Ortho's for planetary or quality plossl ????

[spaceboy]

I recently came across a review on another well known forum that had me a little puzzled   

Last week on Jupiter these were the rankings I perceived with my ortho-plossl collection in 6mm's:

Pentax smc in .965/Clave 27mm, these were the best.

CelestronVixen ortho/Celestron plossl, 2nd level.

Baader BGO/CircleT ortho/Fujiyama ortho, 3rd level.

Baader BCO, the new classic, easily last.

It was real easy to see the differences with the wealth of details on Jupiter. This was done with a 8" f/6.5 dob with a quality 1/14 wave mirror. Their all good, just some better than others.

While I'm not questioning the reviewers top of the pile or indeed any of the rankings I was surprised to see a plossl albeit a well respected optic maker coming in above orthoscopics for offering better planetary detail.

This had me thinking would it not be better considering buying Vixen NLV http://www.firstlightoptics.com/japanese-made-eyepieces/vixen-nlv-eyepieces.html  that in the most part offer better FOV, eye relief and a larger selection of focal lengths than to go with ortho http://www.firstlightoptics.com/japanese-made-eyepieces/hutech-orthoscopic-eyepiece.html that can in shorter FL offer such little ER that it can be challenging on the eyes even for those who don't wear glasses. Given the small price difference if one is going to give you the same or "maybe" better views but with better ER and FOV would it not be an obvious choice ??

Don't get me wrong, I do love me orthos but have I totally missed something here ??

[Reeny]

Don't get me wrong, I do love me orthos but have I totally missed something here ??

Personal preference.

Everybodies eyes are different, and some may prefer a different view.

When I got the ES 82 degree eyepiece, I initially said it wasn't as good as my MaxVisions becasue I wasn't used to it.

Eventually I got used to the eye placement, the wider view, the fold up eyecup - and my expectations changed.

A bad eye piece will always be a bad-un.

But a good eyepiece will offer a different standard of comapatability and comfort for different people.

For me, It takes me a few sessions before I can get the best out of any new equipment.

For planetary work, contrast is going to be a very personal thing.

I assume the author has his preferences, and one type of EP will suit him better than the others.

Sorry - I don't have any experience of the Vixens or Astro Hutech Orthos myself.

[YKSE]

I totally agree that personal preference is the key.

To my eyes, 6mm BCO shows somewhat more scatter on planetary than 10/18mm BCO, but still clearer less than many other EPs I have/had.

Here's a discussion about 6mm orthos, as we can see, lots of different opinions:

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/6251289/page/0/view/collapsed/sb/5/o/all/fpart/all/vc/1

[spaceboy]

This is where I think Alan at 'skies the limit' had the right idea with the try before you buy option. With so many eyepieces and scopes on the market it can be a constant chase to find what works best. As you say it is personal preference but then budget is also a large deciding factor for many with no real opportunity to test drive eyepieces or other equipment with out financial loss buying new or a long wait for 2nd hand.

[YKSE]

 As you say it is personal preference but then budget is also a large deciding factor for many with no real opportunity to test drive eyepieces or other equipment with out financial loss buying new or a long wait for 2nd hand.

This is a very valid point

As to myself, by reading lots of reviews before making a decision, my conclusions is that the differences among the named EPs are very subtle. BCOs are readily available and at a very affordable price, so the choice was an easy one for me

[ronin]

Very little difference in the actual design, the ortho is 4 elements in 2 groups, the plossl is 4 elements in 2 groups.

In the ortho the first group is 3 elements, so groups of 3 and 1 element, whereas in the plossl each group is 2 elements.

If a Celestron plossl came 2nd then I wonder where a TV plossl would have come.

Review appears a little odd in that it puts Pentax's up against a Celestron and misses TV's. Although it may simply be a comparison of what they had and not what they could get a hold of (borrow).

As said personel preference comes into it as does the quality of the eyepiece, there are some good plossl's and some pretty poor ones.

