Pentax SMC XW10mm vs TV Delos 10mm

[issdaol]

Hi All,

Received my First Pentax Eyepiece Yesterday a SMC XW 10mm, (:thumbsup:fok4tel ), for a second hand unit it appears to be in Pristine Showroom Condition.

Assuming clear skies and no other interruptions I plan to do a direct comparison of this against my TV Delos 10mm which should arrive tomorrow afternoon.

Some first points to note for the Pentax is:

The packing and supplied documentation is very good.

The Pentax comes with a Bolt Case and 2 foam inserts in the case to protect the EP. It has good Top and Bottom end caps.

The supplied documentation clearly describes all the physical construction parameters of the EP such as:


Weight 405g
Lens Construction 7 elements in 6 groups
AFOV 70deg
ER 20mm
JIS Class 4 Waterproof

Exact dimensions

Overall the Pentax appears to be extremely well constructed similar to what I would expect from Takahashi or other professional Astro Company.

I was very surprised by the inbuilt EP Height Adjustment. Simply twisting the top part of the Eye Cap makes fine adjustment in height of the EP/Cap. First thoughts are that this is very nice but I will reserve judgment for how it works out practically.

Keep an eye out for the direct comparison which I will add to this post as it moves ahead.

[ausastronomer]

Hi Phil,

I am eagerly waiting to see the results. My gut feeling is that they are going to be very close optically and it will come done to very minor subtle differences between them, as to why you would prefer one over the other.



Is the purpose of buying both to see which of the two you prefer and then you will keep the one you like best and sell the other one?



The Pentax is a very high quality product, in every respect. Particularly when you compare it to something like the floppy and rattly instadjust setup on the TV Radians and Nagler T4's. Shake a TV Radian and you're almost guaranteed to get a rattle from the slop in the instadjust. It sounds like something is loose inside the eyepiece, but it's only the instadjust. Some are less rattly than others. Some almost don't rattle at all, others sound like a baby's rattle.

That having been said, Televue have addressed this issue and the DELOS also has a really nice eyeguard adjustment system. It is a split system with a lock ring and you slide it up and down the barrel, then turn the lock ring to lock it in place. It has graduation marks on the barrell so you know the relative position of the eyeguard it all times. Shake the DELOS and it doesn't rattle. It's a high quality product also. I really like TV's new system. Why did it take Televue 15 years to address the instadjust system?



I am not sure if you have used eyepieces with long eye relief and an adjustable eye guard before? If not some advice.

The following applies to both the Pentax XW and the DELOS. It is important that you spend the time to set the eyeguard height correctly to suit you. This can take some experimentation if you haven't done it before. Once you get it set right for your own needs you shouldn't have to adjust them again.

As a rough guide if you wear eyeglasses start with the eyeguard about 20% of the way up from its lowest position. I have mine up just far enough so that the lenses of my glasses cannot make contact with the eye lens of the eyepiece. Take your glasses off and hold them against the eye guard of the eyepiece to check this. This is important. If the two glass surfaces contact you can destroy the coatings of both.

If you don't wear eyeglasses start with the eyeguard set to the very top position. This will act as an "eye guide" and make it a lot easier to hold the exit pupil and eliminate "blackouts". I know of a couple of people that bought a Pentax XW, left the eye guard right down, experienced horrendous blackouts and quickly sold the eyepiece, without even being aware the eye guard was adjustable.

Once you get your Pentax XW set correctly you will find it to be an extremely comfortable eyepiece to use for long periods and very "eye friendly". I haven't used my new 6mm DELOS yet but I am assuming it will be similar to the XW's, based on the eye lens and eye guard design.

Good luck with them. They are 2 high quality products.

Cheers,
John B

[ausastronomer]

Phil,

What scopes are you going to use them in besides the Takahashi Dall Kirkham Cass?

Cheers,
John B

[wavelandscott]

I think this is particularly sound advice as for non-eyeglass wearers eye placement in the Pentax is a little different than some other eyepieces.

It is not difficult, just different and once you get it figured out the eyepiece is a gem!

[issdaol]

Hi John,

Thanks for the thoughts and input



At this stage the plan is to keep the one I prefer the best. However I do tend to hoard some things :) so one may just be a spare or for simultaneous use when I finally get my grab-n-go scope.



I have not used EP's with such long eye relief or adjustable eye guards extensively so this is great advice :thumbsup:



I plan to use mainly with the Tak Mewlon 300. However I have been looking around for a grab-n-go scope recently. I have narrowed down to a Tak TSA 102 or TSA 120 or a Japanese Made Vixen ED103. I am not terribly interested in Astro-Photography so my principle use is Visual Observation.

[issdaol]

Sorry for not completing this discussion. A combination of sickness and bad weather have conspired to stop me doing any observations.

