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photonovore
Moonatic


Reged: 12/24/04
Posts: 2792
Loc: tacoma wa
A closer look at the 100$ Barska X-Trail 20x80's new
      #984012 - 06/03/06 06:38 PM

Barska X-Trail 20x80 binoculars: A Closer Look

I purchased these to be used as a sighting aid out in the observatory and for casual stargazing on the rare occassions when i get to a dark sky site.

The three most important factors i was looking for in 20x80's were light weight and good balance; sharp optics; and a preferrably "immersive" wide field purely for aesthetic viewing pleasure. What i wasn't worried about was rugged construction, waterproofing and attaining the ninth degree of light conservation. I was impressed by Stephen's comments about the handling of the Barska 30x80's and hoped these would be similiar.

Ergonomics:

This area respresents a *very* pleasant suprise. The actual weight of these binoculars, (postal scale of known accuracy) ready to use is 2kilo, 40 grams; 72 ounces or 4-1/2lbs. The balance is supurb. I have less problem handholding these 20x binoculars in an adequately steady manner than I do the 12x50's i own! A very pleasant suprise. I rather hate tripods as they remove so much of the freedom of movement that I personally feel is *the* key advantage of binocular observing generally. Other than for precision use (as in the resolution testing i will get to shortly or doubles stars etc) I don't feel anything more than a simple monopod is necessary for absolutely satisfactory steadying of these binoculars.

As far as tripod use goes, I find the sliding attachment bar assembly very useful. The position of the binocular can be adjusted so as to provide more clearance from the tripod when viewing near the zenith than would be possible if the attachment point was fixed near the main body. It also allows more positional flexibility when using the monopod.

Eye relief i did not measure but i *can* say it is most probably inadequite for eyeglass wearers.

Mechanical:

All framing, including the barrel bracing and focus assembly plate *is* aluminum, the armoring is cursory and the barrel end pivot is not shimmed tightly and the focus assembly is not exactly built like a rock (although i must say it is much sturdier than the focus assembly on a vintage Japanese-made pair of Bushnell Rangemasters 7x35's I own...)

Diopters are not of an extensive range but I find it more than adequate. Others may not. They are not marked per dioper number, just plus/minus and their range of rotation is on the order of 180degrees stop to stop. the rotation is smooth and without play.

Focusing is very smooth and sure. No issues here. I did not notice any focus shift from eyecup pressure.

Hinges are tight and without play with the exception of the far barrel hinge which does have a small amount of noticable play when the barrels are pressed hard together. This seems to have no operational relevance in use, however.

Coatings:

These binoculars are multicoated on the eyelens and objective lens *only*. The visible prism reflections appear single MgF2 coated judging from their blue-toned reflection. The multicoating that is present seems equivalent in degree of it's reflectivity to any other multicoated optic i have. They certainly do not look like some sort of green dye has been applied as some i have seen do, rather the effect is on the subtle side, but plain to see if a fluorescent fixture's refelction is examined for example. Speaking of the fluorescent tube lights, I feel they work nicely as an aid to examine the construction of the lens system; if one looks closely one can actually see, using the innately linear nature of the reflection of the fluorescent tubes, the relative curvature of the lenses in it's reflection.

Objectives:

Full 80mm clear aperture. I might add these are *not* triplets (which i am thankful for actually). There are only two primary reflections visible from the objective end and one much smaller secondary reflection from the prism, identical in pattern & order to other doublet binoculars i have. If there was another lens element, there would be third primary reflection.

Optics:

I examined the exit pupil with a 7x magnifying loupe. It measures 4mm and is not obstructed by the prisms or any other component in any physical way whatsoever--perfectly round. (This was in contrast to the Japanese Bushnell Rangemasters which exhibited heavy dimming in a square pattern within the exit pupil). Just for kix I also examined an image of the USAF chart as displayed within the exit pupil (also using the magnifying loupe) and noted even light across the field, no distortion until 90% out when mild pincushion set in and centerfield sharpness was maintained to 90% out, almost the very verge of the pupil. (This was *not* reflected in actual use as i'll get to in a moment--but I wonder why the exit pupil image would be flatter and display less distortion than the image seen in actual use is??)

I had only a half hour or so of clear sky for astronomical testing but the quarter Moon was well-placed and I wanted to make sure these binos performed well enough to hold on to before too much time went by.