[YKSE]

Very little difference in the actual design, the ortho is 4 elements in 2 groups, the plossl is 4 elements in 2 groups.

In the ortho the first group is 3 elements, so groups of 3 and 1 element, whereas in the plossl each group is 2 elements.

If a Celestron plossl came 2nd then I wonder where a TV plossl would have come.

Review appears a little odd in that it puts Pentax's up against a Celestron and misses TV's. Although it may simply be a comparison of what they had and not what they could get a hold of (borrow).

As said personel preference comes into it as does the quality of the eyepiece, there are some good plossl's and some pretty poor ones.

The two groups arrangement makes less transmission loss, better throughput than more group arrangement, assuming everything else equal( lens quality, polishing, coating, etc). TV plössls really shine on transmssion by their quality.

Nowadays plössl (TV plössl included) are symmetrical achromat, i.e. achromat pair, which are less sharp on axis than abbe ortho, by this example

http://www.telescope-optics.net/eyepiece_aberration_2.htm

I'm yet to find a review about TV plössl as planetary EP, I'll be very interested if you can find one.

[jetstream]

With quality plossls vs quality orthos the difference will most likely be small and seeing limited.There are a lot of cheap plossls out there though so an "apples to apples" comparison is a must.The KK Fuji's I have are extremely good and compare well to other planetary eyepieces.The only plossl I would personally consider is the Televue,a product of known good quality at a reasonable price.

[Dude_with_the_tube]

i think before you do judgment on above comparison you need to take into consideration a few factors.

1.i can assume this is off some american forum in likes of Cloudy nights as such very little applies to UK skies, if thats the case, as seeing in some US places are by far better then here in foggy albion.

2.Eye pieces used.

Looking at the few Ep`s mentioned:

2.1.Pentax SMC ortho.These are top tier planetary orthos and cost 200-250quid to buy one if you can find one!

2.2.Clave plossl. Boy, first,try and find one and then if you do,expect to pay well over 350USD for one! These are one of the best if not the best Plossls in the world.

2.3.Celestron/Vixen orthos and plossls,again vintage,not that difficult to find.not that sure about celestron ortho that author rated that high and placed above BGO i would debate over this ,but Celestron/Vixen silvertop plossl will give TV plossl run for its money any time.Again some focal length are rare and difficult to find.But Silvertops are superb plossls and i will not over estimate to state that a direct alternative to TV plossls.

All these above EP`s are vintage and are not only superb,but also highly collectible and keep they value very high.

And lastly author is using very high spec mirror on his dob what does affect performance(under ideal viewing conditions)

I personally dont think that you will have much,if any,difference optically if you decide to go for the modern produced orthos in likes of Fujiyamas or Astro hutechs under UK skies,also your mentioned Vixen NLV`s will perform superbly.

It is again down to personal preferance what you want and how much you can afford.Debate over plossl vs ortho for planetary is a big can of worms what have been opened many times over and i dont think anyone got to the bottom of it unless you are wondering into very expensive EP territory.

I can only say one thing: buy one,try one and see what you like yourself.Nothing wrong in trying.

[Dude_with_the_tube]

With quality plossls vs quality orthos the difference will most likely be small and seeing limited.There are a lot of cheap plossls out there though so an "apples to apples" comparison is a must.The KK Fuji's I have are extremely good and compare well to other planetary eyepieces.The only plossl I would personally consider is the Televue,a product of known good quality at a reasonable price.

under UK skies,i would agree that all these different orthos will show very little if any difference.

i will not agree with your statement about plossls.There are a few other quality plossls out there apart of Televue and for a reasonable money and off excelent quality.

it seems that people only know Televue as it is sort of more popular

[MartinB]

For planetary viewing using a 12" dob I use a 10mm Pentax XW and in better seeing a 7mm Pentax XL.  In best seeing I might barlow them up but it's starting to get a struggle with the dob.  Using an orthoscopic is an excercise in futility!  With a 10" SCT I sometimes use a 9mm Baader orthoscopic if the seeing will stand it but generally use the 10mm Pentax.  Using an ED120 I might use one of the Pentax EPs or a 5mm orthoscopic depending on seeing but normally a Pentax again.

