Which 5mm Eyepiece?

[Greenswale]

I need to determine which high quality 5mm eyepiece will go best with my soon to arrive custom 8" F6 dob.

Stuff to consider: planetary stuff will not be my highest priority; I like wide field views, I am over 60 years old; not too pleased with short eye relief; quality is more important than $, up to a point (!).

What suggestions?

In anticipation,

Wren

(I will not be able to respond to replies for a couple of days, going bush....)

[dannat]

how much or what price range are you looking at? low(<100), medium 200-300 or high 500. i have noticed in this size range...5mm only the premium $500 ep's will be good - the others do not quite cut it.

One option you could consider in the medium range is the WO spl 6mm - at $130 it gives reasonable views, has good ER and has about 60 deg fov.

[anj026]

5mm equals 240x in your 8" f6 dob. This is high power that you may not be able to use very often depending on your seeing conditions at the time. If you are not really interested in planetary and want wide field views you may be better served with a 10mm Pentax XW or 9 or 11mm Nagler and a top quality 2x barlow. If you really want a 5mm with the widest field then go for the 5mm Nagler, 5mm Pentax XW or 6mm Ethos. Pentax has the best eye relief.

[PhilW]

What about the Pentax XW 5mm? It has a great balance of qualities including good eye relief. The XWs are also fine planetary eyepieces, which is a bonus. Alas, the plummeting exchange rate has made it a more expensive proposition, albeit still cheaper than a Nagler (US $360 at Optcorp).

A cheaper alternative, with similar eye relief but slightly narrower field of view, is the Vixen LVW 5mm.

Having made those suggestions, I take Andy's point. It is at the high end of useable magnification for your scope. You'd probably find a 10mm XW more useful (120x with a 1.7mm exit pupil).

[Greenswale]

I'm still here....!

Thanks for the quick replies.

A couple of points. I have a Pentax 10mm XW and like it lots; I am assured that the scope's optics will handle the magnification with ease; seeing conditions agreed!; I would expect cost to be over $300.00; as it will be high magnification in the scope, quality of image is paramount.

Thanks,

Wren

[dannat]

if you've got the 10xw, why not get a good quality barlow?

[allan gould]

I have a 5mm Vixen LVW (as well as all the others). I find them sharp, excellent eye relief and all are absolutely parfocal as a set. I upgraded all my eyepieces to the vixen LVW as I had not found any thing to touch them at the price.

[mick pinner]

l agree with Allan, also the LV Vixen range. all have 20mm ER and they are great eyepieces. Pentax and Televue are just way to expensive IMO.

[erick]

What about Paddy's Orion Stratus 5mm?

http://www.iceinspace.com.au/forum/showthread.php?t=38456

[Miaplacidus]

Well, I've used 5 mm EPs on my 8 inch dob for some of the best views of Jupiter ever, so it can be handy to have, although it is one of my least used eyepieces. (I can justify it by using it in my refractor.)
If cost isn't an issue, then the Pentax XW is the go. Value for money, then maybe the Burgess/TMBs Planetaries (if they make a 5mm).
I have the LVW, and it is very good, better than the Radian, but weightier. (I'm coming round to wanting lighter, smaller eye pieces, but with generous eye relief, which is actually a bit of an ask.)
I guess no one is going to mention the Televue 3-6 mm zoom...
Good luck with the quest. I'll be interested to hear how it turns out.
Regards,
Brian.

[Starkler]

Gets my vote :thumbsup:

If you're a purist and want a 5mm ep , you cant go past the 5mm XW if you want best performance and eye relief.

[ausastronomer]

Hi Mick,

I don't necessarily agree.

When you get to the top end of any product range in terms of quality, all small incremental gains in performance cost a disproportianate amount of extra money. This doesn't just apply to eyepieces or astronomical equipment. It applies to just about everything that's bought and sold. It depends on your performance expectations, how serious you are about visual observing and how much money you've got. I concede the Vixen LVW's represent exceptional value for money. In the short focal lengths they are not the equal of the Pentax XW's, notwithstanding they are excellent performers. I am happy to pay the premium for a 5mm Pentax XW over a 5mm Vixen LVW.

Cheers,
John B

[toyos]

This applies to a much lesser extent for luxury goods where the 'prestige value' plays a more important role, not gains in performance (ep's aside since they're not luxury goods). One common example is sports cars, my late-model Porsche gave me less performance and way more problems than the Nissan that cost me significantly less. Even the build quality was questionable. That's one of the reasons why Porsche Group's net profit for 2007 was 57% of the total revenue (= overpriced products that were made at relatively low costs), some people are prepared to pay the premium for the prestige, not necessarily the performance or even quality.

[ausastronomer]

That's actually not correct and in fact you have used an extremely poor analogy. You are forgetting that over 50% of what you paid for the Porsche went to the Government in Excise and Luxury Car Tax and didn't in fact go to anyone connected with Porsche. Buy a Porsche in the USA and proportionately relative to the Nissan, it will cost a lot less than it does in Australia. In fact, Luxury cars in many "advanced" overseas countries aren't that expensive by comparison to the mass produced cars.

I have owned two BMW's, a Jaguar, a Mercedes and a Lexus. Were they worth the money? Outside of the Lexus which was an outstanding car, the answer is probably no. This is because of the inflated prices due to Government taxes in Australia. Ask the same question to a person in the USA, who pays $US 25k for the Nissan and $US 30k for the BMW, and the answer will be "yes". Are they better cars than the mass produced cars which cost a lot less money? Without question, irrespective of the cost or the country you buy them in.

