Spike in star test (question) (1 Viewer)

[4th_point]

Hello, my name is Jason and I'm a new member. I have really enjoyed and benefited from the information posted at Bird Forum. Especially ways to evaluate optics at home. Thank you for providing this information!

I recently purchased two Fieldscopes (angled) and have been performing star tests indoors with LED light (limited distance, however) and outdoors with the brightest star(s) that are viewable at my location. I'm still new to this procedure so I'm not ready to draw any conclusions just yet. However, with one scope I see a very pronounced spike radiating from the 10 to 11 o'clock position in the inside focus condition with just a handful of rings in the pattern. When outside of focus, I don't notice it.

Is there anything that I can look for or inspect? I looked inside the scope body with bright light, made sure exterior lens surfaces are clean, swapped eyepieces between scopes, allowed scope to acclimate to temperature, etc. That spike is always present, although I "think" it is more pronounced the warmer the temperature. I also searched the forum and other sites, but didn't see much on single spikes.

Thanks,

Jason

 

[4th_point]

Update - I was outside comparing the two scopes and two eyepieces, just viewing the scenery near my home. While swapping eyepieces, I peaked into the scope in question and two imperfections clearly stood out. They appear as two lines at the 7 to 8 o'clock position when looking into the scope with EP removed. I think I simply missed seeing these, as I had previously checked with my single vision contact lenses. Today, I had my specs on and removed them to look inside. Lesson learned!

Would it be safe to assume that these lines are responsible for the spike seen in the star test? I don't know anything optical design or if it's possible for the 7 to 8 o'clock orientation to transpose to 10 to 11 o'clock through the eyepiece. I attached two images taken with my phone. Hopefully you can see the parallel lines. They are not on the exterior surface of the lens just forward of the eyepiece, but appear to be inside the scope body.

 

[Binastro]

Hi Jason,

Maybe prism lines from a roof prism.

Other here now more about these particular scopes.

One could try reading a distant newspaper or text to see if one scope resolves better than the other.

Regards,
B.

 

[Tringa45]

Hi Jason,

Maybe prism lines from a roof prism.

Other here now more about these particular scopes.

One could try reading a distant newspaper or text to see if one scope resolves better than the other.

Regards,
B.

Henry Link has stated that the roof prism edge is outside the light path on Nikon Fieldscopes.
Agree, however, that distant newsprint (around 25 m?) in still air would enable a good comparison.

John

 

[4th_point]

Thank you for the responses.

The two parallel lines look like scratches on one lens, but it's difficult to take a picture of it.

 

[4th_point]

Update - I shipped both scopes, minus the eyepieces, to Nikon today.

I also called the service center and asked the representative if they are capable of servicing eyepieces. I was put on hold for several minutes and then was told that Nikon US can service the eyepieces. I read somewhere online that Nikon US no longer services eyepieces. According to Nikon, that is not true but I suppose that I was given bad information.

 

[jring]

Hi Jason,

first of all, welcome to birdforum!

Having looked at the pictures, the problem looks like two scratches or smudges on the prism or the protective glass at the end of the eyepiece opening. In the first image, the two marks show over the baffle, so they can't be in the lenses (which are all in front of the baffles).
If the marks were in the objective lenses (and thus quite far from the focal plane), you probably would not see them even in star test. In general, imperfections get much more visible when they're closer to the focal plane or in the eyepiece (which you have ruled out).

It is quite probable, that those two marks are the reason for the star test artifact you saw - the rationale is as follows:

- the classic Nikon fieldscope series is famous for the oversized and off-center Schmidt prism design that uses a roof prism but keeps the roof edge (which can result into similar marks when star-testing) out of the light cone and thus out of view.

- you have two fieldscopes and only the one with the two marks shows the artifact... go figure...

Not quite sure why both scopes went to Nikon when only one showed a problem... but I hope they can fix it... with some luck, it's only a smudge on the protective glass and can be cleaned easily...

Btw, what bodies and eyepieces did you get?

Joachim

 

[4th_point]

Hi Joachim,

Thanks for the welcome.

Regarding the two scopes, I originally wanted an 82ED-A but couldn't find one in my price range. So I bought an EDIII-A, partly because it had the 30x WF with extendable eyecup which seemed hard to find, and it was much less than the 82mm scopes that I was looking at. Then I found a good deal on an 82ED-A with 25-75x, so I jumped on it!

The 82mm had the spike in the star test, and those "defects" that look like scratches. The 60mm seemed really good when using an artificial star and real star. I didn't see any obvious problems, but am also not that experienced with that test. In actual use during daylight both scopes have nice views.

Anyway, I was planning to sell the 60mm until I saw that spike in the star test with the 82mm. And those scratches on the internal lens, or whatever they are. By the way, as I mentioned earlier they definitely appear to be on a single lens (or at least appear to be in the same plane) as you can see them when peering into the scope body with eyepiece removed and changing the viewing angle. Pictures and video are hard to take, but actually looking into the scope itself it is easy to see. I don't know how I missed it before. They don't appear to be on the lens forward of the eyepiece, but deeper inside. It appears to be a small lens, and the defects move together and never change position relative to each other.

