Long perng 3mm ep? Opinions?

[Steve-hobart (Steve)]

Just had a look at Saturn with my new 10" dob and the 10mm plossl that came with it. It was clear but small. Conclusion is I need a higher magnification.
Anyone have any experience with the Long Perng eps that Andrews are selling? Thinking of the 3mm long eye relief.

Alternatively anyone have any other suggestions. Orion edge on might be another option.

[omegacrux (David)]

Hi Steve
I wouldn't go down to 3mm
Try 6mm I have the same scope
With a 3 I think you would need realy good seeing
Looked at Saturn tonight with a tmb 6mm nice view
you can pick them up for $55
A very good value ep

David

[Satchmo]

These eyepieces are rubbish- I bought a 5mm and the internal reflections and ghost images when looking at the Moon were outrageeous - I sent it back. The Orion is a rebadge.

[brian nordstrom (As avatar)]

I will argue that last comment , I have one , $59 from Andrews .
I also have a 3mm TV Radian , ok .

This is a true comparisim , 3mm TV and 3mm LP .

Yes the TV is slightly better , because of the Radian's better eye relief .
The TV has Kidney Beans , the LP none .
315x with both in my Istar 127mm f8 and 806x in my Takahashi M210 this is where the proof is in the pudding , the TV is better in both scopes , but only just and if you did not have both to compare against you will not see the difference .
I still have both , and use them .

The TV Radaim 3mm ($300) is in with the rest or my Radians ( see photo) and my 3mm LP ($59) is now polarised forever forever as my high power solar eyepiece when I use my Lunt Hershell Wedge in my refractors when viewing the sun . And the sun is an un-forgiving target.

My LP 3mm is a very good high power eyepiece up there with the best , But that's the problem with Chinese optic's , lack of QA , some are good some ain't
but if you are grabbing one from Andrews , grab it , 100% money back .
By the way a 3mm is way to much in your scope , 300x , hard to keep anything in the field at that without a nice drive .

Brian.

[Satchmo]

Brian - the problem was in the design - not quality control....the design was not adequately done to suppress internal reflections and the AR coating were inadequate. From memory when looking at the Moon the central 1/3 of the field was swamped with a ghost image...

Your response is wordy and positive but no reference to my criticism of these short focal length Long Perne . Any comments on ghost reflections?

I reiterate that the 5mm LP was useless for lunar observation - it went straight back.

[bigjoe (JOSEPH)]

Steve. I tried a 5mm orion edge against a 5mm and 3.5mm nagler, and the orion was

too soft, with only 2 mushy belts on jupiter, in a 6" mak and sct, compared to the tv's.

I actually far prefered a GSO 9mm plossel (a very underrated ep) barlowed.

Very dissapointing, though the 9mm and 14.5 Orions where great on globulars.

Cheers and hope this helps.

[doug mc]

Long eye relief eyepieces get some of their eye relief from using barlow lenses in their design. I have owned Long.Perng ,TMB II, and Astrotec Paradigms, all are planetary type eyepieces. So far my testing has shown a quality plossl or orthoscopic, with or without a barlow offer sharper views. I now no longer use TMB planetarys or L.P. eyepieces for critical viewing. These compound eyepieces usually have a lot of internal reflections, mainly on the moon. I found using a baffled barlow and a comfortable plossl or ortho gives the best results. Hope this helps.

[brian nordstrom (As avatar)]

That may be so , but that's the 5mm not the 3mm , totally different production run , I would think ? , as I said my 3mm as Steve originally asked about is a very good eyepiece for $59 .

One point , I noticed Andrews are saying the 5mm is 'Sold Out' in their inventory of these eyepieces , I wonder if they sold out because they are good and lots of people brought them ? of they removed them from sale because or a major design flaw ?
Food for thought .
Brian.

Originally Posted by Satchmo

Brian - the problem was in the design - not quality control....the design was not adequately done to suppress internal reflections and the AR coating were inadequate. From memory when looking at the Moon the central 1/3 of the field was swamped with a ghost image...

Your response is wordy and positive but no reference to my criticism of these short focal length Long Perne . Any comments on ghost reflections?

I reiterate that the 5mm LP was useless for lunar observation - it went straight back.

[dannat (Daniel)]

i would look at the 5mm bst exporer -from telescopesandastronomy in SA (3mm will be too much mag on most nights) -its same ep as astrotech paradigm

[bigjoe (JOSEPH)]

Hi Brian.Your probably right about the 5mm.

These Orions are easy as to look through for my friends, I find.

Most would be great for star parties in some scopes.More than good enough.

I actually love the eye cups.

Though having said that, I prefered a barlowed 9mm GSO / BINTEL PLOSSEL or BGO or Parks gold 5mm,

to ALL ELSE. YES! INCLUDING naglers radians, Deloses for ultra crititical planetary

details and there is NOTHING WRONG with the Tvs!
Cheers bigjoe.

[Profiler (Profiler)]

A Nagler Zoom set at 3mm is extremely good although the ER is modest at around 11-12mm. Otherwise I have found the Pentax XW3.5 is pretty hard to beat with 20mm ER.

[Steve-hobart (Steve)]

Ok, possibly going off my original thread topic, but I'll accept that a 3mm may be optomistic, it looks like the general wisdom is about 4.5mm to 6mm is probably the practical range for a high mag planetary ep for a dob with a 1200mm focal length.
While the televues may nice they are also very expensive. Would like to keep under $100 if possible.
Options look to be
- Meade hd-60 4.5mm for $100
- BST starguider 5mm for about $95 -from UK unless someone knows someone that sells online in Aus
- Gso 6mm plossl for about $30
- orion edge on for about $100

Any thoughts or comments on these or alternatives in the price range?

[bigjoe (JOSEPH)]

Hi Steve.Just tested a 9mm Orion edge on Omega Centauri

and it gave vg partial resolution and vg light through put in only a 4" mak! A tough test.

As for the 6mm orion Im not completely sure, though others like it.

The 9mm Meade hd was also pretty good.

PS:these eps are optimised for longer focal lengths and may be just good in a dob and not great.If it were me I'd go the Meade hd though.
Cheers bigjoe.

[SkyWatch (Dean)]

Hi Folks,
Just saw this thread. I have both the 3mm and 5mm LP eyepieces (from Andrews). I haven't had any problems with internal reflections even on very bright objects or kidney beaning, and the views are very good right across the field. (You do see some light coming into the eyepiece when the moon is just outside the field.)
Considering their price (especially at $59!) they compare surprisingly well with a 3xbarlowed (Televue barlow) 13mm Nagler 6.
Regarding using the 3mm in a dob: I agree that the magnification might be too high. I think you are better off looking for around 200x unless you have a driven mount.
Also, it isn't often that atmospheric conditions will enable much over 200x anyway.
All the best,
Dean

[brian nordstrom (As avatar)]

Your observations match my views thru my LP 3mm as well .
As I said before its almost as good as my 3mm TV Radian and for $59 you wont do better , nice build as well .
I too think that a 3mm will be hard to use on a dobbie as it will be hard to keep what ever you are looking at in the field .
Great if your mount is driven tho .
Brian.