Resolution:

I set them up on a tripod with a Manfrotto fluid head. The 25km crater Ross was chosen as a test object. It subtended an angle across it's diameter of ~12.7"arc at this point in the Moon's orbit (1792"arc diameter at time of observation, 1.94km:1"arc). The image of this crater essentially reduces to a pair of black crescents on a white background separated at their greatest extent by ~12.7"arc. When these crescents merge, it's image no longer is identifiable as a craterform. This represents apparant resolution of about 254"arc. The optics demonstrated they were capable of finer resolution however; as crater Sosigenes at 18km/9.76"arc was also just discernable as a craterform (intermittantly during seeing), representing apparant resolution of just over 180"arc. (Incidently, this crater's diameter is misrepresented in Rukl's in case anyone checks.) I should also note the seeing was such that continuous image distortion was visible even at this low magnification so... I make the assumption that point source resolution would be slightly better than that obtained on these extended targets and that under better seeing there would also be a further albeit marginal improvement in resolution obtained on extended objects.

Field Sharpness:

As for sharpness/focus across the field, i found that crater Ross remained resolved out to about one Moon width (1/2degree) from the edge of both sides of the field. That leaves about a three degree corrected FOV (see below re; FOV) Clouds forced me to conclude the tests at this point.

Overall, I am quite satisfied by the resolution these binoculars deliver.

Field of View:

The FOV of these binoculars is actually marked on them as 212ft/1000yards which is ~4degrees and not 189ft as advertised. 212/1000 would equate to an 80degree AFOV of the eyelens. Indeed the view is quite "immersive", reminiscent of the extent of view I get using the 30mm/80degree AFOV 2" ep in my refractor. Frankly I am looking forward to getting under a really dark sky with these--i anticipate the 'wow' factor will be significant! I did not have a chance to precisely measure the FOV using star fields, but got a good idea that it is at least close to accurate judging from the star field it showed in relation to Arcturus--it encompaassed Arcturus and went beyond 22 Bootes approximately the distance between it and the next brightest star in the "L" shaped asterism back towards Arcturus. Anyway, that is closer to 4 degrees than 3.5.

Collimation:

Collimation is not an issue. The images merge instantly, no problems there at all. I did not bother to peel back the rubber cover to look for collimation screws so whether or not it has any I don't know.

Distortion:

Field distortion (pincushion) is very noticable when viewing linear terrestrial objects in the outer 1/3 of the FOV but not really noticable when viewing the sky. In the short bit of sky scanning I didn't notice any 'rolling' effect in the moving image at all but rather the effect was quite smooth & pleasant. The same applied during daytime testing. This is rather subjective. I can say that compared to the 11degree fov of the Japanese 7x35's, the pincushion distortion in the 80mm's is *much* more evident.

Chroma:

The effects of chroma was plain in the image, manifesting as a rather narrow, yellowish border on the illuminated limb of the Moon. In daylight, electric lines backlit by the sky displayed a discernable purple fringe on one side and a yellow fringe on the other. This is I feel pretty typical--the Japanese binos did the same thing albeit not as plainly as the magnification is so much less. Stars appeared principally white save the brightest (-1 to 2mag or so) which exhibited chromatic color. In daylight I also took a look at the star-like reflection on a phone pole insulator. It appeared mostly white albeit brilliant with mild chroma and some flare; nothing spectacular.

Miscl:

I could detect no image rotation indicating astigmatism in the image of Arcturus between inside & outside focus.

I noted no obvious image ghosting at all.

I examined the interior of the binoculars using a strong beam of focused light. (giant maglite) The barrels are fully blackened and ridged. The paint is subpar; more reflective than I would like. There is a ring where the barrels join the body that, although black, is very reflective. I did test for image flare with the Moon just outside the edge of the field and must admit i found suprisingly little bleed over.

I naturally could not assess the light gathering ability of these binos nor deep sky contrast. I am certain they would prove deficient compared to fully multicoatd models. But, for the purposes I have in mind, (Messier hunting, purely recreational stargazing) I don't feel an extra 1/2 magnmitude or whatever is really essential or even worth doubling the price to get, at least not for me. It's relative--if Jay Freeman was able to complete the Messier list using a MgF2 single coated pair of 7x50 widefields, I'm sure these Barska's will gather more than enough light/contrast for that sort of entertainment and much more.

