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Old 02-08-2019, 04:53 PM
Mickoid (Michael)
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Blemished optics

Does anyone know of a place in Melbourne that would have the expertise to remove marks left by condensation on the internal elements of a SW Esprit 100 apo refractor? I have been given the details of a place in Sydney but if there was someone who could do it closer to home, that would be great.
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Old 02-08-2019, 06:57 PM
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The elements are easily removable on my SW Triplet Esprit what about yours

Can you not just mark the position and remove three screws

BUT if you are cautious you are right to look for a proper shop



.
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Old 04-08-2019, 10:00 AM
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I'd recommend removing the cell and either sending it to Skywatcher Australia or these guys in Europe: https://en.lacerta-optics.com/
They obviously know what they're doing as evidenced by their blog entries: http://interferometrie.blogspot.com/...l?view=sidebar
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Old 04-08-2019, 06:51 PM
Mickoid (Michael)
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Thanks for your responses guys, not sure that I'd be confident enough to tackle such a high end scope as the Esprit 100. To be honest, the residue the condensation has left behind is quite visible but has done little to the images it produces. If I was reassured it has not or will not continue to damage the lens coatings, I will just leave it alone and live with it. I have called Sky watcher Australia and they need to see the lens to assess the condition. I can't imagine it being a cheap fix because if the coatings have been affected then cleaning won't remove the blemishes. I'm worried about using it in winter now because the temperature between outside and inside where the scope is housed are too extreme.
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Old 04-08-2019, 07:05 PM
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It most likely only needs cleaning and will be good as new, but reassembling the lens is a painstaking procedure - needs experience/training to do the job properly.

When bringing the scope inside keeping the cap on until the following morning should be enough to avoid condensation. A dew heater is a good idea too of course.
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Old 05-08-2019, 04:33 PM
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Internal as in BETWEEN the individual lenses? That seems odd and somewhat disconcerting for SW QC.

If it is merely on the rear face of the rear element, cleaning it is actually simple.
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Old 10-08-2019, 03:03 AM
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Forget about opening an Esprit, it is extremely hard. For an Esprit I needed to remove the 16 silicon cap on top of the grub screws that itakes a hour work. Than the lenses should be removed without changing the angles between them. Once they are cleaned, the lenses need to be recnetered between each other and it is necessary to have a collimator with artificial star. Finally, the lens cell should be collimated with the focal plane.



Are you sure it is not a fungus?
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Old 12-08-2019, 11:19 AM
Mickoid (Michael)
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Thanks for your info Adriano. Sounds like it's a job for the experts, I reckon if I started to disassemble it I may bite off more than I can chew. It doesn't look like fungus to me, I've seen plenty of that in some old lenses I own. This looks like water dropplet stains. It's hard to establish which surface has been affected. I'm reluctant to clean the surface of the rear lens as I may make it worse. I'll post a few photos I took of it and see if anyone agrees with my assumption that it's caused by condensation water droplets.
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Old 20-08-2019, 07:18 PM
Mickoid (Michael)
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Originally Posted by Mickoid View Post
Thanks for your info Adriano. Sounds like it's a job for the experts, I reckon if I started to disassemble it I may bite off more than I can chew. It doesn't look like fungus to me, I've seen plenty of that in some old lenses I own. This looks like water dropplet stains. It's hard to establish which surface has been affected. I'm reluctant to clean the surface of the rear lens as I may make it worse. I'll post a few photos I took of it and see if anyone agrees with my assumption that it's caused by condensation water droplets.
So here are some shots of the lens surface and the marks I think the condensation has left.
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Old 20-08-2019, 11:54 PM
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Michael

.. have you already tried cleaning off the front surface yet with a proper lens cleaner solution or whatever is suitable?

Cheers
Bill
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Old 21-08-2019, 03:59 AM
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Quote:
Originally Posted by Mickoid View Post
So here are some shots of the lens surface and the marks I think the condensation has left.
I would personally contact Synta (Skywatcher) and make your concerns known

If my Esprit 120 was like this and it WAS internal I would make a complaint unless you have left it outside or uncovered or in some way contributed to this which I doubt because "ordinary" people like us are not made of money and look after our things.

The actual lens cell can be removed ARE the marks between elements or front and back, BUT will void any guarantee

The dew shield simply unscrews anyway as you know, just unscrew and take off to see the collimatable lens cell
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Old 21-08-2019, 06:24 AM
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That's definitely dew marks left on the FRONT of the lens. They are so tenacious as to not even budge with usual cleaning so people tend to think they are BEHIND the elements, which they aren't. Can be easily removed with good tissues and saliva (yes, SALIVA - Roland from AstroPhysics even says this). Or you can buy really expensive unnecessary fluids to do the same job.

