Optical Quality versus aperture for deep space observations

[Astro_noob]

There are a lot of people that advocate buying the best you can afford and others that advocate buying the largest aperture you can comfortably afford. In some cases these two opinions conflict with each other. I have a theoretical limit for a new binocular purchase of about £150-£200. I want to view open clusters, galaxies, nebula and asterisms. I already have a perfectly adequate 7x35 (Nikon action extreme) so I am looking to introduce a larger binocular. Minimum magnification is 10x.

I am drawn to purchasing a high quality optic and not one of the “good value” Chinese optics that are flying off the shelves but have far too many issues with collimation and optical aberrations. I have experienced an example of this when I purchased and subsequently returned a used pair of Celestron 15x70 as they were out of collimation. Still the view through them when I squinted was nice. I tried a pair of 20x80 but no matter how much I tried to like them they just didn’t blow me away. I sold them for a little under what I paid for them (£80). I now have a pair of 7x35 which seem to give a bright and comfortable image in comparison to the previous binoculars.

This leads me to believe that optical quality is a very important factor in actual resolution as well as how much can be seen. With the 20x80 I was able to see the cluster M13 as a bright mass of stars but I cannot see the same with the 7x35. Is it therefore possible to buy optics of a smaller size such as 10x50 that will offer similar views or better than a larger pair of binoculars such as 15x70 or 20x80? For example with a BA8 series 10x50 resolution and sharpness provide comparable views to a budget collimated Chinese 15x70 or 20x80?

It would be good to hear from those individuals with real experience as this will help me choose wether or not save that little bit extra and wait for the more expensive optics!

Cheers,

Astro_Noob

[Bart]

I can't help you very much I'm afraid as I only use my binocs now and again. But you raise a very good question, well put.

I'm sure some experienced binoc users will help you here

Hope they don't say big aperture, good quality binocs!!!€!€!€!€!

Barry

[Naemeth]

Is there a particular reason you are choosing a binocular over a telescope? Once you get above 15x70s, the cost starts to rocket, the binoculars become heavier and more expensive to mount and start requiring a P-Mount or angled eyepieces (which aren't cheap!). For less than a pair of 15x85 Helios Apollo binoculars you could get an 8" dob which would outdo it in DS work.

[Astro_noob]

yes there is a very good reason, portability. My 200p on eq 5 is a monster and requires regular collimation. My 60mm refractor is lighter but takes time to setup and binocs are so much quicker. I also like the fact I don need to setup a eq mount just a tripod or if I'm feeling particularly lazy slouch on a chair resting my arms on the armrest while balancing the binoculars. This is another reason for opting for 10x50 since they are lighter. My worry is that between 10x and 7x I will see little benefit. However if good optics mean that I will actually see more through A high quality 10x50 than a similarly priced 15x70 or 20x80mm (of course I understand that magnification is a factor here).

[michael.h.f.wilkinson]

This is really not an either/or issue. I love my 15x70 Helios Apollo (not cheap, but highly recommended) to bits, but it is no replacement  for my 8" scope, or for that matter my 80mm F/6, which is a stunning wide-field scope, when a 31T5 or 22T4 Nagler is inserted. The Helios Apollo (BA-8 type) is above your listed price range, but it is a lot better than the Celestron 15x70 (BA-1). The former is a true 15x70, whereas the latter is around 64mm in real aperture. You could look at a 10x50 in the same line-up (sold as WO ED 10x50 from FLO, but also available from APM and TS as "Marine-HD"). These are reported to be very good. 

[michael.h.f.wilkinson]

BTW, you can always build your own p-mount, if desired. 2-3 minutes set-up time in my case

[Scooot]

http://www.firstlightoptics.com/william-optics-binoculars/william-optics-10x50-7x50-ed-binocular.html

I had a pair of 8x48 Jessop biniculars but wanted a better pair so my family clubbed together and bought me the above William Optics 10x50 for Christmas.They are much better in all respects, brighter image and sharper views. I still don't get what I'd describe as pin point views of everything but I think that's because of other considerations, particularly my eyes, but they are noticeably better and I'm very pleased with them.They are much heavier than I imagined so I'm quite pleased I didn't opt for larger ones.

