I would be very grateful for some input from individuals who have Televue Radians and other eyepieces which they have used for planetary observing.
I have been trying to get a short FL Radian (ideally a 3mm) for a very short FL refractor and thus get some magnification without resorting to barlows etc. I am not having much success in this endeavour and so I am wondering whether it is even worth the trouble hunting for this eyepiece in comparison to other EPs that are available such as a Pentax 3.5XW
To shed a little extra light on this situation the reason I am after the Radian in particular is the 20mm of ER. If anyone has any other suggestions or can vouch for the Radian as a particularly good EP I would certainly be happy to hear your thoughts
Hi,
I have astigmatism and changed some time ago to all Delos (3.5, 6, 10, 17.3) plus a Explore Scientific 24mm 68 degree.
I am very happy with all of them, down to the 3.5 for small DS and planetary nebula in a f 7.4 and f 5 APO, I can see the entire field with glasses in all of them. I had a 5 mm Radian and the Delos are at least as good, more field and better designed eye cup adjustement.
I recently compared the 3.5 Delos on Jupiter with a Takahasi Hi-LE 3.6, I had to observe without glasses but at the small exit pupil the astigmatism does not show up.
Result: The Tak Hi-Le was sharper and had slightly brighter image.
For Planetary work this would be my preference, for DS and planetary nebula the larger field and the comfort of the Delos are my preference.
I also had a chance to use the Nagler Zoom3-6 and that will be what I will purchase for Planets, it up there with the Tak but provides the additional benefit of 3-6 mm zoom.
I can't say whether it's the best one for you, as I've never looked through one, but...
Telescope House in the UK have 3 in stock - according to Amazon.co.uk ... I'd be surprised if they weren't interested in shipping. Note that the online price includes 20% tax which wouldn't be applicable if they are happy to export outside the EU.
Also note that this weekend has be European Astro Fest in London, so it'd be worth checking with them on Monday if they still have one...I've always found them to be very helpful over the phone.
Richard, I am using a 3.5mm Vixen LVW on the FS60CB giving 101x on the 355 f/l scope. It is a very nice eyepiece.
It has shown itself useful after all, for I can't use it in the Mewlon. Used it on good mights in the TSA.
LVWs all have 20mm eye relief and are about 65 degrees apparent.
Dear Profiler,
I have a 3mm Radian.
On a good night, it provides quite good planetary views.
I am not interested in selling it (at the moment at least),
but you are welcome to come (to the Pony Club, my place, or wherever) up here and try it out on your scope if you want to see if it is worth pursuing for your setup.
The TV Radians are excellent eyepieces. The later series are very marginally better than the early Radians IMO, although its exceptionally close. They have slightly better coatings than the earlier ones IMO. That having been said I would be very happy with either and it's not a deal breaker.
I have an 8mm (late version) and it is about the equal of my 8.5mm Pentax XF.
I also spent a lot of time (several nights) comparing a 6mm TV Radian (early version), a 6mm TV DELOS, a 3-6 Nagler Zoom, a 6mm UO HD ortho and a 7mm Pentax XW in both my 10" and 14" Newtonians.
The 6mm Radian held up very well and while overall it was probably just a spiders hair behind the 6mm Delos and the 7mm Pentax XW I felt in a couple of aspects it was better than the 6mm Delos. Notably it's off axis sharpness when used in my 10" Newtonian, without a paracorr and its ability to baffle internal reflections. Overall whilst not the winner, I felt the 6mm Radian was an outstanding eyepiece, which I would be very happy to own, if I didn't have the 6mm DELOS. I am sure if you get a 3mm Radian it will be just as good as the 6mm.
Now your going to ask, how do you tell the early version Radian from the late version Radian
I have attached images of both in 6mm. The later version is on the right and has no "knurling" underneath the green lettering, it is smooth.
You would also be very happy with any of the premium 3.5mm eyepieces like the 3.5mm Pentax XW, or the 3.5mm Vixen LVW. The 3-6mm Nagler zoom while very good on axis doesn't have the eye relief of the others and its off axis performance isn't as good as the others either.
I've done a direct comparison between a Radian 5 mm and LVW 5 mm, and much preferred the second. (Both are long ER.) The TV had obvious "warm" colouration, was less bright, and wasn't as sharp as the LVW. In the end though I didn't need the extra ER and found the 3-6mm TV Zoom a much more practical and versatile EP to have for those rare moments when the seeing allows high power views. I have the Pentax XW 10 mm, too, and it outgunned my 12 mm T4 Nagler.
I love my TV Radians but never did buy a 3mm before the disappeared. So I brought a 3mm Long Pernq eyepiece from Andrews for $59 because some had spoken well of it and the price was right. It also has 20mm eyerelief. I think it performs very well and is almost a steal at the price.
I have the Long Perng one as well. It is great for eye-relief and is nice and sharp. I assume it, the Williams and the Orion "edge-on" planetary are just re-badged from the same factory. Mine looks identical with the Orion (selling at Bintel for $119)- but the Williams and the Long Perng have slightly different grips now.
I have since bought the Nagler 3-6 zoom and retired the Long Perng: it is on my desk staring accusingly at me as I type this...
I am very happy with the Nagler: unlike the comment from JohnB I have noticed no off-axis drop off, and the 3-6 zoom is wonderful. It does have shorter eye-relief though.
If you want, I am happy to sell you the Long Perng : say $40 + postage (it was $99 when I bought it, but Andrews have dropped their price). Drop me a pm if you are interested.
