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TMB Optical "Planetary II" 4mm


Alan64

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I'm all about high-powered views, as I use a telescope, regardless of focal-length, for which it is intended, and to see faraway objects up close.  Else, I'd use my eyes or a pair of binoculars for the lower powers, which I rarely ever do. 

Up until now, the only 4mm eyepieces I've managed to collect, over the decades, are these two...

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The Tani orthoscopic on the left needs its lenses cleaned, perhaps in between even.  The symmetrical-Ramsden(SR) on the right is surprisingly good, very good even, and for a kit-eyepiece.  I also have a .965" SR somewhere, yet without its lens(es).

But it was that Celestron kit-4mm that revealed to my eye just how good a 4mm can be.  So much so that last late-summer I began to yearn for an even nicer 4mm, with a larger eye-lens, and at least a modest increase in eye-relief.  Just a little extra, please, as I don't wear prescription-eyeglasses whilst observing.

After looking round and about online, I decided on this one...

https://agenaastro.com/bst-1-25-uwa-planetary-eyepiece-4mm.html

For two months I waited, through September and October, and for the eyepiece to be re-stocked.  At first, the listing stated the anticipated arrival as being "...early October", then "...late October".  Even into November, late October was still being indicated.  Then, in the end, "Please contact us for an update", and as it states currently.  AA is the only vendor in the U.S. who stocks that type of eyepiece.  I couldn't find another economical type in a 4mm, other than a Plossl or another orthoscopic.  I almost bought a Vixen 4mm "NPL" Plossl, and with its own squinty eye-lens and tight eye-relief.  I came precariously close to getting that one, but happily, I didn't. 

Onto the online ocean I embarked, searching every corner of the world.  It wasn't practical ordering one from Europe.  At last, I found one, via AliExpress, and direct from China, the "horse's mouth".  As I pulled it out from my semi-rural mailbox, I immediately noticed that it was quite heavy; good, that...

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4mm4.jpg.3a260b40fe0e73df04e7b5d29198217c.jpg   

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I haven't tried it out yet, but I do have hopes, albeit cautious ones.

I got the eyepiece for less than US$30 total.  It may be a factory-second.  I don't think it's a counterfeit.  If it is a second, then I hope that it is due solely to its cracked lens-cap...

4mm9.jpg.aa507da6124f2ca767c455eb6a358653.jpg

I think I'll break it in upon the upcoming "marriage" between Jupiter and Saturn this solstice.

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For less than $30 (including delivery ?) it's got to be worth a try :smiley:

I agree that the eye relief and tiny eye lenses on the plossl and ortho eyepieces of that focal length make them very challenging to use even if they are sharp.

I think those are made by Barsta who make the BST eyepieces.

 

 

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4 minutes ago, John said:

For less than $30 (including delivery ?) it's got to be worth a try :smiley:

I agree that the eye relief and tiny eye lenses on the plossl and ortho eyepieces of that focal length make them very challenging to use even if they are sharp.

I think those are made by Barsta who make the BST eyepieces.

Yes, the grand total was less than $30, or £23.  The type was introduced to the U.S. market in 2005 by Burgess Optical of Knoxville in east Tennessee.

Barsta may be just a wholesale-distributor for Kunming United Optics.

Incidentally, I unscrewed the bottom portion off of the eyepiece, with its smaller lens(es), and it's going to need blackening internally.

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3 minutes ago, Alan64 said:

Yes, the grand total was less than $30, or £23.  The type was introduced to the U.S. market in 2005 by Burgess Optical of Knoxville in east Tennessee.

Barsta may be just a wholesale-distributor for Kunming United Optics.

 

I recall the Burgess / TMB planetaries - I've owned a couple of those. I think the Planetary II's are a little different.

Shame they still have the TMB logo on them, unless they are paying some royalties to the estate of the late Thomas M Back, which I doubt.

I notice that the Agena Astro ones don't have that branding.

 

 

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2 hours ago, John said:

I recall the Burgess / TMB planetaries - I've owned a couple of those. I think the Planetary II's are a little different.

Shame they still have the TMB logo on them, unless they are paying some royalties to the estate of the late Thomas M Back, which I doubt.

I notice that the Agena Astro ones don't have that branding.

AA's BST planetaries are not branded as far as I can tell from the images, therefore simply an in-house affair I suspect.  Perhaps the owner of AA didn't want to pay extra to have them branded; same eyepieces otherwise, I hope.

I would doubt that as well, regarding the logo.

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I have a 6mm. It's good, but not outstanding. There's a distinct 'rainbow' on the outside of the field stop. So yes, some blackening is required. I use it for doubles. The screw twist up eye cup is very good.

I have a 0.965" 4mm othoscopic bought back in the '70s. It was good quality but cost an arm and a leg. Eye relief is non existent. It also desperately needs a clean. A great way to experience floaters on a 60mm f15 refractor 😜

Back when I had a 250mm Newt, I had a 4mm NLV (x300). That has to be the sharpest, most contrasty eyepiece I've ever used. I had some magical views of Mars with it. 

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10 hours ago, Alan64 said:

Perhaps the owner of AA didn't want to pay extra to have them branded

More likely as a US retailer, AA would have been on the hook to pay royalties to the Back family for use of the logo which they likely still own the rights to.  The Chinese company you bought from is under no such legal requirement because even if Back had registered his trademark in China, their TM enforcement is woefully inadequate.

