Storage of equipment

[Tim]

Query regarding storage of OTA etc.

To save time cooling the thing down, would it be better to store the tube at the temperature it is gonna be used at? Ie, outside temps?

Is there a problem with damp atmospheres doing this, are parts likely to corrode etc?

Thanks

[Ant]

I think that providing that where you keep the OTA is dry then you're OK.

I keeo my little ED80 in it's flight case but in my garage. My other refractor is on round padded hooks on the wall - stored horizontally. Seems to be OK like that.

I've some pic's somewhere of the storage...

Ant

[beamer3.6m]

My 200mm Explorer is stored in my shed on its end (mirror at the bottom).

All dust caps are on the tube and it appears to be fine. I find that because the shed is cold the scope is pretty much ready to observe by the time I have set it up.

[Tim]

ok thanks.

Is there an issue with sub-z temps? Im assuming not after seeing the pics of SteveL's mouse frozen to the bench. I was thinking of storing my (hypothetical atm) scope in a steel gun cabinet (for security) in my shed, with silica crystal pouches to absorb any humidity.

Talking about set-up time, how long does it take usually to go from box to viewing, after all allignment etc is carried out? Im thinking of a HEQ5 (goto) and 8" ota.

Cheers

TJ

[Whippy]

Your first night? About 2 hours. First night with new gear and you'll be thinking 'open the boxes and off I go', nyet comrade. You're going to need the longtitude and latitude of your location and a book showing names of stars just to get your GOTO running. Best thing to do IMO is when the gear turns up, don't expect to go out on the first day, try and set it up and familiarise yourself with all the bits and bobs (unless it all turns up early and you've got all day to have a play). Get your latitude roughly sorted out on the mount beforehand and try to align your finderscope during the day too as it's more difficult do to when it's dark. The good thing is that a fair bit of this only needs to be done once and all you'll need to do next time is a couple of minor adjustments and run the GOTO alignment.

So when you get used to it, 10 mins tops from putting your shoes on to looking at an object.

Tony..

[Ant]

I agree with Tony, first time... who knows...

But from then on ... it depends on the distance from shed to observing spot.

1, Get mount from Shed and put where wanted - roughly polar aligned.

2, Get counter weight and place on shaft.

3, Get OTA placed and balance OTA.

That will take 10 minutes tops.

Then polar alignment can take as long as is needed.

Ant

[The Warthog]

I waltz my scope in and out of the shed on the mount. I leave it in the shed, on the mount, level and covered. If I bring the scope in, I put either scope front end down on the floor in a corner where they won't get knocked over. I put all the covers on when I'm not using them. I put the Newt, especially, mirror end up so that stuff won't settle on the mirror, and make sure the focuser hole has something in it so that scorpions won't build nests in there.

I must be doing OK, because my mirror and my refractor lens are both so clean that people comment on them, and I don't have scorpions.

I keep the eps in their case, inside the house.

[SteveL]

Rule #1 - Never use something in the dark that you havent used at least once in the daylight

First night out with my NS8GPS took a while. Now it takes me <15 minutes for a visual session, and <35 minutes from opening the back door to starting my imaging run, and thats a lot of kit and cables to set up.

[barkis]

Whenever I was testing a mirror in the final stages of figuring, I used to let any visitor look past the knife edge of the Foucault tester, at the surface of the mirror. Usually it would be showing the classic doughnut shadow of the paraboloid. Then I used to place my thumb onto the surface for a few seconds, and then invite them to look again. The look on their face said immediately, that they were seeing something extraordinary. Of course they were, because the heat from my thumb, was sufficient to raise the surface of the glass in that area a few microns, but under the knife edge, this appeared mountainous. So, it was a plain enough reason to explain why a Newtonian mirror had to reach ambient temperature. Another demo could show how air passing in front of the mirror can play havoc with the image, hence, do not use a telescope from a warm environment through a window.

Ron.

[The Warthog]

I'vve often wondered, wouldn't a fan blowing across the surface of the mirror probuce the same effect?

Also, when you press your thuimb on the glass during the Foucault test, is the distortion due to expansion of the glass, or heat waves from the warming of the glass?

Considering the amount of distortion due to lack of transparency and seeing on any particular night, how much extra distortion does a warm mirror produce? My scope is usually at the ambient temperature anyway, but I can't say I've seen a lot of distortion that I could put down to differential heating of air in the tube, and even when I have had my scope stored indoors, I can't say the view has gotten better as the night wore on.

Not arguing here, just curious.

[barkis]

The mirrors In question were only pilkington plate WH. Pyrex produced the same effect, but to a lesser degree. Cervit you could put into an oven and it wouldn't have moved. The testing of mirrors, is done at the radius of curvature, and the effects are magnified thousands of times.

Whilst it demonstrates that a Newt. mirror can and will be affected by temperature changes, and localised air currents, those effects are less dramatic than those produced under a knife edge test. Tube currents are image degrading, especially if the tube diameter is a close fit to the mirror, because they tend to cling to the tube walls, they have more chance of straying into the light path of the mirrors marginal zones, which are a mirrors most important area.. You must also have experienced viewing an object, whilst it was positioned over a roof of a building which had been occupied all day, with full heating going. That warm air rising from the roof will affect the viewing somewhat, by distorting it, just as natural atmospheric turbulence disturbs the light rays coming down to your objective.

Just to clarify, it is the glass that expands due to the heat from the thumb. It will produce a bump on the glass, and when the knife edge cuts into the reflected rays, the ones on the left of the bump will be intercepted by the knife, and darken, the right side rays are returned away from the knife and remain brightly illuminated. Giving the appearance of a hill. Interpreting these shadows can be difficult, just as sometimes when looking at lunar craters, some may see them as hills, and domes as craters.