Pentax XW 10 & 14 mm first light.

[Dave47tuc]

I finally had my chance to use my new Pentax’s. The 14 mm and 10 mm XW.
I quick comment on build quality, all I can say is 10/10.
Well I finally got to observe last night with a few friends Geoff, Mark and Julian.
I was so keen to get a look at these pentax’s. The night was partly cloudy with seeing around 7/10 (correct me if I’m wrong Geoff) Anyway first light was Saturn with the 14 mm. Nock my socks off sure did, what a super sharp image. Eye relief is great in these eyepieces. But you do need to get use to putting your eye in the right spot. If you move too much you can get black out. Once I got use to using them it was not a problem.

The image was clear and clean, only colour was that the Maksutov gives a warm colour on planets and the Moon. No ghosting or light scatter.
Geoff and I where able to compare his XL 14 to my XW 14 mm. Apart from field size that the XW was a little bigger. I personally could to see any difference on this night.
Geoff thought the background was a little darker in the XW but I found it hard to see that.
Stars are pinpoint across the whole field in the Mak.
Jupiter was a high light, in either eyepiece it was a very sharp clean image only limited by the seeing. Image was warm again due to the scope, any colour was atmospheric.
The blue yellow on each side of the Planet is not the eyepiece it’s the atmosphere.
So I’m very happy with the Pentax’s and look forward to many a night with them.
Highly recommended.:thumbsup:

[Starkler]

Hi Dave, if you say the seeing was 7/10 I wont argue with you. I dont bother with trying to put a number to it without a meaningful frame of reference.One persons 7/10 might be anothers 8/10 or 5/10 :shrug:

My seeing scale goes something like this:
Dont bother, crappy, average, above average, good, excellent and woohoo !

I would have rated it as "above average/good" with moments of good to excellent ;)



I noticed that the XW with its slightly wider field than the XL, that the eyecup cannot be wound up as high and still allow viewing of the full fov.
The eyecup on the XL allows you to set it and puts your eye easily in the right place everytime and may have a small advantage over the XW in this regard. Its not a big issue and I certainly wouldnt say that the XW is hard to use.



Maybe I only saw it because I read a very in depth critical review of the XL vs XW (http://www.cloudynights.com/documents/pentax.pdf) here.
I thought I could notice a slight brightening of the background between members of the star cluster we were testing on using the XL. Its hard to be sure about such minor subtleties as the minds eye can loose the real picture in the time it takes to swap over an eyepiece. Maybe it was in my imagination planted by the suggestion in the article :shrug:

Conclusions: Both the XL and the new XW are great eyepieces with very little difference between them :)

[Miaplacidus]

Yeah, well I love my 10mm XW. I've read about this critical eye placement thing, but I can't say I've ever had a problem. Others say they take time to get used to, but frankly it was a lot easier to use straight off the bat than some Naglers I've used. And for on-axis sharpness it's a killer.

[davidpretorius]

thanks guys, pentax it will be for me in a decade or so!

[Starkler]

Come on Dave, you can afford it if you sell your imaging gear ;)

[davidpretorius]

hmmmmmm, toucam + 5 x powermate = $500 = 1 pentax only.

anyone want a heavily modified scope so i can buy a second pentax???

then anyone got a scope they would like to donate to me to use my 2 pentaxes with??????

[ausastronomer]

Hi Dave,

I am glad you are happy with them. I knew it would be a foregone conclusion however its always satisfying to know that someone is happy with their sizeable investment. Particularly when you have been one of the main proponents of the product.

CS-John B

[Dave47tuc]

Good one John,
The more I thought about the viewing the next day, I thought geez those Pentax's are so nice.
The biggest thing was how clean and clear the image was(if you know what I mean):rolleyes:

On another note my LVW 8 mm has arrived. Must say the build quality is just as good as the Pentax's:thumbsup:
Looks like another winner.;)

[janoskiss]

I've had my XWs out a few times now too, in both Dobs but not yet in the Mak, and they are bloomin marvelous indeed. :)

[ausastronomer]

Dave,

I know exactly what you mean and they keep growing on you. As your time with them increases you will like them more and more. A superb product and worth every single cent of the high price IMO.



