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Telegizmo 365 Scope Cover

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Telegizmo 365 Scope Cover

I have been observing for about 10 years now and am located in San Diego, CA-USA.

Chronology Four years ago:

The reality of the newly acquired TMB Optical 229 scope was starting to settle in and the views were outstanding. The scope / mount is setup in a "roofless observatory" (atrium). For protection of the scope while not in use, I started off using several Mylar emergency blankets (intended for hikers). They are light weight and reflect the sun's rays but are very thin and tear easily. The big problem with their use is it would take upwards of 30 minutes to get them into position and properly tied down. It was obvious this was not a good method not only due to the time consumption but I was not going to place my trust in these come the winter's high winds and storms.

My next try was to contact a local marine supplier that made custom covers for boats. He suggested some materials for the outer and inner liner and I provided the dimensional specs. In a week or so I had a nice waterproof cover, albeit large. It was like a circus tent draped over the scope and GEM. To put the cover in place required climbing an 8 foot step ladder. After almost falling over three times that was enough for me so the search for a new cover was begun.

A fellow astronomer recommended Telegizmo covers. He mentioned they used a material used by NASA in space flight. I checked them out on the web and was impressed. One concern was the covers being one piece and if they made one for the TMB-229 in a similar manner I would end up with another large and unwieldy circus tent. I gave Telegizmo a call and discussed the project with Bob Pitney, the company founder. Luckily, Bob is a great guy and loves a challenge as well as pleasing customers. I had in mind a 3 piece cover that would be similar to the emergency blankets I had used but would be more custom fit and substantial. The concept was to cover the gear with three covers, scope, GEM and weights / counterweight shaft. By putting the covers on

from bottom up and having overlap, the equipment should be protected. The sectional covers would be easier to handle. Bob grasped the concept quickly and asked for a simple set of drawings. I made the measurements and sent them off to Telegizmo. The most complex shape was for the GEM, it looked pear shaped and Bob quickly dubbed it the beehive. After a week or two the covers arrived. The material is waterproof and an silver color to reflect the heat. The three piece cover concept worked, placing / removing them was breeze and I never felt like I was going to loose my balance on the ladder.

After a year or so of use I was satisfied with the cover but the intense southern California sun eventually took it's toll and they were beginning to disintegrate. This was not a surprise as Bob mentioned eventually this would happen. I had resigned myself to replacing the cover every 12 to 18 months. Keep in mind the So. CA. sun is so intense

the mylar emergency blankets end up shattering after a month or two outdoors.

Two Years Ago

Enter the 365 cover. Telegizmo had several request from folks that leave their scopes outdoors 365.25 days out of the year. Given the market demand Telegizmo researched and tried out various materials. After Bob was satisfied he had a winner he brought this new product to market. It is intended for scopes that are outdoors continuously in harsh weather including blowing rain, snow and blistering sun. This was what I needed (all but the snow, you can keep that thank you very much).

I placed an order for this new product having complete confidence in it owing to the testing Telegizmo performed prior to market introduction. This time I also upsized the scope cover so I could include a guide scope as well as CCD camera with focuser extended to the focus position and dewshield extended. I wanted to be able to astroimage all night and quickly cover the setup before setting off to work in the morning. Mind you this would have to be fast, convenient and protect the equipment. In discussing it with Telegizmo they were a bit anxious about this much equipment under cover but I told Bob not to worry, I wouldn't hold him liable should my experiment fail. A couple weeks later a new 365 cover arrived. Again it is made in the three section scheme. The scope section is huge because of the extra room for guide scope and CCD imager.

The cover is a two layer affair. The outer layer is a waterproof weave material of some sort; the weave is to tight for water to get in, even when blasted with a water hose. The inside liner is the silver colored material used on the original covers. Since this inner layer is protected from UV by the top layer, it will last essentially forever. The silver color is supposed to reflect the heat even though it's inside now. Since I have guide scopes and many other places to snag this material I asked Telegizmo about a soft felt material instead. Telegizmo was kind enough to oblige the customer (customer service is

high on their priority list). The outer material does add more weight, I would guess the 365 cover is twice as heavy the original Telegizmo. It's not so heavy that one feels you are fighting it, simply put you have a little more weight to deal with. In my years of using this cover I have not felt I was loosing my balance on the ladder.

