Premium 5mm eyepiece purchase

[dweller25]

The Pentax 10mm, is said to be the best of the range !!

Cheers,

Andy.

Yes and with the range of Barlows I have it will give me mags from x208 to x291 in roughly x30 increments - perfect for the planets.

[great_bear]

The 14mm and 20mm however are said to suffer from quite a lot of field curvature. Even the contributor who is the biggest fan of XWs on CN says that starting an XW collection with those focal lengths is "not recommended"...

[great_bear]

There was nothing to choose between the three options in terms of contrast or sharpness.

There was no visual difference in detail between the Pentax and the other three combos. Contrast in the Pentax is slightly lower than the other combos.

So I think premium eyepieces are no sharper than cheaper Orthos and Plossls and have a little less contrast but are much more comfortable to use.

For me the observing comfort is worth the money Pentax ask for.

This is all priceless information, so thanks for sharing.

[michael.h.f.wilkinson]

I was very surprised the XW had slightly lower contrast. Whilst I have not tried Pentax XWs, I have used fairly cheap Plossls (Vixen and Celestron), more upmarket EPs (Vixen LVs) and a premium EP (TV Radian) for planetary work. I also Barlowed a Meade 14mm UWA with the 2x and 3x TeleXtenders. In my opnion the Plossl 10 I had was quite nice, but the LVs beat it slightly in contrast, but certainly in ease of use. The Radian in turn was better than the LVs, both in FOV and edge correction. Contrast was also slightly better. Ease of use of the Radian is equivalent to the LVs. The Radian also seemed to have a slight edge over the Barlowed UWA 14.

I have similar experiences when going from 36 mm Plossl to 40 mm Paragon (WAY better than the Plossl) and from 26mm Plossl to 22mm Nagler.

Thus, premium EPs do give me better contrast on the whole, though the difference is often not that great in the centre of the FOV. At the edges the differences are larger.

[dweller25]

I was very surprised the XW had slightly lower contrast. Whilst I have not tried Pentax XWs, I have used fairly cheap Plossls (Vixen and Celestron), more upmarket EPs (Vixen LVs) and a premium EP (TV Radian) for planetary work. I also Barlowed a Meade 14mm UWA with the 2x and 3x TeleXtenders. In my opnion the Plossl 10 I had was quite nice, but the LVs beat it slightly in contrast, but certainly in ease of use. The Radian in turn was better than the LVs, both in FOV and edge correction. Contrast was also slightly better. Ease of use of the Radian is equivalent to the LVs. The Radian also seemed to have a slight edge over the Barlowed UWA 14.

I have similar experiences when going from 36 mm Plossl to 40 mm Paragon (WAY better than the Plossl) and from 26mm Plossl to 22mm Nagler.

Thus, premium EPs do give me better contrast on the whole, though the difference is often not that great in the centre of the FOV. At the edges the differences are larger.

I wonder if light pollution makes a difference ? I have plenty of it !!

[Moonshane]

you should seriously try and borrow a Radian first in my view.

they are excellent, give sharp, flat views, 60 degree field and 20mm adjustable ER. even better they are usually £100 used in perfect nick.

I only have an 8mm currently. Not sure where you are but I bet someone quite near you will have other shorter FLs.

[Kef9]

Just to ressurect this thread slightly but I too am after a quality 5mm eyepiece. Im thinking I would like to try a pentax to see how good they really are. I wish they did an ethos at this length.

Has anyone used a pentax XO? there supposed to be the best planetary eyepiece around from what I have read. Eye relief is tight so I wouldnt mind getting a cheap 5mm ortho to see if I could handle it.

[John]

There was a thread on here about the Pentax XO a while back:

http://stargazerslounge.com/equipment-help/103143-pentax-xo-orthoscopic-5mm.html

Also, here is a relevant thread from the "Cloudynights" forum:

Telescope Reviews: Should I own a Pentax XO 5 ?

The best 5mm I've used so far has been an 8mm Ethos combined with the Antares 2" 1.6x barlow lens - I've been amazed at what this combination can do and, to my surprise, it shows more planetary detail and contrast than my 5mm T6 Nagler does (which is no slouch itself).

The Pentax XO 5mm seems to be up there with the very best but the eye relief is pretty tight on it and for that reason some prefer the Pentax XW 5mm which offers superb performance coupled with comfortable eye relief.

Your plan of trying a 5mm ortho is probably a good one - if you are OK with the eye relief on that then the XO5 might be a great step

[Kef9]

Yep, I read those. I would just like to talk to someone on here that actually has one!

Interesting about the 8mm ethos and antares barlow! I was looking at getting an 8mm ethos but just realised that with the Antares barlow my 13mm would turn into an 8mm ethos with the barlow put after the diagonal (1.6x) and turn into a 5mm ethos with it before the diagonal (2.4x mag). Very interesting as those are the 2 focal lengths I'm after. Thanks for that suggestion. It could be the cheap answer!

How does the antares barlow effect eye relief? Do you get blackouts, kidney beaning etc? Does it affect light throughput? Also does it have compression rings?

[xboxdevil]

Cough...here was me thinking that my lovely TMB Planetary eyepiece clones were the bees knees....

