LXD-55 SN-10 internal misting

Viewing from my riverside site has its share of problems with dew, despite
using a dewcap made from closed cell foam. I'm often stuck with a choice
between giving up for the night or taking a hair dryer to the corrector
plate with subsequent loss of seeing.

However, a far worse problem is occasional misting up on the *inside* of the
corrector. Anybody else have this problem and solved it? The hair dryer
eventually clears this internal misting if applied for long enough, but you
can imagine the effect on the seeing. I'm thinking of maybe a 1.25 inch dia.
tube containing silica gel that fits into the eyepiece tube when the
telescope is not in use. Is such a device available, or has anybody made
one?

I have access to some very dry air (SCUBA diving cylinders) would it help to
purge out the air from the OTA? Obviously, I would need to drastically
reduce pressure/flow from the 3,500 psi air in the cylinder. Wouldn't want
to blow dust into the OTA. Also, wouldn't want an exploding OTA...

At the end of some nights everything is wet, OTA, finder, Telrad, me,
eyepieces. Should I be concerned about longer term degradation/damage? How
should I put it away to minimise potential damage?

Thanks for any suggestions.

BTW, Mars was excellent last night here in Mid Wales near Welshpool. Clouds
cleared around midnight and atmospheric boiling slowly subsided as it
climbed higher, despite viewing it over the roof of our house. Sporadic good
views until 01:30 when the whole sky became murky within minutes. This was
not cloud drifting in, the murk covered the whole sky simultaneously. I
think it was fog a few hundred feet up because I could see distinct patches
of light above the local street lamps.

Sally

I make silica gel driers for my 'scopes by drilling some holes in the bottom
of a 35mm film canister, put in the silica gel bag and replace the cap. This
is then a perfect fit in a 1.25" eyepiece tube. I leave it in the 'scope
while it is stored.

hth

Mark

"Sally" wrote in message
...
Viewing from my riverside site has its share of problems with dew, despite
using a dewcap made from closed cell foam. I'm often stuck with a choice
between giving up for the night or taking a hair dryer to the corrector
plate with subsequent loss of seeing.

However, a far worse problem is occasional misting up on the *inside* of
the
corrector. Anybody else have this problem and solved it? The hair dryer
eventually clears this internal misting if applied for long enough, but
you
can imagine the effect on the seeing. I'm thinking of maybe a 1.25 inch
dia.
tube containing silica gel that fits into the eyepiece tube when the
telescope is not in use. Is such a device available, or has anybody made
one?

I have access to some very dry air (SCUBA diving cylinders) would it help
to
purge out the air from the OTA? Obviously, I would need to drastically
reduce pressure/flow from the 3,500 psi air in the cylinder. Wouldn't want
to blow dust into the OTA. Also, wouldn't want an exploding OTA...

At the end of some nights everything is wet, OTA, finder, Telrad, me,
eyepieces. Should I be concerned about longer term degradation/damage? How
should I put it away to minimise potential damage?

Thanks for any suggestions.

I make silica gel driers for my 'scopes by drilling some holes in the bottom
of a 35mm film canister, put in the silica gel bag and replace the cap. This
is then a perfect fit in a 1.25" eyepiece tube. I leave it in the 'scope
while it is stored.

hth

Mark

"Sally" wrote in message
...
Viewing from my riverside site has its share of problems with dew, despite
using a dewcap made from closed cell foam. I'm often stuck with a choice
between giving up for the night or taking a hair dryer to the corrector
plate with subsequent loss of seeing.

However, a far worse problem is occasional misting up on the *inside* of
the
corrector. Anybody else have this problem and solved it? The hair dryer
eventually clears this internal misting if applied for long enough, but
you
can imagine the effect on the seeing. I'm thinking of maybe a 1.25 inch
dia.
tube containing silica gel that fits into the eyepiece tube when the
telescope is not in use. Is such a device available, or has anybody made
one?

I have access to some very dry air (SCUBA diving cylinders) would it help
to
purge out the air from the OTA? Obviously, I would need to drastically
reduce pressure/flow from the 3,500 psi air in the cylinder. Wouldn't want
to blow dust into the OTA. Also, wouldn't want an exploding OTA...

At the end of some nights everything is wet, OTA, finder, Telrad, me,
eyepieces. Should I be concerned about longer term degradation/damage? How
should I put it away to minimise potential damage?

Thanks for any suggestions.

"Mark Crossley" mark .dot. crossley .at. dsl .dot. pipex .dot. com wrote
in message ...
I make silica gel driers for my 'scopes by drilling some holes in the
bottom
of a 35mm film canister, put in the silica gel bag and replace the cap.
This
is then a perfect fit in a 1.25" eyepiece tube. I leave it in the 'scope
while it is stored.
Thanks for the suggestion Mark, I shall do something similar. Also working
on a dew heater.
Sally

"Mark Crossley" mark .dot. crossley .at. dsl .dot. pipex .dot. com wrote
in message ...
I make silica gel driers for my 'scopes by drilling some holes in the
bottom
of a 35mm film canister, put in the silica gel bag and replace the cap.
This
is then a perfect fit in a 1.25" eyepiece tube. I leave it in the 'scope
while it is stored.
Thanks for the suggestion Mark, I shall do something similar. Also working
on a dew heater.
Sally