Planetary eyepieces?

[iceman (Mike)]

Ok.. it's getting close to decision time..

I'm going to use IISAC to compare many different types of planetary eyepieces.. with Saturn at opposition and Jupiter rising late, it's be good planet viewing conditions (hopefully!)

My scope is a 10" dob (1250mm FL), and I generally use an EQ platform. So wide FOV isn't a necessity.

I currently own a 9mm GSO plossl that came with the scope. The magnification of 9mm (@ 138x) is ok when the seeing is less than average, but I want something higher mag for when the seeing is "good" and again when the seeing is "great".

A 5mm will give me 250x, a 6mm will give me 208x and a 7mm will give me 178x.

I'm looking for something in that range, perhaps a 5mm and a 7mm. Depends on the style, type and price.

I'll also be getting a 2x barlow (at some stage (I sold my 2x GSO barlow)) to use on this eyepiece when the seeing is great.

For the last 2 months or so, i've had on loan a Tak LE 7.5mm (thanks Louie!) which I've been using as my planetary eyepiece. I find it very comfortable to use, 10mm ER, 52° AFOV, sharp to about 90% and good contrast. They could be picked up for under AU$200.

At the last Kulnura meet, I had a brief chance to try John B's 7mm UO HD Ortho, and compare it to the Tak LE. Unfortunately the seeing was not good and Mars was but a small blurry mess, so it was difficult to draw any conclusions. I tried it on the trap on M42 as well. During the short 1 hour comparison, I could not draw any conclusions as to which was better - both revealed the same detail, had very similar colour reproduction and were sharp with equal contrast. more testing is needed, but at that time, there wasn't a standout. The UO HD Orthos have a 45° AFOV, much tighter ER (probably around 5mm) and cost less as AU$125 brand new.

The Tak LE was slightly more comfortable to use, thanks to the larger eye lens and longer eye relief. But I don't wear glasses so the Ortho was still easy enough for me.

Others in the equation:

- Televue Plossl
- Vixen LV

and then premium widefield (probably overpriced for a planetary EP)
- Pentax 7mm XW
- Nagler 7mm T6
- Vixen 7mm LVW


For the price of a premium widefield, I could get 2 UO HD orthos (5mm and 7mm), and probably a 2x barlow as well! So it'd take some convincing for me to rank a premium widefield higher.

Your thoughts and experiences on any of the eyepieces above? Feel free to throw anything else into the equation.

My budget is around $300, which pretty much rules out the premiums, but if I determine (through my own viewing at IISAC) that a premium is soooo much better than an Ortho or other cheaper plossl then I'll just save up a bit longer to extend the budget.

Thanks

[mick pinner]

this discussion really seems to be hanging on, l have been using a Vixen LV 5mm for a couple of years on planets and it works in everything l have ever put it in, even in good conditions in the LX 200, yes 610x.
20mm eye relief is great, buy one and you will keep it.

[iceman (Mike)]

Thanks for the feedback Mick.

Another option I forgot to throw in, is to try and find (2nd hand) the 4.7mm and 6.7mm versions (and maybe also the 8.8mm) of the Meade s4000 UWA. For no other reason than it'd be nice to have a set (to go with my 14mm), and they're the right focal length, and i've read reviews that say they're a good eyepiece.

Astro_south wouldn't sell me his 4.7mm , and they rarely pop up on the 2nd hand market so it could be a long time waiting for those.

[Merlin66 (Ken)]

I would strongly suggest you at least check out the availablity of monocentric eyepieces. I have a Ziess 6mm which has performed great on planetary work. Poor FOV but when looking at a 40 arc sec image no problem. The results IMHO outclass the competition. There also may be some Hasting eyepieces out there, again worth looking at.
My 2c worth.

[Robert_T]

Originally Posted by iceman

For the last 2 months or so, i've had on loan a Tak LE 7.5mm (thanks Louie!) which I've been using as my planetary eyepiece. I find it very comfortable to use, 10mm ER, 52° AFOV, sharp to about 90% and good contrast. They could be picked up for under AU$200.

At the last Kulnura meet, I had a brief chance to try John B's 7mm UO HD Ortho, and compare it to the Tak LE. The Tak LE was slightly more comfortable to use, thanks to the larger eye lens and longer eye relief. But I don't wear glasses so the Ortho was still easy enough for me.

