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Quick question and an introduction

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#1 Guest_**DONOTDELETE**_*

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Posted 21 June 2004 - 08:52 PM

Hi all, although I'm not a total novice (own a piece of *bleep* dept store 60mm refractor) I haven't been seriously active in astronomy for several years. I treated myself to a 127mm Starmax last Christmas and have been loving every minute I get a chance to get outside with it :grin:

After searching many different sites on the internet, I think I've finally found the best forums and website here at cloudynights. I was wondering what all of you normally do that take your scopes back inside after an observing session. Is it best to replace all the covers on the OTA and eyepieces before going inside, or do you normally take everything inside and let the condensation (if there is any) evaporate before replacing the covers. I've read opinions on both and don't really like the idea of taking everything inside covered up with condensation on the lenses, but also don't like the idea of letting my pride and joy sit all night collecting dust on the lenses when they could be covered.

Darrell

#2 bierbelly

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Posted 21 June 2004 - 08:57 PM

IMO, you're worrying too much. Sooner or later, your corrector lens will get messy, and then you'll be worrying about how to clean it. One way or the other, the dew that's formed on your corrector will cause schmutz to deposit. Best not to worry about it too much, cause it doesn't really affect seeing all that much.

PS, nobody is gonna like that answer, but it's the truth. Just wait and see. ;)

#3 Guest_**DONOTDELETE**_*

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Posted 21 June 2004 - 09:03 PM

IMO, you're worrying too much. Sooner or later, your corrector lens will get messy, and then you'll be worrying about how to clean it. One way or the other, the dew that's formed on your corrector will cause schmutz to deposit. Best not to worry about it too much, cause it doesn't really affect seeing all that much.

PS, nobody is gonna like that answer, but it's the truth. Just wait and see. ;)


LOL you're probably right. After using the 60mm I want to keep my Mak as "pristine as possible" :)

#4 wilash

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Posted 21 June 2004 - 09:06 PM

I have a question. Why do you think your room is dustier than the outdoors?

I bring in my scope covered and in a bag. I put it in an unheated room. When it reaches room temperature, I take it out of the bag to let moisture evaporate. I also run a dehumidifier in the room and dust regularly.

#5 bierbelly

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Posted 21 June 2004 - 09:07 PM

LOL you're probably right. After using the 60mm I want to keep my Mak as "pristine as possible" :)


So what, you think the rule that 'it always rains the day after you wash your car' doesn't apply to astronomy? Astronomy is no different than real life...well, for the most part.

#6 Guest_**DONOTDELETE**_*

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Posted 21 June 2004 - 10:04 PM

I like the bag idea.

#7 Starman1

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Posted 22 June 2004 - 10:16 AM

If you bring cold optics back into a heated house, moisture in the air will condense on the cold surfaces exposed to the air--the corrector (or lens), the tube, the mount, etc. If you have the corrector/lens covered, it does not prevent this unless the cover is air-tight (unlikely). You don't want dew forming on the corrector/lens and then be not able to evaporate as the corrector/lens warms up.
So, leave the corrector/lens uncovered until the moisture evaporates; then cover it back up.
To speed up the process, use a hair-dryer on the moisture on the lens (use a cold setting and hold it WAY back from the lens--you don't want to crack the corrector/lens with strong temperature differentials). Bear in mind that the thermal inertia in the glass that caused it to take a long time to cool down will also make it take a long time to warm up. It will be colder than your room for hours.
Once the dew is evaporated (have you ever noticed that this cements the dust to the lens?), then cover the corrector plate/lens.
As was mentioned elsewhere on this site (another forum), a superlatively clean corrector/lens will require less follow-up cleaning after the inevitable dewing up that comes from bringing it in from the cold.
I take my 5" MCT in and out all the time, and it usually needs the corrector cleaned after about 10-15 times of in-and-out.
I use pure isopropyl alcohol and super-soft tissue without scent or dye.
I blow the dust off the lens with an ear syringe (works well!), and NEVER use a brush (brushes only seem to smear the dust around).
The bag idea may keep dust off the scope, but it will also prevent evaporation of the moisture that forms on the corrector/lens when you bring the scope back inside.
This whole discussion is moot if the humidity is low--the likelihood is that no moisture will form on the lens/corrector when you bring it back inside.
I love nights like that, but they're rare--even in SoCal.
Don


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