The view with the Pentax EPs is much more comfortable so I find it easier to peer for longer periods which is what you really need to do to start to pick out more subtle planetary details.  The orthoscopics give a more neutral colour and have less glass for the light to pass through, they've never given me a wow moment but they have given me a headache.

The worst thing you can do when planetary observing is to keep chopping and changing EPs!  I now only use my orthoscopics at the end of a session out of curiosity!  You will see more with a comfortable EP than with an uncomfortable one.

[alan potts]

I do not have my TV Plossl's yet but I firmly believe there is a case for both. I am trying the TV Plossl's because I read one account on site that colours came out better in them, I would like to see for myself, I will report of course.

Alan.

[John]

I'm pretty sure I've read the report referred to.

If you read enough opinions you will find champions for virtually every design around. It is down to a large extent to personal preferences and almost the reporters "taste" in eyepieces.

The best "planetary" eyepiece I've ever owned / used was a 5mm TMB Supermonocentric but I did not hang onto it for long because it's tiny FoV (32 degrees) and eye lens made viewing with it hard work. I guess if I'd been a "serious" planetary observer I'd have put up with that for the "ultimate" contrast and light scatter control. I must be a bit of a wimp ! 

I'm with Martin now and find the Pentax XW's in focal length's of 10mm and less do a superb job with viewing comfort to boot    

I'll probably keep an ortho but it won't get a lot of use in all honesty.

I've not really found short focal length plossls that I really got on with. The TV 8mm is excellent but high power in my scopes starts around 7mm and shorter.

But the above are just my tastes and, as the old saying goes, "your mileage may vary" and it probably will 

[jetstream]

under UK skies,i would agree that all these different orthos will show very little if any difference.

i will not agree with your statement about plossls.There are a few other quality plossls out there apart of Televue and for a reasonable money and off excelent quality.

it seems that people only know Televue as it is sort of more popular

What other currently made plossls are out there that compete with TV?I may be in the market for a 25mm soon,for solar and HH hunting(if the 18mm BCO doesn't work) any info appreciated

[Jim Steele]

What other currently made plossls are out there that compete with TV?I may be in the market for a 25mm soon,for solar and HH hunting(if the 18mm BCO doesn't work) any info appreciated

I have a Tal 25mm Plossl and it's a peach...

[spaceboy]

I know my next question is going to be a little limited for replies but I wondered what peoples votes were for solar eyepieces as they require similar attributes to planetary ep's but are more prone to light scatter. I see Daystar recomend the use of TV plossl for their Quarks. While I have no doubt to the quality of TV plossl they do come up short in traditional planetary focal lengths.

[timwetherell]

What other currently made plossls are out there that compete with TV?I may be in the market for a 25mm soon,for solar and HH hunting(if the 18mm BCO doesn't work) any info appreciated

I have a skywatcher 25mm Plossl and considering how cheap it was, it's remarkably good - perhaps I just got lucky though, I imagine there may be considerable variation between individual units

Have you also considered a UO 25mm orthoscopic as an alternative? Another relatively low cost eyepiece with excellent performance

[Uplooker]

I must say that although I can not contribute to the debate I am thoroughly enjoying this thread and read all posts with interest, as I am looking for a shorter planetary EP than my BGO 9mm, since this will only give me x 166 in my 300PDS.

Ian

[Stu]

I know my next question is going to be a little limited for replies but I wondered what peoples votes were for solar eyepieces as they require similar attributes to planetary ep's but are more prone to light scatter. I see Daystar recomend the use of TV plossl for their Quarks. While I have no doubt to the quality of TV plossl they do come up short in traditional planetary focal lengths.

