Best Orthos to use with Binoviewer for Planetary/Lunar Observations with an Apo Scope?

[paulastro]

I've been very specific in the title of this post as I'm interested in hearing from anyone who has used Orthos in a binoviewer for this specific purpose.  I will not use the eyepeices alone, so I'm only interested in the images they give when used in a binoviewer.  As I'm writing this I'm thinking that there probably aren't that many bad Orthos around (if any), but they do vary in price, so presumably the price difference reflects some real differences.  In a search of Orthos currently available in the Uk the price varied from £29.00 to £89.94.  I'm happy with the pair of Orthos I have (16.8mm Kysons) which I use with my Takahashi FC 100 DL, and want some that will give a slightly lower power when used with my x2 barlow.

I've deliberately not mentioned the binoviewer I use, or the barlow, as I'm not interested in changing either - unless there is a readily available lower power barlow that may do the trick.  The Kysons give fabulous images with the Tak and am very happy with the images I get with them.

Many thanks for sticking with my rather long-winded post!! 

[jabeoo1]

I am sure Mike & Stu will help you out here Paul ! 

[Mark at Beaufort]

Paul I used 18mm Fujiyama Orthos in my binoviewers which were quality EPs. Unfortunately I found the eye relief too tight for comfortable viewing so I sold them. In the end I just preferred Plossls with a larger eye relief.

[Star Struck]

I currently use 18mm and 12.5mm BGOs in my binoviewers and the view is excellent. I do not have a problem with the eyey relief but other people do.

I was thinking of trying a pair of 25mm Orthos, but I already have a pair of 25mm TV plossls that work fine so I doubt I will ever get around to trying it.

Tony

[Stu]

I'm not vastly experienced with binoviewing for lunar or planetary observing. They just don't work for me for Planetary and I often still use cyclops for lunar, although I want to change that.

I have a few pairs of eyepieces, but always come back to my favourites which are 25mm Zeiss 'Orthos'. I use quotes around the Ortho because they are actually ex microscope eyepieces which converters fitted to take them to 1.25" fittings.

I just find that they beat anything else I use, especially for white light solar, and they Barlow to ludicrous multiples, at least x4 with an AP Barcon and extension tubes. Low scatter, nice big exit lens and good eye relief.

I'm sure there are plenty of other options out there, but these certainly work for me.

[paulastro]

36 minutes ago, Mark at Beaufort said:

Paul I used 18mm Fujiyama Orthos in my binoviewers which were quality EPs. Unfortunately I found the eye relief too tight for comfortable viewing so I sold them. In the end I just preferred Plossls with a larger eye relief.

Many thanks Mark.  That's interesting, the Fujiyama Orthos were the most expensive I have come across so far available in the UK, at £89.  The eye relief of the 18 and 25 are 15.2 and 22.2 which may be ok if I go for one of those.  Thanks again.

[paulastro]

36 minutes ago, Star Struck said:

I currently use 18mm and 12.5mm BGOs in my binoviewers and the view is excellent. I do not have a problem with the eyey relief but other people do.

I was thinking of trying a pair of 25mm Orthos, but I already have a pair of 25mm TV plossls that work fine so I doubt I will ever get around to trying it.

Tony

Thanks Tony, are the BGOs still available?  I did come across the Baader Classics in my search.

[paulastro]

21 minutes ago, Stu said:

I'm not vastly experienced with binoviewing for lunar or planetary observing. They just don't work for me for Planetary and I often still use cyclops for lunar, although I want to change that.

I have a few pairs of eyepieces, but always come back to my favourites which are 25mm Zeiss 'Orthos'. I use quotes around the Ortho because they are actually ex microscope eyepieces which converters fitted to take them to 1.25" fittings.

I just find that they beat anything else I use, especially for white light solar, and they Barlow to ludicrous multiples, at least x4 with an AP Barcon and extension tubes. Low scatter, nice big exit lens and good eye relief.

I'm sure there are plenty of other options out there, but these certainly work for me.

Many thanks Stu, I actually came across these in my search for information, though if available, they may be hard to get or too expensive for me I guess.  The report I read on them was very complimentary. 

[Star Struck]

14 minutes ago, paulastro said:

Thanks Tony, are the BGOs still available?  I did come across the Baader Classics in my search.

BGOs are only available in the used market. However, Fujiyama HD or Astro Hutech orthos are said to be almost identical.

You could post a wanted ad on here  and see what turns up.

 

Tony

[John]

If you wanted to push the boat out a bit the Takahashi Abbe Ortho's seem to get very good feedback

They do 25mm and 32mm in that range.

 

[Moonshane]

I use 18mm Baader classic orthos in my bvs and they are superb for my uses, lunar, solar and planetary.  In fact I thought about a couple  of 11mm TV plossls to go with my 25mm / 15mm pairs but decided to save myself around  £90 for a used pair and buy a used 10mm BCO to make a pair with the one I have already.  ER is short but easier than the 11mm plossl I used to have.  I rate them highly.

