ortho vs plossl for planetary

[Daniel-K]

The only ortho I've owned was a 7mm BGO which never got used and sold on fairly quickly. Recently I have become a lover of lunar scanning around looking for intricate details in craters. So my question is do I need a decent orthoscopic eyepiece for up close work on the moon and planetary viewing. Currently im just have a 10mm plossl but I have a 9.7mm plossl on the way wil an ortho show me better?

[Pete Presland]

eyepiece are very subjective, i used to have a couple of ortho's but i could not tell any difference between my Televue plossl's and the ortho's.

[Moonshane]

personally, I am doubtful whether there is any major difference (on axis) between any brands or designs. They are all designed to give good views in this area. the differences off axis are what cause the cost to increase and generally the further away from axis you go, the more expensive it is to maintain the detail.

I have orthos and plossls based on the focal lengths I felt I wanted rather than their design. if you buy good quality on both sides there will be little difference.

[nightfisher]

Im Luna and planetary, all i can say is i had plossl`s, and now i have a full set of ortho`s, funny thing i struggle with eye relief on 6.7mm plossl but i can use a 4mm ortho, best to try before you buy

[ronin]

Think Al Naglar was asked at something like NEAF if he was going to make an Ortho, his reply was along the lines of buy one of the plossl's they are better.

You can get good and bad eyepieces in all designs, and I have seen people compare the best of one to the worst of another, to get the answer they want. Also a lot of people seem to have one preference over another immaterial of actually tried both. So if you end up comparing a top Ortho to a dirt cheap plossl that is not a valid comparison.

I have TV plossl's and very good. Better or worse then a good ortho? No idea, I have no reason to buy an ortho so not going to waste the money doing so simply to do a comparison. That is the problem when people ask how does A compare to B. If I have A then the odds are I will not buy B. What you get is one says "I have A and it works", and another says  "I have B and it works".

[YKSE]

Agree with ronin totally. I have BCOs, and they work fine for me, so if I'm going to buy an narrow FOV EP, it will be an ortho, not a plössl.

[John]

I've compared TV plossls to Baader GO's and the like many times and the difference is negligible to my eyes. But the TV plossls are the best plossls I've used so, in general, I'd go fo orthos over plossls. You have more choice of quality orthos these days with Baader GO's (used only now), Astro Hutech's,  Fujiyama's and the Baader Classic Orthos offering really excellent lunar and planetary viewing.  

[Pig]

The Delos are a type of Ortho and they give excellent moon detail for the whole FOV even at 400 X mag

[BillP]

Specifically for lunar observing, I do not find much of a difference between Plossls or Abbe Orthos as far as the view.  However, as the focal lengths start getting shorter, say shorter than 12mm focal lengths, the eye relief of the Abbe design is longer than what a Plossl design can achieve, so for shorter focal lengths the Abbe Orthos will usually feel a little better and not feel so tight.  The Abbe Orthos also has a production advantage as it is often available in many short focal lengths whereas Plossls tend not to be.  Optically though, not much of any difference, expecially on the Moon where you have so many very high contrast features.

IMO the Abbe design *generally* shows a very little better contrast performance (due to its optical design and how it minimizes back scatter reflections well), but this advantage I feel is only brought out in the most critical of planetary observations.  On Lunar I've always been happy with either a Plossl or Ortho with no preference between the two.

[bingevader]

"I have B and it works." Both TV and Meade. The TV Bs are marginally "better" than the Meade Bs, but noticeably so. However, personally, I wouldn't go any lower than the 9.7mm Meade B I have, as I'd find the ER to short.

I've looked at the Baader As and fear that at the smaller FLs I'd have the same problem, so I've stopped looking.

I have a Celestron C and a WO D and although there is a diminution in contrast and brightness at the shorter FLs compared to the longer TV A, I am happy with the more comfortable ER and larger FOV.

If I get the chance to use a BGO and I'm comfortable with it maybe I'll reconsider.

Cheers

[Daniel-K]

ive ordered a 9.7 meade series 4000 plossl off the bay and am thinking of ordering a 10mm BCO to compare and sell the one i dont like thanks for the advice guys

[F15Rules]

I have both orthos and plossls. In general I like orthos up to about 10mm focal length, and plossls (decent ones) above that.

On many nights you couldn't tell the difference on  axis. On the (all too few) nights of excellent seeing (steady atmosphere), I find that the orthos are sharp edge to edge (albeit a narrower field of view) and the seem to be "crisper" in bringing out the finer details. I remember a few years ago my best ever view of Mars came with a BGO, and my equivalent plossl on that night did not come close. I also think that light scatter tends to be less with good orthos.

I also like Kellners on planets/lunar. Although a simple, old design (what's wrong with that?), they have fewer elements which means more light throughput and they do seem to tease out the very faint stars. I have  9mm and 12mm Circle T volcano top Kellners and can hardly see ANY difference with the image quality and that of much more expensive eps..so, don't write off older, simple designs :-)

Dave

[Caldwell14]

I have owned a few TV plossils, all of them up to 32mm (which I still own along with an 8mm) Razor sharp optics and can be had at very reasonable prices second hand

[John]

...... Razor sharp optics and can be had at very reasonable prices second hand

Indeed. If you can live without wide / ultra wide fields of view and longer eye relief, you can get top drawer optical quality for £40-£50 per eyepiece on the used market.

