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GBT 100/90 arrived

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#76 GlennLeDrew

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Posted 23 March 2010 - 05:38 PM

Excellent, shots, Mr. Bill! At 32mm, those are generously large prisms for a Porro II. In the RA88 I collimated for a friend, the prism face widths were ~24mm, with the clear aperture being closer to 21-22mm.

When taking photos into prism essemblies, the farther back you can place the camera the better. From up close, perspective effects cause a rapid change of scale with distance from the lens. The result is that an aperture lying farther inside the instrument can appear rather smaller than it really is, when compared to other apertures, etc. closer to the lens.

If necessary, one could move so far back so that the image scale is hardly better than 1mm/pixel (0.5mm/pixel is certainly quite adequate). If the idea is to assess comparative apertures most accurately, better to sacrifice some resolution in order to get closer to an isometric image from which to take measurements.


@EdZ,
I was going to suggest the exit pupil measurement, too, but you beat me to it!

#77 Mateyhv

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Posted 23 March 2010 - 05:47 PM

It would seem to me that all these returns on Garrett's dime for defects would really eat into the profit margin...would'nt it be cheaper and easier to REALLY do the 14 point inspection? The gross defects discussed on this thread and the recent others would easily be detected with the most casual visual inspection.

Makes one wonder whether the collimation check was done.

:tonofbricks:


The sentence I put in italics is absolutely true, after some time its clear for me that there is no such a thing called 14 points inspection. The only inspection seems to be if the binos are in the box and the address to be shipped to... :( very dissappointing..

Matey

#78 Mr. Bill

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Posted 23 March 2010 - 05:50 PM

Thanks for the tip...next time I won't be so lazy and will mount the camera on a tripod. I took about 30 shots to get those.

:p

#79 mtb54703

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Posted 24 March 2010 - 09:13 PM

A bit of follow up on my post...

My 90s arrived back in Tulsa today.

Was offered a full refund but also asked to carefully consider other binocular options they have to offer - specifically the 110 Signature Series.

Obviously another pair of 90s are out - not going there again. 45s? Need to get a feel for the quality in this last batch. Maybe the 110s...


:question:

#80 Mr. Bill

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Posted 24 March 2010 - 09:33 PM

Mike...
Go for the 20x110s....want a report.

:cool:

#81 mtb54703

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Posted 25 March 2010 - 07:50 AM

Mike...
Go for the 20x110s....want a report.

:cool:


I've seen many recommendations for the 110 Signature Series. I'm on the fence between those and another pair of 45s - don't know if I want to roll the dice or not on another pair of 45s.

:tonofbricks:

On my original pair of 45s I really enjoyed using a pair of Smart Astronomy Extra Flat 19mm EPs (65 APOV) for about 28x. So in the Signature series I leaning towards the 28x pair until I saw the usable eye relief was 11mm.

My initial choice in the purchase of the 45s was due to two factors:

- the ability to use different EPs
- the 45 degree design.

After using them I pretty much settled down on a single pair of EPs so I don't think that interchangeable EPs is that big of a factor any more.

I could really go for a 45 degree 100mm or so bino with a fixed magnification of around 25x - that would be sweet.

#82 Pat G.

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Posted 25 March 2010 - 11:51 AM

"I could really go for a 45 degree 100mm or so bino with a fixed magnification of around 25x - that would be sweet."

It seems a shame to limit a large instrument to a single power. Different items look better at different powers.

On another note, I really love my 45° binos for astronomy.

#83 Mr. Bill

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Posted 25 March 2010 - 12:41 PM

Since we're wishing....

How about a fixed magnification 45 degree ocular 25x120 binocular the same build quality as as the Signature 110s apparently are? I would like a 5mm exit pupil with a 65 degree afov for dark site MW scanning. I find 5mm to be optimal under really dark skies.

A weight of 25 pounds would seem reasonable if you figure the 110s are 16 pounds and scale them up.

That's a whole lot better weight wise than the Oberwerk 120s which are about 45 pounds.

