Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

CN Report: Binocular Tests and Comparisons

This topic has been archived. This means that you cannot reply to this topic.
24 replies to this topic

#1 asaint

asaint

    Vanguard

  • *****
  • topic starter
  • Posts: 2,094
  • Joined: 25 Apr 2003

Posted 22 January 2006 - 09:22 AM

Binocular Tests and Comparison

#2 EdZ

EdZ

    Professor EdZ

  • *****
  • Posts: 18,849
  • Joined: 15 Feb 2002

Posted 22 January 2006 - 10:30 AM

This article is formatted and intended to be presented in PDF format. While this direct link above will take you to the review, if you wish to see the article appear in the composed and intended format, you should click on the "Download this Document" button at the top of the report.

thanks, and enjoy,

edz

#3 Glassthrower

Glassthrower

    Vendor - Galactic Stone & Ironworks

  • *****
  • Vendors
  • Posts: 18,572
  • Joined: 07 Apr 2005

Posted 22 January 2006 - 10:39 AM

Wow. Let there be no doubt who the authoritative binocular expert is. EdZ' contributions to the realm of binocular-astronomy cannot be under-estimated. A well researched and written article. Awesome job. :waytogo:

It's a shame the Celestron Skymaster sample in the tests exhibitied defective/faulty optics. I would have liked to see how a properly-functioning sample would compare against the others. Of course, I can probably envision how the testing of a "good" sample would have went - there is little doubt that the Skymaster is the lowest-price and lowest-quality of any of the binoculars on the list.

My first pair of Celestron 25x100 binoculars exhibited the very same optical defect that EdZ describes - the lack of pinpoint focus in one ep versus the other. Eventually, my diopters started to fall apart and I sent the unit back for warranty replacement. The replacement arrived in good condition, in short order, and free of any defects - including the mentioned lack-of-focus. I am quite happy with my new sample versus the original, but this experience of mine is only further proof that the build quality of the Celestron leaves something to be desired. Obviously, EdZ' sample was not a fluke, but may be more representative of the average Skymaster sample. I would be interested to hear from other Skymaster owners on this issue to compare notes.

Anyhoot, thanks again EdZ, outstanding article!

MikeG

#4 jake47

jake47

    Viking 1

  • -----
  • Posts: 540
  • Joined: 03 Mar 2004

Posted 22 January 2006 - 12:16 PM

Ed,

When I click on the "Download this Document" button I get a copy of the article about 100 binocular targets. I'm glad to have it, but I wanted to print a copy of the article that this thread addresses. All of your material on binoculars is helpful. I appreciate your sharing.

Is there a glitch in my browser? Thanks.

#5 EdZ

EdZ

    Professor EdZ

  • *****
  • Posts: 18,849
  • Joined: 15 Feb 2002

Posted 22 January 2006 - 12:38 PM

I notified Allister this morning

it has been fixed now. try again

edz

#6 photonovore

photonovore

    Moonatic

  • *****
  • Posts: 2,879
  • Joined: 24 Dec 2004

Posted 22 January 2006 - 02:47 PM

Ed, congratulations on the most thorough comparison report I have seen on cloudynights on *any* subject. Really outstanding. Wish all comparos were as well done as this.

#7 mplkn1

mplkn1

    Messenger

  • -----
  • Posts: 453
  • Joined: 28 Aug 2005

Posted 22 January 2006 - 11:15 PM

Ed -

My thanks for yet another fine piece of serious work combined with decent writing. I've just spent a very enjoyable hour working my way through this article.

My sincere congratulations on the degree of growth and increasing level of of scholarship displayed in your writing.

As an academic librarian I see a lot of very good and very bad writing. I sense in your work a trajectory carrying you toward an increasing degree of scholarly effort, and I extend my heartiest encouragement to you in your efforts. Even if we were to understand your target community to be the worldwide readership of CloudyNights, your work is attaining evident and increasing significance.

But quite beyond this, I sense that you are finding yourself drawn into deeper waters. I would encourage you, should you feel so drawn, to find an editor worth his or her salt and set your sights upon a broader audience - unless, that is, you feel that the only readers who matter are already here!

More seriously, the best thing I can say, sir, is keep going! Every new example is a pleasure.

