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Black spots in brand new PVS14

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#1 4alien51

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Posted 01 May 2021 - 08:23 PM

Just got my PVS14 un filmed white phosphorus night vision monocular and it is incredible with the views it shows. I am concerned though with the black spots that I can see when looking through it. They become invisible once I am looking at the dark skies through the scope especially with a 6nm Ha filter. But I can definitely see them when looking at 1x straight through the monocular with no filter. TNVC assured me this is completely normal and that some night vision devices have them and some don’t. Is this true? Hoping someone can shed some light on this. You can see them I this photo.


Edited by 4alien51, 01 May 2021 - 08:29 PM.

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#2 4alien51

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Posted 01 May 2021 - 08:31 PM

You can see them in this photo 

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#3 maxmir

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Posted 01 May 2021 - 08:33 PM

It is common
It also easy to get ones with none if you specify this.

How big are they ? What zones ?
This is on the spec sheet

If they are small not a problem
Might be a few hundred less if you sell it

What the other specs like ?
(Don't take a picture of the sheet and post it Itar law)

#4 maxmir

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Posted 01 May 2021 - 08:36 PM

Yes I can see 3
One look very central, zone 1 ?

#5 maxmir

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Posted 01 May 2021 - 09:30 PM

The blemish spots are not large which is good.

 

However, there is one close to center and looks like two very close together.

 

It would not meet my expectations for an Astro tube.

 

Especially if I waited 6 months and paid full price.

 

Nevertheless, I would keep it if the specs are really solid.

A image against a white wall back ground is a better way to share the problem.

 

( I was lucky Ben from Koshersurplus send me test images and the spec sheet before buying)

 

Max



#6 Joko

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Posted 02 May 2021 - 04:07 AM

Yes this is normal for most tubes but not for astronomy use (you need clean tube, at least in zone 1 and 2).



#7 ButterFly

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Posted 02 May 2021 - 11:32 PM

My tube has a spot, not near the middle, that I never notice during use.  If I look for it, I'll probably find it.  It can be stacked out when imaging.

 

Everyone has a gigantic spot that their eye's cannot see.  No one notices it.  It's surprising just how big it is and no one notices it.  Our brains are rather good at glossing over such things with small eye movements and integration.  Give it some time.  If it's too distracting for you, consider returning it.  Closer to the middle is clearly more distracting.

 

I had to clean the spots on my monitor to find the ones in the picture, but I found them eventually.  That's better than having seen them through all the crud.



#8 maxmir

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Posted 03 May 2021 - 08:28 AM

TNVC tubes are usually blem free or there just 1 small spot in Zones 2 or 3.

Check out the night vision forum on AR15.com.  People are listing there specs on tubes they just got.

About 80% of the posts are from TNVC since they are a very large vendor.

 

I can't tell how bad this is with a single astrophoto. It does not look bad.

 

 

It still maybe a keeper if the EBI is lower than 0.5 and the SN is good.

 

It may take a few hundred off resale and nothing else. If you keep it for years this doesn't matter much.

 

The 1 or 2 on the edge looks like an upside down L.

I wonder how they qualify it on the spec sheet size wise.

 

All best to specify limits on specs if the dealer with let you choose


Edited by maxmir, 03 May 2021 - 08:29 AM.


#9 GOLGO13

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Posted 03 May 2021 - 09:49 AM

Personally I don't like that these are there. Especially since it's a pretty pricey item. Only if the tube was crazy good and had these would that be OK with me. 

 

I like doing 1x observing so it would be a bother.



#10 DanDK

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Posted 03 May 2021 - 09:43 PM

My Televue tube has a dark spot in the outer zone, fairly noticeable, at least in photos (more so than yours). It bothered me a bit when I first noticed it.  But the views are so compelling that now I forget that it's there, just like I don't notice the scintillation (noise) any more.  


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#11 4alien51

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Posted 04 May 2021 - 02:26 PM

Here’s the tube on white background 

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#12 4alien51

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Posted 04 May 2021 - 02:29 PM

From what the paper says it has 1 in zone 2 at a size .003-.006 and has 2 in zone 3 at a size .003-.006 and another in zone 3 at a size .006-.009



#13 GOLGO13

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Posted 04 May 2021 - 02:57 PM

Not huge but certainly there.



#14 4alien51

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Posted 04 May 2021 - 02:58 PM

I’m not very familiar in the specs so if anyone could shed some light it would be greatly appreciated 



#15 GOLGO13

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Posted 04 May 2021 - 02:58 PM

 That's a pretty darn good tube though other than the spots. So maybe you should consider if it bothers you enough or not.


Edited by GOLGO13, 04 May 2021 - 03:41 PM.


#16 4alien51

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Posted 04 May 2021 - 03:19 PM

Yea from what I gathered it seemed like pretty good specs so maybe I’ll just stick with it. When I have the 6nm Ha filter on it you can’t see a single black spot. What does Min/max/actual mean for the specs? 



#17 chemisted

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Posted 04 May 2021 - 03:29 PM

I’m not very familiar in the specs so if anyone could shed some light it would be greatly appreciated 

 

Yea from what I gathered it seemed like pretty good specs so maybe I’ll just stick with it. When I have the 6nm Ha filter on it you can’t see a single black spot. What does Min/max/actual mean for the specs? 

You will most definitely be keeping that tube.  Minimum specs are shown for those properties that improve as the numeric value increases.  Maximum specs come into play when the property improves as the numeric value decreases (such as EBI).  So, as far as specs go, you want high numbers for signal-to-noise ratio, gain and photocathode response and 1 or less for EBI.



#18 GOLGO13

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Posted 04 May 2021 - 03:34 PM

You will most definitely be keeping that tube.  Minimum specs are shown for those properties that improve as the numeric value increases.  Maximum specs come into play when the property improves as the numeric value decreases (such as EBI).  So, as far as specs go, you want high numbers for signal-to-noise ratio, gain and photocathode response and 1 or less for EBI.

I agree...really good stuff from what I see. The only thing mine is better at is EBI. The importance of EBI is tough. But yeah, all good there. Especially if you don't see it with the filters and in normal use.

 

Great stuff.



#19 GOLGO13

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Posted 04 May 2021 - 03:40 PM

Probably gotta remove that too. haha. That's a pretty high one actually. I think the actual column is your numbers...the min and max are what they are guaranteeing it to be. 

 

It's better than mine.



#20 4alien51

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Posted 04 May 2021 - 03:45 PM

Well here are some pics from first use 

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#21 GOLGO13

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Posted 04 May 2021 - 03:49 PM

Looks very good. I'm terrible at taking the photos. I'd say you scored pretty good on that. You probably have good dark skies also.



#22 ButterFly

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Posted 04 May 2021 - 04:04 PM

You are indeed getting great stuff around Propus.  Keep Propus out of the field and try the lowest gain that lets you see stuff.



#23 maxmir

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Posted 04 May 2021 - 04:31 PM

Agree, looks like a keeper. Nice Pics too!

These are as small as they come.

Looks like  dust. 

If was not for the spec sheet I would be thinking it needed cleaning

 

Max




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