Hi Mike, I have and use both the Tak LE 7.5mm and the UO 7mm HD ortho and have compared them many times - I use them in F10 and F12 scopes. Both are excellent for planetary. I don't wear glasses but find the eye-relief of the 7mm at the limit of my tolerance - certainly don't think I could abide the 5mm HD ortho. The Tak LE 7.5 is magic and I'd have to give the edge for view and comfort, but I doubt you'll buy them for $200 unless you go second hand. Even with the good Yen exchange rate they're running closer to $300.

I find I can reasonably often (say 1 in 3 viewing sessions) push magnification usefully to 300x when viewing the planets and think you need this sort of mag to get the best possible views and detail when seeing allows. Not sure what this would require in your scope, but the Tak LE's have smaller FL ocular's than the 7.5 that maintain reasonable eye relief. Hope that's of some use.

cheers.

[davidpretorius]

I am so happy with Asimov's 5mm vixen which is on its way back to its owner, that given the number of times i was able to use it. ie 9 out of 10 times with jupiter, that i will be going a 4mm!

20mm eye relief!

[norm]

Mike,

You may already know this, but Astro-Opticals at St Leonards have a special deal on atm: see below:

NEW YEAR SPECIAL!!
Purchase any Vixen LV or LVW Eyepiece and purchase a second (of equal or lesser value) for half price.
For a limited time only. Call for details.
Could be worth looking into, I think the special is only till Jan.

[davidpretorius]

i think this will keep going as long as myastroshop keep offering hot prices on vixens ie sub $200 for single buys

[iceman (Mike)]

Interesting Norm!

I just rang them, the 5mm Vixen LV is $249, the 5mm LVW is $460. Even if you buy two, that's $374 for the LV and $690 for the LVW.

MyAstroShop has the 6mm LV for $165 and the 5mm LVW for $340. Buying two means $330 for the LV and $680 for the LVW.

So MyAstroShop is still cheaper.

merlin, I haven't see those monocentrics come up for sale often. i think it'd be hard to find one.

[ving (David)]

if kyou dont have yourself sorted by the next kulnura meets mike try my ultima. they are suposedly every bit as good as TV plossls

[janoskiss (Steve H)]

What about the Burgess TMB Planetaries that everyone over on CN seems to be buying? Long eye relief (16mm+) and 60 deg FOV for $US99 for the 9 & 4mm and $US49 for the early version 6mm. From all accounts (and there are many) they should be very good. You could get them from www.highpointscientific.com. Postage is near $US70, but it seems to be the same no matter how much stuff you order, so if you order close to customs limit's worth, it is not bad. I just bought a binoviewer + EP from them and it got here in just over a week.

For high magnification planetary viewing I'm pretty happy with the barlowed 12mm HD ortho, which becomes a 5mm in my barlow (can go down to a 4mm with a barrel extension). Very comfortable with plenty of eye relief (with the barlow you get a bit more ER than using the EP alone), and the barlow is good enough to maintain the great contrast of this EP. You do need a good barlow for this; not a crummy Shorty Plus!

But wait there's more! I just received an older style tiny little 10.5mm TV Plossl from Chris (33South) and was looking at Saturn with it the other night. I compared it with the 9 & 12mm HD orthos, and the TV seemed to have the best contrast. The moons of Saturn stood out more clearly (esp. one very close to the planet) in the plossl than in either ortho. I'll have to do more testing to confirm this but I might have a new winner for contrast and maybe transmission too. Eye relief is not too bad, maybe a tad less than the 9mm ortho. I haven't tried it in the barlow yet but should be great at higher elevations in good seeing.

[ausastronomer (John Bambury)]

Originally Posted by janoskiss

But wait there's more! I just received an older style tiny little 10.5mm TV Plossl from Chris (33South) and was looking at Saturn with it the other night. I compared it with the 9 & 12mm HD orthos, and the TV seemed to have the best contrast. The moons of Saturn stood out more clearly (esp. one very close to the planet) in the plossl than in either ortho. I'll have to do more testing to confirm this but I might have a new winner for contrast and maybe transmission too.

