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Particles between lenses of a new SW Esprit 120 Triplet

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#1 aristo

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Posted 13 February 2020 - 09:58 PM

My friend received his new SW Esprit 120 Triplet last week.
Unfortunately when opening box he found small particles in the internal space between the two lenses . Attached image .
Dealer says it’s not a problem and will not impact AP. But will ask SkyWatcher about the issue.
Since it’s a new Telescope what do you suggest should be done: Ignore , Replace  , or clean it in optics’s Laboratory

6FADD7AA-CB01-4D9B-8EC2-FFF2CA980808.jpeg



#2 sunnyday

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Posted 13 February 2020 - 10:03 PM

definitely request a replacement.
after all it's not free this kind of telescope.

 

it’s still incredible that this kind of thing could happen today.undecided.gif


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#3 astro42

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Posted 13 February 2020 - 10:04 PM

I'd return it and get a replacement.

But I'm overly picky. 


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#4 iwannabswiss

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Posted 13 February 2020 - 10:05 PM

Since it's your friends scope. what does your friend think?

 

If it is brand new, I personally would send it back for a replacement.



#5 fcathell

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Posted 13 February 2020 - 10:06 PM

The dealer is probably right and they should not affect the image, BUT, this is no excuse for lax quality control. The surfaces should have been clean prior to assembly of the lens cell.  That is what clean rooms are all about.

 

FC


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#6 J A VOLK

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Posted 13 February 2020 - 10:18 PM

It will not affect the performance, but greatly reduces resale value.  Not Acceptable IMHO - Return it!


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#7 ngc7319_20

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Posted 13 February 2020 - 10:44 PM

I agree it wont affect views or imaging.  Might affect resale value someday. 

 

There is also a psychological aspect -- every time the seeing is bad, or there is some atmospheric haze, your friend may wonder if the dust is causing some problem.

 

I would not try to clean it yourself unless you have access to a collimator / auto-collimator and have lots of experience with triplets. You may have a difficult alignment project afterwards.

 

Returning it is probably a reasonable option.


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#8 tonyt

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Posted 13 February 2020 - 10:47 PM

If the particles are between the lenses return it. Check that they're not on the back surface - it can be hard to tell without close inspection.



#9 DSOs4Me

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Posted 13 February 2020 - 10:52 PM

It's not a $500 scope - Return it!


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#10 geminijk

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Posted 13 February 2020 - 11:01 PM

Send back for sure. 

 

John


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#11 Traveler

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Posted 13 February 2020 - 11:08 PM

No braniner imo.

Not nice to see SW shipped this one.



#12 Sleep Deprived

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Posted 13 February 2020 - 11:19 PM

SW is normally pretty good, but they dropped the ball on this one.  Wonder how it got through.

 

I, of course, am assuming your friend paid the extra for the Clean Lenses Option that the rest of us have paid for.


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#13 BillP

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Posted 13 February 2020 - 11:54 PM

IMO some level of dust should be expected these days.  And those little specs definitely will not have any impact on visual or AP.  But your pic shows a rather disturbing number, size, and concentration.  Beyond what I feel is reasonable.  You have to ask yourself if you saw the scope in a store, with that many and size of visible specs, would you have purchased it?  I think not.  I would return and ask that SW (not the store) clean or replace.  IMO these are bad enough that I would not even ask for a discount.  I would not be paying shipping back either as clearly the vendor needs to absorb that cost.

 

PS - If the specks are between elements, I would not clean it in any 3rd party lab as triplets are tricky and sensitive.  Would definitely only want SW to do it and fully retest it for proper collimation and centering and spacing.


Edited by BillP, 13 February 2020 - 11:57 PM.

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#14 m9x18

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Posted 13 February 2020 - 11:56 PM

What Bill said.



#15 aristo

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Posted 14 February 2020 - 03:47 AM

Many thanks for all of you.

I myself have 2 ESPRIT telescopes, 100 and 120. I have not encountered any problem.

I have recommended my friend to buy the SkyWatcher Esprit 120 ,and I feel responsible for it.

more picture attached.

 

505F0D80-BCA6-4866-AEB1-439F2F0FC312.jpeg



#16 Traveler

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Posted 14 February 2020 - 05:19 AM

You are a good friend!


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#17 Jon Isaacs

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Posted 14 February 2020 - 06:35 AM

But your pic shows a rather disturbing number, size, and concentration.  Beyond what I feel is reasonable.  You have to ask yourself if you saw the scope in a store, with that many and size of visible specs, would you have purchased it?  I think not.  I would return and ask that SW (not the store) clean or replace.  IMO these are bad enough that I would not even ask for a discount.  I would not be paying shipping back either as clearly the vendor needs to absorb that cost.