Glad you liked that one as well. Another of my favourites.

If the few of us yell loud enough and long enough, others may realise there are companies in the world in addition to Televue who make outstanding eyepieces. There are many good choices, it isn't the closed shop that many people seem to think it is. Televue make some great eyepieces, but there are others just as good and some better in certain focal lengths and applications.

As I mentioned in another post a few weeks ago, the 21mm Denkmeier eyepiece I used out at Coonabarabran is also an outstanding eyepiece and worth a lot of consideration if your looking for either a 14mm or 21mm focal length eyepiece. The big advantage of the Denkmeier eyepieces is they are only 1/2 the size and weight of the Vixen LVW's and superb optically with 20mm of eye-relief.

CS-John B

[Starkler]

John if I recall correctly, you used to own a couple of XL's that you replaced with XW's. Do you notice much of a difference between them ?

[circumpolar]

Hi members,

I remember reading in the IIS Reviews(13mm Nagler T6 shootout) that the Pentax XW14mm suffers from edge coma.

Can other member confirm this?

Maybe it's only a prob with 10" dobs:shrug:

Thoughts...

[RapidEye]

No, it is field curvature - but not really that bad.
I've got the 7mm, 10mm, 14mm, and 20mm XW's - they are all outstanding EP's, with the 7mm and 10mm being amazing!!!
The 14mm has a touch of curvature and the 20mm has a touch more.
Both will still blow away any plossl you compare them too ;)

CONGRATS DAVE!!!
Once you cross over into the cult, er, I mean, club, you'll never look to another EP manufacturer :thumbsup:

[ausastronomer]

Geoff,

No I used a couple of Pentax XL's a few times, the 1st time in Florida about 5 or 6 years ago, which ultimately caused me to buy 4 Pentax XW's, when they came onto the market.

There is not much difference between them but I have never A/B'ed them either. You have to assume that the XW's are marginally better due to technological advancement with glass types and partial phase coatings. As Al Nagler was recently quoted in Astronomy Magazine, "We discontinue an eyepiece only if we can make a better one of that focal length"

CS-John B

[janoskiss]

Yes, as RE pointed out this is due to some field curvature, which I was going to mention but I wanted to wait till I tested mine in the 4" Mak.


No it is not just fast dobs. The field curvature (FC) is a property of the eyepiece itself and it is a gradual shift in focus from centre to edge (so you have to refocus for sharp stars near the edge compared with those in the centre). It is quite obvious with the XW14 in both my Dobs f/5 and f/6, and in the f/13 Mak, as well as in a barlow in the f/5 Dob (effective f/11). I have also seen similar FC with Geoff's XL14 in an ED80. It was rather annoying when I was trying to hunt for planetaries the other night. I'd think I found one near the edge only to realise it's just a defocussed star.

The FC can be most dramatically observed on omega centauri. In the 12" it fills the FOV of the XW14 and then some. If you place the glob in the centre and focus and then shift it to the edge it goes from tack sharp to fuzzy. With the glob's centre on the edge of field, you can clearly observe the field curvature. It starts at about 50% of the way from centre to the edge, and becomes quite severe in the last 10 or so degrees. A large aperture that brings out lots of stars helps to see what is going on. To perform the same test with the small Mak I'd need much darker skies. But shifting a single bright star across the field confirms the FC is present with the Mak too.

The FC is a bit of a shame and I can understand why it made Mike prefer the 13mm T6 Nagler over the XW14 in his review. But the T6 has other shortcomings which I consider more of an issue.

[Dave47tuc]

Well I was able to observe again last night for 3 hours.
Seeing was not as good as a couple of nights ago. But was able to use all of my eyepieces.
The Pentax’s again excelled. I just can’t believe how good they are. In my Mak, just so sharp. I screwed my eyecup up a bit more and found that more comfortable to use.
IMO these pentax’s for me are a lot better than naglers. The eye relief alone to me makes them better. Colour is warm in the Mak, as it is. But edge-to-edge it’s sharp as a tack!:eyepop:
I do not notice any field curvature in the 14 mm!