General Miscl:

The binos come with a semi-hard leatherette case with shoulder strap and a neckstrap for the bino's themselves. The lens covers are the snap-in type on the objectives (which fit tightly BTW) and a one piece cap for the eyelenses. However, in deference to the fragility of these binoculars, I set the case aside and got a 20$ hardcase with pluckfoam instead from Harbor Freight (the same as the Lowes cases). The binos fit securely and snugly inside along with a compact monopod. They come with a lifetime warranty against manufacturing defects with the usual exclusions and a 25$ handling fee.



Summary:

To sum up I feel very satisfied as to the optical quality, thrilled by the ergonomics, somewhat underwhelmed by the mechanical quality and overall quite pleased. The mechanical fragility i have mentioned I don't consider to be a significant issue *for me* as i really baby instruments like this anyway. There are no mechanical deficiencies (that i can see) which I would anticipate becoming an issue, not just from the stresses of normal considerate & careful use anyway. Protected by the pluckfoam case I'd have no worries taking them down a jeep trail on a dual sport bike--as I have done often with my ETX-70 and intend to do with these as well.

If money were no object for everyone there would be no reason for binoculars like these to even exist. Such not being the case, (especially MY case!!) they fill a need. For 100$ one can enjoy a perfectly sevicable pair of binoculars which, if consistent care is taken in their use & storage, will doubtless give many years of that unique 'big bino' stargazing pleasure.

added 06-06-06:

I was able to check the true fov and established it is as advertised 4 degrees- Epsilon 2 and the star indicated below the Gamma pair were both contained within the extreme fov. Below is a graphic of the stars i used for this measurement:



Comments, criticisms, etc always welcome.

Edited by photonovore (06/06/06 02:49 PM)


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Art Fritzson
sage


Reged: 01/29/05
Posts: 315
Loc: Northern Virginia, USA
Re: A closer look at the 100$ Barska X-Trail 20x80's new [Re: photonovore]
      #984076 - 06/03/06 07:44 PM

Mardi,

Thanks for a well planned and executed review! I formed very similar impressions of the X-Trail 20x80s when I did a brief comparison of them with my Obie 15x70s and Go 25x100s. Considering that they were only 2/3 the price of the Obie 15x70s, I thought they represented good value. It also sounds like the optics in yours are better than the ones I had - mine appeared to be single coated and they also had a lot of stray reflections in the viewing of bright objects. Perhaps they've improved the more recent ones - or maybe you just got lucky!

- Art

--------------------
2006 "Bagging on a Budget" Award for Excellence in Binocular Astronomy
Garrett 25x100 IF, Oberwerk 15x70, Celestron Noble 10x50, Meade 10x50 and 8x42 Travelviews
William Optics Zenithstar II 80mm APO
Teleport 10" - an incredible all-in-one Planetary/DSO/"Grab and Go"


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mttafire
Pooh-Bah


Reged: 02/02/06
Posts: 1114
Loc: midwest
Re: A closer look at the 100$ Barska X-Trail 20x80's new [Re: Art Fritzson]
      #984126 - 06/03/06 08:38 PM

That is a review!!!! Great job!! Something to think about.

--------------------
God Bless America

Binocular astronomy
for me ONLY.
8x45 Garretts
15x70 Skymasters
2 eyes!


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Erik D
Post Laureate


Reged: 04/28/03
Posts: 4066
Loc: Central New Jersey, USA
Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: mttafire]
      #984235 - 06/03/06 10:18 PM

Mardi,

That's an exceptionally well written report. I feel this one deserve a place in the CN reviews section.

I didn't think I would have much interest when I first saw the title "The $100 Brsaka 20X80" but I was WRONG. It's good to have this article to refer to the next time someone asks about decent low cost 20X80.

There is only one problem: People like you, Art F and KJ post up such quality report for a mini-review you leave no room for the rest of us. I need to ask EdZ for a small-mini section for the Novice..... ;-))

Erik D


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SaberScorpX
Post Laureate


Reged: 01/12/05
Posts: 4224
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Re: A closer look at the 100$ Barska X-Trail 20x80 [Re: Erik D]
      #984334 - 06/04/06 12:17 AM

Congrats on the new addition, Mardi.
Echoes my experience with the XT 30s.
A lotta big binocular for a little price.



