Circle-T Abbe Orthos

[starscy]

Is anyone using the Circle-T Abbe Orthos? I know that this eyepiece type is better for lunar and planetary observing as the AFOV is narrow, but how is the performance on other objects?

[AndyH]

Good on dimmer objects like double stars, clusters and small galaxies. They work well because of the light throughput and contrast IMHO.

Cheers,

Andy.

[mdstuart]

yes they have a high light throughput so a galaxy might be visible when in another eyepiece it is not...Also good quality so sharp images...BUT narrow FOV and low eye relief on the high power lenses..

And the darn lenses are so small they cannot be cleaned with a lens pen....any ideas folks on how to clean them when the time comes..

Mark

[lunator]

I have a full range of these.

The field of view is not a great issue for me. I do like the crisp views.

Cheers

Ian

[AndyH]

yes they have a high light throughput so a galaxy might be visible when in another eyepiece it is not...Also good quality so sharp images...BUT narrow FOV and low eye relief on the high power lenses..

And the darn lenses are so small they cannot be cleaned with a lens pen....any ideas folks on how to clean them when the time comes..

Mark

Good question Mark.

I got round it, on the small focal length ones, by getting a piece of thin plastic rod or similar, filing down the end, so it was free of burrs. Then got a lens/glasses cloth, covered the rod and cleaned carefully. Works well .

Cheers,

Andy.

[Doc]

I have a full set as well and on planets and lunar they excell. They are very sharp with great contrast.

The 12.5mm is fantastic, I think the best of the bunch.

[Brass n glass]

I use the 18mm a lot, often with a 4X Powermate. The low-power ones have reasonable eye relief. The fact that orthos can hold their own against modern wide-angle LER eyepieces says it all - not bad for a design that's well over 100 years old - Hugh

[AndyH]

........The fact that orthos can hold their own against modern wide-angle LER eyepieces says it all - not bad for a design that's well over 100 years old - Hugh

Indeedy.

Whilst they have never gone away, I have noticed more and more discussions/interest regarding orthos, over the last few years, on the net.

I love 'em and at the very least, they are great for testing your scopes optics, as they introduce little in the way of optical abberations, to the view.

Andy.

[AndyH]

I use the 18mm a lot, often with a 4X Powermate. The low-power ones have reasonable eye relief. The fact that orthos can hold their own against modern wide-angle LER eyepieces says it all - not bad for a design that's well over 100 years old - Hugh

Hugh - I take it, these orthos work well with the powermates? Any difference seen between that pairing and a single high power ortho??

Cheers,

Andy.

[Brass n glass]

I can't see any difference between the Circle T 18mm ortho/Powermate combination and a 5mm Baader ortho on its own - except viewing comfort. I find the 4X Powermate less obtrusive than any 2X Barlow I've ever used - Hugh

[AndyH]

Good to know Hugh.

Thanks,

Andy.

[Stardust]

I've recently picked up a few orthos, 12,18 & 25mm, had the 12 on Mars tonight, very nice view inbetween the clouds.

[dweller25]

I have used volcano top Orthoscopics since 1985, they are very sharp on axis, have great contrast and great light throughput. Eye relief can be tight 5mm down and FOV is narrow. They are really cheap second hand and are a great buy overall.