Binoviewers in fl7 4 inch refractor

[Moonlit Knight]

Has anyone any experience of using binoviewers with a fl7 4 inch refractor, purely for solar system objects you understand. 
Do they help with floaters and what are the pitfalls with this type of telescope? Do I need to use them with a Barlow and what are your eyepiece selections? I intend to use them with a manual AZ mount. 
 

Floaters are starting to become very annoying. I like my outfit very much and would hate to get into reflectors, bigger scopes less floaters I have read. 

[Stu]

Yes, absolutely I do! Mainly for solar and lunar but also about 50/50 on planetary; sometimes I prefer single eyepieces.

I don’t tend to use them for low or mid power viewing, preferring single eyepieces, but for high power they are excellent. Whilst they don’t remove floaters completely, the do make them much less distracting as your brain has two signals to work with and processes them out to a large extent.

I am a bit of an odd ball in terms of eyepiece choice, so don’t listen to me! I tend to use 25mm ortho eyepieces then use a GPC and barlowed to get up to the mags I want. It works for me, but may not be everyone’s cup of tea. I’ve recently acquired some 10mm BCOs and have found these work very well too, requiring less barlowing of course.

In summary, binoviewers are a very personal thing. Some people love them, others can’t get on with them but I would definitely give them a try.

[MalcolmM]

I'm one who loves them. Pros are (for me): stunning views (almost 3Dish), very relaxed viewing. The cons are that they can be a bit of a faff to use; they are quite heavy leading to potential balancing issues, sometimes merging the images from each eye can be difficult, getting them to come to focus can be tricky due to their extra lightpath and changing magnification necessitates 2 eyepiece changes (though not the way @Stu does it)

I use ortho eyepieces mostly in a bid to minimise the extra weight.

I use them for low, medium and high power viewing. I don't use them all the time (I still enjoy mono as it's less fuss and arguably a slightly sharper view), but when I do use them, I go wow!

Malcolm 

[Don Pensack]

6 hours ago, Moonlit Knight said:

Has anyone any experience of using binoviewers with a fl7 4 inch refractor, purely for solar system objects you understand. 
Do they help with floaters and what are the pitfalls with this type of telescope? Do I need to use them with a Barlow and what are your eyepiece selections? I intend to use them with a manual AZ mount. 
 

Floaters are starting to become very annoying. I like my outfit very much and would hate to get into reflectors, bigger scopes less floaters I have read. 

It's important to learn where the images get compromised by floaters and simply stay away from there.

I also have a 102mm f/7 apo refractor, and I learned I can use a 4.7mm eyepiece (152x, 0.67mm exit pupil) and a 4mm (179x, 0.57mm exit pupil), but not a 3.7mm (193x, 0.53mm exit pupil) or 3mm (238x, 0.43mm exit pupil) on the Moon.

On planets, the 3.7mm becomes usable without floaters interfering, but not the 3mm.  And on double stars, the 3mm becomes usable.

For general viewing, though, I never go smaller than the 4.7mm's 0.67mm exit pupil.

 

Perhaps your floater problem is worse than mine.  If it is, I understand.  I have a good friend about my age who can't go below a 1mm exit pupil on the moon without floaters being a problem.

 

Shorter f/ratios yield larger exit pupils.  In my upcoming 16", that 3.7mm will yield a 0.86mm exit pupil at 474x.  in my 2.5" it yields a 0.64mm exit pupil at 493x.  That's the advantage of larger, faster, scopes--a brighter image at higher powers.

[Stu]

17 minutes ago, Don Pensack said:

It's important to learn where the images get compromised by floaters and simply stay away from there.

I also have a 102mm f/7 apo refractor, and I learned I can use a 4.7mm eyepiece (152x, 0.67mm exit pupil) and a 4mm (179x, 0.57mm exit pupil), but not a 3.7mm (193x, 0.53mm exit pupil) or 3mm (238x, 0.43mm exit pupil) on the Moon.

On planets, the 3.7mm becomes usable without floaters interfering, but not the 3mm.  And on double stars, the 3mm becomes usable.