Oh, and around $1500 since the 110s are $700 this seems doable..OK I'll go $2K

;)

#84 Erik D

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Posted 25 March 2010 - 01:12 PM

Since we're wishing....

How about a fixed magnification 45 degree ocular 120x25 binocular the same build quality as as the Signature 110s apparently are?
;)


Clarification please. Do you mean 25X125 mm?

I usually prefer 4 mm exit pupil for binoculars 60 mm or bigger. My skies are not very dark, usually mag 4 to 4.5 so higher magnification with 4 mm exit pupil do better for me.


ERik D

#85 Mr. Bill

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Posted 25 March 2010 - 02:32 PM

Since we're wishing....

How about a fixed magnification 45 degree ocular 120x25 binocular the same build quality as as the Signature 110s apparently are?
;)


Clarification please. Do you mean 25X125 mm?

I usually prefer 4 mm exit pupil for binoculars 60 mm or bigger. My skies are not very dark, usually mag 4 to 4.5 so higher magnification with 4 mm exit pupil do better for me.


ERik D


Dyslexia in my fingertips.. :grin: also, rounding off to 5mm; should have said 4.8mm

I have the skies to take advantage of 5mm (4.8mm) exit pupils so for me that would be optimal. My eyes can dilate to around 5.2mm, so that's about all I can effectively use.

#86 mtb54703

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Posted 26 March 2010 - 08:16 AM

I too currently have a pair of the Garrett Optical 90 Binocular Telescope, at least until tomorrow. I would like to note that they also appear to be the same model sold by Orion Telescopes.


Just as a follow up I sent an email to Orion asking about clear aperture on their new 100/90 models. Their reply was.... well... email them and ask them yourself.

As for thoughts on look-a-likes...

We know these 100/45s and 100/90s offered by Garrett, Orion, APM, Baraska are all from BA6 series offered by United Optics.

While I do believe importers can customize their selection, I doubt that to be anything more than glass selection, coatings, focal length within constraints of the physical enclosure, EP selection, color, and embossing.

Given that United Optics offers one model of a 100mm 90 degree binoculars (22x/33x/40x100
#BA6-203037100) I suspect that offerings by Garrett and Orion are identical in the physical respect. We've estimated what size opening is required at the front of the prism housing given the objective diameter, focal length and length of the main tube - and having had a pair of those 90s in my possession I can say its physically not possible, so I don't see how the Orion offering could have a different clear aperture than the Garretts.

#87 GamesForOne

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Posted 26 March 2010 - 10:07 AM

Just as a follow up I sent an email to Orion asking about clear aperture on their new 100/90 models. Their reply was.... well... email them and ask them yourself.


What a teaser! Ah, c'mon what was the reply?

#88 Rich V.

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Posted 26 March 2010 - 10:44 AM

I'm betting they had no idea! :confused:

Rich V

#89 F.Meiresonne

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Posted 26 March 2010 - 10:51 AM

I usually prefer 4 mm exit pupil for binoculars 60 mm or bigger



Me too, and that also because my skies are not that dark.
That also the reason i tend to opt for higher magnification model like a 15x70 or 22x85 instead 10.5x and 15x respectively.

#90 mtb54703

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Posted 26 March 2010 - 10:54 AM


Just as a follow up I sent an email to Orion asking about clear aperture on their new 100/90 models. Their reply was.... well... email them and ask them yourself.


What a teaser! Ah, c'mon what was the reply?


Ignorance is bliss I guess.... ;)

#91 mtb54703

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Posted 26 March 2010 - 12:14 PM


Just as a follow up I sent an email to Orion asking about clear aperture on their new 100/90 models. Their reply was.... well... email them and ask them yourself.


What a teaser! Ah, c'mon what was the reply?


Ignorance is bliss I guess.... ;)


I ended up not being to contain myself and I replied to the support dude at Orion with and explanation on how to check clear aperture and some photos from the GO model.

#92 Rich V.