Stephen Saber
PAC/Astronomical League
http://www.geocities.com/saberscorpx/home.html


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jdickson
professor emeritus


Reged: 04/26/04
Posts: 685
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Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: SaberScorpX]
      #985036 - 06/04/06 03:42 PM

Nice review. I enjoyed my cheapo 15x70 Barskas for a long time, even though I had to use duct tape to hold the focus from shifting I now have some Nova 20x80 FMC triplets that I am also enjoying.

--------------------
Joe
10" f5 ATM dob, 20x80 p-mount binos.



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KennyJ
The British Flash


Reged: 04/27/03
Posts: 20139
Loc: Lancashire UK
Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: jdickson]
      #985307 - 06/04/06 06:35 PM

Mardi ,

Thanks you for a very well planned and clearly presented review , which for ME , was littered with many pleasant surprises !

I was probably more surprised than YOU were in that you found these 20 x 80s easier to hold steady than 12 x 50s , and having recently spent a few weeks on and off testing a specimen of Barska 15 x 70s ( which I'd previously read came highly recommended ) was equally surprised that you found no problem with focus interference as a result of ocular pressure , nor any problem with ghosting / stray light effects .

The apparantly " perfect collimation " was a pleasant surprise too !

I found your reference to the ( welcome absence of ) green DYE in the coatings , very amusing , for all the right reasons :-) , as I did your reported sense of RELIEF at the confirmation that the objectives NOT being of the TRIPLET variety !

You included some seldom mentioned but very interesting simple D.I.Y types of tests , and resurrected what only last week many of us seemed to have agreed was a lost cause in trying to find a 20x binocular with a TFOV in excess of 3.5 degrees !

Your acquisition of the foam - lined hard case was a useful tip for others to follow , and I REALLY liked your line of :

< If money were no object for everyone there would be no reason for binoculars like these to even exist. Such not being the case, (especially MY case!!) they fill a need. >

It COULD be said ( I KNOW this because I'M saying it NOW ! )that people who know LITTLE about BINOCULARS , yet may be familiar with the price of telescopes , might not expect TOO much from TWO 80mm telescopes joined together --

-- all for $100 !

I also suspect that the MORE people know about binoculars , the LESS they would expect from 100mm giants costing so little , so to that end , your conclusions must be uplifting for many readers !

Regards , Kenny

--------------------


Milton Wilcox R.I.P






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EdZ
Professor EdZ


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Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: KennyJ]
      #985490 - 06/04/06 08:32 PM

Mardi ,

I too enjoyed your review. A lot of information in there, as we have grown accustomed to receiving from you. Good job.

I thought I'd mention one comment from Kenny

Quote:


You... resurrected what only last week many of us seemed to have agreed was a lost cause in trying to find a 20x binocular with a TFOV in excess of 3.5 degrees !




I thought back to just recently when I posted the minireview on the Anttler 20x80, which BTW, I think is the same binocular as Mardi has reviewed here.

Quote:

Anttler 20x80

This is a less expensive 20x80 for those in the market that donít want to pay $279 or $299 for the 20x80 triplets that are available.

It is light weight for a 20x80. It weighs in at 4# 10oz.
......
It has a multi-coated objective lens, but the rest of the components are single coated.

Iíve measured the field of view several times. Once I measured only 3.5į. But further use and more precise measures indicate it is closer to 3.7į.




--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21


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Glassthrower
Vendor - Galactic Stone & Ironworks


Reged: 04/07/05
Posts: 17931
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Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: KennyJ]
      #985491 - 06/04/06 08:33 PM

Quote:


I also suspect that the MORE people know about binoculars , the LESS they would expect from 100mm giants costing so little , ...





That sure is the truth. Finding a "good" binocular is partly dependent on finding a bino that meets one's expectations. The more elevated or unrealisitic the expectations may be, the greater probability is for disappointment later.

This thread, and the recent thread about disappointment over the new model Fuji 16x70, provides a stark example of the expectation issue.

Mardi bought a $100 giant binocular with realisitic expectations and was pleasantly surprised with the performance.

Starramus bought a $600(?) premium binocular with elevated expectations and was sorely disappointed.

There is something to be learned here, for both the budget-minded and the free-spender.

MikeG

--------------------
Michael Gilmer - Member of the Meteoritical Society & Collector of Falling Stars.