For general viewing, though, I never go smaller than the 4.7mm's 0.67mm exit pupil.

 

Perhaps your floater problem is worse than mine.  If it is, I understand.  I have a good friend about my age who can't go below a 1mm exit pupil on the moon without floaters being a problem.

 

Shorter f/ratios yield larger exit pupils.  In my upcoming 16", that 3.7mm will yield a 0.86mm exit pupil at 474x.  in my 2.5" it yields a 0.64mm exit pupil at 493x.  That's the advantage of larger, faster, scopes--a brighter image at higher powers.

True enough Don, but if you have floaters and want to get to those higher powers in a smaller scope then binoviewers can really help. I regularly use 0.5mm exit pupils on the Sun and Moon despite having a few annoying floaters and they are much less intrusive when using both eyes.

[mikeDnight]

 I've used a binoviewer since 2008 and consider it the best accessory I've ever bought. In 2015 i bought a 100mm F7.4 refractor and the lunar and planetary views on a good night were simply awesome. I personally think the use of a binoviewer somehow reduces the effects of atmospheric turbulence as well as floaters, though I'm not sure if that's true.  The beauty of using a binoviewer of course is that you can use longer focal length eyepieces which adds to your comfort and a more relaxing view, as the eye relief is maintained.  A barlow or gpc attached to the nose of a binoviewer allows for higher power viewing  while giving a 3D effect, especially on lunar. The added distance between the eyepiece and Barlow increases the amplification by about 4X, so a 25mm pair will give around 120X give or take. An 18mm pair will give 165X etc when a 2X barlow is used.  In 2017 a friend came to check out my scope, a Tak FC100DC at the time; he brought with him a 5mm TMB Super Monocentric eyepiece and a Nagler of similar focal length. The night was pristine and the 5mm mono gave a view that appeard to be impossible to out class. I'd have offered him £500 just for that eyepiece if I'd had it lying around as it was so good. Then i removed the mono and replaced it with my cheap binoviewer and a pair of 16.8mm Kson Orthoscopics, equally cheap. You could have knocked me down with a feather as the apparently unsurpassable super mono got its backside kicked by a large margin. I'd been using the binoviewer for close to ten years, but it was only when using a top end eyepiece in the same scope on the same night that it hit home just what a massive game changer the bv actually was, especially when observing the Moon. 

 Floaters are definitely reduced. Perhaps that's because you're using both eyes, and both retinas, effectively doubling the sensitivity to detail and reducing the need to look through a pinhole eyepiece. Instead of only one eye resolving to the limit of a 4", you have both eyes resolving to the limit of a 4" and the effect can be glorious. The brightness does not decrease noticeably as you might imagine it would, at least when it comes to lunar, planetary and some brighter deep sky. Although the light beam is divided in the binoviewer, the combined retina sensitivity and just as importantly, the brain, receives practically all the light/information that enters the prism, so you still get the light grasp and resolution of a 4", only with better definition. At least that's the way I have come to understand it.

 I don't use expensive eyepieces for bino viewing. Good quality Plossl's or orthoscopics are all you really need, although there are many great eyepieces of other designs too. No need to buy Naglers and the like!

The uncapped pairs below are mainly old 5 element pseudo Masuyama's such as Celestron Ultima's, Parks Gold etc 35, 25, 18, 12.5, 10 & 7.5mm, apart from my trusty 16.8mm Kson ortho's.   (I rarely ever use the 12.5, 10, & 7.5mm).

 

[jetstream]

1 minute ago, mikeDnight said:

I personally think the use of a binoviewer somehow reduces the effects of atmospheric turbulence

It does, kind of.

Because of binocular summation and what this allows the brain to do things can be "averaged out" IMHO or definition actually increased as you say later on.  This and the "false exit pupil theory"  that come with binoviewing are an interest of mine.

[Moonlit Knight]

Thank you all for your input, it's really very much appreciated.

