Warming up the Scope

[leon]

Hi All

I have just had an interesting PM session with a fellow IIS member, who lives on the tip of the Northern Territory.
I'm sure he wont mind me sharing this with you.

As we have to wait for our scopes to cool to ambient temp, he actually has to wait for his to warm up outside, after bringing it out from the air conditioning, about 22 degrees he reckons.

And for postal service, well, after it has gone by road, rail, plane, and probably donkey at least a couple of weeks, and that's not waiting for stock either.

Cheers

[astro_nutt]

Originally Posted by leon

Hi All

I have just had an interesting PM session with a fellow IIS member, who lives on the tip of the Northern Territory.
I'm sure he wont mind me sharing this with you.

As we have to wait for our scopes to cool to ambient temp, he actually has to wait for his to warm up outside, after bringing it out from the air conditioning, about 22 degrees he reckons.

And for postal service, well, after it has gone by road, rail, plane, and probably donkey at least a couple of weeks, and that's not waiting for stock either.

Cheers

Interesting thought!!...that would mean the mirrors could fog up outside and he'd have to wait until they clear before any viewing!!..unless you cover the scope with an insulator of some kind...tricky!!

[ving (David)]

i wonder what heat up time is like? woudl it take the same time to heat up as ours take to cool?
darwin needs an astro shop

[hogly52 (Graeme)]

Originally Posted by astro_nutt

Interesting thought!!...that would mean the mirrors could fog up outside and he'd have to wait until they clear before any viewing!!..unless you cover the scope with an insulator of some kind...tricky!!

Yes, the mirrors do fog up as soon as you take the scope outside (from an air conditioned room). EP's also have the same problem. Depending on the humidity at the time it doesn't take the condensation long to clear. In answer to Ving, I don't know how long it takes for the mirror to reach the outdoor temperature, nor do I know what impact a cooler mirror in a warm evironment would have on air currents within the scope.

Cheers,

Graeme

[Starkler (Geoff)]

Originally Posted by ving

i wonder what heat up time is like? woudl it take the same time to heat up as ours take to cool?

I would think that everything else being equal, the time would be identical for a given temperature differential between mirror and ambient whether cooling or warming.

[33South (Chris)]

Originally Posted by ving

i wonder what heat up time is like? woudl it take the same time to heat up as ours take to cool?
darwin needs an astro shop

"The rate of change in temperature is proportional to the difference in temperature between an object and its surroundings"

Interestingly this is called "Newtons law of cooling" however it would apply to heating if the ambient temp is higher, so the heat up time would be the same as cool down time for the same temperature difference I think.

Would the business volume justify a shop in Darwin? , enough of a struggle in Sydney.

[hogly52 (Graeme)]

Originally Posted by 33South

"The rate of change in temperature is proportional to the difference in temperature between an object and its surroundings"

Interestingly this is called "Newtons law of cooling" however it would apply to heating if the ambient temp is higher, so the heat up time would be the same as cool down time for the same temperature difference I think.

Would the business volume justify a shop in Darwin? , enough of a struggle in Sydney.

All the thermal co-efficients are the same, so the time to effect a change in temperature (for the same temperature differential) should remain the same. Fortunately, as the scope is kept at a constant 23'c, it's not a big difference to outside ambient temperatures, depending on season.

I doubt a scope shop in Darwin would have a large customer base. For me, I've had no problem getting things from down south, I just have to be prepared for the delivery wait. That said, I've had some remarkable delivery times out of Sydney for air freightable items.

Cheers,

Graeme

[JimmyH155]

Changing the subject, hogly52, where do you observe from up there in Gove? I lived there for several years - it was a magic place then Bet you get through heaps of aeroguard when observing??

[ving (David)]

Originally Posted by 33South

"The rate of change in temperature is proportional to the difference in temperature between an object and its surroundings"

are you try to hurt my brain? you do realise its monday morning dont you ?

[hogly52 (Graeme)]

Originally Posted by JimmyH155

Changing the subject, hogly52, where do you observe from up there in Gove? I lived there for several years - it was a magic place then Bet you get through heaps of aeroguard when observing??

Hi, I've been here now for a little over 15 months and I have to agree it is a magic place. In Gove/Nhulunbuy we now have a dedicated dark site some 15km out of down on the Dhupma Rd. Not far from the airport, just off the main track, with a parking area, picnic tables and a pier mount concreted in. Yep, the mozzies have their moments, but we put the coils out, and Rid is the insect weapon of choice. We still get some light pollution from the mine and town. Not enough to deter the views though. On Saturday it was viewing between the clouds, which is a little unusual for this time of year. Usually pretty good viewing, most of the year (watch the wet though).

For those from the south, complaining of the cold and ice, viewing attire on Saturday night was the usual t-shirt, stubbies and thongs.

Cheers,

Graeme