☄ ⒼⒶⓁⒶⒸⓉⒾⒸ ⓈⓉⓄⓃⒺ ☞ www.galactic-stone.com


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DJB
Carpal Tunnel


Reged: 02/23/05
Posts: 1742
Loc: Lisle NY
Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: Glassthrower]
      #985955 - 06/05/06 04:11 AM

Hi all,

Again, an interesting thread, IF I can keep on topic ED (LOL)!

I have two 20x80s. The original, the ORION 9#, long FL, was purshased in 1984 for around $400-. I have retained the invoice.

It has a field of 3.7*. It was made in Japan. It is a bit heavy for me with my bad back. This is a reiteration, I know. The other 20x80 is the OB triplet, shorter FL, at about 7#. Makes a difference to me.

Sure, there is a bit of yellow cast on the moon rising in and above the trees in the east. But the colour is maintained withing less than half of a degree, on EITHER side. However, this is a really fine binocular, but I will surmise that for all PRACTICAL purposes, this difference between 3.5* and 3.7* is all but imperceptible, unless measured, that is.

Well, I have measured the ORION by using the old tried-and-true method of measuring transit time across the widest part of the field. A star will do, but either limb of the moon will also work, as well as planets, etc. I doubly checked my results, and I measured/timed 3.84 degrees on average.

Now, if the earth did not slow down a bit those nights, I trust my results. The hardest part, doing it this way, is defining the very widest part of the field of view. Trust me, it can be done. And, no, I didn't correct for the siderial time differential for such a short transit. FYI.

Regards,
Dave.


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EdZ
Professor EdZ


Reged: 02/15/02
Posts: 18806
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Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: DJB]
      #986004 - 06/05/06 06:01 AM

Quote:

Well, I have measured the ORION by using the old tried-and-true method of measuring transit time across the widest part of the field. A star will do, but either limb of the moon will also work, as well as planets, etc. I doubly checked my results, and I measured/timed 3.84 degrees on average.

Now, if the earth did not slow down a bit those nights, I trust my results. The hardest part, doing it this way, is defining the very widest part of the field of view. Trust me, it can be done. And, no, I didn't correct for the siderial time differential for such a short transit. FYI.





Did you correct for the declination of the object by multiplying your transit time x the cosine of the declination. if not all your times need adjustment. the only times that don't need to be adjusted are those times for objects on the celestial equator.

edz

--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21


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photonovore
Moonatic


Reged: 12/24/04
Posts: 2792
Loc: tacoma wa
Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: EdZ]
      #986773 - 06/05/06 06:00 PM

Thanks for the positive comments.

Ed, I just read through the thread on the Anttler 20x80 you tested. The performance does indeed sound similiar. There are some differences which would preclude the example i have of this Barska from being 'the same' as the Anttler 20x80 however.

For example, after seeing your review comment about the exit pupil diameter on the Anttler i re-measured the EP of the Barska's using a 7x loupe and a steel machinist's scale for measurement (the same way I measure lunar features on the Bowker & Hughes Lunar Orbiter atlas I have). Then i remeasured using a micrometer and unaided eye--after averaging several separate measurements by two methods I still come up with an exit pupil of 4mm. So I feel it is likely a 20x unit. Second, these focus closer, at less than 100 feet, than your report on the Anttlers indicates to be the case. The neighbor's garage door (with missing paint and exposed woodgrain for a target) across the alley is 90feet and that's within sharp focus range. And the last significant difference is that the eyelens *is* multicoated on these, not single coated as with the Anttlers, showing the same green cast as the objective lens primary reflection does. (All remaining reflections within the eyelenses are blue tinted indicating single MgF2 coatings elsewhere.)

The FOV difference from what is advertised (189ft vs. 212 on the binos i have) still confused me so I gave Barska a call to ask about that. They told me that the model i got is a later model from what is currently shown on all the websites including their own (and even on the box these came in!) The pictures don't match either (prism covering material was of a different pattern, indicitive to me of a different "batch"). I was told they're in the process of updating the spec references on several models including this one and that this effort hasn't caught up with the actual product specs yet. I was also told that they own their own factory in China which manufactures for Barska only.

As to the differences between the Barska and Anttlers 20x80's, I have a feeling that who makes what and where is an essentially unanswerable question to any specific degree; apparant 'look alikes' having slightly differing optical specs seems to be common these days. There is also the possibility of 'seconds', discontinued models etc with non-uniform specs making their way into the market I suppose.