I was thinking of an WO one and TeleVue plossls, how does that sound? I am very open to suggestions. I think the WO comes with a x2 Barlow, so perhaps 15 and 11 mm for solar system objects? I use a manual AZ, a Gibraltar btw, does that change anything?

[Moonlit Knight]

Having just re-read what Mark said 25 and 20 mms plossls should be ample if I have understood correctly.

[jetstream]

1 minute ago, Moonlit Knight said:

TeleVue plossls,

They are excellent for binoviewing IMHO. I use the 32mm, 25mm in the Binotron 27's with the powerswitch. I also use the Tak 18mm, 12.5mm othos and like the extra bit of eye relief they give over plossls in this range.

[Franklin]

19 minutes ago, Moonlit Knight said:

I think the WO comes with a x2 Barlow

The WO set comes with a 1.6x nosepiece and a pair of WO 20mm wide eyepieces which work very well, it's a nice set. WO sell a separate 2x nosepiece but you'd be better just using the element from a shorty barlow.

[mikeDnight]

 I love my 25mm Parks Gold for lunar. I really don't think you can go wrong with the longer TV plossl's. 32, 25, 15mm. 

[Moonlit Knight]

I had a full set of TV plasma once, perhaps a decade ago, always liked them.

[Ricochet]

1 hour ago, Moonlit Knight said:

Thank you all for your input, it's really very much appreciated.

I was thinking of an WO one and TeleVue plossls, how does that sound? I am very open to suggestions. I think the WO comes with a x2 Barlow, so perhaps 15 and 11 mm for solar system objects? I use a manual AZ, a Gibraltar btw, does that change anything?

I suggest you buy the Baader Maxbright II instead as it is massively superior, both optically and mechanically. If you can’t afford/wait for the Maxbright, go for the OVL which is the same binoviewer as the WO with upgraded eyepiece clamps.

[Franklin]

12 minutes ago, Ricochet said:

go for the OVL which is the same binoviewer as the WO with upgraded eyepiece clamps.

I've got an OVL and I've had a WO and a Maxbright (1st generation) and to be honest, apart from a few cosmetic differences, the view through all three is the same. Maxbright II has larger prisms and greater clear aperture so performance will be better, whether that's worth the extra cost is a personal matter.

[Ricochet]

1 hour ago, Franklin said:

I've got an OVL and I've had a WO and a Maxbright (1st generation) and to be honest, apart from a few cosmetic differences, the view through all three is the same. Maxbright II has larger prisms and greater clear aperture so performance will be better, whether that's worth the extra cost is a personal matter.

I think it’s more than just the prism size. They’re sharper due with less ca, although maybe that’s due to using a gpc rather than a standard Barlow. The coatings are better and the baffling and edge blackening is better resulting in a reduction in reflections. 

Edited February 28, 2023 by Ricochet

[Don Pensack]

3 hours ago, Moonlit Knight said:

Thank you all for your input, it's really very much appreciated.

I was thinking of an WO one and TeleVue plossls, how does that sound? I am very open to suggestions. I think the WO comes with a x2 Barlow, so perhaps 15 and 11 mm for solar system objects? I use a manual AZ, a Gibraltar btw, does that change anything?

Caveat emptor!

The 2X GPC that William Optics makes adds chromatic and spherical aberration to the images.

The WO binoviewer is fine by itself, but you really need another GPC other than the WO one.

 

And, IMO, the 20mm WO eyepieces are not good.

I second Ricochet's remarks about the Baader.  The GPC is FAR better.

Edited February 28, 2023 by Don Pensack

[Highburymark]

Agree with pretty much everything above. I am now 100% binoviewing for solar WL and Ha, and lunar. About 50% planets. Good Plossls and orthos are perfect, unless you want width. And then - if you can stretch to the Baader Maxbright II over the WO - it’s a big step up. NOT - I hasten to add - in sharpness or quality of views on axis, but in pretty much every other respect. It bears repeating, the optical difference between a £180 and a £1300 binoviewer  on axis is very slim. But it’s vital to pick the right solution for your scope and needs. Binoviewers and associated eyepieces become as personal to the user as a pair of spectacles.

