Flexible soft-top telescope cover???

[Merlin66]

This looks similar to my earlier “BBQ cover” option, but on a bigger scale.

https://www.aliexpress.com/item/32845894015.html

[billdan]

You can buy an observatory tent from the USA, can't remember who from now.
It was light enough to pick up the frame and rotate it, if you were tracking an object.
You would need a method of holding it down if a storm passed through.

[mura_gadi]

Hello,

The Telstra/NBN pit barriers, they come with a opening apex roof and canvas tent style protection. Some can sell fairly cheaply around $400 with the extras.



Steve

[h0ughy]

I recently got this one to use as a portable observatory
The astrodome (https://youtu.be/AOc_eIdc7i0)

https://youtu.be/AOc_eIdc7i0

[h0ughy]

Whoa that's over 2grand for that one, I got mine compete with delivery for $275

[xelasnave]

David that unit is excellent and a great price.
Alex

[mswhin63]

I am trying to design and build a setup where the whole system can be transported on-site.

So far the prototype is working well and with a bit of strength, I can operate with one person, although my next iteration will be half the weight, maybe more.

Unfortunately, I can only build it for EQ5 tripods. The cost is some time off at the moment, still deciding how to process it.

So far I have asked for dimensions in telescopes that are used for EQ5 in the hope to get a base plate cut out for the next iteration. I place a post, but no responses so far.

I may have to make 3 or more based plates so I expect I may have 3 available as prototypes selling them for cost.

The image is the prototype and seals tight, and been rained on for a month now and still dry. The next version will be lighter and better sealed.

[glend]

Condensation Traps. Any of these sort of portable structures sitting on the ground is likely to be a condensation trap, more so if open on the bottom. I used to use pop up toilet cubicles as a portable dark site PC shelter, and it was very wet inside at times, despite having roof ventilation openings.
I have yet to see a soft cover that works well enough to trust with my gear.

[h0ughy]

Yeah I agree but I have had many different toilet tents, they are not all the same. Various success with having the computer hutch in them. The scope however is open to the elements. So the fold over option is gold

[toc]

You guys will probably laugh, but I just use a tarp, some bungee cords and a plastic garbage bin over the top. Been doing this for more than a year without any issues - Been through HEAVY rain, storms heat, frost. In other words typical Melbourne weather :)

No condensation so far, but my mount is sitting on a bunch of concrete pavers, rather than grass. I think rust and dust will be a problem, but I think I have just as much of that when the mount is in my shed.

[mura_gadi]

Hello,

I was thinking of a similar satchel design, have a flap extending with a central cut-out and a couple of velcro straps to close the bottom off with. The other was to place a slab of large hole honeycomb foam as the top plate, that will allow air flow over the head as well.

The trouble with very water proof setups, is they tend to hold any water/humidity that gets in just as well as it keeps it out. You need some sort of vent to allow humidity in and out of the bag. I was thinking just a 1" pvc pipe breather, top of the satchel with a weather cap like a chimney.



Steve

[hamishbarker]

My optical tube (with all the cables and power supplies - which there are quite a few since I have a spectrograph installed which needs 3 cameras) goes into the garage, then I wrap the mount with a doubled tarp, carefully folding over the peak so as not make a rain trap. The tarp is secured with spring clamps (the type which look like a big pair of pliers). Quicker and more secure than straps etc which have previously had a tendency to loosen and result in tarp flapping or worse in wind.


So far so good - but plastic bin on top does sound like a good idea. Setup is reasonably prompt, about 5-10 minutes, but do I now have spousal approval for a nice little timber rolloff roof shed provided I also install a lower roof under the roll off tracks for storage of mower etc.

[toc]

Oh I should add that this is for the mount only. :)

The scope, cameras, PC etc...is all mounted on a rail on the OTA, so I just take that in and out when I need it. Leave it out overnight sometimes, but it always comes back in next morning.

[xelasnave]

First of all I compliment you upon working on the matter.
I have been thinking about your design in an effort to contribute without critism, and I find none, however perhaps you could give some consideration to including something to tie the unit to the ground to make sure it does not come off in a very strong wind or if it acts as a sail in a strong wind is incapable of tipping over due to some system of tie down. I recall very early reading of a chap you was having a night out camping at a dark site where he covered up his prize dob telescope to be secure in the rain that interupted the night, as he said very securely, only to find that it was blown over in the very strong wind. I often would have tent pegs available because of that story being in the back of my mind particularly when I was imaging up here at the main house which being on top of the hill can be rather windy.
Alex

[pmrid]

The suggestion about a PVC chimney with a cap on top set me to thinking a bit about how to encourage the air flow out the vent. I am a bit of a solar power tragic so the idea I have is to use a battery to run a dew strap rolled up and fasten into one end of the PVC - they draw a small amount of power only and a battery would be able to run it for several hours. I would like to experiment a bit. and would be glad to hear suggestions.

[billdan]

I would have thought a steel (exhaust) pipe used as a chimney, would be better at transferring heat to the air than PVC.

[mswhin63]

Thanks, Alex, We have had almost continual strong winds and rain at the moment, so it is getting a really good workout. I have the mount inside I am experimenting on Peltier cooling my DSLR at the moment.
The reason why it hasn't blown down is that it is fairly heavy, although I have thought of that, I instead on the next iteration to get place hook on the plate under the mount with tie-downs.

The top dome is currently held down with 3 x tie-down straps underneath. (See image). As this is only ever expected to be a way of storing outside my home or on an extended camping trip, I never intend to leave it untethered if strong winds are expected. The highest winds we have had so far while testing has been up to 100kph recently, although based on my house orientation, I only experienced about 60kph. My wife tricked me in the morning saying it fell down, but it was fine.

