Sag over time

[steve000]

Hi Guys and Gals.

Has anyone ever experienced sag or deformation of parts of a mount or scope setup 24/7 in an observatory?

I ask this because I have been thinking. I have around 20kg of counter weights at the end of the bar and 20kg of scope. over time, im talking some years id imagine gravity would gradually deform parts to the point of where the scope or mount is useless or inaccurate.

Has anyone experienced this or thought of this?

Steve

[torana68]

shouldnt unless the wrong metals or massively overloaded, there are a lot of very old telescopes around without any sag. If you overload or under engineer it could. A bigger worry is the newer electronic ones will fail eventually , whereas a mechanical should go on and on ......

[GeoffW1]

Hi,

In engineering terms this is called "creep", eventually leading to "creepiness" :rofl:

Not really :P

Some materials are quite prone to this phenomenon, eg lead and some aluminium alloys, but not steels except at higher temperatures.

So, the main consideration for you at ordinary temperatures would be whether you are loading the parts to near the yield strength, where they might bend in an ordinary way.

Taking an EQ5 balance weight shaft as an example (probably chrome plated mild steel or similar), 250 mm long and 20 mm diameter, stuck out horizontally, you would need to pile on about 80 Kg of weights before things began to get creepy.

In short, no problemo :thumbsup:

Cheers

[2stroke]

Hahaha i don't now about astronomy gear, but female gear sure does. I think your wife may have made you think like this OP

[steve000]

haha thats just creepy. Thanks heaps for that info, good to see it should be ok. and lol jay, curse u gravity!!.