[RobertI]

I’m a big fan of binoviewers in my 102ED F7. I have the WO with the 20mm eyepieces and they transformed my viewing of planets, moon and sun. I use the Baader Classic barlow screwed directly onto the end of the nosepiece and get around 170x which I find perfect for moon and planets. With BVs I can spend so much longer viewing and teasing out those fine details. I have a massive ‘mesh’ floater in my left eye but it’s not much of an issue with BVs and I benefit hugely from using both eyes. Can also be used for doubles stars or lower power viewing of DSOs at 57x (it JUST reaches focus with the 1.6x GPC) but I prefer cyclops viewing for these.

[Paz]

I agree binoviewers would help with planetary. I have been binoviewing with a 102mm f7 reflector and various other scopes for a couple of years or so now and I prefer binoviewing when it is possible.

It can be a bit of a rabbit hole as there are many options but with a bit of research like this plus perhaps a bit of trial and error you should end up with a set up that you are glad you have.

[Moonlit Knight]

So first thanks again for the replies. I’m now thinking Baader and TV plossl. What else do I need to consider, a Barlow I am guessing, anything else? 
 

At the moment I am using 82 degree series 6.7 and 4.7 for planetary sessions. I use a manual AZ mount, I very much enjoy the long drift times. How much difference do we think binos will plossls will make to drift/nudge time 

[bosun21]

On 28/02/2023 at 17:08, Moonlit Knight said:

I think the WO comes with a x2 Barlow,

They are actually sold with a 1.6x barlow which is reportedly better optically than the more powerful 2x which is an optional extra.

[Space Hopper]

On 28/02/2023 at 20:46, Highburymark said:

Agree with pretty much everything above. I am now 100% binoviewing for solar WL and Ha, and lunar. About 50% planets. Good Plossls and orthos are perfect, unless you want width. And then - if you can stretch to the Baader Maxbright II over the WO - it’s a big step up. NOT - I hasten to add - in sharpness or quality of views on axis, but in pretty much every other respect. It bears repeating, the optical difference between a £180 and a £1300 binoviewer  on axis is very slim. But it’s vital to pick the right solution for your scope and needs. Binoviewers and associated eyepieces become as personal to the user as a pair of spectacles.

Yes, I'm with Mark here.

I bino-view nearly all the time, and just have the one scope now a 140mm refractor.

Comfort when viewing is the main reason, and i also enjoy rich field viewing natively with a pair of 24mm Panoptics.

If you can get hold of the Baader Max 2, do so. They are a really nice unit with the T2 compatibility. Also (and this is often overlooked imo) the eyepiece holders

on the Max 2 are just excellent and set the benchmark. Beautifully designed clicklock holders and diopter adjusters and nicer than the ones on the Mk 5 that I use.

Regarding eyepieces, check out APMs 65º flat field series. 

I have the 15mm, and they are really nice and great value as well.

 

https://www.apm-telescopes.net/en/apm-ultra-flat-field-15mm-eyepiece-65-fov

 

 

[cajen2]

3 hours ago, Space Hopper said:

Yes, I'm with Mark here.

I bino-view nearly all the time, and just have the one scope now a 140mm refractor.

Comfort when viewing is the main reason, and i also enjoy rich field viewing natively with a pair of 24mm Panoptics.

If you can get hold of the Baader Max 2, do so. They are a really nice unit with the T2 compatibility. Also (and this is often overlooked imo) the eyepiece holders

on the Max 2 are just excellent and set the benchmark. Beautifully designed clicklock holders and diopter adjusters and nicer than the ones on the Mk 5 that I use.

Regarding eyepieces, check out APMs 65º flat field series. 

I have the 15mm, and they are really nice and great value as well.

 

https://www.apm-telescopes.net/en/apm-ultra-flat-field-15mm-eyepiece-65-fov

 

 

I BELIEVE the StellaLyra UFF range is the same as the APMs (I know the 30mm is) and these would be cheaper than importing the latter.

[Space Hopper]

Yes, good call. They are the same.

Nice eyepieces.