108 replies to this topic

[RichA]

 

Some told me that I should NOT looking AT optics, and that I should looking THROUGH optics and see if optical performance is affected, and they are very probably right!

 

I do not want share with you MANY MANY ugly images I did over many years, because some could get heart attack LOL!

 

Kind regards,
Denis

Same thing was said to me by the later Roger Tuthill.  All of the old Vernonscope/AP 94mm apos had minor fine scratches on the elements when examined under glancing or very bright light.  None of them made any difference to the visual use of the scope.  Tiny inclusions, small, small scratches or tiny, but few bubbles are problems for high-powered lasers, not visual observing by amateurs.

Edited by RichA, 20 June 2024 - 11:55 PM.

[j.gardavsky]

As we are living in the universe of standards, conformity prescriptions, etc.,

the optics is no exception, and the optics quality is subject to

Optical glass standards: https://www.degruyte...-2015-0047/html

Surface roughness specifications: https://blog.rossopt...-specifications

and many more.

 

Even if lots of the scratched, cracked, and dirty optics can be regarded by the manufacturers as still good enough for some of the hobby astronomy,

even then, the price of such optics is not low enough.

 

Best,

JG

[Scott99]

But the dust at Burningman is everywhere and it gets absolutely everywhere and in everything. It's a fine powder, like talcum with a really low PH. Really nasty stuff. Fun times, but after six years, I just couldn't handle the dust anymore so I haven't been back.

It's interesting to me this event was originally held in dowtown SF - Baker Beach I think?   It's a telling sign of our government & culture that it was forced to one of the most inhospitable places in the USA.  In European cities like Berlin, Amsterdam and others they celebrate weeklong art fests and parades during "techno week". 

 

back to your regularly scheduled programming.....

[Mike B]

As we are living in the universe of standards, conformity prescriptions, etc.,

the optics is no exception, and the optics quality is subject to

Optical glass standards: https://www.degruyte...-2015-0047/html

Surface roughness specifications: https://blog.rossopt...-specifications

and many more.

 

Even if lots of the scratched, cracked, and dirty optics can be regarded by the manufacturers as still good enough for some of the hobby astronomy,

even then, the price of such optics is not low enough.

 

Best,

JG

Boy, howdy- we sure as shootin’ are!… that, along with carefully manipulated marketed expectations & buzz-words & phrases. It all works marvelously at insulating pricing from dropping too low 

[Highburymark]

Are you sure? Try this..

Put it in 24mm , and then without a telescope look through it in the direction of a very bright light.

I just tried this with a full on spotlight - the same technique that exposed a thick layer of dust in my Tak orthos - and I was surprised to see an almost completely clean eyepiece. The cleanest eyepiece out of 25-30 which I’ve subjected to this unforgiving examination.

[RichA]

I just tried this with a full on spotlight - the same technique that exposed a thick layer of dust in my Tak orthos - and I was surprised to see an almost completely clean eyepiece. The cleanest eyepiece out of 25-30 which I’ve subjected to this unforgiving examination.

As a technique, it can show things you might need to see and a lot that don't have any impact but can "look" bad, like the average mirror surface.  Just like evaluating a ronchigram or a star image, you need to know which things impact the image. 

[denis0007dl]

https://www.cloudyni...his/?p=13575727

 

[denis0007dl]

Agree on that statement

 

https://www.cloudyni...eks/?p=12316095

 

and even weak LED light reveal many times many sleeks, and other imperfections + even daylight can sometimes reveal sleeks or lens scratches on lenses/glass/mirrors.

 

Denis

[denis0007dl]

Lets update thread: 

 

had in my hands superexpensive Nikon WX 10x50 binoculars, and eyepiece lenses have long scratches.

 

In contact whith two of my friends who own same binoculars, they notice same scratches....

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