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Old 03-12-2018, 11:47 AM
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Merlin66 (Ken)
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Recommendations for "reasonable" 6mm eyepiece

Looking for suggestions...
A 6mm eyepiece to use in f5 to f7.5 100mm refractor.....
Must have at least some eye relief!! and workable FOV....
Available here in Australia.....
Over to you.
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Old 03-12-2018, 02:20 PM
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wavelandscott (Scott)
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Depending on budget...

Used original TMB Planetary or TeleVue Radians might be of interest...

Newer Delites and Delos from TV

Pentax XW 5 or 7 mm

I started with least expensive and moved upward in quality...all should be found somewhere in Australia...
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Old 03-12-2018, 05:15 PM
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Quote:
Originally Posted by Merlin66 View Post
Looking for suggestions...
A 6mm eyepiece to use in f5 to f7.5 100mm refractor.....
Must have at least some eye relief!! and workable FOV....
Available here in Australia.....
Over to you.
Ken ..Vixen SLVs.. great EP LIKE former NLVs, only better IMO...and I mostly use TAK ABBES AND TAK TOEs.These awfully close ...huge eyerelief and big eyelens..
LANTHANUM glass etc; one or two have to some a glare issue on really bright targets..but Super sharp over their field

Myastroshop or FLO a bit cheaper if you buy 2 even posted there cheaper only 170 each!

bigjoe

Last edited by bigjoe; 03-12-2018 at 05:20 PM. Reason: add
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Old 03-12-2018, 06:41 PM
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Merlin66 (Ken)
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Thanks guys!
The eyepieces I use at the moment are smooth side TV from the 80’s..
Geeee, I think the first telescope I build only cost me (6” f8) 25 gbp.
Thinking about spending >$150 for an eyepiece just doesn’t seem to make sense to me.....sorry.
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Old 04-12-2018, 03:26 AM
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wavelandscott (Scott)
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Not sure about Australia but in the US the TMB Planetary (and similar) run around $50 new...in the states.

Do some reading on them as they are an interesting story about the original, the clones and knockoffs. In spite of the intrigue, I found them to be decent and comfortable especially for planets and moon.

While I still lived in Australia, I got a few pairs for binoviewing, I do not know the status of availability now. Near 20 mm eye relief and 58 degree (or so) FOV.
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Old 04-12-2018, 05:20 AM
astro744
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Quote:
Originally Posted by Merlin66 View Post
Thanks guys!
The eyepieces I use at the moment are smooth side TV from the 80’s..
Geeee, I think the first telescope I build only cost me (6” f8) 25 gbp.
Thinking about spending >$150 for an eyepiece just doesn’t seem to make sense to me.....sorry.
You will find that your 25GBP is worth well over $200 in today's dollars. Considering a new 6" f8 is $400 to $450 at present then spending $150 for a quality eyepiece is reasonable. I highly recommend a used 6mm Radian if you can pick one up. The comfort factor of the 20mm eye relief is very easy on the eye and the image quality superb.
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Old 04-12-2018, 10:35 AM
N1 (Mirko)
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+1 for TMB Planetary
The clones can be had cheaply (e.g. on Aliexpress Ebay), and if you aren't bothered by the ghosting, they are actually quite decent.
I've settled on the ES62°5.5 for non critical everyday viewing, and it's a solid performer (f/6 and f/7.5 refractors and f/6 reflector) that appears to tick all the OP's boxes and be at least one step up from the "TMBs".
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Old 04-12-2018, 12:14 PM
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Merlin66 (Ken)
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I can't see any ES eyepieces available in Australia....
I'll have a look at the TMB 6mm.....
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Old 04-12-2018, 01:53 PM
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[QUOTE=Merlin66;1407144]I can't see any ES eyepieces available in Australia....
I'll have a look at the TMB 6mm.....[/QUOTE

Ken the TMB clones are 5 element and sharp if you dont mind some ghosting..the ORIGINAL TMB were 6 ELEMENTS ..better at the edges!
Ebay ones 5 element but sharp over most of the field ..no good in most dobs if you cant tolerate edge problems. GOOD at f/6 AND ABOVE ..ORION 9MM EXPANSE CLONE is VERY SHARP..the RED and BLACK one for $33 on Ebay...6MM near as good...
BUT some blackout probs if you dont place your eyeball correctly...
that's why I stick to TV ,Tak,Vixen Burgesss MONO etc...But Im fanatical about This
bigjoe.

