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Radar

The Pier Expansion

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Check this screenshot out. I'd polar aligned and was getting great alignment. I turn on the air conditioner inside my observatory to get the camera down to minus 20 and the PA plot goes crazy. This tells me that I either need to ensure the inside of the observatory is always at the same temperature (pretty hard to do in Australia during summer) or that I need to cool down the pier to a specific  temp  whenever I perform PA.

In the plot below, where the graph begins to go up, that is the moment I turned on my air conditioner. I had no idea my pier was so temperamental. 

Pier Contraction.JPG

Ideas on how to solve this welcome.

Ray

 

 

 

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Turning the air conditioner off has the opposite effect, almost instantaneously. Very surprised how easily the pier loses PA with temperature.

Pier Contraction.JPG

Ray

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Might explain your recent problems mate. Between movement when extended and changes with temp. I would ditch that pier for a more standard design.

 

Shane

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Might have to design with a material that hardly expands. Not sure what the Invar cost will be, but I'll do some digging. 

Ray

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Very interesting mate. They look well built as well. I'll check them out in the coming days. 

Ray

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Problem with guiding on the south celestial pole seems fixed.  My guide camera wasn't square to the RA and Dec. I rotated it so it was perfect and I am getting round stars again. Must have knocked it sometime without realizing. Anyway, getting some good data, back to collecting photons. 

Ray

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I have wrapped the aluminium lifting column with insulation. I will do a test tomorrow, polar align, turn on air con, see if things shift. 

image1.jpeg

image2.jpeg

Fingers crossed. Otherwise it is water cooling for the camera. 

Ray

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Insulation working incredibly well. Goodbye sudden temperature drops ruining my imaging runs. We love physics.

Ray

Edited by Radar
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Nice job on working out a problem and coming up with a cheap solution Ray. Damn moon and/or clouds here so I haven't been collecting any photons at all. I guess that means more for you B).

 

Shane

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6 hours ago, poppasmurf said:

Damn moon and/or clouds here

No cloud for the first time is ages, but I'm only shooting narrowband during the full moon. That will be my thing now, I'll do the RGB during new moons. The weather has changed so much over the last few years, so much cloud that I have to grab whatever nights I can. I'm enjoying being out there again. 

Ray

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Unfortunately I don't yet have NB filters, although the plan has always to get some eventually. I tend to laugh at anti climate change comments, as an amateur astronomer, the proof is in the change to observing/imaging time available compared to several years ago. When I first got into planetary imaging it was during the decade long drought, and 99% of the time was cloud free and great seeing and transparency, having said that it was great when the drought broke.

 

Shane

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22 hours ago, poppasmurf said:

99% of the time was cloud free and great seeing and transparency

Same here in W.A. Such a difference now compared to a decade ago. Plus, most climate change deniers are not scientists, they are armchair experts with no scientific skillset that have probably watched some diatribe on Facebook or somewhere, so I find it entertaining they lock horns with people that have written a thesis on climatology. 

N.B certainly maximises the time you can image. The full moon is no longer a hassle with N.B. 

Ray

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