*Kenny*-- I can imagine from your comments in the Anttler's thread how askance you must *really* look at my copinion that the 20x80's offered a more easily attained handheld view of a given degree of steadiness than the 12x50's! I'd submit that ease of handheld steadiness to a specific standard has a significant relationship not simply to magnification (as we most often assume is the *only* relevant factor) but is also significantly connected to the binocular's mass. The positive effect upon damping that increased mass provides is pretty well established after all (Newton's second law).

The 12x50's i have weigh in at 790 grams. The 20x80's are 2040 grams. Amount (force) & duration of user sourced defection input constrained, and the effect of increased weight upon user fatigue also ignored for simplicity, a given deflection force and duration (shake) would impart about 60% more velocity (movement speed and amplitude) on the 790gram binos than on the 2040gram binos. Of course the apparant velocity is 'amplified' by magnification in the latter by 40% in the case of 12x vs. 20x. This would imply that target steadiness, with defelction input forces constrained at whatever level one chooses, would become equivalent between these two masses at relative magnifications of 12x vs. 30x--and that a 20x 2040gram binocular would be ~20% steadier to handhold than a 790gram 12x50.

Of course user fatigue from increased binocular weight is ignoered here and that is a significant yet unquantifiably subjective factor that would only act to increase net target deflection.

So I tried a little 'Newtonian' experiment to see what would happen to image steadiness if i doubled the weight of the 12x50's. Guess what? It improved. With a 770gram bar attached across the barrels, i was consistently able to read the stenciled number on a distant electrical transformer more often in a given period of time than without the weight attached. The weight had less effect in countering gross movement, but considerable effect upon more discreet deflections which resulted in betetr net effective resolution.

So I suspect that the mass factor may be another legitimate consideration worth adding magnification differences alone when assessing the potential of target steadyness variations betweeen binoculars when handheld.

--------------------
Mardi




4" achromat, ETX-70, 8"cat.
Whitepeak Lunar Observatory Website


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KennyJ
The British Flash


Reged: 04/27/03
Posts: 20139
Loc: Lancashire UK
Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: photonovore]
      #986832 - 06/05/06 06:41 PM

Mardi ,

I seem to have a knack of drawing out incredibly detailed and very interesting responses as a result of either asking a simple question or making what I more often than not originally conceive to be no more than " common sense " comments .

Perhaps I ought to have been some kind of professional INTERVIEWER !

I MUST say , your mini - disertation on the application and effects of Newton's Second Law on hand - held binocular observation is the stuff worthy of Award Nomination in applied Physics ! :-)

As a result I intend to commence forthwith on the project of RE - COVERING all my binoculars with SHEET LEAD , utilising skills I learned during my apprenticeship as a Gas Fitter , using special tools and materials lost in the mists of time , including mandrels , dressers , boxwood mallets , bobbins and followers , shave - hooks ( hand - made , of course ) , bent bolts , turn -pins , plumber's black , tallow , " mouth lamps " , turpentine , bar solder , gimlets , bradawls , rasps , rubber jaws and wiping cloths of various dimensions !

Ah -- now THAT brought back some happy memories :-)

Believe it or not , ONCE upon a time , before I became a TECHNICIAN , I was actually a fully qualified ,regularly practising ( which one NEEDS to be in THAT sort of work ) " good , old fashioned CRAFTSMAN " ( long before craftsPERSON was considered the politically correct description of such an unfortunate soul ) !

Regards , Kenny

--------------------


Milton Wilcox R.I.P






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Art Fritzson
sage


Reged: 01/29/05
Posts: 315
Loc: Northern Virginia, USA
Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: photonovore]
      #987136 - 06/05/06 10:11 PM

Mardi,

After reading your comparisons to the Anttlers, I'm more intrigued than ever about the differences in your X-trail and the one I had a chance to look over. Would you mind sharing where you purchased it? Maybe a picture?

Thanks!

- Art

--------------------
2006 "Bagging on a Budget" Award for Excellence in Binocular Astronomy
Garrett 25x100 IF, Oberwerk 15x70, Celestron Noble 10x50, Meade 10x50 and 8x42 Travelviews
William Optics Zenithstar II 80mm APO
Teleport 10" - an incredible all-in-one Planetary/DSO/"Grab and Go"


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DJB
Carpal Tunnel


Reged: 02/23/05
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Loc: Lisle NY
Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: Art Fritzson]
      #987459 - 06/06/06 05:20 AM

Hi Ed,

Absolutely. I know the "position" of my typical observing site (back yard) to within about three feet, thanks to the now uncoded GPS signals. This gives Lat. and Long. Cooridnates precise to several decimal places in degrees.