So I decided to ship the 82mm and for very little extra money, I decided to also send the 60mm. I had previously called the Nikon US service center and the representative said that one can always send in a Fieldscope for inspection. I figured why not, and if I do end up selling the 60mm it would be nice to have a clean bill of health from Nikon to provide to the new owner (assuming that Nikon provides such a document). Also, the seller of the 60mm scope said that they would pay for any repairs. So really nothing to lose, and it fit inside the box I used to ship the 82mm.

Both scopes have a bit of dust inside of them. I don't know if that is typical for these old Fieldscopes, but it seems like optics of that vintage were not as clean as what I see today. So I requested a quote for cleaning and purging. The 60mm also had something on one internal lens, like a faint splatter pattern (not random dust). I was told that it might be assembly grease or the grease used for the helical focuser assembly. The sunshade is a freckle loose on the 60mm as well. Almost like a dry o-ring, if that is what keeps it snug?

I might be being a bit picky, as both scopes have really sharp views and function fine, but I want the most optical performance that I can get for the money. And really peace of mind that everything is as good as can be with these models. Plus if I sell either, I can assure the new owner of their actual condition.

I really don't want to spend money on a so called "alpha", especially with so many reports of poor star test results. I'm hoping that I can get at least one really nice old Fieldscope out of this activity!

Jason

 

[4th_point]

PS - the scopes are out for delivery to the Nikon service center today. According to Nikon, it takes one business day for processing once the service department receives product. That seems pretty good to me, compared to other optics companies. I'd imagine that Nikon has a pretty well sorted out process for cleaning and repair of camera items though.

If anyone is interested in the outcome of all this, I'd be happy to follow up.

 

[Alexis Powell]

If anyone is interested in the outcome of all this, I'd be happy to follow up.

Yes, please.

--AP

 

[4th_point]

So both scopes were delivered yesterday by USPS at 11:30 AM PST. That same day, at 1:32 PM PST, I received an email for the "Nikon Service Acknowledgement/Estimate". So far so good.

Nikon Service took my concerns/requests submitted to them, and distilled them into "FOCUS IS BLURRY / NOT SHARP NOT SHARP CLEAN PRODUCT & CHECK ALL OPERATIONS". I'd imagine that they have certain internal codes to categorize service work.

The estimate provided was, "Total cost of repair: $0.00*". And, "* This price is an estimate and is subject to change.".

I believe that Nikon states that turnaround is five business days. I will update this thread once I know more.

 

[4th_point]

UPDATE, 08/31/2022

Nikon return shipped yesterday, 08/30/2022. The scopes were delivered to Nikon on 08/25/2022. I'm very happy with that turnaround time. Unfortunately it appears that I am only getting the 60mm back. The 82mm will be replaced with SRO voucher.

I wonder if the 82mm was unrepairable due to the defects in the lens that I saw, or something else. Who knows, but I'm not disappointed in trying the 82ED.

Definitely a good learning experience, especially with the star testing. Thank you to Binastro, jring, Henry Link, and others for posting about it over the years at Bird Forum!

ETA - I called customer service and was told that the 82mm would be replaced. At least that was what representative could determine from the notes in the system. But I don't know what that means. With a Monarch, or store credit? Not clear over the phone but I should be getting a follow up email.

 

[4th_point]

For anyone that is still following along, I called Nikon Service on 08/31/2022 and asked if there was any information about the 82mm. The representative on the phone said that she would contact the Service group for more information and that I should receive an email in a day or two. On 09/02/2022 I received an email from Nikon Customer Service, with the following:

"After evaluation, we have determined that your product is beyond economic repair, and we no longer sell this model or a comparable product."

 

[Hermann]

For anyone that is still following along, I called Nikon Service on 08/31/2022 and asked if there was any information about the 82mm. The representative on the phone said that she would contact the Service group for more information and that I should receive an email in a day or two. On 09/02/2022 I received an email from Nikon Customer Service, with the following:

"After evaluation, we have determined that your product is beyond economic repair, and we no longer sell this model or a comparable product."

Thanks for the update!

That reply makes me wonder. Sure, they stopped making the "old" Fieldscopes a number of years ago. But they sell no "comparable product"? Isn't the Monarch 82 a comparable product? That's weird.

Hermann

 

[Ruff-Leg]

Odd indeed. My ED Fieldscope 82 was replaced by NikonUSA with a Monarch ED 82. We had some unpleasant go-arounds in between their COVID shutdowns, but they came through in the end.

 

[4th_point]

I think that they might have given me the Monarch 82 but they have been backordered for awhile. The angled that is, the straight version seems to be in stock. My ED-82 was the angled version.

