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Have I broken my Barlow?

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blinky

blinky

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I bought a 3X TeleVu barlow from Rus a couple of months ago. It was in A1 condition, I was was as it now aint :rolleyes: I took it out the other day for a view of Saturn through my webcam and noticed a couple of bits of dust. Thinking I was being clever I decided not to just blow them off with a breath of hot air. No No thinks me I will get that can of compressed air that will work a treat! Well it did'nt the anti reflective coating thing seemed to go a bit oily, and last night there appears to be a finger smudge on it! I thought it might be OK but when looking at Saturn with the webcam there seem to be what I can only describe as big black blobs on screen at certain points. I had to keep moving Saturn to keep it clear of them when imaging!

So can anything be done? or am I best to leave it as is? I wondered about getting some lensd cleaner on it and even if it removed all of the anti reflective coating would than not be be better?

It's annoying as I thought I was doing the correct thing by using the air canister!

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GordonCopestake

GordonCopestake

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You are best off using a bulb blower rather than an air canister as Kai rightly points out the propellents are nasty stuff. I would give it a good wipe down with IPA to remove any residue and see where that got me. If the coatings are damaged you have a nice expensive extension tube :rolleyes:

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Andrew*

Andrew*

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IsoPropyl Alcohol is actually an old fashioned term for propan-2-ol (an isomer of propanol). It's a kind of alcohol, but rather than being C2H5OH (ethanol), it's got another carbon atom: C3H7OH.

THAT's the technical side. Basically, it's a substance that's very useful for cleaning. I think you could use turpentine too. They often put IPA (I still call it that in spite of myself!) in little bottles labelled "cleaning fluid" supplied in lens cleaning kits.

Andrew

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The Warthog

The Warthog

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I wouldnt use turpentine, as it's got all kinds of goop in it. Usually those canned air propellants dry very quickly (I use them for keyboards, mice, voles, motherboards, etc.) Why not get a lens cleaning kit, wet the glass with the cleaning fluid and wipe with the lens cleaning tissues?

I use a lens pen for cleaning my eps. It works a treat!

If you ever decide to use the canned air again, hold it about 10 cm from the surface, no closer.

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blinky

blinky

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I called TeleVue and the person there said to use Actetone. After hunting round a couple of chemists I found some nail varnish remover without fruit oils or moisturiser in it!

Did it work?

Well sort of, if I look straight through it is clear as a whistle but looking accross the lens it kind of looks a bit worse. Will just have to try it and see. This nail varnish rmover has a couple of additives in it so I might need to try the other thing that was suggested to remove the additives that are now sitting on the lens. The other thing BTW was Meths spirit, but the guy said acetone was best.

Ho hum if it is goosed then I have learned a valuable (if expensie) lesson, Look after your kit!

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FLO

FLO

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when looking at Saturn with the webcam there seem to be what I can only describe as big black blobs on screen at certain points.

If you can see them on the image they are more likely to be on the imaging chip. If on the barlow, I'd expect them to be out of focus.

Are you sure they said Acetone! Sounds a bit severe, dangerous even. I'd use isopropyl Alcohol diluted with distilled water... Dampen (less is more) a micro-fiber lens cloth and wipe carefully; keep re-folding the cloth for a clean bit.

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blinky

blinky

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The guy did say Acteone. Anyway as that did not work I went and got some Mets spirit and that worked a treat :rolleyes:

On another note I have been thinking about mirror cleaning. How come the advice is to not clean the mirror etc as it will scratch the suface blah blah. When I look at the specs for mirrors they all seem to say they have a coating of Silicon Dioxide on them. Surely this would protect the mirror if you wanted to give it a quick dust.? Not talking about Mr Sheen or anything but I would have thought there would be no problem using something like meths spirit and some cotton wool? Yet all the advice says never clean unless really realy nessesery?

Anyways I am just happy I have my Barlow lens operational again!

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