible to wrap a heat band around the D-ERF cell. So that it would do any good at demisting the glass elements themselves. 

 There is no metallic connection to conduct heat from the steel main tube to the objective cell. The main tube is furnished with a small pressed flange. Which ensures the locking of the birch ply counter-cell against movement. Without requiring fixing screws. 

 Not a great picture but it shows the problem. The D-ERF cell is quite substantial in aluminium. The D-ERF has thick glass. Which does not respond well to dew removal with a hair drier.

 I have to balance the main tube with a weight on a cord before removing the weighty D-ERF in its cell.  Otherwise the telescope objective would instantly swing upwards. The focuser descending rapidly towards the computer monitor mounted on the north side of the pier. I have no locks on the axes. Simply relying on the friction clutches. Three plastic pads pressing radially against each of  the 50mm stainless steel shafts.

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