Cheers,
John B

[Miaplacidus]

Yeah, get that Lexus 5 mm. It'll do you for a lifetime. (Although you might have some balance issues...)

:)

[Dave47tuc]

5 mm Pentax XW. No ?
Or Penatx XW 10 mm. Plus 2 x Barlow as was pointed out elsewhere.:thumbsup:

[Greenswale]

It's great to be back in town, sort of. A weekend doing stuff in the Falls Creek hinterland does wonders for the soul, sort of like looking through a really nice eyepiece...?!

Back to the now. Thank you for the many relies. Outcome - very likely a Pentax 5mm XW. If it is in the same league as my 10mm XW, all will be well. There may be other cool eyepieces around though......

Despite the advantages, a barlow will not happen, because of the additional losses that it will introduce to the system.

And on the subject of cars, here's a torment. I drive a Land Rover!

Thanks to all,

Wren

[Greenswale]

Hmmm.

I've been thinking about the suggestion that magnification with a 5mm might restrict usefulness to really good seeing conditions. Maybe a 7mm would be a better idea, being likely to be more useful more often.

I'm still pretty set on a Pentax XW, but can anyone offer comparison between the Pentax and a Takahashi 7.5mm?

[wavelandscott]

I can't speak for the Takahashi...I imagine they would be nice.

I can speak for the Pentax XW 7 mm and 10 mm...they are both fine eyepieces...If you like the 10, you will like the 7 too!

[ausastronomer]

Hi,

I think the 7mm will be a better focal length for your needs.

In comparing the 7mm Pentax XW and the 7.5mm Takahashi I can offer the following. Optically on axis there isn't a lot between them. Maybe a slight edge to the 7mm Pentax XW but it is pretty close. The 7mm XW is slightly cooler (whites are whiter) in its colour tone, which I prefer. The FOV of the Takahashi is significantly narrower and the eye relief is a lot tighter. If you prefer longer eye relief you won't like the Tak.

Of the two, I would be buying the 7mm Pentax XW each and every time, if the additional cost isn't a serious concern.

Cheers,
John B

[PhilW]

I've owned both of them, & sold the Tak LE 7.5 in favour of the XW 7. The Tak is an excellent eyepiece, but the greater comfort & FOV of the XW won out for me too.

One slightly cheaper alternative: you might be able to find a used Pentax XL 7mm (the model that preceded the XW). The FOV is slightly narrower at 65 degrees, but a fine eyepiece nonetheless.

[skies2clear]

Hi Wren,

a lot of good stuff already said about the XW's which is true. Given planetary is not your main concern and you like comfortable widefield eyepieces, you would be better served with the 5XW, or 7XW if your seeing conditions are often poor. In my case, I use the 5mm a lot with a similar scope and find no problems at all. This "trio" of XW's are excellent partners.

Since you asked about the Tak LE's, I also have extensively used the Tak LE 5 and 7.5 and have a pretty good idea of the differences, which may not necessarily agree with others opinions. The main difference, apart from cost (less), the Taks have a narrower field of view and shorter eye relief (about 12mm I think) which might still be comfortable for you.....not too sure though! In terms of performance, they are sharp across the entire field of view, as is the 5XW and 7XW. When looking at the moon, I feel the Taks give less false colour than the XW's and a "whiter" or cooler colour tone. They are very sharp eyepieces that resolve very well, though I note there has been some comment of slight scattering caused by an internal reflection, though I have never found this to be an issue. Apparantly this can be easily fixed by placing a suitable baffle into the field lens end of the eyepiece. When doing critical planetary observations, I personally prefer the Taks ever so slightly to the XW's, but for most other general viewing, the XW's get the nod wth excellent light transmission and a wider corrected field. Obviously the XW's will allow a longer observing time before you have to nudge the scope again. These comments are not intended to show the Taks as superior to the XW's, only to show both are truly excellent, but slightly different. Of course, there are other specialised "planetary" contenders which are generally not suitable to your needs that edge out both of these.
Given what you have said so far, it safe to say, I'd probably stick with the XW's.

Clear skies
Nick

[PhilW]

The LE 7.5mm has 9mm of eye relief, compared to the XW's 20mm.

[skies2clear]

Yeah I was wrong about the 12 mm eyerelief of the Tak LE 5 and 7.5 ED's. They are in fact 10mm and AFOV is 52 deg, so noticably less than the 70 deg AFOV of the XW's.

[Arthur Alchin]

Birthday present last week, Wife bought me a Televue 5mm Radian last week: cost a motsa, have yet to try it out, has adjustable eye relief but it looks and sounds good.

Arthur Alchin

[Greenswale]

Begins to look like I will have a bit of a Pentax XW family! I hope that Santa is nice to me.....!!

Thanks for the info, again.

- Wren

[matt]

In its price range...I'd have to agree the 5mm Vixen LVW is a great option.

Having said that, I am also a Pentax XW owner (7 and 10mm) and love these eyepieces.

It really comes down to budget.

[Dave47tuc]

Something else to think on is the Pentax XL range.

These are very nice eyepieces and about 50% of the cost of a new XW.

Shop around there are a few local people who mite sell you one Tak66
is one person to contact. I got a 7 mm XL of him and very happy with price and the EP is like brand new.

XL are not 50% of the XW more like just as good or just a tad off.
Most noticeable is a little less field, but much easier on the skyrocket.;)