The Best 5mm EP under $200.

[Suzy]

Could anyone please recommend a really good planetary eyepiece, 5mm, with good eye relief, neutral colour, over 50mm fov, and under $200.

I hear the wide fovs degrade contrast? And I know from experience putting a barlow on degrades quality somewhat, despite having a decent ED one. The 10mm I have at the moment isn't a good one (it came with the scope). Unless you'll can suggest a good 10mm that can handle a barlow ED well. Otherwise, I'll just use the 5mm straight. This will give me 240X on my 6" Dob.

I want to get decent views of the bands on Saturn and Jupiter. I was reading up on the TMB's but one review said it gives a warm and ruddy colour and you get better contrast by staying neutral. And as for the Orion Stratas, a review said there was flaring on the edges. And the Uni. orthos had a lack of eye relief and a small fov so were uncomfortable. I don't care what country I have to get this ep from, my invisible plane is ready to go.

This will be my last ep (yeah, you laugh!), so I want it to be a really good one.

[Wavytone]

TMB SuperMonoCentric (SMC) (if you can handle the small field of view)
TMB Planetary
Vixen LV or NLV.

Zeiss Abbe orthos will be outside your price.

Two things degrade contrast:

1. Lots of lens-air surfaces (also lots of elements). The best high-contrast eyepieces are those with just 2 air-glass surfaces - TMB SMC's have three elements cemented.

2. "Multicoated" anti-reflection coatings. While very durable and having very low reflection, "multicoated" coatings scatter more transmitted light than do the magnesium-fluoride coatings.

The reason I suggest the Vixen LV / NLV is that these are very comfortable to use as they have a massive 20mm eyerelief, far more than any ortho or plossl. For contrast, color, etc my own LV's compare favourably with the other planetary ep's., so no complaints there.

[peter_4059 (Peter)]

I've got Vixen LV's (4mm, 6mm, 9mm) for planetary viewing through my dob and really like them. They have good eye relief and about 50deg AFOV. Can't remember how much I paid for the 4mm new (about $180) however you can pick these up second hand for around $100. The seeing needs to be reasonable to break out the 4mm in my 10" dob.

[astro744]

May I suggest the Tele Vue 5mm Radian. It has 20mm eye relief with 60deg apparent field and sharp to the edge. Yes it is over budget but perhaps save up a little longer. May pick one up used for less otherwise BINTEL is the go.

An alternative for a lot more cost would be the Tele Vue 3-6mm Nagler zoom. It has ample eye relief for visual and a good eye lens (compared to orthos) and you can dial in just the magnification you want with click stops at 3,4,5 & 6 (In-between possible).

[Starkler (Geoff)]

A Uo orthoscopic will give the sharpest view with best contrast and minimum light scatter and would unreservedly recommend it if you had a scope on a driven mount. For a dob, no.

Vixen LV has nice eye relief but a rather narrow fov and light scatter.
TMB planetarys have comfy ER, and widish fov at 60 degrees but suffer light scatter and can be soft off axis, but you're f8 so should be ok.

Personally unless you want to shell out for a pentax xl or xw I would suggest the tmb planetary.

[torana68 (Roger)]

[QUOTE=Starkler;578762]A Uo orthoscopic will give the sharpest view with best contrast and minimum light scatter and would unreservedly recommend it if you had a scope on a driven mount. For a dob, no.

Im more than happy with mine (8" f6 f7 and F8) , but whats the difference between dob and GEM for eyepieces?

[Starkler (Geoff)]

With a GEM keeping a planet in the centre of fov in an ortho is a much simpler matter than with a dob. If that doesnt bother you thats great

[peter_4059 (Peter)]

Originally Posted by Starkler

A Uo orthoscopic will give the sharpest view with best contrast and minimum light scatter and would unreservedly recommend it if you had a scope on a driven mount. For a dob, no.

Vixen LV has nice eye relief but a rather narrow fov

Interesting you say that - according to astroplanner the Vixen has a wider FOV than the UO Orthoscopic?

[Brian W (Brian)]

Hi, I have a 13mm Orion Stratus and it is a good eye piece in my 8" LightBridge. I also use a 7mm Celestron Ortho and it is better in that it gives sharper more detailed views, but of a smaller area and things do move through the fov with some speed.

