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Old 21-02-2009, 03:14 PM
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strongmanmike (Michael)
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Nervous lens cleaning

After 14 years I thought it was time to clean away the junk that had accumulated on the inside face of the objective in my AP 152EDF Starfire. I have tended to store the scope in the upright position for the last few years so any dust or crap that has managed to get in the tube in that time had settled on the inside face of the lens cell. While not bad it wa just time to get rid of it.

I had been nervous about this for a while and didn't have the correct allen wrench to remove the lens cell screws but today I went to the hardware store and grabed the 7/64 wrench I needed (had to buy a whole set though).

Taking out a piece of high precission glass worth several thousand dollars is pretty nerve racking I must say and I had a few beads of sweat running down my cheek.

I first blew off any loose dust and then brushed the glass surface gently with a soft Wooster brush. I used an isoproyl alcohol mix, originally formulated by Dr Clay Sherrod in the US and sold by OPT in California. I used pure cotton swabs to gently clean the glass with the solution.

The Dr Clay solution is a mix of Distilled water, pure isoproyl alcohol, Photo-Flo and Windex.

The process went well and the objective looks like new - clean both inside and out now.

Such a rare event required some photos of course

http://www.pbase.com/strongmanmike2002/6_inch_baby

Mike
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Old 21-02-2009, 04:01 PM
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h0ughy (David)
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hope you wore a mask and gloves, and an operation smock
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Old 21-02-2009, 05:00 PM
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Originally Posted by h0ughy View Post
hope you wore a mask and gloves, and an operation smock
No but there was a period there where I didn't breath for a few minutes
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Old 21-02-2009, 07:10 PM
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No but there was a period there where I didn't breath for a few minutes
aha so the pulse was there
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Old 21-02-2009, 07:23 PM
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Know the feeling Mike, I actually caused myself a head ache and held my breath for long periods whilst I replaced the filter in front of the Canon 5D's sensor.

Scary stuff, but now that i had done it a couple of times it was much easier second time round.

Leon
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Old 21-02-2009, 07:26 PM
Dennis
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Hey Mike

Nerves of steel from the man of steel – top job; I’m sure glad that the whole process went so smoothly, with such a positive outcome.

Truly a case of nothing ventured, nothing gained!

Cheers

Dennis
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Old 21-02-2009, 08:46 PM
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I think i see a fingerprint on that lens...

no wait, it's my screen...
looks good!

frank
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Old 21-02-2009, 11:47 PM
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Thanks guys

It was an easy thing to do in the end really, the actual lens cell is easily removed by undoing three screws, the main tube end housing was squared at the factory at time of manufacture and this is what sets the front lens cell square and thus collimated, so all that is necessary is to remove the lens cell, clean and replace, collimation is unaffected (hopefully?) Roland Christien assured me so I believe him since he made it...but I'll be happier once I see those tiny perfectly focused dots on my screen

Tomorrow?...install the Astronomik narrow band filter set, giving me L R G B Ha SII OIII in my 7 position filterwheel, stay tuned I have the HBetta too but it won't fit in the wheel unless I remove a filter

Mike
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Old 22-02-2009, 09:49 AM
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Woah! I bet that was uber scary.

Nice work, I just love good glass.

Michael
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Old 22-02-2009, 11:32 AM
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Hi Mike,

No doubt a very stressful process but looks like a top job

You mention in your post the cleaning mixture you used, can you clarify whether you acquired the raw materials and mixed it up yourself or if you were able to source the cleaning mixture already mixed.

Regards
Trevor
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Old 22-02-2009, 02:12 PM
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Quote:
Originally Posted by Tilt View Post
Woah! I bet that was uber scary.

Nice work, I just love good glass.

Michael
Ooooooh yeh! 6" of oil spaced priceless triplet magic

Quote:
Originally Posted by Quark View Post
Hi Mike,

No doubt a very stressful process but looks like a top job

You mention in your post the cleaning mixture you used, can you clarify whether you acquired the raw materials and mixed it up yourself or if you were able to source the cleaning mixture already mixed.