All the best,
Dean
You know you want the XW 3.5 ...really want it…..mines sitting there waiting for the time when 514X is the only magnification that will do.
It's called the XW factor
Matt
I am very happy with the Nagler: unlike the comment from JohnB I have noticed no off-axis drop off, and the 3-6 zoom is wonderful. It does have shorter eye-relief though.
All the best,
Dean
Hi Dean,
What telescope (s) are you using the Nagler 3-6 zoom in. This can make a difference.
I believe John (see his earlier post) has made such a comparison in the 6mm Radian with the 7mm XW. My impression of his comments was that the Radian was very good but the XW slightly better.
Dean I have one of those LP 3mm and also a 3mm radian and you are right these are a very good high power eyepiece only a shade behind the TV in all ways .
I to like its 20mm eye relief , just like the Radian .
I have since fitted a polarising filter to my LP 3mm and its now my high power solar eyepiece when viewing the sun in either of my refractors with my Lunt Hershell wedge and its awesome for that .
The only problem I can see with these LP's , Orion and WO's is that the QC is not as good as TV's and the chances of getting a dud are slightly higher , but Bintel and Andrews along with others will exchange no 'Q's' asked .
Good luck with your search Peter , and sorry mate my Radians are not for sale either . love them to much .
Brian.
Quote:
Originally Posted by SkyWatch
I have the Long Perng one as well. It is great for eye-relief and is nice and sharp. I assume it, the Williams and the Orion "edge-on" planetary are just re-badged from the same factory. Mine looks identical with the Orion (selling at Bintel for $119)- but the Williams and the Long Perng have slightly different grips now.
I have since bought the Nagler 3-6 zoom and retired the Long Perng: it is on my desk staring accusingly at me as I type this...
I am very happy with the Nagler: unlike the comment from JohnB I have noticed no off-axis drop off, and the 3-6 zoom is wonderful. It does have shorter eye-relief though.
If you want, I am happy to sell you the Long Perng : say $40 + postage (it was $99 when I bought it, but Andrews have dropped their price). Drop me a pm if you are interested.
All the best,
Dean
What telescope (s) are you using the Nagler 3-6 zoom in. This can make a difference.
Cheers,
John B
Hi John: I notice your scopes are all pretty fast, and you are right- that can make a big difference. I use mine with my refractors: a Stellarvue 70ED (f6) and a Tak TSA 102 (f8).
You have some nice scopes there!
I believe John (see his earlier post) has made such a comparison in the 6mm Radian with the 7mm XW. My impression of his comments was that the Radian was very good but the XW slightly better.
Hi John: I notice your scopes are all pretty fast, and you are right- that can make a big difference. I use mine with my refractors: a Stellarvue 70ED (f6) and a Tak TSA 102 (f8).
You have some nice scopes there!
Hi Dean,
The predominant aberration I noticed with the 3-6 Nagler zoom was field curvature. Referring to my testing notes on a single bright star (Achernar) when used in my 10"/f5.3 newtonian (without paracorr), I recorded, "The star image bloated in size from 60% of the way off axis, but stayed circular to the field stop". This indicates straight field curvature as a result of the scope / eyepiece interaction. A newtonian has minor inherent +ve field curvature and based on what I observed I believe the 3-6 Nagler zoom also has inherent minor +ve field curvature. The 2 positive field curvatures compound and manifest in the observed field curvature. A refractor on the other hand has inherent -ve field curvature and when an eyepiece having slight +ve field curvature is used in a refractor the two cancel out and give a flat field view. Consequently the 3-6 Nagler will perform superbly in a refractor, less so in a newtonian. Whilst I haven't tried it with the 3-6 zoom I am sure that using a paracorr, which has inherent -ve field curvature, with the 3-6 zoom would result in a nice flat field view when used in a newtonian. This is the case with the 14mm and 20mm Pentax XW's which both have +ve field curvature. Aside from the field curvature and the shorter eye relief the 3-6 Nagler performed very well.
Tomorrow when I am at my notebook pc I will attach to this post the testing notes and scores on all 5 eyepieces when used in my 10"/f5.3 newtonian when aimed at a single bright star only (Achernar). The scores are not indicative of each eyepieces performance on any other target type, or in any other telescope. I can't do it at the moment from my tablet as I need to convert the file from excel to pdf format.
Thanks for the analysis John. My guess is that TV eyepieces were developed first and foremost for their refractors, and so the slight +ve field curvature you have noted is deliberate to offset the -ve of the refractors. This would be particularly so for the shorter FL eyepieces, as they would be used much less with SCT's and large reflectors simply because the powers would be too high for most conditions.
Mind you, they are pretty good with reflectors too! I love my 13mm t6 Nagler with any scope that I have tried!
Please find attached my test results for various 6mm eyepieces (and 7mm Pentax XW) on a single bright star, in my 10"/F5.3 Newtonian without paracorr.
This information only relates to testing on a single bright star at high elevation. It does not incorporate any test data or results in relation to testing on any other types of astronomical targets. I am yet to tabulate that data.
Cheers,
John B
Last edited by ausastronomer; 14-02-2014 at 12:29 PM.
Reason: Aligned the numbers better under each column in the table
: say $40 + postage (it was $99 when I bought it, but Andrews have dropped their price). Drop me a pm if you are interested.
Dean I have one of those LP 3mm and also a 3mm radian and you are right these are a very good high power eyepiece only a shade behind the TV in all ways .
