Dew Shields and Heat strips

[king-jaffethehutt]

Here we go Idiot question no.1

I have a skymax 127 mak and was wondering if 1 heat strip is enough? Also if this was used in conjunction with a dew shield (camping mat - home made) what part of the scope would i situate it?.

obviously I know around the tube but was thinking would nearer the primary mirror end be best?

Question no.2

You would normally have to leave your scope to cool down, would putting heat strips and dew shields negate the need for this?

Thanks in advance guys.

[jimmyjamjoejoe]

Put the strip around the base of the dew shield, around the objective lens. The shield is usually enough, but sometimes the strip will be needed.

You still need to cool your scope though, you need to eliminate tube currents. The strip won't add enough heat to add significant currents (dunno if it has one, but consider getting a controller so you can turn it down and keep it at the minimum required heat rather than going overkill every time).

[king-jaffethehutt]

Cheers Jimmy,

The only reason I mentioned the rear mirror is, whilst observing Jupiter last week I noticed that the rear mirror seemed to have patchy mist on it.

The mist stayed on the rear mirror for a good few days afterwards(even though I kept the scope indoors), it seemed to be staining under the glass of the mirror and not on the surface.

I have been reasonably lucky as it seems to have cleared up totally but it did give a Novice a terrible scare!!

just thought that it may have been because the rear mirror was very cold when scope was brought indoors?

cheers

[jimmyjamjoejoe]

Sounds scary, it was most likely dew though. People have different rituals when bringing a scope in at the end of a night, the general consensus though is not to cap it, and to allow any dew that forms to evaporate naturally overnight.

Maks are notoriously slow at cooling, so one can assume they'l be slow to warm up/demist too. It all depends on the difference in temperature. If only a few degrees, then it'l clear up quick (hour or so), if we're talking about frosty nights with crunchy grass and then walking straight into a toasty warm centrally heated home (or viceversa), then things are bound to get really misty, and take many hours to equalize.

Best bet is to keep the scope somewhere as close to outside temps as possible. If that isn't possible, try and find a "buffer zone" where you can place it for a few hours. EG - place the scope on a particularly chilly windowsill for a few hours, then take it out for conventional cooling an hour or so before viewing. At the end of the session put it back on the windowsill until morning, and then put it away properly.

Many people keep scopes in their garages or sheds, this is by far the best option so long as you don't mind the risk (in all fairness, how many people go looking through peoples sheds for valuables?).

[king-jaffethehutt]

where I live too many!! I think my shed would be reasonably secure though all brick wash house with decent doors with bolts and mortice locks!

I think I will give it a try anyway.

Thanks again Jimmy

Rgds

Scott