Regards
Trevor
Hi Trev

I got it from OPT in kit form back in 2004'ish but it is still available exactly as I purchsed:

http://www.optcorp.com/product.aspx?pid=1952

Was a good bargain when we were at AU$1 = US$0.90c+ but now it'd be about AU$90 delivered I guess? Still an excellent product and lasts a long time, I've used it to clean most of my optical components and some a few times and there is still plenty left

Mike
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Old 22-02-2009, 06:47 PM
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You could try windex and a tissue! Quote from Al Nagler " If the eyepiece or objective lens has particles stuck to it that can't be blown off, moisten (do not soak) a tissue with Windex and gently blot the surface, without rubbing."
See here for more details.
Geoff
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Old 22-02-2009, 07:21 PM
Dennis
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Originally Posted by ghsmith45 View Post
You could try windex and a tissue!
Geoff
I understand that some recipes of Windex may contain ammonia as an ingredient and from what I have read, ammonia should not be used for cleaning coated optics.

Some time ago, in a previous post about cleaning LCD’s, I was advised not to use Windex on my LCD screen, due to its ammonia content.

It seems there may be Windex sans Ammonia and Windex with Ammonia?

Cheers

Dennis
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Old 22-02-2009, 08:49 PM
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It depends on what is contaminating your optical surfaces. Isopropyl Alcohol is great for only one good reason, it's rate of evaporation is such that there is no condensation of nasties from the atmosphere as is produced by ethyl or methyl. The rate of the evaporating isopropyl is such that it's evaporating cloud shields the surface from condensation due to evaporative cooling.

To remove non polar nasties analytical quality petroleum ether is good. A very dilute non ionic detergent such as Teepol is also good. These should be very gently cycled until all residue is removed.

The anti reflection coatings on your optics are porous at a molecular level to the contaminants that really take hold. Only the best methods of coating can minimise this porousity. RF ion bombardment coating helps.

Unless you know what you are doing do not do it. Get advice.

Sometimes even a tiny bit of caustic in a cleaning solution is better than repeated attempts that cause physical (abrasive) damage to the AR coatings. The AR coating is unaffected by weak caustic solutions. It is the bond between the glass and the AR coating that is damaged as any caustic solution will dissolve glass at the molecular level at the glass AR coating surface interface! This of course will vary by how much Sodium is in the glass. Yes sodium silicate is soluble in even a mild caustic solution. Remember those 'tree gardens'.

After all that, I bet Mike is glad he has already done it! He used a tried and true method.

I have found one of the stickyest contaminants is a vapour or micro drops? That comes from gum trees.

I have had all sorts of contaminants on my 300mm lens including a very big deposit left by a magpie just after dawn. There is no point having good optics if you dont use them. The cunning design of the canon 300mm lens is that the front element is a flat and is 'relatively' cheap to replace. It does the same job as a UV filter.

Sorry for the rave. I have had too many cough medicines .

Bert
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Old 22-02-2009, 09:45 PM
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renormalised (Carl)
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Quote:
Sorry for the rave. I have had too many cough medicines
Been sampling some of that Isopropyl alcohol, hey Bert

Your "optics" need cleaning
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Old 22-02-2009, 10:41 PM
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No I was having a go at the former Japanese Minister for Trade who claimed he had too much cough and cold medication.

bert
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Old 22-02-2009, 10:48 PM
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No I was having a go at the former Japanese Minister for Trade who claimed he had too much cough and cold medication.

bert
Probably why he looks so shady....all that alcohol base and he's plastered!!!. Squinting too much
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Old 23-02-2009, 12:18 PM
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Quote:
Originally Posted by strongmanmike View Post
I used an isoproyl alcohol mix, originally formulated by Dr Clay Sherrod in the US and sold by OPT in California. I used pure cotton swabs to gently clean the glass with the solution.

The Dr Clay solution is a mix of Distilled water, pure isoproyl alcohol, Photo-Flo and Windex.
I believe (I am willing to stand corrected), but you cannot get all the bits you need any longer as some of it is considered prohibited to ship. I was going to buy it a few years ago (via Scopestuff I think), but apparently it all got too hard as it was unclear what would and wouldn't be shipped. Check before you order as it might get all the way to customs and then get turned back. Mike I think may have been lucky.


Quote:
Originally Posted by Quark View Post
You mention in your post the cleaning mixture you used, can you clarify whether you acquired the raw materials and mixed it up yourself or if you were able to source the cleaning mixture already mixed.
I am lead to believe when I enquired (again, I'll stand corrected), but the UHTC Cleaning solution that Bintel sells is made to the same formula.

I have a bottle of the stuff sitting on my shelf, unopened. I reviewed how dirty the corrector was, and then decided against it. I think it might be getting time though...

Turbo
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