Roland's suggestion is to moisten a CLEAN fingertip with your tongue and rub it around. Follow up with regular lens cleaning solutions and good quality tissues (like KimWipes). He also suggests acetone and denatured alcohol (metho).

His EXACT words:
"To get rid of the shiny spots, we have to use a magical cleaner, which is available at no charge to everyone. That cleaner is saliva. Rub the surface where the shiny spots are with your finger moistened with saliva (don't worry, the finger will never scratch the surface of the coatings because it is the most ideal cleaning pad available for delicate optics. No cleaning cloth is as gentle as the human skin.) This must be followed immediately by either Purosol or Baader Optical Wonder applied with Kleenex so that the saliva does not remain on the surface more than a few seconds. You may have to repeat this procedure a few times for stubborn spots, but eventually they will grow smaller and disappear"

He's the optical designer, hand-figurer and owner of AstroPhysics...I think he knows a thing or 2.

Last edited by LewisM; 21-08-2019 at 06:36 AM.
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Old 21-08-2019, 09:22 AM
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Even if the marks are only on the front surface (which appears to be the case) the lens should be cleaned whenever it accumulates significant deposits. Even it you don't get dust/pollen etc on the surface, dew contains substances that permanently mark the coatings over time.

You just need to avoid dragging particles across the surface or letting solvent wick around the edge of the lens.
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Old 21-08-2019, 09:55 AM
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Windex + distilled water + soft wiper....
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Old 21-08-2019, 03:03 PM
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Quote:
Originally Posted by Mickoid View Post
So here are some shots of the lens surface and the marks I think the condensation has left.

Hi Michael, forget about these little stains on your refractor. They will not produce any problem. Once every year, clean the front lens but very gently as the coatings on the Esprit are not the strongest.



If you do not want to leave halos on the lens, use a solvent that would evaporate completely.
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Old 21-08-2019, 04:27 PM
Mickoid (Michael)
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Thank you to everyone's response. I really appreciate the interest and time you all have made to give me advice and food for thought. I'm thinking that I will try and gently clean the front of the lens, a small area near the edge, just in case the stains are internal. If they are internal then as Jeremy suggested, it may be a complaint to Synta as to why the spaces between the lens elements were not sealed properly and so contain moisture. I would have thought that the lenses would have been assembled in a dry environment considering the price of the Esprit range. They should be sealed well enough not to allow any moisture entering internally.

I can appreciate condensation forming on the outer surfaces when bringing a cold scope into a warm space but it shouldn't develop within the lens elements. Hopefully, as one suggested, it turns out to be on the front surface, then the saliva on the finger trick will confirm that.
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Old 21-08-2019, 10:14 PM
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Mick for what it's worth I was always told by manufacturers to do what some of the others said first but then to finish off with a wipe of distilled water. Also have you ever considered getting a portable dehumidifier like the ones used in gun safes? They work a treat for getting rid of moisture around scopes. I have one fixed to the inside of lens cap which keeps inside the hood dry. Then I use a desiccant cap in the focuser end. The dehumidifier lasts about 3-4 weeks between charges and has a ten year life span.

Here's a link to one similar to mine. https://www.eva-dry.com/product/e-33...-dehumidifier/
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Old 21-08-2019, 11:15 PM
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Hi Mick,

If you don't feel confident enough to tackle the job yourself, I'd recommend:

https://www.rogersopticsrestoration....9SyVLIlKqr_yUw

Best,

L.
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Old 22-08-2019, 08:29 AM
Mickoid (Michael)
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Originally Posted by LostInSp_ce View Post
Mick for what it's worth I was always told by manufacturers to do what some of the others said first but then to finish off with a wipe of distilled water. Also have you ever considered getting a portable dehumidifier like the ones used in gun safes? They work a treat for getting rid of moisture around scopes. I have one fixed to the inside of lens cap which keeps inside the hood dry. Then I use a desiccant cap in the focuser end. The dehumidifier lasts about 3-4 weeks between charges and has a ten year life span.

Here's a link to one similar to mine. https://www.eva-dry.com/product/e-33...-dehumidifier/
Thanks for that, might look into buying one, they're not too expensive either.

Quote:
Originally Posted by ngcles View Post
Hi Mick,

If you don't feel confident enough to tackle the job yourself, I'd recommend:

https://www.rogersopticsrestoration....9SyVLIlKqr_yUw

Best,

L.
Will certainly give the guy a call once he's back from leave. Pity he's based in Sydney, not many options of places that do that type of thing here in Melbourne. Thanks for the recommendation.
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Old 22-08-2019, 04:33 PM
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Originally Posted by Adox View Post
Hi Michael, forget about these little stains on your refractor. They will not produce any problem. Once every year, clean the front lens but very gently as the coatings on the Esprit are not the strongest.



If you do not want to leave halos on the lens, use a solvent that would evaporate completely.


I would like some reference for this comment please, thank you
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