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16 minutes ago, Don Pensack said:

Also available under these labels (needn't go to China to get one):

Astromania Planetary
BST (Barsta) 58 degree Series
Omegon Cronus
Skywatcher Planetary
Telescope Service Planetary HR

The 4mm planetary is available in Europe, and with the usual mark-up.

In so far as "going" to China, do we not go for the rest as well?  Yes, quite. 

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9 hours ago, Louis D said:

More likely as a US retailer, AA would have been on the hook to pay royalties to the Back family for use of the logo which they likely still own the rights to.  The Chinese company you bought from is under no such legal requirement because even if Back had registered his trademark in China, their TM enforcement is woefully inadequate.

Yes, I'm beginning to look more upon these as being grey-market, at least, if not black.

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Hmm, I can get 120x out of this regression of the refractive design and evolution...

2114078982_fastfastfast.jpg.581e95487a49ec0dd797160cddcd1774.jpg

...and with that 4mm, alone, but not with that 2" star-mirror.

But first, I must saunter outside into the cold, cold night, and consult fair Luna...

112820.jpg.b8269b4282ac5a20cb95f24a14323ad2.jpg

<mumble mumble mumble>

And she replied, "Talk about soft!"

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In the early morning, November 29th, I brought out the Zhumell "Z100" 100mm f/4 Newtonian on the ES "Twilight Nano" alt-azimuth mount, and for a look-see at the Moon.  The sky was saturated with clouds, and the Moon nigh at full-phase...

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How theatrical, no?

But I did manage at least one afocal-shot, courtesy of my old Minolta point-and-shoot, through the 4mm, and at 100x...

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Not very good, I'm afraid, as the collimation of the Newtonian is not spot-on, in addition.  I got this eyepiece primarily for that telescope, and to test it, with a 2x-barlow at least.  The parabolas of it and the S-W "Heritage" 100P are not specified as being "diffraction limited".  Rather "frugal" on behalf of the manufacturer, I must say.  Still, I have high hopes, but first I must tweak the collimation further.  The live view didn't look half-bad, whilst peering through the clouds.  Incidentally, I did not see the slightest hint of false-colour during that observation.  The eyepiece paired quite well with that "apochromat", in that at least.

It rained on the 30th, and the sky completely overcast.

Last early morning, on the 1st, I brought out the Antares 805 80mm f/6 achromat...

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It was below freezing at the time.  The Moon was up, and in a crystal-clear sky...

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At 120x...

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Grey-scaled...

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Possibly during a moment of steady seeing, I saw a broken line of "pearls", nigh tack-sharp, along the rim of this small crater...

1756124700_4mm-Antares805e.jpg.01e748aa0216f2ebacce020af1968ce0.jpg

The camera couldn't capture that, of course.  There was false-colour seen, as evidenced within those images, but that was the fault of the short achromat.

The Moon isn't the ideal test-subject, particularly when at almost full-phase.  But this accursed cold weather is hampering my efforts.

The alleged eye-relief(16mm) was noticeably reduced when using the eyepiece with those two telescopes, yet the relief was somewhat greater with the f/6 achromat, naturally so I assume.

The next test will be with a 90mm f/10 achromat, and a star-test utilising great Polaris A in addition. 

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The Meade 90mm f/10 achromat, with a very good if not excellent doublet, blackened and flocked throughout, and mounted onto an Astro-Tech(GSO) "Voyager I" alt-azimuth, given the telescope's larger/longer size...

27884929_4mm-Meade90mm.jpg.eac0da00fe9e459e1b7c90a2f36e8eb7.jpg

...and a low-slung chair due to the current removal of the mount's pier.

At 225x, the afocal-shot taken with the old Minolta with its shutter set at 1/10th of a second, and to compensate for shakes, wobbles, and the transiting across the field-of-view...

242345133_4mm-Meade90mm2.jpg.26ce0c0b5037964e2aedb3479cf4486c.jpg

It's slightly blurred there.

Taken at 1/45th of a second...

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...for what that's worth.  The live view was better, of course.  That last image approximates the live view best.  I was dogged by the cold and moisture in the air.

I then turned the telescope to ole reliable, Polaris. 

The seeing was somewhat turbulent.  A few times I saw the star's Airy-disc as a perfect sphere.  The first and second diffraction-rings were partial and dancing round the disc, yet they were nigh razor-thin.  The false-colour of the 90mm at f/10 did rear its head, but not nearly as bad as that of the Antares 80mm f/6.

It was so much nicer to simply observe, instead of taking snapshots.  I seem to be seeing more clearly with my left eye, as I switched back and forth.  Up until now I've always observed with my right.  I'll need to give the left some more practice in future, apparently.

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  • 1 year later...

I have a question. Got a tmb optical planetary ii 4mm. My first EP aside from stock sky watcher units. It feels and looks solid and very well made but something rattling inside. I suspect lenses are not properly secured? Did you have same with yours? Should I return it as defective?

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18 hours ago, maxys said:

I have a question. Got a tmb optical planetary ii 4mm. My first EP aside from stock sky watcher units. It feels and looks solid and very well made but something rattling inside. I suspect lenses are not properly secured? Did you have same with yours? Should I return it as defective?

It probably just needs a retaining ring to be lightly snugged somewhere.

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  • 1 year later...

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