However for a price which was way good to refuse :D I have now purchased a Takahashi TSA-120 and iOptron Minitower Pro Mount as my "Grab-n-Go" system :). It is meant to arrive within the next 2-3 weeks.

So I will continue the comparison then but also include side-by-side comparison of each EP in the Mewlon 300 and the TSA-120.

Cheers

[AG Hybrid]

Will be interesting to read your thoughts. According to other who have done the same comparison, you will find that the Delos will have a warmer tone. i.e when looking at the moon it will be slightly yellowish. Very slightly.

[MortonH]

Just received my 10mm XW today. No car available tonight so I spent an hour on my balcony with my 80mm ED scope surrounded by various blankets and towels to block out all the stray lights.

I don't have a 10mm Delos for comparison but I do have a 14mm Delos which I've used a couple of times. It does seem that Tele Vue have gone for a similar design to the XW, but they definitely haven't captured the Pentax comfort factor that John mentions above. My Pentax XL 21mm is the most comfortable eyepiece I've ever used, so much so that I've bought various other eyepieces over the years to replace it but always kept it in the end.

The 10mm XW feels very similar to my 21mm XL. Very easy on the eye. And it does seem to have a certain penetration even in my light-polluted location. I'm looking forward to getting out under a darkish sky.

[AG Hybrid]

When I first used my new Pentax 10mm XW I had buyers remorse. I though the view was not as good as I was hoping it would be. I thought from what I had heard and read that the view was incredible and magical, like Steve Jobs trying to sell you an over sized iPod touch. I thought the view just wasn't worth that extra premium.

The key word being "thought". It's kind of hard to put into words what I'm thinking right now. But, you will get the idea.
I've now had the opportunity to use it about 5 times. On both my AR102 and 12" newt. I've done side by side comparisons with my current ES eyepieces and I've learned a couple of things. I learned that eye-relief and thus comfort is really an under-rated feature of eyepieces. Being able to sit at the eyepieces and look through for extended periods while attempting critical observations is appreciable. Another thing I learned is that the improved sharpness and improved contrast of the Pentax eyepieces is really there and it's noticeable. They are worth the premium. The 70 degree field of view is still an appreciably wide field of view, and allows enough time for objects to drift through the field of view in a non tracking scope. Even though I'm now used to 82-100* eyepieces. Most importantly I get the feeling that I am actually looking through my telescope at the sky and not looking at something in the eyepiece. I guess that's the product of the whole "port-hole on space" theme the hyper wides are marketed as.

All in all its left me with a dilemma. Right now I am deeply considering selling my 6.7 mm, 14mm 82* degrees eyepieces and my 9mm + 14mm 100* degree eyepieces and replacing them with a 6mm or 7mm and 14mm 70-72* eyepieces.

The question is do I get a 6mm and 14 mm Delos or a 7mm and 14mm Pentax XW.
I can get the 2 pentax eyepieces from the US for about $580 including shipping, or a 6mm Delos and 14 mm Delos from Bintel which has them extremely well priced at the moment, but they still work out to be more then $80 more then the 2 Pentax's. Not an easy decision, but I suppose from a certain point of view an enviable one as well.

[MortonH]

Nice dilemma! As someone said to me recently, the Pentaxes are no longer being made and therefore willl be even more "premium" in the future. That partly influenced my decision to get the 10mm XW over the Delos.

I was also tempted to go for the 7mm but the money was running low so I went ES 6.7mm instead.

[ausastronomer]

Hi Adrian,

In an F5 scope you may or may not find the slight field curvature of the 14mm Pentax XW tolerable. If you use a paracorr it flattens the field beautifully but I don't think you have a paracorr? At the 14mm focal length you may find the 14mm Delos a safer bet if you don't have a paracorr.

I haven't spent very much time with the 6mm DELOS at this stage, as weather has been really bad here for several weeks. However, my one night to date using all the 6mm eyepieces subject to my review and also the 7mm Pentax XW is that of the two I prefer the 7mm Pentax XW. It is a bit more comfortable, easier to hold the exit pupil and is better corrected at the EOF in a fast newtonian. The differences are subtle but of the two I prefer the 7mm Pentax XW. The DELOS is very good and I will definately be keeping it, but you asked "which one".

When you have used that 10mm Pentax XW 500 times not 5, you will really get to appreciate what a good eyepiece it is. It just keeps growing on you. The 7mm is every bit as good as the 10mm. The 14mm is excellent on axis but not quite the equal of the 5mm, 7mm and 10mm at the EOF if you don't use a paracorr.

Cheers,
John B

[AG Hybrid]

Think I'll just save my money and get a Paracorr type 2 and improve the quality of all my eyepieces. While not an inexpensive solution, it is less expensive then 2 more eyepieces.

