orthoscopic versus plossl?

[Ags]

I'm tempted by a Baader 7mm Ortho; I've bought the sales pitch that this will give the ultimate optical performance for less than £100 new (but I will buy second hand). But why would an ortho be better than a plossl? They have the same number of lenses and the same number of glass-air surfaces, after all.

I could get a Televue plossl for less money and with more FOV, after all.

[John]

Tele Vue don't do a 7mm plossl - 8mm is as short as they go in the current series - the older "smooth side" range went down to 7.4mm.

Personally I don't think there is much to pick between TV plossls and the Baader GO's although some folk detect a slightly "warmer" tone to the Tele Vue's which some don't like.

Both have their fans and, from my perspective, both are excellent eyepieces.

[dweller25]

My findings are exactly as Johns.

I have :-

Baader Orthos : 5, 6, 7, 9, 12.5, 18

TV Plossls : 8, 10.5, 15

All are excellent value for money and very sharp.

[brianb]

Personally I don't think there is much to pick between TV plossls and the Baader GO's although some folk detect a slightly "warmer" tone to the Tele Vue's which some don't like.

Yeah, the TVs do have more than a hint of "coffee stain" tone to my eyes.

Basically:

the BGOs have more contrast due to less ghosting, and marginally more eye relief for the same focal length

the Plossls have a bit more field of view.

[great_bear]

There's so little in it, you could choose either and still be happy that you've got a world-class eyepiece. When you get down to this tiny level of difference, your choice of either is likely to be influenced more by whether the magnification factors work out best in your scope.

BGOs have more lengths available at the short end, and TV have more lengths at the long end.

An eyepiece collection could quite easily have a mixture of both!

[Rob]

Orthos are narrow.. some find them hard to use due short eye relief. I like them a lot as they tend to pull a sharper image, however that said you may want to look at the TMB planetary's.. Skies the limit (ebay) are offering a clone range for £36 and are great value. I have the 6mm and find it fantastic. Nice ER and sharp

1.25" 6mm 58 Degree TMB designed Planetary eyepiece on eBay (end time 30-Oct-10 20:20:50 BST)

Rob

[Ags]

I currently have a couple of TS Planetary HR eyepieces (TMB clones). They are quite good, but I want something a step up on these around the 7mm mark. I'm prepared to sacrifice FOV and eye relief for better optical performance. In particular I want to minimize ghosting.

All my current EPs have long eye relief, but I find I am always observing without my glasses and also finding eye positioning tricky - I keep wanting to place my eye too close to the EPs, so I think I may get along with a 7mm BGO.

SaN magazine had a (poor) planetary EP review that gave high marks to the BGO on test, especially for contrast and clarity.

[Moonshane]

There's so little in it, you could choose either and still be happy that you've got a world-class eyepiece. When you get down to this tiny level of difference, your choice of either is likely to be influenced more by whether the magnification factors work out best in your scope.

BGOs have more lengths available at the short end, and TV have more lengths at the long end.

An eyepiece collection could quite easily have a mixture of both!

Best thing is they match colourwise too. mmmmm green and black. I wish people would stop asking questions about shiny things I don't have and then want!