[Naemeth]

ive ordered a 9.7 meade series 4000 plossl off the bay and am thinking of ordering a 10mm BCO to compare and sell the one i dont like thanks for the advice guys

I think the BCO will probably outperform the Meade, but who knows? This is why eyepieces should be bought second hand, so they can be sold on if something better is found.

[hunterknox]

I like orthos over plossls because all the plossls I've used tend to show a 'warm' colour cast. Also, at shorter focal lengths, orthos have more useable eye relief.

Plossls tend to have a greater field of view, better eyecups, better availability and, pound for pound, similar on-axis sharpness. You pay your money and take your choice...

[Bender]

I bought a TV plossl 8mm a while ago to complete my plossl line up. After initial testing I found the er lacking and put it back in the case to be sold at some point.

Now I received a BGO last week to replace my VT 7mm ortho. Initial testing showed little difference on the moon but the conditions were not ideal with the atmosphere boiling and the moon moving constantly in and out of focus.

(I found light scatter more or less absent on both and the shadows maybe ever so slightly darker in the BGO, but that could well be wishful thinking)

It was then that I remembered the TV 8mm and got it out to see how it would compare, what can I say, my first thought after a second was – why did I even bother with the orthos tonight.

The view was steady, surely down to less magnification, and in everything els it was just as good as the orthos.

Going from the 7mm othos to a 8mm plossl even made the er more tolerable.

After this short session I was sure that I will keep the TV plossl to fill the gap between my 7 and 9mm BGO.

[Moonshane]

I completely agree with this and it's why I have 3-6mm zoom, 7mmBGO, 8mm Radian, 9mm BGO, 10mm Radian, 11mm TV plossl, 12.5mm BGO, and 15mm TV plossl as my double/solar system set. http://stargazerslounge.com/topic/188794-eyepiece-groups/

[paulastro]

I've observed planets over a very long time (and with just about most types of eyepiece), and in my view the thing that will make the biggest difference is to use a binoviewer - with almost any eyepieces.  Just a thought1

[Mark in Macc]

+1 for the binoviewers. You will never look back!

[Bender]

I certainly agree that a binoviewer is a step up with the relaxed views they give. Bit sometimes I don't want to trouble myself to much with balancing my scope on an alt az mount and go for a minimal weight ep.

[Astroraider]

I have a full set of the Celestron Plossl (Silvertop - all silver with Orange Engraved Lettering - 7.5, 10, 15, 17, 22, 26, 30, 36, 45, 2" 50) that are excellent eyepieces. I also have a full set of the original Naglers (Circle N/J Smoothside 4.8, 7, 9, 11, 13), the 20mm Nagler Type II and the Televue Wide Field 32mm and 40mm (Circle N/J smoothside).

In recent history, I also owned a set of the Celestron Volcano Top Orthos (Circle V with Silver Engraved Lettering on volcano slant - 4, 5, 6, 7, 9, 12, 18)  which I sold. Mostly because they offered no better performance than the other eyepieces I owned and all had very narrow fields of view. I do find the eye relief of the 7.5mm and 10mm Silvertops to be somewhat less than desirable but I have the Naglers to pinch hit for them!

In my case, the on axis images were at least the same or better than the Orthos and the narrow field of view of the Orthos allowed the Orthos to be at least as good as the Naglers but the Naglers have such a wide field of view so it is difficult to rate the Orthos better in any respect.

[Astroraider]

To add to this ... the workhorses of my eyepieces:

For the C11, the 40mm Wide Field, the 20mm Nagler Type II and the 13mm Nagler get used most of the time followed by the 11mm Nagler when seeing conditions permit.

For the C5, the 19mm Panoptic, and the 7mm Nagler get the most use!

I use the Celestron Plossl Occulars when I travel with the C5 to distant locations (Chile, Australia, Hawaii, Hong Kong, China). I can carry on the C5 OTA and sometimes the Celestron Nexstar 6SE/8SE drive base with a tripod adapter plate. I can always buy a cheap video tripod when I get to the destination. I can always fit the C5 OTA and Eyepieces in carry on luggage. The Nexstar usually has to be in checked baggage when I fly domestic part of fthe way but if I fly International all the way, the rules are relaxed. I can drive to Miami and fly International ONLY to Chile.

[Astro_Baby]

On cost the orthos probably win out....I have owned a great many budget and mid priced Plossls and none even came close to the very reasonably priced orthos in sharpness or neutrality of color. The only eyepieces which I have found which are sharper than my orthos are all in the very up market bracket of eyepieces.

[F15Rules]

The main drawback I find on plossls for high power viewing is the short eye relief.

I don't wear specs to view but do have long eyelashes which can be a pain when I have to get my eye too close to the glass:I'd personally avoid plossls of less than c9mm focal length.

The silvertops you mention are very good. My favourite was the 26mm which was pretty much perfect to my eyes.

For high power viewing I don't think you can beat a good ortho..you don't need a wide field (unless you're into studying empty space:) so a 40 or so degree field is fine as long as you have an RA drive for tracking.

The new Baader Classics are great IMO as they give ortho performance with 50 deg field which is sharp out to c90-95% of the field. I think they offer unbeatable value for money for the performance..same for used BGOs, and Circle VTs aren't far behind..

Naglers are great for wide field but seem a waste of money to me for high power- but if I wanted a high power wide field I'd choose Pentax XWs anyway:).

Dave