Plossl or Orth EP?

[steve_bham]

Which design would be better for planets and hig mag work a good plossl or an Ortho EP.

Steve

[Breakintheclouds]

Orthos are excellent for planets. I recently go a Baader genuine ortho 5mm and it's superb for detailed work. You're looking through a pretty small hole, but it just doesn't matter for that sort of thing, I feel.

[steve_bham]

thanks for speed rely, have you used a plossl for detailed work. Reason im asking is ive got some low mag SW ones and they are great just wondered what the higher mags would be like compared to the orthos.

[brianb]

IMHO of all the eyepieces currently manufactured, and irrespective of price, the Baader Genuine Orthos are the best for planetary work. Really sharp, flat field, very little ghosting.

Plossls always have more ghosting than a good ortho, this reduces contrast in planetary views. The eye relief is similar (proportionate to focal length). The field of a Plossl is wider but they usually aren't quite as sharp in the edge of the field as a good ortho. The best Plossls can give quite good views of planets but I've never seen one that was in the same ballpark as the BGO.

Televue Radian is recommended if you can't get on with the limited eye relief given by orthos in short focal length.

[Stardust]

I was playing around with an 8" dob last night on the Moon and the best view was through a university optics HD 12mm ortho. So crisp, really enjoyed it.

[dweller25]

I have the following :-

10.5mm TV Plossl

9mm volcano top Ortho

8mm TV Plossl

7mm Antares Ortho

6mm volcano top Ortho

5mm BGO Ortho

They are all very good and all much of a same in terms of on axis sharpness.

I also have a TV 8-24mm Zoom which is just as sharp on axis as all the above.

For planetary I do find the coffee colour tint from the TV Plossls helps with contrast.

[Breakintheclouds]

Steve,

Yes, I've certainly used plossls for planetary viewing, and they're good - don't get me wrong! - it's just the orthos are better. If I had to put a figure to it, purely for the purposes of illustration, then let's say an ortho gives you something like 10-15% more. But when you're looking at something as difficult as Mars or Saturn, you appreciate that small boost.

Ian

[lunator]

Hi Steve

I have a full range of orthos and for planetary they are pretty unbeatable

If you can live with the eye-relief they are ideal.

Cheers

Ian

[steve_bham]

Cheers for advice

[steve_bham]

Just been looking on Telescope House website at TV plossl's and it says

"Tele Vue Plössls deliver sharper images than any other brand of 4 or 5 element "Plossl" or Orthoscopic designs."

Is this true or just a sales pitch?

[beamish]

Can't really judge as I've only the one -8mm, but it is a fab plossl

[Andrew*]

TeleVue ploessls are some of the best ploessls on the market, so they will perform better than some poorer orthoscopics, but I think the ortho design inherently outperforms ploessls of the same quality. However, I once heard that TV's ploessls are not of standard design...

The fact is though, that ploessls have less eye relief than orthos of the same f/l. Furthermore, there is generally a larger selection of high-power f/ls in orthos.

Andrew

[brianb]

Tele Vue Plössls deliver sharper images than any other brand of 4 or 5 element "Plossl" or Orthoscopic designs.

IMHO, claptrap. TV Plossls are optically very similar to the other ordinary Plossls marketed under many brand names, except for the rather pronounced "coffee stain" colouration, which you either love or loathe. What marks the TV Plossls out from the cheap generic ones is the mechanical construction ... they really are rather nicely built.

[dweller25]

My TV 10.5mm Plossl is perfectly parfocal with a 25 year old Celestron 10mm Plossl, so I don't think optically TV Plossls are unique.

But they are good and so are the Orthos.

As I said earlier the views the TV Plossls and Orthos throw up are much the same, you won't regret either choice.

[lostinspace]

i recently got a 6mm plossi and the moon looked fantastic through it, i spent ages sweeping and trying to name the craters and seas. i cant comment on other eps as i haven`t tried them yet. good luck with your search,

john

[mdstuart]

I have tried so many different eyepieces and my Othos are just so much brighter and they are all sharp accross the field...For me when you are trying to get that last bit of detail in a faint object then nothing beats them.

Mark

[John]

IMHO, claptrap. TV Plossls are optically very similar to the other ordinary Plossls marketed under many brand names, except for the rather pronounced "coffee stain" colouration, which you either love or loathe. What marks the TV Plossls out from the cheap generic ones is the mechanical construction ... they really are rather nicely built.