I havent used larger bins but the image will obviously be brighter, but if the optics aren't as good, not so sharp, so I'd imagine its a bit of a trade off and down to what's most important to you. I have mine for wide field views, portability and to quickly use in partly cloudy skies. If I want to view detailed deep space etc I'll use my scope.

[michael.h.f.wilkinson]

I agree about the "non-pinpoint" view. The view through my APM triplet with Nagler 31T5 at 15.5x was noticeably sharper than through either the Helios Apollo 15x70 HD or a Vixen ARK 20x80. The scope with EP costs more than both bins put together, so that is understandable.

[Naemeth]

yes there is a very good reason, portability. My 200p on eq 5 is a monster and requires regular collimation. My 60mm refractor is lighter but takes time to setup and binocs are so much quicker. I also like the fact I don need to setup a eq mount just a tripod or if I'm feeling particularly lazy slouch on a chair resting my arms on the armrest while balancing the binoculars. This is another reason for opting for 10x50 since they are lighter. My worry is that between 10x and 7x I will see little benefit. However if good optics mean that I will actually see more through A high quality 10x50 than a similarly priced 15x70 or 20x80mm (of course I understand that magnification is a factor here).

Fair enough, but how come you use an EQ mount for it? Surely a dob mount would be much easier to use in this situation .

I think you should probably be aiming for a high quality pair of 15x binoculars .

[astronymonkey]

Hi,

There is a term in the Hotrod car scheme that "Theres no replacement for displacement" and I suppose the same goes for aperture when it comes to visual observing.

Ive managed to compare ED binoculars side by side with their standard glass cousins and I was really suprised at how much sharper they seemed on terrestrial objects but when it comes to looking for faint deep sky objects I think the extra light gathering of a bigger objective would win every time. Even with the increased contrast of better glass I think the larger objective would simply pull in more light to make the object simply brighter in the first place.

Cheers

[Moonshane]

yes there is a very good reason, portability. My 200p on eq 5 is a monster and requires regular collimation. My 60mm refractor is lighter but takes time to setup and binocs are so much quicker. I also like the fact I don need to setup a eq mount just a tripod or if I'm feeling particularly lazy slouch on a chair resting my arms on the armrest while balancing the binoculars. This is another reason for opting for 10x50 since they are lighter. My worry is that between 10x and 7x I will see little benefit. However if good optics mean that I will actually see more through A high quality 10x50 than a similarly priced 15x70 or 20x80mm (of course I understand that magnification is a factor here).

could you not get a small alt-az mount (like a mini giro) and add to your tripod? you could then use your small frac which would be a better option, with a lot more flexibility I'd think.

[Alien 13]

A long time ago i had the pleasure of looking through some military hardware it was a sighting scope of some sort about 60-70 mm objective the eyepiece diameter was something like 2.5 inches, it was a compound design with quite a low overall magnification X6 or 7 and the whole thing weighed in at about 5kg.

The views through this scope where amazing it was like looking at the sky with the brighness and contrast turned up there was never a thought that i was looking through a piece of glass pin sharp edges no distortion no CA in fact nothing that told you that it was a scope image.

I would imagine something like that would have cost 20-40K in todays money (i worked in the defence industry for 20 years so i get to know costs) but it proved to me that optical quality is the defining factor in any scope or binos.

Ive been on a quest for many years trying to find one but to no avail.

Alan

[RT65CB-SWL]

I would go with Moonshane's idea. You get the flexibility and benefits of bino's and a 'scope.

My TeleVue Ranger (70mm) is operational in <10 minutes (allowing for it to reach ambient temprature when mounted on my Giro mount), either on its own or alongside my ETX105 or C6/SCT. I do you use 20x80 or 7x50 bino's too, though not on the same mount at present, and I understand your reason(s).

[Astro_noob]

Unfortunately it's not that small at 900mm so isn't really a grab and go kind of scope. It's also an older circle T 0.965" scope which does well with planets but can't do DSO too well. I am really only interested in quality binoculars for those nights that I want to take a quick look.