[John]

I've not noticed any of the defects you list when I use the Antares 1.6x barlow with the Ethos - it just seems to "get out of the way". The eye relief must be lengthened to some degree of course but I've not noticed and problems because of that. The Nagler T6 is a fine eyepiece so I was surprised that the barlowed Ethos was consistently showing slightly better contrast and more detail on Jupiter and this has happened on a number of occasions with different scopes and seeing conditions.

Of course the combination is rather bulky, but its still manageable I feel. Trouble is the experience has convinced me that I need another Ethos now - they really are remarkable eyepieces

[dweller25]

I ended up buying the 5 and 7mm Pentax XW's and a 12mm XF. I have compared then to the Baader 5, 7 and 12.5mm Orthos.

The detail shown between the two sets is the same. The Pentax's pick up more of my local light pollution and 'appear' to have less contrast in the overall field of view but when just looking at the planets surface they are the same.

The eye relief on the Pentax eyepieces is just what I was looking for - they are very comfortable - but you have to pay a big price to get it !!

The Baader Orthos (and TV Plossls) represent astonishing value for money if you can live with the field of view and eye relief.

[Marmite]

Pentax XW, Takahashi LE, Nagler T6, in that order.

(I haven't used any of the others listed.)

[Moonshane]

I have not used a Radian as short as 5mm but have used an 8mm, 14mm and 18mm; I still have the 8 but sold the 14 and 18 to get the 13mm Ethos. in my view these are superbly sharp, contrasty and comfortable as well as being reasonably cheap used. I'd highly recommend them especially at the shorten end.

You'd be welcome to try my 8mm in your 2x powermate sometime which would give you a broad idea and be a lot more manageable. If you bought a 10mm then with your 2x PM this would be a good combo.

ps I know cost comes into this but think about practicality - I recall the comparison between your SW 5-8 zoom plus 2" Powermate 'baseball bat' and my 6-3 Nagler zoom. I feel the right tool for the job is better even if you have to save longer to get it.

[Kef9]

I've not noticed any of the defects you list when I use the Antares 1.6x barlow with the Ethos - it just seems to "get out of the way". The eye relief must be lengthened to some degree of course but I've not noticed and problems because of that. The Nagler T6 is a fine eyepiece so I was surprised that the barlowed Ethos was consistently showing slightly better contrast and more detail on Jupiter and this has happened on a number of occasions with different scopes and seeing conditions.

Of course the combination is rather bulky, but its still manageable I feel. Trouble is the experience has convinced me that I need another Ethos now - they really are remarkable eyepieces

Yep

I think it might be okay to use 1.6x but I think 2.4x might be pushing it a bit on the eye relief. There surely would be no way you could see the whole 100 degree FoV I think but I maybe wrong. Very interesting remarks about the nagler.

I ended up buying the 5 and 7mm Pentax XW's and a 12mm XF. I have compared then to the Baader 5, 7 and 12.5mm Orthos.

The detail shown between the two sets is the same. The Pentax's pick up more of my local light pollution and 'appear' to have less contrast in the overall field of view but when just looking at the planets surface they are the same.

The eye relief on the Pentax eyepieces is just what I was looking for - they are very comfortable - but you have to pay a big price to get it !!

The Baader Orthos (and TV Plossls) represent astonishing value for money if you can live with the field of view and eye relief.

From what I've read the XW is 95% performance of the XO but with generous eye relief and more FoV. It seems like the XW is a step above the naglers in term of performance and on par with the ethos. I would love to look through one. Seems the most sensible choice.

ps I know cost comes into this but think about practicality - I recall the comparison between your SW 5-8 zoom plus 2" Powermate 'baseball bat' and my 6-3 Nagler zoom. I feel the right tool for the job is better even if you have to save longer to get it.

Yes that combination does have its problems but it wasnt helped by the fact that the tripod was set at maximum height. Back home I take the tripod lower which then allows you to look in a natural position. This however is a pain because you then have to raise it again when looking through normal eyepieces. Remember though that this only applies when you want the 4-2.5mm range due to the extra length of the powermate.

The eyepiece does have its problems. When I compare it like for like against the ethos powermated to give 6.5mm the image is definitely not as bright (for the money though what do you expect ) and also there is the dust problem which only became noticeable for some reason when powermated to 2.5mm. I dissapears at the other settings for some reason? However these are negatives I can live with because I love the big FoV (upto 89 degrees) and zoom practicallity. For the money I paid it was an excellent purchase and I think I will never let it go.

To finish I think for me 5mm is the best setting for planetary with maybe a 4mm or 3.5mm useful for when seeing is very good.

After all the comments and to summarise here is what I think if I'm after ethos like performance at 5mm (minus the 100 degree FoV).

I don't think the T6 naglers can cut it at this level.

A 3.5mm XW and 5mm XW seems the most sensible choice.

Not sure about the radians although I like the instajust.

The 3-6 nagler zoom would be very versitile and cover all bases.

The XO would give the ultimate view if I could take the eye relief.

I dont feel a 3.7mm ethos would be worth the money but I could be wrong.

The baader orthos could be the most cost effective solution if I again could handle the eye relief.

Are there any othger eyepieces that I'm not considering? What do you guys think?