Orthoscopic Alternative

[MrCit]

As you can guess from my signature, my primary scope is an 8 inch f/6 dob. I started observing with this scope a couple years ago, and my first eyepiece purchases were from the Celestron X-Cel LX line. I especially like the 7 mm, and I used this eyepiece for almost all my planetary viewing (and doubles, etc. when I need high power).

At the end of last summer, I got a 6 mm Baader Classic Ortho, and it was a revelation. I love the sharpness of this eyepiece for planets. I don't really mind the narrower field of view, and I don't even mind the fact that it feels like I have to put my eyeball right on to the glass to use it. That is, I don't mind these things except for the fact that: 1. I tend to get the eyepiece dirty with the oils from my eyelashes, and 2. on cooler nights (or mornings, as the case may be), putting my eye so close to the eyepiece causes the eyepiece to fog up pretty quickly.

So my question is, what would you recommend that has the performance of an ortho, but offers more eye relief? Am I on the right track thinking that the Tele Vue Delos might fit the bill for someone with semi-inifinte funds (which I don't have, but let us dream...)? Other contenders?

Thanks for your thoughts!

[Lady Fraktor]

The Vixen SLV are nice eyepieces as well.
50° AFOV but with 20mm eye relief.
https://www.vixenoptics.com/category-s/159.htm

[notFritzArgelander]

I've directly compared my TV Delos against BCO and KK Fujiyama orthoscopic eyepieces.

There is a very slight degradation of contrast in the Delos. I notice the difference mostly in observing shadow transits on Jupiter. The shadow is minutely less contrasty in the Delos. This is on a hard contrast object.

On soft contrast details, like internal wisps and nebular filaments the BCOs are more clearly better.

[Bigzmey]

The Vixen SLV are nice eyepieces as well.
50° AFOV but with 20mm eye relief.
https://www.vixenoptics.com/category-s/159.htm

Yes! SLVs have ortho-like performance with 20mm eye relief, very comfortable to observe. I compared them side by side to BCOs on many occasions and in terms of contrast, sharpness and light scatter they are neck to neck. BCOs may still have slight advantage on very faint nebulae, but for double splitting, lunar and planets I don't bring orthos any longer and go with SLVs.

They go on sale at least once a year for ~$100 a piece. I also picked a few used for less than that on Astromart and CN.

[Bigzmey]

I've directly compared my TV Delos against BCO and KK Fujiyama orthoscopic eyepieces.

There is a very slight degradation of contrast in the Delos. I notice the difference mostly in observing shadow transits on Jupiter. The shadow is minutely less contrasty in the Delos. This is on a hard contrast object.

On soft contrast details, like internal wisps and nebular filaments the BCOs are more clearly better.

I have compared BCOs to Delites. Pretty much neck to neck on Moon and planets. Again, BCOs may have slight advantage on extra faint targets, but I need to do more comparison.

The only EP which actually had an edge over 10mm BCO on faint targets is Pentax XW 10mm.

[Ruud]

TeleVue DeLite, 3mm and up, 62°, 20 mm eye relief, $255

Delite (and Delos too) have excellent optics and ergonomics.

[John Baars]

I am familiar with the problems as my best planetary eyepiece has the same problem.
Since no eyepiece has the same excellent viewing properties as the one, I decided to accept the shortcomings.
To avoid them, I observe at a greater eye distance and take the even smaller field of view for granted. After all, all I have to do is see the planet. The eyepiece is no longer getting greasy and dewy. I do exclude outside light by means of a hood, so that I have to keep my eye even further away to prevent dew by my breath.
One way or another, it remains a Spartan eyepiece.. But the views are great!

[j.gardavsky]

The problem with the BCOs is their minimum mass, and hence their rapid cool down, causing the fogging.

Check out the tube on the focuser in which the EP is inserted. In another situation - on my RACI - I have made a wrap with an isolating material around the EP holder, and it slows the cool down and helpss against fogging. Otherwise, the RACI EP has been fogged within 20 minutes.

What would also help is a sort of rubber armour on the flat top around the eye lens on the EP.
This has been perfectly well understood by Pentax, and the old Pentax SMC Abbe Orthos have this thin rubber armour on their tops.

Somehow, the other designers did not get it that the astronomy equipment is used during the night hours and that a not protected telescope with its accessories is radiating heat like mad into the Universe.
It's not enough to learn just the optics, some thermomechanics can be also useful,

JG

[pakarinen]

The Vixen SLV are nice eyepieces as well.
50° AFOV but with 20mm eye relief.
https://www.vixenoptics.com/category-s/159.htm

I've bought two (on sale no less) based on LF's recommendation. I'm not an EP expert, but they are very good EPs IMO.