On the "coffee stain" issue, I've recently been testing Tele Vue Nagler Type 6's and an Ethos 13mm alongside a Baader Genuine Ortho 7mm and a Pentax XW 10mm. There is no obvious colouration tint in the Tele Vues that I can see. I've tried the similar comparisons with Tele Vue Plossls (both the older smooth sides and the current range), Panoptics and the older Wide Fields and they again showed no obvious tinting to me when compared to Baader Hyperions, Vixen LVW's, TMB Planetaries, classic "volcano top" orthos and a range of other quality eyepieces.

At most I think the Tele Vues have a very slightly "warmer" tint than some other brands and I really feel the term "rather pronounced "coffee stain" colouration" is a great exaggeration, based on my personal experiences at least.

As they say "your mileage may vary" though ....

[dweller25]

I do notice the warm brown tint the TV Plossls give and the extra contrast it gives on the planets.

I see this as a major benefit.

Clear skies to all.

[Andrew*]

Now that it's mentioned, I actually do remember my 3-6mm Nagler zoom (once was yours, John!), did have a noticably warmer colour than other eyepieces. I remember it did interfere with my ability to determine the true colour of things, but I never really considered it a drawback TBH. I do respect that some are disturbed by this, but I agree with John, that "Coffee stain" is somewhat of an exaggeration - "slightly warmer" is more to the truth.

I don't recall having the same impression with any of my other TV eyepieces (19mm Panoptic, 19&32mm WF, 20 T2 Nagler), but then again I only used them for low-power DSOs.

I apologise for drawing this thread further off-topic. Please try and keep it on topic from now on, or if we wish to continue discussing this matter, I could split the thread???

Andrew

[John]

Ooops - sorry about diverting the thread onto colour casts or otherwise in a certain brand of eyepiece

Steve - if the eyerelief is not an issue for you then orthos are probably the sharpest. I also seem to recall that the eye relief on plossls can be tighter than orthos, or at least no better.

The views through the 7mm Baader Genuine Ortho that FLO has kindly lent me certainly seem very sharp and contrasty with no light scatter, ghosting or other issues that I can see.

[Astro Adj]

I wish I could use a high-powered ortho but I found the combination of small eye relief and even smaller aperture meant I had trouble keeping my target in view. I did a bit of research and ended up buying a Baader Hyperion 5mm. It's incredibly comfortable and, to my inexperienced eyes, an excellent performer.

I suppose another option for me would be to combine a longer focal length ortho with a barlow. Would the addition of the barlow degrade the image noticably?

[steve_bham]

So apart from Ortho EP what would make a good high power EP? are plossl's ruled? Are the hyprions good or do they lose a bit of light becuase they are about 7 lenses?

[Astro Adj]

I've got no complaints with mine, although I've not used it in the dob yet. In the 130 the 5mm gives around 130x magnification, and with my 2x barlow this figure becomes 260. At 260x the image is noticeably dimmer, although I believe this is more to do with the exit pupil (0.50mm) than the eyepiece itself. Might be entirely wrong there, though!

I can't wait to use the Hyperion on my new dob - it should be able to show a decent level of planetary detail (I hope!) and I plan to compare the Hyperion with my 6mm SW Ultrawide.

One other bonus the Hyperion has over other eyepieces is that you can combine it with a tuning ring to change the focal length of the eyepiece. For example, the 5mm can be turned into a 4mm, 3.2mm and 2.6mm using various combinations of the 2 tuning rings.

[John]

Two alternatives that would be worth thinking about are the TS Planetary HR range (sold by Telescope Service in Germany and Modern Astronomy in the UK) and the William Optics SPL's although the latter have a limited range of focal lengths - 3, 6 and 12.5mm. Both of these types have good eye relief, a slightly wider than average field of view and seem to get good reviews. I've used some of the TS Planetaries and they are nice and sharp.

[mdstuart]

But in the end you may come back to a set of Orthos as they let more light through with their design than many lenses with more lenses 6,7+.....So even though you might be able to move your eye away from the lens with a flashy wide angle seven lens system and see a wide field of view there may be something missing..yes that very faint galaxy might not be visible at all....

BUT you may not be a galaxy fiend like me..

Mark