Hey Thomas

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I have never had this problem because I have a permanent observatory but you might have luck with putting a low wattage light bulb, filament type, under the cover to keep a gentle heat under there. I do not know if anyone else has or does this but it would be interesting to see if someone has. You only need to elevate the temp perhaps 10 degrees above ambient to keep dew from forming I would think. It goes without saying that you should have a dew shield and a dew heater but as far as storage goes the bulb may be enough.

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The bad part of getting moisture on correctors and mirrors is that there is usually already a fine coating of dust on these elements and when the dew appears it turns this dust to mud which then sticks to the lens or mirror and makes it harder to clean without removing the mirror and putting it under running water after soaking in a mild soap solution.

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There are many good articles and YouTube Videos on cleaning but preventing this in the first place is better of course. An ounce of prevention is better than a pound of cure!

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That small amount of heat might be just enough to prevent condensation. It usually gets very humid just before dawn as evidenced by the dew on the lawns.

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It is a very common thing to put a cloth over a frost sensitive plant with a light bulb under it so this might work for the scope. It is just a miniature heater of course. Maybe 60 watts could help.

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You would of course have to make sure the bulb is in a cage or something to prevent a fire hazard. That is what I would do if my scope was outside.

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I wonder if anyone else has tried this bulb heating idea?

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Gary

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Carpe Noctem.

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Yea maybe I went off on that when I should not have. “Fools rush in where wise men dare not tread”!

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I guess what I was trying to say in too many words was that even the best machines in a lot of cases cannot produce a perfect product and then one has to jump in and tweak things. It is all too common and I have been there many times. Some call it cheating and most call it just plain making it work. A lot of stuff you make that has to really be down there in the Microns has to be hand worked. That is what I was trying to say. Even back in the day when I worked on the stamping lines at Ford when I was 22 there were guys on the end of the line pounding, sanding, and tweaking the quarter panels as they came off the line. Most fenders and quarter panels were good but there was always the slugs and scratches, and inclusions in the metal ?that had to be removed manually. It is just the way of it.

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Well if I can find that article on how even the biggest mirrors have defects that have to be reworked in small spots I will post it. I might have seen it in one of my collection of movies.

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Three of my favorites are The Journey To Palomar, Observatories Stonehenge to Space Telescopes, and Seeing in the Dark. It might have been mentioned in one of the first two I don’t remember.

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If you or anyone else wants to watch a good movie about the Palomar telescope I highly recommend the first movie.

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Seeing in the Dark is recent of course and every time I feel like just giving up and taking up drooling and drinking I watch Seeing in The Dark. It motivates me. It was made by Timothy Faris a Berkley Professor. I contacted him and we talked. I asked him if he had any pictures of his observatory because I wanted to build one like it. He said “no but had some photos he sent me and I kind of reverse engineered his observatory and built mine.

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Seeing what other amateur astronomers went through is just mind boggling. George Ellery Hale’s life and his accomplishments will make you cry. His struggle to build the million pound Palomar 200 inch telescope in the 1930s and 43 was an epic battle and the man struggled with his sanity to boot. You want to talk about holding tolerances in that day. All I can say is my hat is off to him.

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The story of the mirror and Corning glass is one of the greatest documentaries I have seen, well at least on astronomy. I wish all could see it as it is a tribute to the man and his accomplishments. Even the War put the mirror in storage for 10 years but still the scope was built on a mountain that had no roads. It traveled by truck across the US and every town had hundreds of people lining the streets to watch “The Big Eye” as it was called go by with full police escort as it traveled across the length of the US. It was a great time to be alive and an American.

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Well sorry for going off on you I just get passionate sometimes. I have seen so many people say things about machining that have never done any and I just shake my head. I guess it just comes with the years I spent turning the handles as we say in the trade. I love machines? but they do have their limitations. Over at ASU where my best friend still works, and I do part time, they have a milling machine that has hollow lead screws in it through which flows coolant which goes through its own cooling system and keeps the lead screws to a constant temp in order that they do not change length and of course is able to maintain very accurate control of the tables and consequently the part tolerances as it produces parts. Still lapping and honing is standard practice in manufacturing when tolerances become so small that you almost cannot measure them except optically like when it comes to scopes and optics.

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I have worked on Automobile Dies so large that I had to climb into them and lay on my back to grind them into shape and have worked on parts so small like those in electron microscope cartridges that I can honestly I have worked on everything from the “ridiculous to the sublime”! ASU has over 20 electron microscopes and I have worked on a lot of them. They have one called the “Midas”, cost 1.5 million. I have taken many parts out of it and rebuilt them or made modifications to it like an Electron Energy Analyzer I built for one of the users. I did not design that but did build many modifications to that and other Electron Microscopes but that was another time.

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Take Care

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Gary

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Carpe Noctem

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Stan

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I was not going to get into this any further but want to say one last thing.

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I do not know if you have run any machine tools or for that matter built anything of a complex nature but this is something that a lot of people do not understand.

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Machines are fine and they do good jobs to a point. The more precise things have to be made more and more things come into play like temperature, wearing to the tools slop in the machines and of course competency of the operator. All this goes into the mix. Tools wear out and machines wear out. Cutting tools are abrading things and they wear out even diamond tools or ceramic cutting tools.

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Materials when cast like glass, steel, and on and on when cast have tremendous internal stresses. When you machine these materials, and I have machined almost every conceivable material known to man you release great internal stresses. I have known people that made parts and put them away for a month or two only to open the box to find them in hundreds of pieces because of the stresses. I know these things and why because I was trained as a tool and die maker by Ford Motor Company when I was in my twenties, I am now 70.

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I have worked all my life in the trades and spent the last 20 years working for the Physics & Astronomy Department at Arizona State University. While most people only read about things I have built some instruments and projects for the Center For Solid State Sciences that to list all would require another two or three pages but suffice it to know that I have work on Electron Microscopes, built Scanning Tunneling Microscopes, parts for three Thermal emission Spectrometers for three Mars missions a field enlarge to go onto one of the telescopes down in Tucson for Jeff Hestor the guy that took the picture of the Pillars of Creation and the list goes on and on. If you want references to my projects I will supply them. I currently work for Rogier Windhorst the guy that is working on the James Web Space Telescope.

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I don’t usually get into this but I do make exceptions.

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OK enough of that crap. I just want you to know that I have built stuff with my hands that most people can only dream about and still am. When I say something I speak with a little authority, not much, but with some. I worked for a company called Oberg Industries and worked on dies that stamped out the Lead Frames, that is the metal parts of integrated circuits and did all my grinding with diamond wheels some 100 grit and some DuPont 600 grit wheels which you could not remove more than a thousandth or more at one time. I have worked in gear factories when I was 20. I worked in a stamping plant for Ford and built many dies for them. I have worked for Monsanto and serviced their bottle blowing machines. I have worked for Johnson & Johnson and the list goes on and on and on.

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I know what it is to lean on a Parker Grinder when grinding a carbide insert for a die which must be ground to 50 millionths of an inch every day. Not maybe 50 millionths but closer than 50 millionths.

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So when I ask you does a wild bear poo in the woods or if a frogs butt is water tight you might just answer yes but when I say a rooster can pull a freight train you had better hook him up.

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I have lapped many things in with 3 micron diamond lap and too many other things to list. I have been in the trades for over 50 years so I have picked up a little on the way, not much but more than the average bear boo boo.

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Now I am done and you can say what you want.

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Gary

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