I think we would all agree that trying this measurement on Polaris would be rather futile, right.

I made the correction, or deviation from norm, as I call it, in a slightly different manner as I already had calculated the deviation at my position for every tenth of a degree over a continuous range, useful for the project.

I simply created a spreadsheet with the factors, entered only one corrected "seed" line, filled down, printed out, and I was set to go. All that was left to do was to do the timings.

Good point, and thanks for bringing it up in case others wish to try it.

BTW, conduct this timing on the equator? No way. 72*F is my favourite summer temp. when working outdoors, day or night! Well, it rarely works this way for me.

Best regards,
Dave.


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photonovore
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Reged: 12/24/04
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Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: KennyJ]
      #987768 - 06/06/06 11:37 AM

Oh, Kenny, you comedian! Adding weight to your binoculars to improve steadyness may sound amusing to you but if you have ever done any shooting (another sport where steadiness counts) you'd find that a heavier pistol is much easier to shoot accurately, keep on target etc than light-weight models. Same goes for rifles. I grew up in a gun nut family in South Dakota and was one myself for a while (by osmosis ) That's why i got to thinking about this 'mystery' in this way actually.

Art-- the differences really are minor. One more lens multicoated, shorter minimum focus, closer to the spec'ed magnification, and the only difference in appearance is a diffferent pattern rubber body cover. I don't think there are any quality differences, per se. It's just another inexpensive, imported big bino --but at a better price than any other--which reminds me to answer your other question; I got these from Optics Planet.

--------------------
Mardi




4" achromat, ETX-70, 8"cat.
Whitepeak Lunar Observatory Website


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EdZ
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Posts: 18806
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Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: photonovore]
      #987792 - 06/06/06 11:52 AM

Hi mardi,

and it sounds like the big difference in these and Anttler's is the eyepieces. Other than that, pretty similar? But that alone would make for some differences in just about all aspects of the view.

edz

--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21

Edited by EdZ (06/06/06 11:54 AM)


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photonovore
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Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: EdZ]
      #988010 - 06/06/06 02:54 PM

Ed, yes I agree. I also was able to field check the true fov last night, see the original post; i edited in the results.

I was wondering if you know why the image in the exit pupil (as examined by a magnifying loupe) and the actual image the binos produce for the user appear different? Primarily this difference is in distortion--in the exit pupil image there is much less displayed than in actual use. Does this have to do perhaps with the (flat) exit pupil being projected upon a curved surface (retina) in the latter case and being essentially a flat image when examined by itself in the former?

--------------------
Mardi




4" achromat, ETX-70, 8"cat.
Whitepeak Lunar Observatory Website


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EdZ
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Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: photonovore]
      #988058 - 06/06/06 03:26 PM

not sure. i started to answer this as pertains fov and exit pupil distance, but your question is different.

please clarify this:
Primarily this difference is in distortion--in the exit pupil image there is much less displayed than in actual use.

Does this mean in the exit pupil image thru the loupe there is much less than the exit pupil thru the binocular alone?

edz

--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21


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photonovore
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Re: A closer look at the 100$ Barska X-Trail 20x80 new [Re: EdZ]
      #988090 - 06/06/06 03:42 PM

Ah, you suspect the possibility that the loupe's lens may be distorting the image it shows of the exit pupil? Mmm, i don't think that's what's causing this---what i did was is this; used a USAF target on the table and brought the binos over it so that the chart's image filled the exit pupil. I did look at this image as best i was able without optical aid, but of course i could see a better, larger more detailed image through the magnifying loupe. But I didn't notice that the loupe changed the distortion actually. It (edges of the chart) seemed to stay quite true right out to the edge of the exit pupil image, however i viewed it--but in the actual outside view (garage doorjamb test) it has a typical amount of pincushion distortion (similar to what you have described in the past seeing in other large binos), much more so than the image in the exit pupil would lead one to expect to see! Maybe try it with one of your 20x80's and see if you can see the same thing happening... I'm stumped. Not that it really matters (as everything works fine in practice as far as i am concerned) but it's just one of those little optical anomolys that gets under one's skin, no?

--------------------
Mardi




4" achromat, ETX-70, 8"cat.
Whitepeak Lunar Observatory Website


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