It is heavier than I like it, I intend the next iteration to use a different composite material for the dome. I am now waiting on Lockdown to subside to get the parts together.

[xelasnave]

Well I think you are doing very well and I sense your desire to contribute to others enjoyment, which is a wonderful thing.

Carbon fibre!!!! Everyone will want one if it's carbon fibre....and add the word "turbo" in the name...although I am not sure "turbo" carries the same impact as in years gone by...but I guess what I am saying is that I think you have reached the point where the marketing department is called in and perhaps give some thought to colour options....in any event we need many field trips for testing so you had better start planing those.

Alex

[mura_gadi]

Hello,

I really like the idea of exchanging the pvc out to metal, that would create a natural pull fan effect. Nice suggestion and good use of thermal properties imo.

Though the cap (of the chimney) is the only metal required if you wanted the weight down and non-rusting weather resistance that pvc gives. PVC a little nicer to glue to other foams/plastics as well.

Steve

[pmrid]

As I see it, for a scope setup to be left outside for an extended period, there are 3 issues:
1. Temperature. In summer, heat and optics are a poor mix. In winter, cold combined with humidity are the issue.
2. Condensation inside any protective enclosure.
3. Weight and ease of use.

For 1, I’m now thinking about glueing thin polystyrene sheeting to some semi-rigid plastic or perspex sheeting that I can use to make a cover/enclosure. Keeping overall weight down is the first objective, insulation the second and discouraging condensation the third.

Having to construct some sort of baseplate seems to be overkill if there is some simpler way to support the weight and secure it in windy conditions. Velcro strapping attaching to tripod legs would serve to secure the cover but not support the weight? So perhaps some 1 inch PVC legs would be needed. These could be fastened to the tripod legs and hold the whole thing high enough so it doesn’t have to sit on the scope itself.

To prevent buildup of moist or warm air inside the box, a simple 12 volt PC Case fan would do the trick. Fixed into the side of the cover with perhaps a little hood to keep rain out. A little battery charged up with a small solar panel would do the job easily.

Thoughts?

[mura_gadi]

Hello,

If you shift to lighter materials you should be able to keep it fairly light, not sure how close the loading already is on the mount though.

I'd be thinking about 5kilo hand weights to use as easy guide ropes to keep the box down as more of a worry.(like a weighted kite string holder really)

Also suggest abandoning the box design, easy to build but leaves you with large wind sheer faces and a cook top. Something along the lines of two cones sealed end to end at the bases, and a cutout for the scope. Be a lot friendlier in wind and a smaller top surface area. Make sure there is good gapping for air flow.

If you abandon a rigid design, create your own round/teepee drop cloth with half a dozen or so tent peg loops at the base and a air exchange at the center(top). (Take the hem low and the air vent fairly large and you shouldn't end up with a parachute...)


Steve

[mswhin63]

Thanks, Carbon Fibre, that will be either my 3rd or 4th iteration. My next one will be poor person fibreglass, or as I put it Clayton's fibreglass.

I may provide options in the 3rd or 4th iteration combined. Work in progress.

As far as humidity, that is also a work in progress. The business I closed in 2015, I used to service Video surveillance systems for the railways and it was a common problem in sealed enclosures. Fortunately, there is no big build-up at the moment due to not enclosing it and preventing the rise in the upward movement of moist air.

In my final year project at Uni, I used a special plug that allows for air to release outward and block air flowing inwards. Another work in progress.

[xelasnave]

I am rather skilled with fibre glass but have not used carbon fibre which I gather is the same idea just using different matt. I often use filbre glass to strengthen ply wood and even make items in cardboard or thick paper and paint them with resin to great effect...I made a pier for my little heq5 in plywood and made it steel like with a couple of layers of glass and resin which I colour with black tile grout.
I purchased two little heater fans from some auto shop, not Super cheap but they are in the same shop as Jcar Lismore..but simple things..supposed to be car heaters or demisters and I would run them blowing up under my cover over the scope off an old battery that they would flatten, I know terrible but crook battery to start with , I have them packed away otherwise I would post a photo but one would by worth your investigation for you unit.
Even an exhaust fan (computer fan) with the intake thru something with absorption ability ...rice even...just over some silica gel...and the battery only has to last until Sun rise in effect.
Alex

[mswhin63]

I would like to achieve some skills with Fibreglass, I get the impression Carbon fibre is the same, maybe a different adhesive. But initially, I would rather start with Fake Fibreglass, using nylon fabric with some bitumen-based coating. This is the coating I am using at the moment on the outer shell of a large bag I got for really cheap. This bitumen coating is exactly as it says, waterproof and very good. Fibreglass though will last the longest.
I also have insulation internally as well, later I hope to build a simple temperature humidity monitor to carry out some tests.

Silica Gel is a good idea, it is one of the many things I am already looking at. Although as much as possible I will keep it as simple as possible to reduce costs.

Using a natural environment is definitely the best method, but not the most foolproof.

[SB]

Hi All,
I use two 4WD windscreen reflective covers sewn together on the straight long side and the short sides. They were $4.50 each from K-Mart. The elastic is fastened in place round the scope mount front and back to hold the cover in place. Great when leaving out in the day time in Summer. Is shower proof also.

Chris.

[xelasnave]

Yes thats the stuff I use but I bought a long roll from Bunnings ...its big advantage as you say is saving gear from the heat.

Alex