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Baader Lense Coating Issues??


Paul73
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Hi Guys

I purchased a use new Baader MkIII Zoom from FLO last Christmas and found it too limiting in FOV. However, for solar viewing it really really rocked. So I bought a second one from an ABS last year to complete my side by side white light / Ha solar setup. On receiving the eyepiece after a very smooth transaction, I discovered some very very obvious blemishes when solar viewing. So much so, that it was unusable. This wouldn't show during normal night time use. I could see blemishes on the lense (eye end) which wouldn't shift with cleaning. They apear to be holes in the coating. The seller imedeately offered a refund even though he haven't noticed anything during night use.

Yesterday a different MKIII Zoo apeared on ABS with the same issue (stated clearly in the advert and priced accordingly).

Is this a known Baader issue?

Paul

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I've owned a few Baader eyepieces including 2 of their zooms (a Mk II and a Mk III). I've not noticed any particular issues with their coatings while I've had them. I guess FLO might know if they get regular returns of these eyepieces for this issue ?

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10 minutes ago, John said:

I guess FLO might know if they get regular returns of these eyepieces for this issue ?

I don't think we have ever seen a MkIII Zoom with faulty coatings.

@Paul73 it is best you contact the seller, see if he/she will accept it back. 

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Not a known issue with the coatings then. 

I guess that there is always a risk with 2nd hand kit, especially items with moving parts.

I would like to add that both sellers have acted completely honestly. One flagging the issue in the advert and the othe immediately offering a refund. 

I still have the offending eyepiece. Never did get round to sending it back for the refund. I'll pass it on to my 5yo son for use in his mini dob.

I'll probably risk another 2nd hand one at some stage.

Paul

Edited by Paul73
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The blemishes on the eye lens coating probably won't affect the performance in any way. I have a 31mm Nagler with some coating marks on the eye lens (declared when I purchased it) and they don't seem to affect performance at all. They did make an impact on the price I paid though - about 50% the normal used price.

 

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A friend bought a (very rare) Vixen 130mm SS apo doublet. It has not blemishes, but two chips in the objective's glass, at the edge. They cover about 1/3 of 1% of the front lens' area. The effect on viewing and imaging is nil, but the effect on price is he paid 1,500€ for a scope that sold for 4,000€ new. The seller warned of the chipped lens, showed a picture of it. My friend had not even noticed the smaller chip on the lens before he received it, cause it was so tiny.

Could be wrong but I believe a very dusty objective would lose more contrast than the chipped objective, because the minuscule localized chips do almost nothing to the wavefront, but dust sprinkled over the whole lens kinda changes the lens' figure over the total surface. Like the lens is not well polished.

Anyway, japanese, american and russian 130mm apo's were way too costly for him, now thanks to a negligible defect he has a dream scope he could otherwise only dream about (I spotted the scope because I read blogs in other languages, thank you, my obsessive curiosity regarding telescopes).

There's good and bad in little defects.

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  • 2 weeks later...

Chips from the lenses could cause performance issues but I don't think coating blemishes will unless they are very severe. They play on your mind though if you paid full whack and were not made aware of them prior to purchase :rolleyes2:

Edited by John
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In this case the flaws are as plain as day! The additional light throughput of solar work will accentuate blemishes and grime. I paid an ok 2nd hand price.

It rattles as well! 

 I do have one bought from FLO brand new. So I know how they should be.

Paul

 

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13 minutes ago, Paul73 said:

In this case the flaws are as plain as day! The additional light throughput of solar work will accentuate blemishes and grime. I paid an ok 2nd hand price.

It rattles as well! 

 I do have one bought from FLO brand new. So I know how they should be.

Paul

 

The ones I've (bought used) had have been fine with no rattles so I agree that yours has been mistreated.

I thought solar vieweing was less exacting on eyepieces though ?

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16 hours ago, Paul73 said:

 It seems to be that the extra light gets scattered more noticeably by anything on the lense surface. Same for Televue or  generic stock eyepiece. 

Design wise, I agree completely.

Paul

I've not seen the marks on your eyepiece coating, obviously. Those on my Nagler 31 are pretty subtle and certainly don't make any difference on nighttime viewing (I don't do solar observing with that one !). I've compared them to those with my Ethos 21 (which is mint) and there are no discernable differences to view quality.

Sorry that you had that bad experience with your 2nd Baader zoom.

 

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37 minutes ago, John said:

 

Sorry that you had that bad experience with your 2nd Baader zoom.

 

There is always a small risk when buying second hand. It is worth reiterating that I don't blame the seller. He offered a full refund. I just never got round to sending it back!

I've always been pretty lucky when buying used. So no biggy.

Paul

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There was a thread on CN about the rattling zooms and I think the concensus was that a lot of them did and it wasn't a problem. Mine had a rattle from new and I never had any issues with it in use - worked perfectly. I never noticed any coating problem either. 

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If I remember correctly the ones that didn't rattle were more prone to lock up in cold weather. I maybe suffering from false memory syndrome so you might want to search CN for that/those threads.

The MK 4 is apparently optimised for cold weather so I will let you know if it rattles when I get it tomorrow. ?

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Mine only get used for solar ??. 

Maybe I should be getting a discount on the non rattley examples??

I don't get on at all well with these zooms for night use. But, in slower scopes, they are cracking performers. It isn't really fair to compare them to a case full of Green & Blacks!! 

Paul

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