Anyway, they gave me a voucher for sporting optics or imaging.

I purchased another ED-82A yesterday for a decent price. Keeping my fingers crossed on the second one!

 

[4th_point]

So I decided to ship the 82mm and for very little extra money, I decided to also send the 60mm. I had previously called the Nikon US service center and the representative said that one can always send in a Fieldscope for inspection. I figured why not, and if I do end up selling the 60mm it would be nice to have a clean bill of health from Nikon to provide to the new owner (assuming that Nikon provides such a document). Also, the seller of the 60mm scope said that they would pay for any repairs. So really nothing to lose, and it fit inside the box I used to ship the 82mm.

I know that this thread was about the defective/damaged 82mm, but I thought I'd provide an update on the 60mm since I mentioned it above. I received the scope from Nikon on 09/06/2022. It was scheduled to arrive on 09/02/2022 but UPS had delays, plus the holiday weekend here in the US.

Anyway, Nikon did send a QC Report with the scope indicating that it passed their standards.

I took the 60mm outside and did a quasi-star test during the middle of the day using pine sap on a distant pine cone. Very neat and handy! I was able to see a clear diffraction pattern inside of focus. I think that is towards infinity? Or is it the other way around? Either way, I was not able to test on the other side of focus.

I used an artificial star (LED) last night and was able to view both sides of focus and near focus. I also used a few real stars in the sky. I don't seen anything wrong with the results but would need someone more experienced than myself to double check. To my eyes, it is close to perfect. During the day, it is sharp at 60x. This 60mm doesn't seem to be a lemon!

 

[Hermann]

I used an artificial star (LED) last night and was able to view both sides of focus and near focus. I also used a few real stars in the sky. I don't seen anything wrong with the results but would need someone more experienced than myself to double check. To my eyes, it is close to perfect. During the day, it is sharp at 60x. This 60mm doesn't seem to be a lemon!

Fieldscopes are usually very, very good in that respect. Lemons are IME quite rare. We've got five Fieldscopes in the family (EDII, EDIIA, EDIII), and in a pretty thorough comparison I found one was just a tiny bit better than the others, but the others were still very good. Sharp at 60x, good star tests, even boosted to 72x (24xWA+Zeiss Tripler) the image quality was more than decent. I have yet to see a true lemon.

The ED82s I've seen were also all very good, and pretty sharp up to 75x. The ED50 is another matter. While most are pretty good, I came across a couple of lemons over the years. Still a better result than with most other scope models.

Hermann

 

[4th_point]

Hi Hermann,

Thank you for the information on the Fieldscopes. I'm glad that you took the time to post it. I think it is really helpful for anyone interested in these scopes and a good overview. In fact, your posts and those from some other members here are what motivated me to buy the EDIII-A and ED82-A.

I've owned several budget spotting scopes but was never really happy with them. I don't want to invest in a so called alpha, especially with the reports of lemons or subpar samples, so the Fieldscopes are exactly what I was looking for. The eye relief and FOV don't bother me at all. I was expecting much worse, based on various posts at different forums.

The sharp images from the Fieldscopes are impressive compared to other scopes that I have tried (even the defective/damaged ED82-A was super sharp to my eyes). Especially when approaching 1x magnification per 1mm of objective size. In the past, I assumed that most scopes were good to about 1/2 their objective size. For example, a 60mm would only be usable to about 30x or maybe a little less. So having a 60mm ED sharp at 60x, or even usable when boosted to 72x, is pretty remarkable to me. While not having to invest alpha-levels of money!

They have been a great learning tool as well, allowing me to gain experience with basic diffraction and resolution tests. And having an instrument that appears to test somewhere near perfect is super helpful! A member at another forum is giving me a Nikon camera adapter and I am looking forward to learning how to take good pictures.

I had an ED50 several years ago but only used the 16x DS and standard 13-30x eyepieces. Myself and a few friends compared it to an old 50mm Bushnell. During casual viewing, none of us thought that the ED50 was any sharper than the Bushnell but I didn't have the MCII eyepiece then. I believe the main knock against the Bushnell was an obvious tint to the view and short eye relief.

I've thought about selling the EDIII-A and getting another ED50 to go along with my next ED82-A (due to arrive this week) but this 60mm is a cute little scope as it is. And reminds me of lab instrument, rather than a cheap toy. Your experience with the ED50 is again helpful. Thank you!

Jason

 

[4th_point]

I think there's a happy ending to this story. The second 82mm arrived today, and earlier than I expected. The seller stated that it is in mint condition, and I wouldn't disagree. I did a quick star test using an LED indoors, and pine sap outdoors. Preliminary results appear perfect to my eyes, on either side of focus. I'll do a more thorough evaluation in the future.

The view is absolutely stunning to me. Super sharp and bright with MCII 25-75x.

ETA - if I can take good pictures of the star test, I'll start another thread and post them.