[Ian Flowes]

I did a comparison between my XW10 and XF8.5
Had them for a year now and had used both side by side for about a dozen times.
Except for a slightly smaller fov on the XF, I have to say, I could not see any difference in performance!
Optically, contrast, sharpness and on and off axis performance, the XF is just as good. I am thinking of selling the XW10 now and use the money to buy the XF12 and an ES6.7.

[AG Hybrid]

Just bought the 8mm and 14mm Delos from our friends at Bintel. Hopefully I'll get a chance to try it out tonight. They will complement my 10XW nicely.

[AG Hybrid]

Well, I did get to use them. They are absolutely superb. The comfort is excellent. With the soft rubber eye cup they felt a bit more comfortable then my XW10. You can sort of just rest for face on the eye cup. No difficulty in eye position what so ever, much like the XW10. Contrast, color tone, sharpness and light through put is near as makes no difference as good as the XW10. No perceivable coma in stars at the outer edge at F5 in any of them.

I think the raise-able eye guard in the Delos is better then the XW10. Considerably quicker to put into position. But, that's a moot point really when you only have to put the eye guard up once at the start of the session.

The XW10 however, clearly does a better job on light scatter on really bright objects like Jupiter and Sirius. The Delos were still just as sharp but the XW10's view had almost no light halo around the object. It was obvious on Jupiter at first. But, if you can focus your eye on your target it sort of disappears and you don't notice it there after. Another place where the XW shows its strength is its size. Definitely smaller then the Delos eyepieces anda bit lighter too.
But, the 8mm Delos and the 10XW beautifully split Sirius at 187x and 150x respectively. Sirius B is hiding in a diffraction spike for me so I was not able to see it at 107x with the 14mm Delos.

On Jupiter. I have to be honest. Ive never seen a better view then I did last night. The 8mm Delos and 10XW showed me things I had never seen before. I could see clearly 4 bands. The GRS was clearly visible in both the 8D and 10XW. The bands were not just brown lines either smeared across the front of a ball. I could see swirls, wisps and other shapes as well. It was truely marvelous.

Deep sky all these eyepieces were sharp as a tack. Easily seeing E and F star in the Trapezium in Orion with the 14mm Delos at 107x. The contrast and the sharpness brought out very impressive detail in the nebula even though I was observing right in the center of Sydney. The view was naturally only improved even further with the introduction of a UHC filter.

I was able to observer a small handful of open star clusters. They both perform fantastically. Completely flat fields and tack sharp stars from edge to edge. Its amazing how sharp,tight and pinpoint stars are in these eyepieces. I thought I was looking through my AR102 instead of a Dob with diffraction spikes.

I would have looked at more target but the clouds rolled in. All in all a good first light for my 2 new Delos. Definitely keepers indeed.
It means in the new year though I'll selling 4 of my ES eyepieces. Not my 30mm ES though. You'll have to pry that one from my cold dead hands. :) I might use the funds raised to get a XW7. 214x is a nice mag boost from the 8mm, but still useable most nights. Don't think I'd get the 6mm Delos though. 250x is just too much to be regularly useable.

To answer the question of the difference between the 10mm Delos and the XW10. Don't think it really matters. You cannot possibly go wrong with either. :)

[MortonH]

Sounds like a great night and some great purchases!

[bytor666]

Nice report Adrian! :thumbsup:

[Suzy]

Awesome report Adrian! :thumbsup:

Just curious- And I'm pretty certain the ES wouldn't rate as well as the XWs & Delos, but at some stage can you do a side by side comparison with the XW? I'm curious to know how much of a difference there is.

I read in a Cloudy Nights review here (http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/3819290/Main/3815434)regarding the with 82deg 4.7mm, there was an issue with glare from bright objects out of the FOV.

The great thing about premium eyepieces as you've just found out, is that they show so much more detail and colour and make those hard to see faint fuzzy things suddenly pop into the eyepiece. :D I really feel the telescope isn't done it's true justice without them.

[AG Hybrid]

I agree. I think premium eyepieces can make an ordinary - mass produced telescope into something special.

In regards to comparing the ES 9mm 100 and Pentax 10XW are pretty close in magnification so I don't see why not.

Speaking of the 82 degree range I had another look through my 6.7mm ES. Forgot how good an eyepiece it was. I'll be keeping that one and let the 7XW slide. Might throw it in the comparison as well.

[Suzy]

Oh yes, please do it on the 7mm as well!

I look forward to your report when you have time Adrian, thank you. :D

[Varangian]

Agree. I had a 7mm XW and couldn't tell the difference so I kept the ES 6.7 with its superior FOV. I've just purchased my first Tele Vue - a 10mm Delos and I'm a bit concerned about approaching a slippery slope.