It is the old mantra but if you have a chance to go to a star party to look through various ep's it would make your choice a lot easier.
B

[torana68 (Roger)]

Originally Posted by Starkler

With a GEM keeping a planet in the centre of fov in an ortho is a much simpler matter than with a dob. If that doesnt bother you thats great

gotcha, another reason I dont have a dob

fov comes up at 42 via a quick google

[Wavytone]

Actually you should consider using what Questar chose to mate with what is arguably the finest planetary telescope - Brandon eyepieces, from Vernonscope. You can buy these without buying a Questar.

The Vixen LV's in the range 4-25 mm have a 45 degree field of view.

HOWEVER, FoV is not really the issue here - for a fine planetary eyepiece - as Suzy correctly indicated - the priorities are CONTRAST and lack of COLOUR, and to that I'll add SHARPNESS on-axis. A huge field of field of view is not a high priority.

Secondly the attributes that make a fine planetary eyepiece effectively eliminate everything from Televue - Plossls, Naglers, Ethoi and Radians included.

The point is to have as few elements as possible, as few glass-air surfaces as possible, and preferably MgF coatings.

Brandons have just 4 air-glass surfaces, and have MgF coatings, and this is one of the reasons why Questar use them - over all others.

Likewise the TMB SMC's have just 2 air-glass surfaces, and MgF coatings, for half the price of the Brandons, and a better range to match Suzy's scope (the shortest Brandon is 8mm).

[peter_4059 (Peter)]

How do orthos go with eye relief?

[torana68 (Roger)]

5mm UO fov 42 (googled )

[Starkler (Geoff)]

Originally Posted by peter_4059

Interesting you say that - according to astroplanner the Vixen has a wider FOV than the UO Orthoscopic?

Yes but still narrow enough to be a concern with a dob. I didnt mention fov wrt orthos as I assumed it to be well known and a given.

FWIW I think pretty much all of the specialist planetary eps are on the small side for fov. TMB monos, brandons, orthos, tak LE etc.

I reckon the tmb planetary will perform well enough in an f8 scope, and are sharp and comfortable to use.

[peter_4059 (Peter)]

Geoff, I don't understand your point about narrow FOV being a concern with a Dob - can you elaborate?

Cheers

Peter

[Suzy]

Peter, a smaller fov, say 42 like in the orthos, on a Dob it's out of my view in 3 seconds, and I have to keep manually tracking it, and losing it, and getting back, and losing it and so on.

Thankyou all for your input so far, please please keep it coming as I need to be as educated as I can before I get this ep.

[peter_4059 (Peter)]

So you are wanting a larger FOV so the planet doesn't disappear as fast from view under high magnification using the dob?

I've calculated some numbers for a few eyepieces in AP based on my 10" f5 dob:
6mm UO ortho - AFOV 43deg, true FOV 12.2'
6mm LV - AFOV 45 deg, true FOV 12.8', 1.05xortho TFOV
5mm LVW - AFOV 65 deg, true FOV 15.4', 1.26xortho TFOV
6mm Ethos - AFOV 100deg, true FOV 28.3', 2.3xortho TFOV

So an Ethos would give you 7 seconds viewing compared to an ortho at 3 sec.

[RobF (Rob)]

Come to the dark side Suzy - buy a ToUcam webcam, collect a few hundred frames to your laptop, stack in freeware program Registax, then enjoy an image befitting the moments of best seeing you'll see in the eyepiece.......

From the Brissy 'burbs I find myself using my 13mm Type 6 Nagler + ED 2x barlow more than a 6mm radian (in an 8" F5 reflector).
Visitors enjoy the better eye relief and FOV of this arrangement too. Almost bought a TMB, but no experience to share/compare there sorry - very competitive price-wise though with great reputation.

[torana68 (Roger)]

Do not be seduced by the dark side, once you start down the dark path, forever will it dominate your destiny

[RobF (Rob)]

Originally Posted by torana68

Do not be seduced by the dark side, once you start down the dark path, forever will it dominate your destiny

(and your wallet....)