5 or 6 mm planetary

[GrahamL]

been enjoying the moon through my xf a little of late
and was wondering whats around in the 5/6 mm range (12" f5)

The abbes get a good review most everwhere I read
anything else worth some thought ?.. don't really have a fixed budget

cheers
graham

[Wavytone]

The choice is a tradeoff between:
- sharpness,
- transmission and contrast,
- field of view,
- eyerelief,
- distortion,
- lateral colour.

If you want the best contrast, this means as few surfaces (elements) as possible, but this is at the expense of field of view and eyerelief.

If you can say what you want most, this will identify the right eyepiece for you. For example
- TMB Super Mono's are a good candidate if contrast is the priority.
http://www.perseu.pt/en-us/dept_191.html

- Vixen LV's and LVW's (now obsolete) have great eye-relief but are a compromise in the other areas, OK but not outstanding in any of the above, many others too, you can find them secondhand though they are rare as people who have a set tend not to part with them.

- TV Ethos 6mm - huge field of view but so many internal elements means transmission and contrast won't match the TMB's.

- TV Nagler VI in 5 or 7 mm... or the Zoom 3-6mm


Many other types have their pro's and cons.

[Starkler (Geoff)]

Pentax 5mm xw

[Quark (Trevor)]

Hi Graham,
I think your on the right track with the Abbes.
For high mag planetary observing it is hard to go past a good Orthoscopic and the Abbe design has stood the test of time.

About 25 yrs ago I purchased a 6mm and 4mm version.
I have a 16" F4.5 Newt in my observatory and a 12" F5 Dob that I take out and about. I use the 6mm exclusively for the planets, about any night of the year and if the seeing is very good then the 4mm.

The contrast is excellent with these eyepieces, detail is sharp as. Have never noticed a problem with the FOV, spend my observing time admiring the stunning detail of the planet in the centre of the FOV.

This is a very subjective subject but these are my thoughts.

Cheers
Trevor

[wavelandscott (Scott)]

Originally Posted by Starkler

Pentax 5mm xw

Ditto, +1 , I agree...

You get the idea...

[gb_astro]

Hi graham.

Have you read this very extensive Cloudy Nights review: ?

http://www.cloudynights.com/item.php?item_id=1935

Greg.

[GrahamL]

thanks for the replys.. lost a couple of attempts to post

try another day

[ausastronomer (John Bambury)]

Hi Greg and Graham,

Whilst I agree with at least 90% of what Bill put into that review, it is a little limited because a lot of excellent general purpose widefield and specialist planetary eyepieces are excluded because they do not manufacture an eyepiece at the 6mm focal length.

eg, 5mm Pentax XO, 5mm Pentax XW, 5mm Takahashi LE, 5mm Vixen LVW, to name a few.

What I can add is this.

I own a full set of University Optics HD orthos, including 5mm and 6mm focal lengths. They are excellent eyepieces, especially when you consider their price. I also own a 5mm Pentax XW. The 5mm Pentax XW is at least the equal of the 5mm UO HD ortho in terms of its optical performance. The difference is in eye relief (comfort) and field of view and there it's an absolute emphatic win to the Pentax XW. Of critical importance is the extra comfort of the Pentax XW which makes it infinitely easier and more comfortable to use for long periods of time.

If cost isn't an issue I would be buying the 5mm Pentax XW. If cost is a factor you would be very happy with the optical performance of the 5mm or 6mm UO HD orthos, which represent outstanding value for money.

If you want the very best in lunar planetary optical performance you would be hard pressed to find better than the 5mm Pentax XO, or if you can afford it the 6mm ZAO II. I haven't used the ZAO II's but have used the ZAO and they are outstanding.

Cheers,
John B

[CoombellKid]

Graham,

Next time your out here. I have a 7mm U/O HD it will give you an idea
what the 5 or 6mm might be like. You can then compare it to my 5mm XW.

I think you might find you'll prefer the XW for all the reasons John
meantions above.

Cheers

[PhilW]

I used to have the 5mm Pentax XO. It was a superb lunar and planetary eyepiece, and I used it for DSOs too (esp globulars). The only problem was the eye relief: it was very tight at 3.6mm. So I've replaced it with the 6mm ZAO II, which has goldilocks eye relief, ie just right (for me at least), at a whisker over 5mm. That doesn't sound like much difference, but it is enough to make it much more comfortable for me. They are expensive, but they should hold their resale value well.

I would also agree with previous comments about the balance of qualities that the XWs possess (comfort/FOV/on-axis sharpness/colour purity). The XL predecessor models are also worth considering. They have 5 degrees less FOV, but are a great buy used.

[GrahamL]

thanks guys .. yeah I will have a look through your eyepieces rob.

I've been waiting for the seller to me of a 5 & 6 ortho to jump in and ask what gives ...Internal dummy spit on focuser travel adjustments made me sell em just before I got all the issues sorted figures in

I was looking at the xo ..and xw ..for a while when The US dollar was kind a while back I'm probably going to spring for something that I can use
fairly often .. 5mm around home isn't going to work ... ALL your posts are pretty much
exactly what I was looking at ... I'll wait look a little and still enjoy the view .

cheers graham

[reeaal (Mark)]

Quote:
Originally Posted by Starkler http://www.iceinspace.com.au/vbiis/i...s/viewpost.gif
Pentax 5mm xw

Ditto, +1 , I agree...


Where can I get one of these at a decent price in Australia?

[PhilW]

You can't

you could consider ordering from Japan (http://www.kkohki.com/English/kkohkiparts.html)

Or look for used ones - & don't overlook the XLs. The 5mm XL is also a lovely eyepiece.

Phil

[GrahamL]

Yeah I've ordered from Barry before Phil great to deal with .. Just don't order the week before the japenese national holiday cuz no one does anything for a whole week...
Price hike or exchange woes pentax eyepieces sure are a pricey
proposition these days