As for the 8 mm LVW it is a high power Ep. But I did like eye relief it was very easy to use. A very nice field size. Seeing just was not up to using it often. But when I did I thought this one will be very good also. As I said build quality is as good as the Pentax’s.:thumbsup:
All in all I’m very very happy with these eyepieces.;)

[matt]

Dave

I'm also very happy with my EPs which are also pretty much just Vixen LVWs and Pentax's.

I believe anyone who gives the XWs and LVWs a fair try will be very quickly won over.

They are excellent.

[Dave47tuc]

Fully agree Matt.:thumbsup:
I must admit I have been in the past, oh TV only but thanks to John and Geoff, who's XL's I have tried. I'm very happy I have these eyepieces.

I URGE people who are looking for high end eyepieces take a good look if you can at Pentax and Vixen LVW's:eyepop:
Once you use them you will buy them.:D

[janoskiss]

But some people just cannot do without that last 10 or so degrees of 80+ degree ultrawides and then choices are rather limited. :shrug:

I don't see the need for anything over a 70 degree field as the very edge of field of ultrawides is very difficult to see without pressing your eyeball against the lens and/or getting blackout & kidney beaning.

I personally think the XWs are a winner. Funny thing is that I took a lot of convincing because when I tried one of Geoff's XLs last year I found it really hard to look through; prone to blackout. All I needed to do is adjust the eyecup. :rolleyes: Now I'm finding them the most comfy EPs ever once adjusted. Goes to show you trying EPs at star parties is not always all it's cracked up to be. :P And like John B says, you don't appreciate the more subtle but important aspects from the quick looks you take at such events.

[ausastronomer]

Life does get far worse than this Matt. I went there as a student with no money and a couple of Unitron orthoscopics with about 3mm of eye relief each, which weren't petty cash at the time either. At that time I thought I was in heaven, how little did I know :)

CS-John B

[ausastronomer]

Lucky Man !!! I made friends with a bottle of Bulleit Bourbon and enemies with my wife. Observing wasn't an option, wrestling was :lol:



Every time you come back from an observing session with these eyepieces for some time still to come, little things are going to stick in your mind, where they continue to show you little subleties, where they excel and grow on you. They continued to grow on me for 2 years. They just got nicer and nicer, as I continued to appreciate how good they were.

Someone else mentioned the minor field curvature in the 14mm Pentax XW. I am prepared to forgive it this little sin for everything else that it gets right and does exceptionally well. It does not have quite as flat a field as the 13mm Nagler T6 but it gives it a bit of a shakedown in most other critical aspects IMO, particularly on axis sharpness, light transmission and contrast. Funnily enough, I read a comparison today on Astromart, albeit an old one, where the reviewer compared the 13mm NT6 and the 14mm Pentax XW. He rated the Nagler sharper on axis than the Pentax. The only conclusion I could draw from his review is that I don't want to end up with his eyesight :)

In respect to the longer focal length 20mm range, I rate the 21mm Denkmeier as the pick very closely followed by the 22mm Vixen LVW then the 24mm Panoptic.

CS-John B

[Dave47tuc]

Well it’s cloudy and not much happing at home.:rolleyes:
So I have been browsing the net as we do on scope stuff and thought I would stay on the Pentax bandwagon and found a nice read why you should buy these wonderful eyepieces.:thumbsup:

http://www.cloudynights.com/item.php?item_id=1353

:)

[janoskiss]

I read that review before. The reviewer is perhaps a little over-enthusiastic. :rolleyes: He claims that "Pentax has stated that visible light transmission is 98%". That would be excellent even for a plossl or ortho. Pentax's own figures give a peak transmission between 95 & 96% (depending on focal length, at yellow-green 550nm), dropping off to about 90% at the red and violet ends of the spectrum: http://www.pentax.co.jp/japan/tech/xo-xw/63.html

Not saying that this means the eyepieces are no good (and indeed the figures are very impressive even if they are not an impossible 98%!), but one exaggerated claim like that can diminish the credibility of a whole review.