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#251 Fomalhaut

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Posted 12 November 2019 - 06:39 PM

When I intended to get a perfect sample of one Vixen F102 thirty years ago, I in fact got it by mentioning to my that times' dealer that I was going to write a test-report on it...
OTOH, if I now were a dealer myself and had let a manufacturer produce a big batch of scopes and would (of course) hope to sell as many of them as possible, then I might be strongly tempted to provide some well-respected and prominent testers with excellently testing samples first of all, in order to after their reports having been published comfortably recline my seat and watch in peace the rest of the batch go away like hot cakes.

Edited by Fomalhaut, 12 November 2019 - 06:42 PM.

 

#252 YAOG

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Posted 12 November 2019 - 06:49 PM

Let me get this straight... After a rocky introduction of the APM 152, many experienced CN members have primarily positive recent reports with no major optical issues. One issue arises in this thread so all the recent positive reports on the APM 152 are because the owners don't know how to star test a scope.  The Skywatcher 150 has a rocky introduction.  Recent reports are mostly positive (or non-existent, take your pick) but these owners DO know how to properly star test a scope.  Is this correct?

 

How absurd.

 

I hope Thomas gets a good lens or his money back.   

Umm, no. I suspect many people think their scopes star test well when in reality they do not. I'll edit my post to reflect this.

 

What is absurd about thinking that people don't really know how to do a good star test and interpret the results? APM's own posted star test image is inadequate and even at low mag. still manages to show the lens has zones.   

 

I'm pretty sure we all hope Astrojensen gets a good APM 152ED at some point or at least all of his money back. 


Edited by YAOG, 12 November 2019 - 07:46 PM.

 

#253 Steve Allison

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Posted 12 November 2019 - 07:41 PM

Would people quit talking about the possibility the 'scope was knocked out of collimation? The lens has an obvious turned downed edge, for heaven sake, and Thomas clearly knows how to test for collimation problems.

 

Whatever the reason for the poor lens in Thomas' example turns out to be, it has been established that it is not the result of shipping damage. Sheesh!


 

#254 areyoukiddingme

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Posted 12 November 2019 - 07:46 PM

Would people quit talking about the possibility the 'scope was knocked out of collimation? The lens has an obvious turned downed edge, for heaven sake, and Thomas clearly knows how to test for collimation problems.

 

Whatever the reason for the poor lens in Thomas' example turns out to be, it has been established that it is not the result of shipping damage. Sheesh!

We will find out. It's entirely possible that it's both bad figure and bad collimation. And who are you to tell everyone what they can and cannot discuss?


 

#255 YAOG

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Posted 12 November 2019 - 07:50 PM

When I intended to get a perfect sample of one Vixen F102 thirty years ago, I in fact got it by mentioning to my that times' dealer that I was going to write a test-report on it...
OTOH, if I now were a dealer myself and had let a manufacturer produce a big batch of scopes and would (of course) hope to sell as many of them as possible, then I might be strongly tempted to provide some well-respected and prominent testers with excellently testing samples first of all, in order to after their reports having been published comfortably recline my seat and watch in peace the rest of the batch go away like hot cakes.

So what are you saying? That manufacturers and dealers make sure the people doing reviews get the hot scopes to promote sales? That's kind of cynical don't you think? 


 

#256 Steve Allison

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Posted 12 November 2019 - 07:55 PM

We will find out. It's entirely possible that it's both bad figure and bad collimation. And who are you to tell everyone what they can and cannot discuss?

Based on everything that has been posted so far, please tell me what is suggestive of bad collimation? I do not believe a turned down edge can be the result of bad collimation (please correct me if I am wrong) and this problem alone means the lens is poor and not as represented.

 

I asked if people would stop talking about collimation, I did not tell them to stop. But, yeah, it is certainly not my place to tell posters what they can and cannot post about. My apologies if any posters felt that that was what I was trying to do.


Edited by Steve Allison, 12 November 2019 - 08:01 PM.

 

#257 Jon Isaacs

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Posted 12 November 2019 - 08:02 PM

So what are you saying? That manufacturers and dealers make sure the people doing reviews get the hot scopes to promote sales? That's kind of cynical don't you think? 