Last edited by bigjoe; 04-12-2018 at 02:49 PM.
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Old 04-12-2018, 03:19 PM
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ab1963 (Andrew)
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Hi Ken
I would advise anything you can pick up in a Vixen 6mm as the Japanese are mad refractor fans and made for the home market and at the short fl correct light scatter very well ,Televue are made for big dobs hence correction down to f4 or so being important ,Tak abbe ortho 6mm has horrendous er and to me was unusable that's just what i have found on the numerous ep's i have used and narrowed my viewing ep's mono down to 3
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Old 04-12-2018, 03:38 PM
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A) This 6mm is likely just a rebrand of the TMB Planetary Line as same elements and ER (7 elements / 4 groups) - https://www.ozscopes.com.au/skywatch...-eyepiece.html

B) This 6.5mm is likely just a rebrand of the Celestron X-Cel LX line as same elements and ER (6 elements) - https://www.ozscopes.com.au/saxon-ci...-eyepiece.html

C) This 5mm is likely a rebrand of the Baader Hyperion as same elements and ER (8 elements) - https://www.opticscentral.com.au/sax...l#.XAYFv2NRepo


I've owned all three under their primary branding (TMB, Celestron, Baader) and used in scopes from f/4.7 Dob to f/8 Apos. I liked C the best because very comfortable 20mm ER with big eye lens and 68 degree AFOV. Not sure on this branding but the Baader branding can add "fine tuning rings" that lengthen the eyepiece and change the focal length. Do not see that on the Saxon site so these probably stay fixed. But it was fun as they had 3 different ring sizes so could get a lot of different focal lengths from one eyepiece with those very inexpensive rings. After C I liked B next best, then A. The A Celestron X-Cel LX worked fine but off axis was not as good as others in fast scopes and had some edge of field brightening. All three come in at $150 or less in AU.

Last edited by WilliamPaolini; 04-12-2018 at 03:50 PM.
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  #12  
Old 04-12-2018, 03:48 PM
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William,
From what I can find the TMB Planetary II is:
""
These planetary eyepieces have a revised, modified Plossl build, 5 lenses in 3 groups (the 9 mm eyepiece has 6 lenses in 4 groups)
""
Did you find something different??
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Old 04-12-2018, 04:25 PM
WilliamPaolini
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Quote:
Originally Posted by Merlin66 View Post
William,
From what I can find the TMB Planetary II is:
""
These planetary eyepieces have a revised, modified Plossl build, 5 lenses in 3 groups (the 9 mm eyepiece has 6 lenses in 4 groups)
""
Did you find something different??
The original Burgess/TMB Planetary eyepieces designed by Thomas Back were marketed as 6 element design across all focal lengths. I did not take any apart to find out different. After Tom passed the eyepiece was cloned by many others and then a Version II was released. Astronomics also later sold them solely under the TMB branding without Burgess. Of all the brandings and changes to their design (evidently), I liked the original ones first sold by Burgess. They had the least scatter and performed best IMO.

Now the one I gave you a link to looks to be the same in every respect, however the vendor stats say it is 7 elements. Over all these years the design could have easily changed to take advantage of current glass stocks that are prevalent in the industry. But from a performance perspective the linked eyepiece is all that the original was...16mm ER, 58 degree AFOV, slim form factor. Not sure what glass types Tom used in the originals, but if any became no longer produced then the original manufacturer would of course have to adjust the design to continue to produce, so perhaps why 7 elements. Sky-Watcher might have ordered a changed design from the manufacturer as well to better correct. Or the stats on the site might be wrong. Just no way of telling what is correct until someone takes one apart.


I popped a note off to the SW rep in the U.S. about it. Will see what he knows.
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Old 04-12-2018, 04:47 PM
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William,
I've just stripped down a "TMB Optical" SW 9mm, Planetary II.

It has a front two element Smyth lens in the nosepiece, and a two element lens front lens plus single eye lens in the main body. All lenses have blackened edges.
So, I suppose you could say a 2:2:1 design.
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Old 05-12-2018, 10:53 AM
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I bought and tested the entire TMB Planetary Type II line currently available. As with ALL eyepieces, one should not dismiss or praise an entire line based wholly on one single example and used in just one scope type. Contemporary EP designs can see a line designed for a refractor (convex focal plane), have some individual focal lengths perform not very well in Newtonians (concave focal plane), but there may be one, two or more individual focal lengths in that line up that will perform remarkably well in Newts! And these TMB Planetary Type II's are exactly like this. I tested these in an ED80 and an 8" f/4 Newt. This very fast Newt would very quickly show up the weakest performers in Newts, but you also need to remember that if used in a slower Newt, the performance of these would also improve.