 

:waytogo:

 

If the scope were used and the seller had not mentioned the particles, I would probably return it. I the seller had included the photo shown here, I wouldn't have purchased it. 

 

Jon


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#18 aristo

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Posted 14 February 2020 - 07:28 AM

Meanwhile seller has mailed SkyWatcher about ESPRIT issue, hopefully their answer will be : send it back for replacement.
Unfortunately Chinese workers are out of the company till February 19 because of the CORONA.


Edited by aristo, 14 February 2020 - 07:28 AM.


#19 Dougal

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Posted 14 February 2020 - 08:50 AM

Agree with everyone to return it. I bought the same scope new recently and didn’t see anything like that. Objective was pristine. Based on what I see in your photos, I would have sent it back immediately. Apart from anything else, your friend would take a significant hit if he decides to sell it on at some point.

#20 skyward_eyes

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Posted 14 February 2020 - 10:27 AM

This should be addressed with the local Sky-Watcher division the scope was purchased from ( I have spoken with the OP and he is not within the North American region). 

 

I would be very surprised if these particles were actually between the lens elements. Great care goes into assembly of these scopes and particles between the elements would be exceptionally rare. I would guess its on the rear element and can be addressed but not having the actual sample in hand I cannot 100% confirm that.

 

Regardless it should be taken up with the local Sky-Watcher division on the best action to correct the issue. 


Edited by skyward_eyes, 14 February 2020 - 10:28 AM.

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#21 Bcteleskier

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Posted 14 February 2020 - 11:02 AM

My Esprit 120 also had one or two specs of dust that appeared to me between the lenses But ion further inspection I was able to reach inside with a ruler and cleaning cloth and lightly brush the backside of the lenses. Waalaaa. It is now spotless. Hope that the case here, otherwise I’d send it back.

Edited by Bcteleskier, 14 February 2020 - 11:03 AM.


#22 aristo

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Posted 16 February 2020 - 01:26 PM

My Esprit 120 also had one or two specs of dust that appeared to me between the lenses But ion further inspection I was able to reach inside with a ruler and cleaning cloth and lightly brush the backside of the lenses. Waalaaa. It is now spotless. Hope that the case here, otherwise I’d send it back.WELL

Well. Thank you very much , you are right .

The telescope was checked again today ,by optical laboratory . They found that the particles were on the external backside surface of the third internal lens, and not in the space between lenses.

The lens was carefully cleaned , and every thing is O.K. now

But now we are left with the questions: How could particles get inside . The scope Assembly process should be done in a clean room.

What about quality control . Do they have well inspected proccess ?.

This kind of defect cannot be accepted with such an expensive product.


Edited by aristo, 16 February 2020 - 01:53 PM.

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#23 J A VOLK

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Posted 16 February 2020 - 01:57 PM

There can be small particles that are dislodged from the inside of the tube during shipping that find themselves to the back of the lens and are held electrostatically - tube should have been cleaned better before assembly.  I once sold someone an older TV Nagler that looked perfect optically.  The buyer complained about 'hairs' between the elements and sent it back for a refund.  It turned out to be strands of what I believe to be dried out thread sealant that had become dislodged during shipping (a great distance).  It was between lens groups, so I unscrewed the barrel, blew it out and all was good.  No way it was there when I sent it, I had cleaned and inspected it carefully.


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#24 BravoFoxtrot

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Posted 16 February 2020 - 08:31 PM

Well. Thank you very much , you are right .

The telescope was checked again today ,by optical laboratory . They found that the particles were on the external backside surface of the third internal lens, and not in the space between lenses.

The lens was carefully cleaned , and every thing is O.K. now

But now we are left with the questions: How could particles get inside . The scope Assembly process should be done in a clean room.

What about quality control . Do they have well inspected proccess ?.

This kind of defect cannot be accepted with such an expensive product.

You’re going to get particles and other contamination on all exterior lens surfaces from normal use (even the surface inside of the OTA).  



#25 BillP

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Posted 16 February 2020 - 08:45 PM

But now we are left with the questions: How could particles get inside . The scope Assembly process should be done in a clean room.

FWIW, I highly doubt that much of any of the consumer-level scopes are assembled in an actual "clean room" due to the expense.  Maybe for military specs or very demanding commercial specs, but for consumer equipment?  I think doubtful.  Anyway, at the bottom of this link are the various standards ratings for clean rooms - https://www.cleanair...tions-class.php


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