Opinión on BT 82 binocular.

[tico]

Hello,
Currently I am looking for some information about the BT-82 XL binocular.
I would use it for deep sky observation at low magnification, and also for terrestrial observation, since to observe planets, for example, I have an SC 8" telescope. In your opinion, how would it work for these purposes?
I have a good Manfrotto photographic tripod and a Manfrotto 501 head to put on it.
You have used it to observe Messier objects, is the image good with sharpness and contrast?
What magnification do you usually use?
thank you so much
Best regards,

Edited September 8, 2023 by Cornelius Varley
background colour to text removed

[The60mmKid]

Hi,

Which make and model of 82mm binocular telescope are you referring to? There are a few different ones out there.

Edited September 9, 2023 by The60mmKid

[tico]

Hello,, 

Yes, is true!! 

For example, a Explore Scientific or APM.. 

 

[The60mmKid]

I've used 100mm and 70mm versions, so I can offer informed speculations about the 82mm. They are fantastic instruments, with a few things to keep in mind. Here are my opinions.

I think the 82mm would work well on a relatively heavy Manfrotto tripod (e.g., 475B) and with one of the continuous counterbalance heads (i.e., Nitrotech or the more recent ones).

The views are spellbinding from dark skies. I'd never noticed as much color in stars until I started using a binocular telescope. And the "binocular summation factor" is obvious. Everything looks significantly brighter than through a single telescope of the same aperture. With the 82mm, I would expect views similar in brightness to a 5" telescope but with the lovely, wide FOV and the huge added bonus of having both eyes open, which is so much more comfortable and engaging.

If I were to buy one again, which I might someday, I would purchase either from Oberwerk or Teleskop Service. They both have excellent customer service and stand by their products. APM does not. I learned this the hard way.

If you get a good sample (and, based on my own experience, I'd avoid APM if you want assurance of this), they offer sharp, contrasty views that excel on open clusters and bright nebulae and galaxies. Sitting and scanning around with them is utterly lovely... two eyes bathed in starlight.

In my experience, they get along best with eyepieces that have a ~60-70° FOV and that have smooth, not tapered, barrels. This makes it easier to seat the eyepieces correctly and merge images. I've used them up to about 100x. Past that, you may experience collimation/merging issues... This seems to vary depending on the instrument and observer.

I'd be glad to respond further if you have more questions ☺️

Edited September 9, 2023 by The60mmKid

[tico]

Thank you very much for your kind answer.
Out of curiosity, what models and brand do you have?
I imagine there will be a big difference between the 100 and the 70...!!
Did they have the eyepieces at 45° or 90°, in your opinion which of them works more comfortably for astronomical observation?
For a place with some light pollution, how do they work?
I have a more or less robust Manfrotto 055 tripod and a Manfrotto 501 head... I am deciding right now between the 82 and the 70... (the 100 seems more cumbersome and heavy for my support) and the balance is opting for the 82..., on the other hand I have an Opticron 15x70 with straight eyepieces. and I use it frequently, I love it even though it is achromatic, but above a certain altitude it is impossible to use it in a thorough and judicious way so as not to break my neck. I use it for astronomy, airplane observation and for land and birds. I like it more than observing with a telescope, it lacks "life" if I can say something like that...
How sharp and contrast are yours? Have you been able to use nebular filters to observe nebulae?
Please excuse me for such a long message.
I thank you very much for your advice, opinion and time spent answering my questions!!
Best regards.

Tico.

Edited September 9, 2023 by Cornelius Varley
background colour to text removed

[The60mmKid]

The models I've owned are the BT100XL-ED by Oberwerk and the 70mm SD-APO by APM. The Oberwerk was a 45° model, and the APM is a 90° model. I find the 90° models far more comfortable for viewing the sky. The 45° versions also demand a larger/sturdier tripod because you have to raise them up higher to view comfortably.

These are impacted by light pollution in the same way as any telescope... so, using eyepieces that yield a smaller exit pupil is a good strategy, and rich-field observing doesn't work as it would under dark skies. They are magnificent under dark skies.

My APMs are sharp and contrasty, but I had to get them serviced because of an initial quality control issue. Convincing APM to honor their warranty was not easy. But that's a different topic...