[SteveNickolls]

Interesting question Astro_Noob. I have a pair of Helios Apollo 15x70's and Pentax 20x60 PCF WP II's. I suppose they are both considered decent binoculars and I have loved comparing the views through them on different objects. While the Apollo's have the largest aperture by 10mm the Pentax have the greater magnification, edge to edge sharpness and are useful for seeing more magnified detail in specific objects. The views I have had for example of M34 and the Perseus Double Cluster using the Pentax have been magnificent. I use the Apollo's as my main observing pair but love to savour select views through the Pentax.

Cheers,

Steve

[Astro_noob]

Steve I have owned a pair of the Helios Apollo 15x70 however due to a defect in the optical coatings they were returned and I received a full refund. I used the refund to buy my 200p and eq5 so I have no complaints. I did feel the 15x70 was robust and had a good field of view but crucially I felt the interpuppillary distance at the minimum setting was too wide for me. I also felt the binocular was very heavy. I had a pair of Revelation Astro 20x80 in the past and they weighed the same as the Apollo 15x70, both require a very substantial tripod. I feel the Apollo 15x70 is a little too large for my type of viewing, quick and brief when the clouds part and reveal the stars. There usually isn't enough time to get out the scope but just enough to bring out binoculars. 

I am very interested in your opinion of the Pentax 20x60 as this is really my ideal binocular! At 20X it will show enough detail to satisfy me and at 60mm with fantastic coatings can keep up with light throughput of larger 70-80mm binoculars, or so I have read. My only concern is the weight, interpupillary distance and narrow field of view and optical quality compared to the BA8 series?

Thanks,

Richard.

[rowan46]

to be frank at 150-200 they will not be quality they may be good but quality is a step up from good. I'm a quality over quantity sort of guy myself I have a decent pair of 20 x 80 which I never use or a quality set of 8x 42 which I do use. If I want low power I have a triplet 80 apo which blows the 20 x 80 bins out of the water it's more comfortable because it has a diagonal and it has better views because it is better glass. If I don't want to use a tripod I use the 8x42 binoculars not alpha glass perhaps but a very significant step up from any other bins I have owned, definitely quality  but maybe not top quality. Good optics may not give you the most light compared to larger apparture but they present it in a more pleasing way, fewer irritating abberations and just easier on the eyes. When it comes to binoculars I would choose optical quality over quantity, its just more comfortable. The ba8's that michael mentioned are quality by the way they are amongst the best bins that the chinese make and that isn't damning with faint praise.

[Astro_noob]

Would a pair of William optics 10x50 (ed) offer better views in terms of quality than a pair of pentax pcf wp or a pair of opticron imagics? If the imagics equal the view of the BA8 then maybe the savings are worth it?

[Scooot]

http://www.allbinos.com/allbinos_ranking-binoculars_ranking-10x50.html

Can't comment on the comparison with pentax or opticron but this might give you a bit more feedback if you haven't seen it.

I liked the individual focusing of the WO, but they are the heaviest although quite comfortable to handle. They seem very well made as well.

[michael.h.f.wilkinson]

Individual focusing is really what you want in astronomy. Set the thing to infinity and NEVER change focus again. If you also want to do some birding, central focus is preferable

[Alfian]

Hi - I have the (BA8) WO10x50EDs and like them very much. Big ,sturdy and beatifully made with great optics and a treat to use. I tend to get the tremors holding any binos for long, but I think the weight of the WOs damps this down a lot so its fine for a quick look/see. However a monopod really does make a difference and is ultra portable. Individual focus is great for astro work, once set up - very little changes - but would be hard work for terrestial viewing if constant changes were needed.

The Pentax 20x60s are interesting - have quite a "giant killer" reputation IF you can cope with 2.2 degree fov. Have played with the idea of them myself. The Apollo 15x70 are inevitably cited as the ones to go for and for all the right reasons - reputedly only a gnats whisker off a Fujinon.

I tried some Barr & Stroud Savannah 10x56EDs (United Optics BW3s I think) and they were impressive. Bright, contrasty and sharp. Big for roof prisms but really nice to handle. They also do a 12x56ED which could make for an interesting bino - but never seen a review of them.

[clubjoker]

If you've got a mount of some description, then magnification is as important as aperture. There are various measures of binoculars' effectiveness: it's some combination of aperture, magnification, and optical quality.