 

In the motorcycle world, it was standard practice for a manufacturer to provide better than stock bikes to testers. Probably in the car world too. 

 

In any event, I am interested to see what sort of lens Thomas receives next. I have to think the "why do you believe" thread is a response to this thread. 

 

Jon


 

#258 Steve Allison

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Posted 12 November 2019 - 08:06 PM

Yeah, there was a superbike shoot-out in the early '70's by a motorcycle magazine and the "stock" bike provided by Harley-Davidson was disqualified for being modified. I am still a Harley fan, though! smile.gif


 

#259 John Fitzgerald

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Posted 12 November 2019 - 08:13 PM

In the motorcycle world, it was standard practice for a manufacturer to provide better than stock bikes to testers. Probably in the car world too. 

 

In any event, I am interested to see what sort of lens Thomas receives next. I have to think the "why do you believe" thread is a response to this thread. 

 

Jon

I don't think the why do you believe thread should be locked though.  It's been innocuous enough.


 

#260 Crow Haven

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Posted 12 November 2019 - 08:14 PM

I honestly never expected a perfect star test. What I expected was good, full-aperture performance, based on the reviews by Bill Paolini, Bomber Bob, hfjacinto and others. 

 

I really didn't expect there to be any major issues, so I went and made the thread, much like I did when I bought the Altair 102/1122 ED. Once the thread was running, I felt compelled to tell the bad news, as so many people wanted to hear about the first light impression.

 

How do you think the thread would have run, if I had simply said "I've had first light, but I can't say more right now", when people started to wonder why I suddenly stopped posting? 

 

 

Clear skies!
Thomas, Denmark

Thomas, I'm sorry that you're going through this big hassel, I'd be upset too, however, I'm sure you will get it sorted out and will be enjoying beautiful views through a 6" APO soon. 

Best wishes!

---Maya


 

#261 ris242

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Posted 12 November 2019 - 08:24 PM

If theres 'bad collimation' @ 152mm

Can it be a good collimation with a 130mm mask?


 

#262 YAOG

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Posted 12 November 2019 - 08:27 PM

Of course parts can be mixed up. Do you think they make each lens and OTA in separate rooms? All made by the same guy? Of course there are multiple OTAs and lens sets. Where you work has nothing to do with it. Mistakes happen, and that may have happened here. It's a logical possibility. Multiple OTAs, multiple lenses, multiple reports. Lots of opportunities for a mistake.

 

As to the second highlight, it's possible for a box to be stood on its end and pushed over with little to no damage to the box, but a major shock can be transmitted through to the OTA. 

 

With these long cases that come with 6" apos, my bet is that this is a common source of mis-collimation. A typical scenario would  be that the box gets pushed up on to its edge to get it on a hand truck, and then it gets nudged and falls over on its side. Rinse and repeat.

 

When I got a beat up scope from Explore Scientific it was clear that this had happened. The box was actually in pretty good shape. The scopes focuser (knocked off the pinion) and collimation were both terrible. ES fixed it. I returned it to them at their cost, and then they shipped the scope back freight--it was stuck flat onto a pallet, and was wrapped in industrial strength cling film so that it couldn't be stood on it's end.

 

So of the two, my bet is that it is the latter. It will be interesting to see if the same lens set comes back from APM, and we can find out if it was bad figure or bad collimation.

With good assembly practice and QC there is a build order document that travels with the assembly. Parts and assembly numbers are on the sheet and as new assemblies are added they are added to the build document. It should be very hard to mixup documents and assemblies in a low volume production assembly line. They are German and every German plant or assembly space I've seen is highly organized and assemblies are well documented. This is just in the culture there, it's like driving in Germany, everything has order and rules are followed strictly. I love driving in Germany even with the continued loss of unlimited speed Autobahn zones. Germany is where I learned the need and value of having an organized assembly space. 

 

The fact of the matter is the lens is likely ground and or figured poorly. It is not out of collimation as Thomas has observed in his testing. Read what Thomas has posted, if you know much about optics you should be able to figure it out. Optics don't behave like this when out of collimation, they display these traits when poorly ground and figured maybe spaced but then the CA would be an issue which it is not. Go back and read Thomas's testing with a mask.