My preference is for 70mm models because they provide a wider max FOV,  which is what I want out of this instrument. There is a little less light gathering vs. 82mm, but I did not find the difference too significant when I compared them to a friend's Kowa Highlander Prominar.

I haven't used nebula filters with mine, but I could if I needed to. I usually prefer the unfiltered view, and I typically use 2" filters with a larger telescope when I do use filters.

Glad to help, so please let me know if you have further questions.

Edited September 9, 2023 by The60mmKid

[Barry Fitz-Gerald]

I have owned the APM 100mm binos and wanting a bit more aperture got the APM120SD's. They were/are both superb instruments for deep sky and lunar observing and are fare more comfortable to use than a telescope because of the two eye effect. Both had the extra collimating service that APM offer and performed brilliantly. The 100 was a nice size - large yet portable and well balanced for use on a sensible tripod. The 120's magnificent both in terms of light grasp and resolution but are extremely front heavy, just about portable and better suited to a semi permanent setup. Both are 90 degree eyepiece.

As an experiment I got an APM 82mm Semi Apo 45 degree - the collimation certificate states they were collimated up to x100. These were a big surprise, they are physically a bit like a miniature version of the 120's so quite long tubes, but very portable, and easy to mount on a Manfrotto Tripod 475B Pro tripod with a central crank. Being 45 degree ones central crank is pretty essential to view anything above say 60 degrees elevation - some may be able to manage it without a central shaft but not me with my dodgy neck. I did think I would manage with the  45degree ones - I could just view stuff low down or wait until objects rotated to a lower elevation, but for some reason all the good stuff turns out to be high up!  Being semi-apo, in other words achromats there is some false colour around brighter objects, but even on the moon it is not really distracting or to my eye all that apparent. But if you are a DSO hunter then this is where these binos come in to their own, either with OIII or UHC filters or without. The Veil nebula for instance is conspicuous without any filters, but with the OIII's a lot of detail can be seen. On open or globulars the view is again spectacular, and any CA there is is not really apparent. I use the APM 15mm or 18mm EP's with them and they are very good eyepieces, but I also use 12mm, 10mm and 6mm TV Delos (for some reason the 17.3 will not come to focus) and these provide more immersive views than the APM's.

As another experiment I got the APM 70MM SD's (90 degree) - these are very light, compact, and easy to mount, and the eyepiece placement is perfect for use at the zenith. Using the EP's mentioned above the views on the moon and brighter objects are noticeably sharper than the 82's, though on DSO's and clusters the difference is not hugely pronounced. I was rather surprised that with 6mm EP's the double double Epsilon Lyra was resolvable in moments of good seeing - not bad for a 70mm.

Putting this all together an 82mm SD version with 90 degree eyepieces would be the perfect compromise and hard to beat for astro use, superb light grasp, uber portable and if the SD optics on the 70's and 120's are anything to go by capable of sharp high resolution views on everyting including the brightest objects.

As mentioned above QC could be an issue with APM, but I am happy that what is stated on the collimation certificates that came with them is accurate (x180 on the 120's - but not that I ever venture in to that sort of territory with binos). Use at high power is more probably limited by wobble and settling of the OTA's and mount as you adjust the helical focuser as opposed to optical performance. One of 82mm Semi Apo unit I got needed to go back to APM because of a bulge in one of the optical tubes (which did not impact the optics) but the vendor I used dealt with this in a very pro-active manner and the replacement unit was collimated to a higher standard than the original.

Once you go down the bino route there is no going back - they make observing so comfortable and immersive that reverting to single eye use is a bit of a chore.

 

 

 

[bosun21]

18 hours ago, tico said:

Thank you very much for your kind answer.
Out of curiosity, what models and brand do you have?
I imagine there will be a big difference between the 100 and the 70...!!
Did they have the eyepieces at 45° or 90°, in your opinion which of them works more comfortably for astronomical observation?
For a place with some light pollution, how do they work?
I have a more or less robust Manfrotto 055 tripod and a Manfrotto 501 head... I am deciding right now between the 82 and the 70... (the 100 seems more cumbersome and heavy for my support) and the balance is opting for the 82..., on the other hand I have an Opticron 15x70 with straight eyepieces. and I use it frequently, I love it even though it is achromatic, but above a certain altitude it is impossible to use it in a thorough and judicious way so as not to break my neck. I use it for astronomy, airplane observation and for land and birds. I like it more than observing with a telescope, it lacks "life" if I can say something like that...
How sharp and contrast are yours? Have you been able to use nebular filters to observe nebulae?
Please excuse me for such a long message.
I thank you very much for your advice, opinion and time spent answering my questions!!
Best regards.