[jetstream]

I find where the exit pupil ends up with a barlow or OCS to be a big factor. With my refractors the 18mm Tak orthos give superb views- but with challenging eye placement depending on my powerswitch setting (pushes exit pupil out). Oddly enough the faster dobs don't have the issue and seem to suck the exit pupil in(?).

Eventhough the symmetric plossls might not have the technical "sharpness" of an ortho- they still provide excellent views and the shorter eye relief inherent to the design can be used to "tune" the set up for viewing comfort if need be.

For me comfortable viewing is a must have with binos.

[dweller25]

Hello Paul,

I use a pair of 18mm Fujiyama Orthos in by Binoviewers, I can still wear my glasses when viewing with them, so eye relief is decent.

I am visual planetary and find they give low glare and high contrast views.

Hope that helps.

[paulastro]

20 hours ago, Star Struck said:

BGOs are only available in the used market. However, Fujiyama HD or Astro Hutech orthos are said to be almost identical.

You could post a wanted ad on here  and see what turns up.

 

Tony

Many thanks Tony, that's a good idea, I just need to make sure of what focal lengths I need.  Thanks again.

[paulastro]

20 hours ago, John said:

If you wanted to push the boat out a bit the Takahashi Abbe Ortho's seem to get very good feedback

They do 25mm and 32mm in that range.

 

Many thanks John, though I don't think I can push the boat out that far

[paulastro]

19 hours ago, Moonshane said:

I use 18mm Baader classic orthos in my bvs and they are superb for my uses, lunar, solar and planetary.  In fact I thought about a couple  of 11mm TV plossls to go with my 25mm / 15mm pairs but decided to save myself around  £90 for a used pair and buy a used 10mm BCO to make a pair with the one I have already.  ER is short but easier than the 11mm plossl I used to have.  I rate them highly.

Many thanks, that's really useful information.

[paulastro]

14 hours ago, jetstream said:

I find where the exit pupil ends up with a barlow or OCS to be a big factor. With my refractors the 18mm Tak orthos give superb views- but with challenging eye placement depending on my powerswitch setting (pushes exit pupil out). Oddly enough the faster dobs don't have the issue and seem to suck the exit pupil in(?).

Eventhough the symmetric plossls might not have the technical "sharpness" of an ortho- they still provide excellent views and the shorter eye relief inherent to the design can be used to "tune" the set up for viewing comfort if need be.

For me comfortable viewing is a must have with binos.

Many thanks Gerry.  That's really useful.  As I'm looking for a lower power than my 16.8s give the comfort factor is ok for me.  I have to keep my specs on during observing (astigmatism in both eyes) and even with my 16.8s I don't have a problem in this respect.  Thanks again.

[paulastro]

11 hours ago, dweller25 said:

Hello Paul,

I use a pair of 18mm Fujiyama Orthos in by Binoviewers, I can still wear my glasses when viewing with them, so eye relief is decent.

I am visual planetary and find they give low glare and high contrast views.

Hope that helps.

Many thanks David, that really does help.  I have a pair of 19mm Wide Eye Relief eyepieces which I currently use as a lower power option to my 16.8s, but they don't really cut the mustard as they are not as sharp as my Orthos.  I certainly have some thinking to do, thanks again.

[paulastro]

Many thanks to everyone for all your replies.  They have all been very informative, and most helpful, and amongst all your replies there is certainly all the information I need to make some decisions.    Many thanks to all of you. 

[YKSE]

I have 25mm takahashi ortho and 18mm BCO, my planetary bino-EPs so far, combined with 3 GPCs, after or in front of diagonal (T2 prism and 2" prism), I have the 1,2x to 3.8x barlow effect, covers all I needed with 120ED or C8.

Takashshi ortho has very good build quality, recess eye lens, and eye cup, snap to focus better than BCO, scatter controll is a tad better than 18mm BCO which is already very good.

coping with long ER varies a lot among observers, as I understand it. I binoview without glasses as I find too much glare from the glasses. and I have no difficulty holding right eye position with 3.8x GPC effect, and standing, while some may need be seated with a somewhat longer ER.

[YKSE]

21 hours ago, YKSE said:

I have the 1,2x to 3.8x barlow effect, covers all I needed with 120ED or C8.

Actually that's not toally correct, the upper GPC effect I've measured is 4.7x

 

[paulastro]

4 minutes ago, YKSE said:

Actually that's not toally correct, the upper GPC effect I've measured is 4.7x

 

Many thanks for the update.  Alas I haven't the luxury of GPCs and have to make do with a single barlow .  The good news is that it still works very well, even if it's not so flexible .

[YKSE]

Paul,

I don't know how flexible your barlow is, if it somehow can be placed in front of the diagonal, then you'll get much higher barlow effect.

The 2.6x GPC is only 2.5x when placed directly in front of the binoviewer, it becomes 4.7x when placed in front of the 2" prism diagonal as in the picture.

 

[Stu]

Do GPCs not correct for CA caused by the Binoviewer prisms as well?

[Moonshane]

Yep