Many sincere thanks,

#8 GLR GROUP

GLR GROUP

    Vostok 1

  • -----
  • Posts: 198
  • Joined: 22 Mar 2004

Posted 23 January 2006 - 04:41 AM

Great, great Review Edz!
Clear Skies
Piergiovanni

#9 EdZ

EdZ

    Professor EdZ

  • *****
  • Posts: 18,849
  • Joined: 15 Feb 2002

Posted 23 January 2006 - 08:41 AM

Thank you very much for all these wonderful comments. It is these kinds of responses that certainly lead me to spend even more efforts on this type of work. If only I didn't have a day job.

edz

#10 Guest_**DONOTDELETE**_*

Guest_**DONOTDELETE**_*
  • -----

Posted 23 January 2006 - 06:00 PM

I'm not new to astronomy, but fairly new to binoculars, and loved the review. I have "bino-fever" of late, and am looking to get a set of 20x80 (or 15/30x80) binoculars. I have had good luck with Orion products, and have a 15x63 pair from Orion now. These are good, but do not have great edge of field clarity.

However, Orion started advertising some 20/30 x 80 mm "MegaView" binoculars they say have improved edge-of-field sharpness. I also noticed they are much more expensive than some other 80 mm binos. I am wondering if anyone has had experience with these and if they are worth the extra cost? I'd pay for better edge-of-field viewing.

Songstar

#11 spaceydee

spaceydee

    James Webb Space Telescope

  • *****
  • Posts: 17,634
  • Joined: 16 Apr 2004

Posted 23 January 2006 - 06:26 PM

Hello songstar, welcome to cloudy nights!

For your info, there is a binocular forum if you look at the "Main Index" of fora here. Also, there is a search feature where you can try to see if there have been discussions on these binoculars using a keyword search.

#12 Fiske

Fiske

    Fly Me to the Moon

  • *****
  • Posts: 6,684
  • Joined: 14 Mar 2004

Posted 23 January 2006 - 10:43 PM

EdZ:

You HAVE been busy! :) Another fine addition to the CN Reviews section. If CN doesn't have the finest selection of astronomy binocular reviews available anywhere, I would like to know who does. You've contributed more than your share in this regard Ed. Great job!

If I weren't busy building a 22-inch Dob, I would have to take a close look at the Oberwerk BT100s...

#13 Mitrovarr

Mitrovarr

    Aurora

  • *****
  • Posts: 4,586
  • Joined: 12 Sep 2004

Posted 25 January 2006 - 12:46 AM

I noted a problem when I was reading this:

So for a 100mm objective, rather than (nominal) 10,000 sq mm, in a binocular the effective area for information gathering is 12,000 sq mm or 14,000 sq mm or the equivalent of what would be delivered from as much as a 118mm aperture.


100mm objectives don't have an area of 10,000mm^2, that's the area they'd have if they were 100mm x 100mm square. They have an area equal to pi*r^2, or something like 7800mm^2. That gives an effective area of ~9400mm^2 for two lenses (assuming the +20% bonus you gave is correct), and an effective aperture of 109mm. Taking the +40% you list for contrast increase, the effective area is ~11000^2 and the effective diameter is 118mm. So you had the right effective aperture, assuming you did your calculation for 40%, but the areas listed were off.

It probably doesn't matter with regard to the review's material, but I thought I'd mention it.

#14 sjs42

sjs42

    Explorer 1

  • *****
  • Posts: 65
  • Joined: 07 Oct 2004

Posted 25 January 2006 - 11:26 AM

I agree. A book on the subject, authored by Ed Z would be most welcome. It's written already, really. It just needs to be organized and edited.

#15 EdZ

EdZ

    Professor EdZ

  • *****
  • Posts: 18,849
  • Joined: 15 Feb 2002

Posted 25 January 2006 - 12:39 PM

Actually this presents no problem at all. It is common practice to use nominal area (and not go thru the Pi R squared calculation) when "comparing the area" of circular lenses. As you will see if you perform the calculations both ways, all the results will come out exactly the same so it eliminates an unnecessary calculation and adds simplicity to an already difficult subject.

edz

#16 lighttrap

lighttrap

    Soyuz

  • *****
  • Posts: 3,833
  • Joined: 06 Feb 2004

Posted 26 January 2006 - 04:23 PM

Outstanding article, Ed. You keep raising the bar. You're bringing a level of professionalism to amatuer gear reviewing that I'd like to see brought to the reviews of other consumer products. I've rarely read such detailed comparisons even on expensive items like cars. Keep up the good work.