All perform really well in scopes with a convex focal plane, ie refractors, SCTs and Maks, with the 6mm being the weakest performer (it was the weakest in the original TMB line up, and still the weakest when the Type II line was released). The 6mm is still usable, but I wouldn't recommend it nowb. In the 8" f/4 Newt, the best performers (sharp edge-to-edge is the definition I'm using for best performance here) were the 2.5mm, 4mm, 5mm, 7mm, 7.5mm & 8mm. I also got to compare the 2.5mm and 5mm with the very exotic 2.5mm and 5mm Pentax XO's. In a refractor, the XO's were outstanding which is to be expected as they were designed for refractors, and the TMB's performed just as well! In the 8" f/4 Newt, the 2.5mm XO was outstanding, as was the TMB, however, the 5mm XO was poor while the TMB was razor sharp across the whole FOV. Both of these TMB's were just as sharp and showed the same amount of stars as the much more pricey XO's. I won't be selling my 2.5mm or 5mm TMB's...

Of the other focal lengths, these still perform well in Newts, though the very edge does soften a little, but still usable. Just give the 6mm a miss.

Another great thing about these is the eye lens of all of these is the same BIG size with all of them, and the eye relief is the same generous amount also across the whole line - no need to park your cornea on the eye lens of the 2.5mm with this one! They also all have a 58° AFOV, which while somewhat modest is still way better than what a plossl gives.

Below is a pic of the TMB Planetary Type II's I tested. You'll notice that there are 14 eyepieces, and that's because I got four duplicates to test for QC.

Click image for larger version

Name:	T (1).JPG
Views:	14
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ID:	237265

QC is the weak link with these, unfortunately. Being made so fast, and sold so cheaply, assembly mistakes do happen, and of the 14 eyepieces I tested, three were unusable. The good thing though is if you get yours through Ebay and the EP is faulty, you can get your money back. Ghosting can be a distraction, but this is not to dismiss them outright. These are modest eyepieces after all, and somewhere along the line something has got to give.

For their price there is nothing that matches these. If $$$ need to be watched, or you just don't want to spend a lot of money on high power eyepieces, these are excellent value. Of the 14 I tested, I've kept 5 for my kit, the three duds are binned, and the others I did sell and now wish I had kept a couple of them... And I still often use them with my lunar sketching as the focal lengths I've kept fill some focal length niches that can mean the difference between a productive night at the scope or watching TV. Are these as refined as say Radians? No. But for many people they will be just the ticket.

Alex.

Last edited by mental4astro; 05-12-2018 at 11:10 AM.
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Old 05-12-2018, 11:10 AM
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Alex,
Appreciate the "review"....

I only looking at the 6mm fl.
""
the 6mm being the weakest performer (it was the weakest in the original TMB line up, and still the weakest when the Type II line was released)
""
Seems to answer the question....

This has been suggested...
https://www.ebay.com.au/itm/6mm-Long.../282537992314?

Anyone actually tried it??
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Old 05-12-2018, 11:17 AM
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Ken, still consider the 5mm or 7mm. Difference in fl is not that significant and these two focal lengths I've kept.

Alex
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Old 05-12-2018, 11:25 AM
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Alex,
I already have a 7.4mm TV Plossl, a 7mm TMB Planetary II and a 4.8mm Nagler.....
Looking for something in between.
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Old 05-12-2018, 11:30 AM
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Got ya.

I'm curious too about that Ebay special. I'm always on the lookout for inexpensive gems to be able to recommend.
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Old 05-12-2018, 12:10 PM
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Quote:
Originally Posted by Merlin66 View Post
Alex,
Appreciate the "review"....

I only looking at the 6mm fl.
""
the 6mm being the weakest performer (it was the weakest in the original TMB line up, and still the weakest when the Type II line was released)
""
Seems to answer the question....

This has been suggested...
https://www.ebay.com.au/itm/6mm-Long.../282537992314?

Anyone actually tried it??
Ken... these are the same ep as the orion expanse ...the red and black versions I mentioned earlier seem a bit better..some blackout problems if eyeball placed incorrectly..9mm is a gem minor ghosting and scatter ..SHARP and recommended above f/6!
Was a big surprise to me..bought some for a nephew and was about to dismiss them as useable only ..but got a big surprise on Mars etc.
bigjoe.

Last edited by bigjoe; 05-12-2018 at 12:14 PM. Reason: add.
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