 

#263 YAOG

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Posted 12 November 2019 - 08:29 PM

If theres 'bad collimation' @ 152mm

Can it be a good collimation with a 130mm mask?

Not in this universe.


 

#264 Derek Wong

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Posted 12 November 2019 - 08:58 PM

Wow I come back for a look at CN and some things never change, just the names of the vendors.

 

Having purchased a substantial number of scopes from multiple vendors, I can say that scopes have reached either me or close friends from every major scope company with apparently no shipping damage and significant issues.  I'm not playing fanboy here, I'll name some names: AP, Televue, Takahashi, Stellarvue, TEC, and your favorite company of the month.  Yes, even Zeiss scopes have issues.  My guess is that some of these are from shipping damage that was never seen, or lenses that for some reason got swapped, etc.  Some of them may be dogs.  Things can slip through, and likely there are more subpar samples in the cheaper scopes than in the more expensive ones.

 

Sometimes these things happen and the person doesn't even know, or they resell what they think is a bad sample.  I just got my second reversed lens (long story, Astrojensen fixed my first one and I this one) and the individuals who sold them swore that they were good.  They were, after the lens was reversed and the horrible spherical and other aberrations disappeared.  If some of those folks had received scopes that were subpar they may have never known.

 

I know Markus has a colorful past and there have been a lot of reports about him.  From a personal standpoint as a customer, however, I will say that I have purchased MANY items from him, and each one has been just as he described it.  I have gotten one of a kind items that I would never have gotten anywhere else.  He has also made products that no one else had the guts to do first, like the 152ED and the large binos he is now making.

 

Before we crucify people, I suggest we listen to the other folks in the thread who are urging restraint.  Let Markus rectify the situation.  There are few enough astronomy sales that we can't afford to bash every vendor who is left over a bad sample.  Why is it that Tak or AP will get a pass when something happens and APM doesn't?  Markus knows that Astrojensen is a superb observer who knows good optics.  I think he will send a good sample, then it is up to the postal system.


Edited by Derek Wong, 12 November 2019 - 09:15 PM.

 

#265 Steve Allison

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Posted 12 November 2019 - 09:22 PM

I have never heard of AP or Takahashi misrepresenting the quality of a particular telescope by claiming it was personally tested as good and even issuing a certificate to that effect when it was not. I feel confident they would not get a pass if that were to happen.

 

Honest mistakes are one thing...


 

#266 Bomber Bob

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Posted 12 November 2019 - 09:28 PM

Could we keep the terms straight?

 

Alignment refers to the lens elements within the cell.  I've seen all kinds of issues that hurt the performance when the elements aren't aligned properly.  My Goto 60mm F20 uses a Steinheil contact doublet, and it is very sensitive to misalignment -- just a few millimeters left / right of ideal degrades the image; and, an air gap wrecks it.  Once I identified the best position, I taped the elements together.

 

Collimation refers to making the objective's optical axis match the eyepiece's optical axis.  If the lens cell has no adjustment screws, then we talk about squaring the focuser -- tilting / adjusting it so that the optical axis passes straight through the focuser tube(s) to the eyepiece.  Checking collimation in a refractor is pretty easy, and can be done indoors with a Cheshire, a laser collimator, or a simple paper mask with the center marked.

 

I don't think the problem with this scope is collimation.

 

I think there could be alignment problems -- those can be trickier to assess without DPAC.

 

It's not the buyer's responsibility to figure out what the defect is.  It's the seller who should replace or refund on a brand new scope.

 

I'm aggravated with this situation because I've encouraged folks to buy the 152, based on the excellent performance of mine -- and it's at the low end of the bench tests that other 152 owners received & posted.

 

I would like to know:  When did APM drop the bench test reports for a Star Test Certificate??


Edited by Bomber Bob, 12 November 2019 - 09:30 PM.

 

#267 YAOG

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Posted 12 November 2019 - 09:59 PM

I have never heard of AP or Takahashi misrepresenting the quality of a particular telescope by claiming it was personally tested as good and even issuing a certificate to that effect when it was not. I feel confident they would not get a pass if that were to happen.

 

Honest mistakes are one thing...

I agree but I think at this point have to wait and see. I have to believe that APM will get a good tube to Thomas at some point based on his mostly excellent reputation. It's a tough business.


 


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