Closing up the equipment after a night of imaging goes quickly and without pain. The dew on the scope must be removed before placing the cover on. I have my scope polished with a polymer based polish and the dew is easily toweled off. The covers go on in order, counterweights, GEM then scope. There is plenty of overlap between them therefore rain goes from the top / outer cover to the next lower cover, similar to shingles on a roof. Even with blowing rain, water has not been able to work it's way beyond the overlaps and into the equipment. The next night setup is very easy, covers removed (gravity assists this part nicely) and the mount is moved to the park position. That is, after imaging, the CCD Commander scripts park the mount. I have it set to put the scope in a protected positon but not the position intended to be covered. The scope is manually moved to park and the CCD Commander start-up scripts take care of re-syncing the mount and establishing precise focus.

The 365 cover is a cream-white color and not the reflective aluminum. Originally I had some concerns about this but after several summers of experience it turns out the scope only gets warm to the touch after being in the summer sun. If I pull the cover off the scope as soon as the sun is set enough to put the scope in shade, it will reach ambient temperature by nightfall. An image of the cover in place is included below.


The big questions were would this cover hold up over time and afford full protection to the equipment? Short answer is a resounding YES to both concerns however since I have had several years to evaluate the cover the details deserve mentioned.

Protection: Over the years, the scope has endured the elements without any harm. One original concern I had was the objective getting dewed up when covered. If this happens frequently it's obviously not good for the optics. When describing my setup some folks recommended a small light bulb under the cover to prevent moisture build up. I was hoping this would not be needed due to the possible fire hazard. Luckily the moisture buildup is not a problem and the objective is not subject to dewing. I did have a problem once when I put the (original) cover on the scope while it was still wet with dew. The objective ended up dew covered. I sent Bob an email to ask (his opinion on his opinion was of this) as I thought the excess moisture would eventually escape and not zero in on the objective. I was very surprised when he quickly called back to discuss this. He was very concerned the customer is always happy and after a time he figured out the problem was in the dew on the scope. He suggested taking the cover off, folding it inside out and

letting it dry thoroughly for a couple days. I was very impressed with his quick response and resolution. I did as advised and since then, always dry the scope before putting the cover on and trapped moisture has never been a problem since. Little did I know the magnitude of the ultimate test of this cover.

A couple October's ago, on a nice Sunday afternoon I was visiting Palomar Observatory. On the ride back down the mountain I stopped at various overlooks to take in the southern California landscape. Looking East a small fire was throwing up a large smoke plum blowing west and blanketing parts of San Diego county. On the radio, folks downwind were talking about how bad the smoke was. I did not give the fire much thought even though I was due west of it and the winds were from that direction. Well, the next day the winds had kicked up to 60 MPH and the fire moved like a freight train through the night. The order came in early to evacuate and with the thick smoke and reddish horizon it was time to bail. There was no way to do anything about the scope other than hope for the best. One of the big problems with these sort of fires is the strong winds send embers a long way. Had the scope cover been a thinner material I would be really worried, as it was, I was only worried. It took a couple days but the brave firefighters got things under control and I was able to return home. I was happy to see to scope cover was intact and no harm had come to it. There was a lot of fine ash everywhere, kicked up by the wind. The 365 cover was "covered" in ash but I recalled Bob mentioning one could hose this cover off. When it came time to clean the cover this is exactly what I did, just hosed it off with a water hose and gave it a couple days to dry. When I was finally able to pull the cover, none of the ash had penetrated the defensive shield of the Telegizmo 365. The gear was clean and shiny as if nothing had happened. Now one has to understand the magnitude and aftermath of the southern California wildfires. The blanket ash can be 1/4" deep and take months to finally clear away. The sky was useless for astronomy, even the folks at Palomar made that comment. In my case the wild fire had come to within 1 mile. More trivial weather problems, like Pacific storms with downpours and blowing wind, the cover just shrugs these off. The equipment underneath is protected; I can sleep at night without any concerns.

Longevity: I have had the Telegizmo 365 cover for three years now. To date I can not detect any degradation of the material. The internal material is also holding up and looks as good as new. I am very careful about sharp edges on the scope / GEM and protect the cover from these. With care it looks like this cover is going to last a very long time.

Some things I've learned to protect a scope that lives outdoors follows.

1) Wax everything, a polymer wax with UV protection is recommended.

2) Before putting the cover on, towel off any dew on the scope. This

is where #1 above makes removing the moisture easier. The moisture

won't end up under the cover where it will become a problem.

3) If possible seal the scope tube. On the TMB 229, I taped the lens

cell to the flange which sealed the front part of the tube. This

eliminated one area moisture could enter the tube. The focuser on the

classic CNC tubes is easily sealed with a giant o-ring on the focuser

draw tube. A Particle Wave Technologies end cap with desiccant packs

removes any moisture that got into the tube during use. In my case, the

desiccant will last several weeks before needing changed, therefore I

know the scope is sealed otherwise the packs would exhaust themselves


4) Most important get the Telegizmo 365


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