Hi Nick,

Having played around with many eyepieces for solar, I came to the conclusion that the 11mm TV Plossl was best in my PST. To me it always seemed to give around the optimum performance so I stopped trying any others.

In my TV85/Herschel wedge, I reached a similar conclusion, settling on the 12.5mm BGO for most conditions, but finding that the 9mm was useful for steady seeing at the beginning or end of the day. I do prefer the BGOs to the TVPs, I think they are a smidge sharper, but the 11mm in the PST is just right from a mag point of view.

In all these cases, the transmission and scatter control are great, very nice to use.

I originally drew the line at the 7mm BGO because of eye relief, but have since bought a 6mm, and a 5mm Hutech and I still find these manageable. It's easier on a tracking mount of course.

Outside Orthos, I think the best option might be the newish Vixen SLV. I've not looked through one but if seeking a shorter focal length with better eye relief and ortho performance they are reported to be an excellent choice. But pricier though!!

Stu

[John]

I must say that although I can not contribute to the debate I am thoroughly enjoying this thread and read all posts with interest, as I am looking for a shorter planetary EP than my BGO 9mm, since this will only give me x 166 in my 300PDS.

Ian

I've been really impressed with the Vixen SLV's - they seem to have all the optical quality of the Baader Genuine Ortho but with a slightly wider field of view, 20mm of eye relief, a wide and welcoming eye lens and a nice twist up eye cup too. They are a bit more pricey than an orthoscopic though - £109 V's £80.

[timwetherell]

Having played around with many eyepieces for solar, I came to the conclusion that the 11mm TV Plossl was best in my PST. To me it always seemed to give around the optimum performance so I stopped trying any others.

Interesting you should say that, I also found Ha solar scopes hugely fussy and ended up using Plossls in mine too. Other EPs that outperform my plossls on planets didn't work so well for solar. My guess is that it relates to the single wavelength of Ha vs broad spectrum on planets. Perhaps the fractional loss of contrast that comes with extra glass to control chromatic aberration works against you in a solar scope. The best Ha barlow I've used is a home made one made from a single concave lens. Shockingly terrible in white light but excellent on solar

[John]

When I had a PST I found that simple plossl eyepieces worked best. I did try complex designs such as Ethos and Naglers and they worked OK but a £25 plossl seemed to deliver images that were just as good and perhaps a little better in Ha light.

[jetstream]

I have a skywatcher 25mm Plossl and considering how cheap it was, it's remarkably good - perhaps I just got lucky though, I imagine there may be considerable variation between individual units

Have you also considered a UO 25mm orthoscopic as an alternative? Another relatively low cost eyepiece with excellent performance

Tim,thank you for the UO idea,I didn't know they were back after Tani retired.I wonder how the 25mm UO compares to the 25mm TV plossl....most likely splitting hairs.I wish Baader made a 25mm ortho,gotta love those coatings.

[timwetherell]

Tim,thank you for the UO idea,I didn't know they were back after Tani retired.I wonder how the 25mm UO compares to the 25mm TV plossl....most likely splitting hairs.I wish Baader made a 25mm ortho,gotta love those coatings.

Never done a side by side but have been very impressed by the HD orthos. Now you've got me thinking about swapping by 25mm volcano top ortho for an HD ortho to match the rest of the set. My impression was the HDs were just a hair better but the 25mm wasn't available in the HD range when I bought mine a few years ago. 

They say talk is cheap, but I find that talking about astro gear often ends up costing me money! 

all the best

Tim

[Stu]

Tim,thank you for the UO idea,I didn't know they were back after Tani retired.I wonder how the 25mm UO compares to the 25mm TV plossl....most likely splitting hairs.I wish Baader made a 25mm ortho,gotta love those coatings.

Gerry, there is a 25mm available in the Hutech range, effectively the same as the BGO's. Not sure if these are available over on your side of the pond?

http://www.firstlightoptics.com/japanese-made-eyepieces/hutech-orthoscopic-eyepiece.html

Stu