Pick me a planetery eyepiece on a $150 budget...

[Ravenit]

Hi guys
Looking to get a nice quality planet eyepiece for my skywatcher 6inch dob.
The cheaply 10mm that came with it barlowed x2 is OK but need better.
I don't want a 5mm plossl with a pin hole so from the list bellow what is recommended or feed free to add to it. $150 max budget including postage.
Price listed is online price

Explore scientific 4.7mm 82d water proof $140
Baader Hyperion 5mm $140
Vixen Lanthanum 4 or 6mm $139
William optics SPL 3or 6mm $108
Baader orthoscopic 6mm $74
Maede series 5000 HD60 4.5 or 6.5mm $80
Maede series 5000 ultra wide water proof 5.5mm $129
Celestron Xcel lx 5mm $70

Thanks

[Profiler (Profiler)]

The answer depends on what degree of eye-relief (ER) you want in the eyepiece and what balance you place on fov versus optimal optical performance.

If you want a good amount of eye-relief with maximum optical performance although smaller fov then the pick of the bunch IMHO would be the Vixen LV

Thereafter I would pick the Baader Hyperion which still gives good ER but not as sharp but larger fov

The opposite end of the spectrum would probably be the Explore Scientific which has modest ER but a big fov and still pretty sharp

[MortonH]

Assuming your Dob's focal length is 1200mm many of those options may give too much magnification unless you have a steady sky.

I'd consider the Explore Scientific 6.7mm.

[Ravenit]

Yes 1200mm. Eye relief is important as its a family / friends scope so ease of viewing is a must as well as a large for would be good.
I have viewed Saturn at 10mm 2x Barlow so 5mm and it looked good.
5mm is 240x magnification on my scope

[MortonH]

I used to have an 8" f/6, so also 1200mm focal length, and found that a 6mm Radian was excellent for planetary at 200x. Later I swapped it for a 5mm Radian to get more power but found the atmosphere wouldn't support 240x on a lot of nights.

Better to get a good eyepiece you can use all the time. Of course, Radians are now discontinued but you can get them used for a good price.

[omegacrux (David)]

Another option
Celestron Ultima LX
They come up every now and then , for about $120
Or order a new one from the US way cheaper than here

David

[MortonH]

TMB planetary 6mm for $83.99...


http://www.vtioptics.com.au/tmb-6mm-...very-few-left/

[brian nordstrom (As avatar)]

That's probably the best deal in astronomy today !.

I would jump on this fast as they state they only have a few ,, grab one now with both hands and be impressed as there is not a better 6mm eyepiece on the planet for this price available anywhere .

Thanks for the link Morton .

Brian.

Originally Posted by MortonH

TMB planetary 6mm for $83.99...


http://www.vtioptics.com.au/tmb-6mm-...very-few-left/

[David Niven (David Niven)]

Originally Posted by brian nordstrom

That's probably the best deal in astronomy today !.

I would jump on this fast as they state they only have a few ,, grab one now with both hands and be impressed as there is not a better 6mm eyepiece on the planet for this price available anywhere .

Thanks for the link Morton .

Brian.

Agreed and they are good, considering the price.

[Ravenit]

Thanks guys grabbed the TMB with both hands and both feet.
Really hope these are real as there is so much talk around about the TMB clones on ebay.
What I can see is the clones have 6MM but real has 6mm in small letters, someone else said they came out of the same factory.????

Anyway thanks for the link, VTI need to get credit card payments happening on their site as the direct deposit option can take a few days to process.
Thanks again guys for the recommendations...

[MortonH]

Pretty sure these are the real ones at VTI. Hope you enjoy it.

[Ravenit]

Bit of feedback guys. I really like the tmb. So much clearer and made out the gap in Saturn rings.
Kids like the larger eye relief and bigger field of view.
Cheers

[MortonH]

Originally Posted by Ravenit

Bit of feedback guys. I really like the tmb. So much clearer and made out the gap in Saturn rings.
Kids like the larger eye relief and bigger field of view.
Cheers

[ThunderStorm (Alan)]

I don't want to hijack this post but a quick one:
looks most of the eyepieces are 1.25inch? Becasue 2inch are much more expensive?

[Camelopardalis (Dunk)]

Originally Posted by ThunderStorm

I don't want to hijack this post but a quick one:
looks most of the eyepieces are 1.25inch? Becasue 2inch are much more expensive?

There's no physical need for a 2" barrel with such short focal lengths. Look at 20+ mm eyepieces and it becomes a more mixed story.

[brian nordstrom (As avatar)]

Brian.

Originally Posted by Ravenit

Bit of feedback guys. I really like the tmb. So much clearer and made out the gap in Saturn rings.
Kids like the larger eye relief and bigger field of view.
Cheers

[brunono2 (Brian)]

FYI- Agena astro has an explore scientific 4.7 82 for 99.99 USD at the moment normal 140 USD- they have low postage costs

Cheers

Bruno

[ThunderStorm (Alan)]

Originally Posted by Camelopardalis

There's no physical need for a 2" barrel with such short focal lengths. Look at 20+ mm eyepieces and it becomes a more mixed story.

Ah...most of 2" eyepiece are 20+mm eyepiece?

[MortonH]

Originally Posted by ThunderStorm

Ah...most of 2" eyepiece are 20+mm eyepiece?

Sort of. It depends on the "apparent field of view" or AFOV. The larger the AFOV, the wider the actual field you'll see through the eyepiece.

You'll see a variety of different values for AFOV. They can range from 45° to over 100°.

For example, you can get one 9mm eyepiece with AFOV of 50° and another 9mm eyepiece with 100° AFOV. They give the same magnification because their focal length is 9mm, but the overall view will be much wider in the 100° eyepiece.

Now, the greater the AFOV the larger the physical size of the eyepiece. So once you get to around 20mm in focal length, if you want your AFOV to be greater than 70° or so you physically need a 2" eyepiece.

It's only a rough rule as there are so many different AFOVs, e.g. 45°, 50°, 60°, 65°, 68°, 70°, 72°, 82°, 100°, and even some over 100°.

When the manufacturer designs an eyepiece of a given focal length, the AFOV he wants will determine whether it needs to be 1.25" or 2".

Hope that's not too confusing!

Cheers.

[dannat (Daniel)]

the makig of either a 2" (say 50mm) or 1.25"(30mm) ep depends on the field stop (basically the edge of fov of the eyepiece)

a 9mm eyepiece will have a field stop close to 9mm, therefore there is no reason to fit it into a 2" housing -the 1.25" size is more than enough

a 40mm will benefit as if you put it into a 30mm housing you are clipping the fov, so it will benefit from the larger 2" housing -you can effectively use a arger fov in the longer f/l eyepieces