Steve,

The difference in magnification and exit pupil between these 3 eyepieces is too great to prove much in terms of light transmission, contrast and sharpness. When comparing eyepieces, particularly as the focal length gets shorter, they need to be the same focal length or at worst within 1mm of each other, particularly when testing on targets on the threshhold of visibility. The reason is that visible limiting magnitude changes as magnification and exit pupil changes. In other words the 10.5mm focal length of the TV plossl could be "the sweet spot" at which those targets are best viewed in your scope.

The differences between these two eyepieces and the 5 element Japanese Manufactured plossls from Celestron, Meade, Parks and Orion in the USA and Antares in Canada is marginal at best. Also include the Tak LE's for that matter, which again are a 5 element plossl. They are all outstanding and so close in performance its not funny. If anything the TV plossls give a slightly warmer tone than the others IMO, which is something you may or may not like.

CS-John B

[janoskiss (Steve H)]

That occurred to me too John, about the 10.5 maybe being more suited to the conditions than the 9 or 12mm. That's good! I wasn't just imagining things. There really is a gap between my 9 & 12mm HDs, which the 10.5 TV will fill nicely.

[ausastronomer (John Bambury)]

Originally Posted by iceman

Ok.. it's getting close to decision time..

and then premium widefield (probably overpriced for a planetary EP)

- Pentax 7mm XW
- Nagler 7mm T6
- Vixen 7mm LVW


For the price of a premium widefield, I could get 2 UO HD orthos (5mm and 7mm), and probably a 2x barlow as well! So it'd take some convincing for me to rank a premium widefield higher.

Your thoughts and experiences on any of the eyepieces above? Feel free to throw anything else into the equation.

My budget is around $300, which pretty much rules out the premiums, but if I determine (through my own viewing at IISAC) that a premium is soooo much better than an Ortho or other cheaper plossl then I'll just save up a bit longer to extend the budget.

Thanks

Mike,

The premium widefields gain you absolutely nothing in image quality. What your paying for is a wide flat field of view when used in combination with a fast f-ratio telescope. Actually from my limited comparisons, I think the UO HD orthos will outperfom the Nagler T6's and Vixen LVW's as a planetary eyepiece. There is little between the Pentax XW's and UO HD orthos in terms of an axis performance. To gain better planetary performance than the 5 element Japanese Plossls (Masuyama), TV Plossls, Tak LE, UO HD orthos, Vixen LV etc, which are all superb, you really need to go to the more expensive premium specialist planetary eyepieces like TMB Monocentrics, Zeiss orthoscopics, Brandon Orthoscopics and Clave Plossls. I haven't used the TMB monos, but I have used the other 3 and they are superb, but are all expensive and a lot more money for a small performance gain.

Try out my HD orthos again at Lostock but the big thing in their favour is they are only about $125 each and you could buy the 5mm, 6mm and 7mm for less than $400. This gives you a bit more flexibity in marginal seeing conditions, having 3 options as opposed to 2.

CS-John B

[BerzerkerNerd]

U.O ortho EP's rule , even for a manual dob (own opinion) Have a 6mm that really does the visible jovians justice- no regrets. And have on occasion bludged a 9mm U.O for same. Clean, clear field stop . With automation would be tempted to fully go ortho, maybe koenig, for anything under 15 mm.

hope your choice works well
Steve M

[Robert_T]

Originally Posted by BerzerkerNerd

U.O ortho EP's rule , even for a manual dob (own opinion) Have a 6mm that really does the visible jovians justice- no regrets. And have on occasion bludged a 9mm U.O for same. Clean, clear field stop . With automation would be tempted to fully go ortho, maybe koenig, for anything under 15 mm.

hope your choice works well
Steve M

certainly these have my vote for the best bang for buck too - good luck with your choice Mike

[asimov (John)]

Must be a matter of personal choice or something, I got rid of my 6mm UO ortho because I wasn't overly impressed. I like my ER too much perhaps (LV's)

[BerzerkerNerd]

Well it all comes down to personal optical parameters and capabilities, which are as varied as the stars. never stop searching - in fact the skies round here now are clearly beckoning me, oppportunity wasting away; as much as i would like to shoot the .... must go.
Steve M