Tico.

Is it the ED version you are looking at or the Standard BT 82 XL?. I believe the later have now been discontinued and they are also achromatic.

[tico]

I think that it's the Standard BT 82 XL of Explore Scientific.. 

[tico]

But will I really and honestly be able to see the difference in the image between a 15x70 straight binocular, like the one I use, an achromatic Opticron, and one with a 45° or 90° 70mm binocular with the same magnification? And in this case I am not referring to the comfort of the neck but rather differences in the image...
I ask because there is a big difference in price.
Tico

Edited September 10, 2023 by Cornelius Varley
Background colour removed

[Barry Fitz-Gerald]

12 hours ago, tico said:

But will I really and honestly be able to see the difference in the image between a 15x70 straight binocular

From what I have experiences with the APM 82 Semi Apo's, which are essentially posh achromatic binos, the view through them is much much better than a dedicated pair of fixed eyepiece straight through binos. I would suspect that the objecctives of the 82's would be superior to say the usual big bino offerings in the 15x70, 20x80 category of instrument, but of course you pay for the difference.  And with the APM type you can use quality eyepieces - the ones that usually come with these APM's and their clones (but then again I guess the APM's are themselves clones!) are the 18mm UFF's with a 65degree FOV, and these give you a very wide and immersive view that makes using ordinary big binos a bit like looking down two toilet roll tubes - use better EP's like the Delos range and the views are even better. Being able to use different EP's gives you great flexibility. If you stepped up to ED or SD the optical performance is just a league above normal hand held binos.

So from my perspective normal straight through binos like 15x70's would be out classed by the semi-apo version (great on DSO's and star fields abd no slouch on the Moon) of these BT's and far outclassed by the ED's and SD's (which are great on everything).  But buying optical equipment is a bit like buying shoes, some things look great in the adverts, but for some reason they do not fit your eyes, your face or how you like observing.

 

[PeterW]

15x70 vs 70mm binoscope… there is a comparison thread on the CloudyNights bino forum now… short answer is yes!  It’s very obvious with my old Helios 15x70. The 70mm APM on a manfrotto 501 is possible if you always secure them on the lock, especially at high elevation- astro only , get the 90degree otherwise the 45degree. They are backpackable in the daytime and give huge wide views beyond normal bino powers. I use 12.5mm Morpheus for around 30x, though best for not changing location or moving about too much. Individual eyepiece focus is fine if you’re not constantly looking at different distance objects (in the daytime).

 

Peter

[tico]

I'm Looking this BT binoculars for astronomical use, but not only but planespotting, bird watch in sea, lake... Terrestrial. 

[Barry Fitz-Gerald]

45 degree on a central crank tripod then......................

[tico]

.. But on the other hand I think that those with 90° eyepieces are much better in terms of comfort for astronomical observation, as in any telescope we use, especially for zenith observations. , which is when the objects are best seen... the higher I mean!
Have any of you been able to compare 90° with 45°?
On the other hand, I already have some straight Opticron 15x70 that are good for terrestrial or not very tall raptors...
As for collimation, does either of them, 45° or 90°, have any advantages?
I mean, does one decollate more than the other, for example?
Best regards,
Tico

Edited September 14, 2023 by Cornelius Varley
reformatted to remove background colour to text

[Barry Fitz-Gerald]

21 hours ago, tico said:

Have any of you been able to compare 90° with 45°?

Yes - the 45 degree ones are a pain in the neck, literally for anything over say 50 degree elevation, getting your eyes square on the the EP's becomes more difficult with higher elevations. For terrestrial though they would be more comfortable than the 90's.

The 90's are ideal for astro due to the better eye placement at high elevations - for terrestrial they would be uncomfortable.

Optically I think they are the same - and I have never had a collimation issue with either the 45's or 90's, but I paid extra for the collimation service prior to delivery.

So, if you are just interested in astro use - I would suggest the 90's as the best fit, if you are mixed astro and terrestrial use such as birding then the 45's would be better.