Mike

#17 chasd

chasd

    Lift Off

  • -----
  • Posts: 5
  • Joined: 27 Jan 2006

Posted 27 January 2006 - 02:40 PM

Very interesting and well written review. I saw a minor error that I thought was a typo, but it occurs twice. Do you really have a 47 1/4 inch refractor ( 1200mm ) ? Common sense says it is likely a 120mm refractor. It appears the same mistake is in the article "Binocular Mounts, Tripods & Mounting."

Charles Dostale

#18 EdZ

EdZ

    Professor EdZ

  • *****
  • Posts: 18,849
  • Joined: 15 Feb 2002

Posted 27 January 2006 - 03:22 PM

1200mm, that would be the focal length of my 6" refractor, which I would sometimes list as 150/1200. But in this case, "The BT100, at 26# (12kg), is heavier than my largest telescope, a 1200mm f8 6" refractor.", I think is pretty self-explanatory.

edz

#19 kulginov

kulginov

    Explorer 1

  • -----
  • Posts: 55
  • Joined: 10 Nov 2005

Posted 06 February 2006 - 06:46 AM

Ed,

There is a Bogen/Manfrotto spreader that is supposed to use with all their tripods. Do you have any experience with it? Does spreader improve stability of a tripod?

Dmitri

#20 EdZ

EdZ

    Professor EdZ

  • *****
  • Posts: 18,849
  • Joined: 15 Feb 2002

Posted 06 February 2006 - 04:41 PM

I have three different Bogen spreaders. They are good for keeping legs from splaying outward, for instance as when using surveyor tripods on a hard surface, but I don't think they really add too much to stability.

edz

#21 Phil Wheeler

Phil Wheeler

    Vanguard

  • -----
  • Posts: 2,086
  • Joined: 31 Dec 2005

Posted 06 February 2006 - 09:11 PM

I have three different Bogen spreaders. They are good for keeping legs from splaying outward, for instance as when using surveyor tripods on a hard surface, but I don't think they really add too much to stability.


I agree re the spreaders that just attach to the legs (as on my surveyor's tripod). But the spreader (if that's what it's called) on my Bogen 475 attaches the center post to each of the three legs, vs. floating. That really adds stability to the tripod.

Phil

#22 kulginov

kulginov

    Explorer 1

  • -----
  • Posts: 55
  • Joined: 10 Nov 2005

Posted 07 February 2006 - 03:28 AM

Thanks Ed.

Dmitri

#23 EdZ

EdZ

    Professor EdZ

  • *****
  • Posts: 18,849
  • Joined: 15 Feb 2002

Posted 07 February 2006 - 11:14 AM

I agree re the spreaders that just attach to the legs (as on my surveyor's tripod). But the spreader (if that's what it's called) on my Bogen 475 attaches the center post to each of the three legs, vs. floating. That really adds stability to the tripod.

Phil


Agreed Phil,

The center brace on Bogen camera tripods such as the 3246, the 475 or the Manfrotto 028B, provides much more stability than the snap-on leg spreader that is attached to surveyor tripods.

If you can jiggle the spreader bars around once your tripod is set, the spreader is doing absolutely nothing to improve the stability of the tripod.
One way to increase the benefit of the snap-on spreader is get your legs spread, lock the adjustable spreader, then pick up the tripod and reset the legs, spreading the feet apart that final half inch or so to put tension on the Bogen spreader.

edz

#24 EdZ

EdZ

    Professor EdZ

  • *****
  • Posts: 18,849
  • Joined: 15 Feb 2002

Posted 22 April 2006 - 10:59 AM

A recent queery led me to recheck the IPD of the Garrett Optical 20x80 Gemini. In my article I listed it as 61mm to 71mm. It is actually 61mm to 74mm.

Although the prism housings and the eyepiece assemblies appear exactly the same on the Garrett Optical 20x80 Gemini and the Oberwerk Giant 25x100, the Oberwerk 25x100 is limited to 71mm wide IPD at the upper end. The Garrett 20x80 extends to 74mm.

The difference has to do with the length of the hinges conneting the two barrels at the prism housings. The hinge bars are several mm longer on the Oberwerk, which means they come together at the widest IPD setting limit just a bit before the Garrett does.

Sorry for the slip folks.

edz

#25 Glassthrower

Glassthrower

    Vendor - Galactic Stone & Ironworks

  • *****
  • Vendors
  • Posts: 18,572
  • Joined: 07 Apr 2005

Posted 22 April 2006 - 11:43 AM

Sorry for the slip folks.


We'll let it slide this time! Just don't let it happen again! ;)

MikeG


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics