orthoscopics

[joelhall]

I've been recommended orthoscopics for planetary viewing, but am wondering about the field of view, as the eye lens appears to be smaller then on some other types. Are there such things available as wide F.O.V. orthoscopics or would it be a good idea using the larger focal length eyepieces with a barlow? I'm not really that up on telesope acessories and there's such a load of products out there it's hard to know whats's what.

[FLO]

Some do claim to have designed a wide-field orthoscopic but to my mind it is a contradiction of terms.

The chart shows the different field of views offered by a number of eyepieces. The thing to remember is that they are all 9mm and so all produce the same magnification. (Its as though you are in a space-ship looking at something thru a port-hole; the different fields of view represent different diameter portholes).

If you wear glasses, you need to watch out for eye-relief (the distance in mm from the eyepiece to your eye). Orthoscopics typically have less eye-relief than other eyepiece types.

[joelhall]

Cheers Steve. I think we spoke on the phone about this before, but I never got round to asking you about the FOV. I'd like the orthscopics for the planetary views, but I was concerned about the FOV for lunar viewing. Are there any wide FOV eyepieces you would recommend which compare well to orthoscopics?

[MartinB]

FOV is not an issue for planetary viewing but may be for lunar. The great thing about orthoscopics is that they don't contain a lot of glass for light to pass through therefore give a very clean view. I have a Baader 9 and a 5mm. They are perfectly comfortable. I was expecting to have to press my up close but that is simply not the case. Highly recommended!

[FLO]

Orthoscopics are exceptionally clear, bright, neautral and flat-field. To get achieve similar performance from a wide-field eyepiece is expensive - Pentax and Televue territory.

If you keep the FOV to a more manageable 60 degrees, the Meade Series 5000 Super Plossls are good. (The eye cannot see much over 65-70 degrees without tilting the head to see the edges).

If you can live with the short eye-relief (not a problem unless you wear glasses) an orthoscopic is an excellent idea. There aren't any bad orthoscopics but the Baader Genuine Orthoscopics are as good as you can get without buying a Pentax XO.

[joelhall]

Yeah, I checked out the Baader one on the FLO site. Thanks for your help guys.

[Kai]

Steve any chance of bringing a couple of orthos to Wales to have a look through ??

[John]

At the moment my high power eyepiece options are either i) using an Ultima 2x barlow on my Tele Vue Plossl 15mm, 11mm and 8mm eyepieces or ii) using my Meade 3000 series 6.7mm and 5mm eyepieces. I'm wondering if I would see a worthwhile performance improvement investing in Baader Ortho's in place of either of these options or would the difference be marginal ?.

John

[Kai]

Same situation John

thats why im asking Steve ,hope i can look through them through my scope to see the difference

[GazOC]

As Steve has said, there arn't many bad orthos of any brand, they are just a good eyepiece design. Why not try a couple secondhand for around £20 and then if (when!!) you like them go for the Baaders?

Widefield orthos defeat the object of having as few glass elements in an eyepiece as possible in order to maximize contrast to planetary viewing.

As you may have guessed, I'm a BIG fan of orthos.....

[FLO]

Steve any chance of bringing a couple of orthos to Wales to have a look through ??

Definitely

John, you will see a discernible difference, whether there is enough difference is subjective.

I'm also a big fan of orthos. They offer big money quality at sensible prices 8)

[lunator]

Cheers Steve. I think we spoke on the phone about this before, but I never got round to asking you about the FOV. I'd like the orthscopics for the planetary views, but I was concerned about the FOV for lunar viewing. Are there any wide FOV eyepieces you would recommend which compare well to orthoscopics?

As the other ortho fan in the forum I have to say that for the money the you can't beat orthos.

Also I can comfortably get the whole Moon in the Field of view of an 18mm ortho using my F6 newt.

What scope are you planning on using?

Cheers

ian

[GazOC]

As the other ortho fan in the forum

The gang of three, eh?

[joelhall]

skymax 150-pro, it's got a focal length of 1800mm so i don't really want too short a focal length eyepeice. On the FLO site, they have orthoscopics up to 18mm. Is this the limit for these?

[GazOC]

I've got a 25mm and there was a 40mm advertised S/H a while back IIRC.

The 12mm would make a good high power eyepiece in the 150 Mak.

[tom.yates]

I have a full set of baader Ortho's really impressed by um

[Merlin]

I have three BAADER orthos (12.5mm, 9mm, 6mm) and they give truly fantastic brightness and clarity. We shouldn't bother too much about the smaller FOV in comparison to some other eyepiece types; it isn't THAT small.

The eye-relief for an ortho is the same as its focal length, whereas a Plossl has only 75%.

I use TELEVUE Plossls down to 15mm, below this and the eye-relief gets to be more restricted than with an ortho.

With the exception of wide-field sweeping, orthos can be used for everything.