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Posted 26 March 2010 - 01:53 PM

Well done, Mike! :bow:

Rich V

#93 Mr. Bill

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Posted 26 March 2010 - 02:26 PM

I talked to Cory Suddarth about his collimation class coming up (hopefully) this fall and he mentioned he did the week long class for the Orion service dept. so I would think that there are competent people there....although I've apparently never had the opportunity to talk to any when I called with technical questions.

:p

#94 daniel_h

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Posted 26 March 2010 - 05:22 PM

mr Bill..i have also talked with Cory more later

#95 AndR1

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Posted 10 October 2012 - 03:58 PM

[img]http://http://www.cloudynights.com/ubbthreads/attachments/3696797-10090-01.jpg[/img]
The distance from the front of the tubes (dew shields retracted) to the gold ring just in front of the lower prism housing is 12.125". I measured the outside of the edge of the objective to 1.625" from the front edge of the tube (again with the dew shields retracted). [img]http://http://www.cloudynights.com/ubbthreads/attachments/3696797-10090-01.jpg[/img]

I've bought the same (different color... and no logo like here) directly from Kunyang Zhicheng Optical Co. It arrived some days ago. Same sizes, same design (see no real difference... but there is no ruler at photo here to compair all sizes). I've made the same test and ... there is NO sector cutting, it has round circle 96-97 mm aperture (96,0 -96,5 for left and near 97,0 mm for right)...
Maybe I've missed some new theme about the issue... but if not, could you, please, give me any idea how they managed to make it much better? :confused:

Andrew

#96 GamesForOne

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Posted 11 October 2012 - 12:34 AM

I've bought the same (different color... and no logo like here) directly from Kunyang Zhicheng Optical Co. It arrived some days ago. Same sizes, same design (see no real difference... but there is no ruler at photo here to compair all sizes). I've made the same test and ... there is NO sector cutting, it has round circle 96-97 mm aperture (96,0 -96,5 for left and near 97,0 mm for right)...
Maybe I've missed some new theme about the issue... but if not, could you, please, give me any idea how they managed to make it much better? :confused:


Is your bino a 45 degree or 90 degree? I don't think we've had a report of a 90 degree model with 96mm clear aperture. The 45 degree models, yes.

---
Michael Mc

#97 AndR1

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Posted 11 October 2012 - 09:01 AM

Is your bino a 45 degree or 90 degree? I don't think we've had a report of a 90 degree model with 96mm clear aperture. The 45 degree models, yes.

---
Michael Mc


90 degree! Mine looks like just the same as shown at the photo from the post #3696797 - 05:48 22/03/2010 - just different color ! (Tried to insert this photo again but failed to make it for some reason... :question: ...Well, it doesn't matter as mine is REALLY identical - just black instead of white colour - to mentioned one and adding image gives nothing new at all.)

#98 Mark9473

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Posted 11 October 2012 - 12:36 PM

Check that your image is below 200 kB.

#99 GamesForOne

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Posted 11 October 2012 - 03:24 PM

Is your bino a 45 degree or 90 degree? I don't think we've had a report of a 90 degree model with 96mm clear aperture. The 45 degree models, yes.


90 degree! Mine looks like just the same as shown at the photo from the post #3696797 - 05:48 22/03/2010 - just different color ! (Tried to insert this photo again but failed to make it for some reason... :question: ...Well, it doesn't matter as mine is REALLY identical - just black instead of white colour - to mentioned one and adding image gives nothing new at all.)


How about posting photos of the projected image circle for your measurement with a ruler visible, and a picture of your measurement setup showing the bino and light source placement?

From whom did you actually order the binos? Was it from here?

---
Michael Mc

#100 AndR1

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Posted 11 October 2012 - 04:00 PM

How about posting photos of the projected image circle for your measurement with a ruler visible, and a picture of your measurement setup showing the bino and light source placement?

Well... now I've disassembled all staff and actually I've got no photo for measurment procedure (just some photos of bino) as my camera is in need of repirement just now... But I did all just as it was recommended by Glann LeDrew...
I'm going to place photo as soon as my camera would work.

From whom did you actually order the binos? Was it from here?

Yes! It's right place and right product (but different color)...


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