15.10.2020 Take three dew heaters to the observatory?

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Thursday 15th A long, grey, cool day despite the promise of lots of sunshine by both national weather services. Wind blowing from the NE. Typical! There is a new AR I could be imaging in the SE.

The new 12V DC PS with cigarette lighter socket arrived. Excellent service from that online dealer as always. I promptly wrapped my three dew heater bands around the telescope. One on the D-ERF and objective cell, the next on the back of the main tube just behind the objective cell. The last band went on the main tube next to the backplate. 

The Hitechastro 4-way, dew heater controller was fixed to the saddle with double sided tape. I hoped that having a single lead to the central controller [from the PS] would avoid tangles. The long leads of the three heater strips were wrapped neatly around the main tube to use up most of their spare length.

The ambient temperature in the dome was 50F. 47F outside. After setting three control knobs to 12 o'clock, each band reached 65F [inside] within a few minutes. I used the sensor of a digital thermometer tucked under each heater strip, in turn, to check their temperatures. There was some variation of a degree or so but hardly worth worrying about. 

I have no idea whether 65F is adequate to rid the objective lens of dew from scratch. I am afraid to run them all night, unattended, because of a possible fire risk. Experience will tell if more heat is required. Wrapping insulation around the dew bands [while I am in attendance] may speed dew removal after a cold night. The aluminium coated, sponge dewshields did nothing useful! 

The dealer has sent the remaining [base] adapter for the FTF2535 by quick mail and free of delivery charge. It should arrive tomorrow. Though, of course, I did have to pay for the adapter itself. There was also an apology for the confusion over the exact parts required. 

The second image shows the massive, FTF, flat, base plate fixed onto the new backplate. I put the backplate back in the lathe and took a light cut with a sharply pointed tool to make a guide circle. Then I drilled and tapped the four holes. The M4 stainless steel screws are slightly too long. So I used packing nuts until I can get the correct length of screws.

The weight is certainly adding up. I'm hoping the increased moment will help to steady the telescopes when it is windy. It will certainly mean moving the OTA up through the rings to achieve tube balance. I will probably have to move the main counterweights much further out too. 

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