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5mm Radian/5mm BGO shootout.


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Last night I had a brief opportunity to view Saturn with my 10 inch Skywatcher dobsonian. While Saturn was low in the sky,it still alowed me a chance to compare the two eyepieces.

My impression was that both eyepieces gave a clear view Saturn which was large in the field.My own preference was for the wider field of view that the Radian offered.This especially with the dobsonian where movement is manual.

Both eyepieces performed very well in my opinion and could not be faulted.I am glad that I managed to buy the Radian.But all said and done,the opprtunity to buy good quality used eyepieces gives one the opportunity to try out different models.I dare say that some would prefer the BGO even in a dobbo.

With regards to the shoot out analogy,I think that both parties put their guns back ih their holsters and went to have a frierndly drink in the saloon bar.Lol

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Nice report :smiley:

I've only recently started using Radians, having used mostly the ultra-wide Tele Vue designs in the past. I currently have the 4mm and 3mm and find them excellent eyepieces. Great value for the price they go for on the used market :smiley:

The 5mm BGO is really good too but you do need to be "in the right mood" for the tiny eye lens and short eye relief I find.

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I think in a straight competition between exact focal lengths, the more comfy eyepiece often wins. did you notice the slight difference in tint between the two eyepieces? I find the BGOs a bit more white/neutral and the Radians a bit more yellow but you only see it when going from one to the other.

I doubt I'll be selling my Radians (8mm and 10mm) or my BGOs (12.5mm, 9mm and 7mm) any time soon.

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In the past I did own 25mm and 18mm volcano top orthscopic eyepieces.They were more comfortable to use than the flat top BGO'S.There is a space in my collection for these two eyepieces.I shall be on the look out sooner or later to aquire them.

With regards to the 5mm Radian I did expect to notice some warmness in the view.But it was not evident to me.I did notice it in a TMB 8mm that I once owned.

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GM,

I have the 5mm and 4mm Radian and like you I have read so many times about a warm colour cast. The funny thing is I remember back in the days of film paying a lot of money for Lee 81, A B and C Warm filters.

I honestly have never noticed it unless I put it against my 5mm XW and even then you have to really look for it. I sometimes think some of the reports on eyepieces by others must be done with the help of spectroscopic analysis.

Alan

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I agree Alan. it's not an issue that should make you put off by Radians at all as it's a non issue. in actuality I feel that the tint if anything creates a subtle decrease in brightness and therefore reveals more contrast and detail. a bit like a weak moon filter.

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I listened to the reports of this until somebody asked if I had actually tried a Radian.So there.Reports are just a guide for you to make up your own mind by experience.

Martin.

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I listened to the reports of this until somebody asked if I had actually tried a Radian.So there.Reports are just a guide for you to make up your own mind by experience.

Martin.

Well put Martin - quite agree :smiley:

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It was indeed you Moonshane.A slight rapp on my knuckles.

I once read an article on Meade 4000 series plossl's made in Japan.This particular chap took delivery of several of these.Having discovered that they were made in Chine and not in Japan,he sent them back complaining to the supplier.Another post in response asked if he had actually tried them out.Slight snobbery perhaps.

I was guiolty of snobbery with the Radian and you put me cloth cap back on as it were Moonshane. :grin: :grin: :police:

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By the way Moonshane,I am interested to know if there is a dobbo section.I have just gone back to dobbo viewing and am loving it. :icon_profileleft:

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It was indeed you Moonshane.A slight rapp on my knuckles.

I once read an article on Meade 4000 series plossl's made in Japan.This particular chap took delivery of several of these.Having discovered that they were made in Chine and not in Japan,he sent them back complaining to the supplier.Another post in response asked if he had actually tried them out.Slight snobbery perhaps.

I was guiolty of snobbery with the Radian and you put me cloth cap back on as it were Moonshane. :grin: :grin: :police:

it was honestly not meant as a wrap on the knuckles at all, just a question. as I did honestly think some people don't consider Radians due to the tint; it's often overstated I think. as you now know, they are well worthy of adding to any collection and my concern was that you'd relied on what others say but now you know :grin:

re the dob section I don't think there is one specifically as where would it stop I suppose? there are probably more entries in the DIY section on dobs than most scopes though as they are almost infinitely mod-able. :smiley:

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Nice to hear that kind of comparison :).

For what it's worth, I've seen some reports that put the Vixen LV / NLV equal to the Radian and perhaps slightly ahead (just a narrower FOV).

When I've compared my TV plossl and LVs, the only difference I can notice when not observing the Moon is that the LV (probably just like the Radian), is slightly warmer than the TV plossl. Perhaps this is a by-product of using Lanthanum glass?

For completeness sake, the LV does exhibit a blue ring of fire at the field stop when viewing the Moon, I've heard this reported in other eyepieces (like Ethos for example), and think it's a by-product of having a more complex design.

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....For what it's worth, I've seen some reports that put the Vixen LV / NLV equal to the Radian and perhaps slightly ahead (just a narrower FOV).....

Thats the problem - if you look hard enough around the web you can find a wide range of views / test results many of which are contradictory. As I've posted before, with eyepieces that are pretty close in performance (as many are nowadays) viewing some objects under some conditions with certain scopes and a certain individuals eyes will throw up one result whereas variations on some of these factors can produce the reverse result, or a dead heat !

I feel now that reading reviews is fine to establish broad information but the final analysis needs to be performed with ones own eyes / scopes / viewing conditions :smiley:

Thank goodness the used market gives use the chance of trying things without risking major financial loss if things don't work out !

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Thank goodness the used market gives use the chance of trying things without risking major financial loss if things don't work out !

Agreed. I'm glad I bought my Tal x2 barlow second hand, as I'm sure I should be able to sell it once I do :).

I think with eyepieces, you should always try and try before you buy, but failing that getting them 2nd hand and selling them at the price you paid for them is a safe way to go :).

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Moonshane,I was only jesting.I have never experienced anything but good nature and helpfulness here on SGL.

Martin. :kiss::smiley: :smiley: :smiley:

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GM,

I have the 5mm and 4mm Radian and like you I have read so many times about a warm colour cast. The funny thing is I remember back in the days of film paying a lot of money for Lee 81, A B and C Warm filters.

I honestly have never noticed it unless I put it against my 5mm XW and even then you have to really look for it. I sometimes think some of the reports on eyepieces by others must be done with the help of spectroscopic analysis.

Alan

My eyes must have a built-in spectroscope ;)

There is a difference, but it is slight, and you do not notice it, until you compare it to a more neutral EP, in a quick, side by side comparison. I only replaced my Radian 8mm because I got a Pentax XF 8.5 on my birthday, and that just edged the Radian out on transmission and neutrality. We are talking gnat's whiskers here. In all other respects they performed equally. Then later two used XWs came along (7mm and 10mm) which I could get for the price of two new Radians. Their larger FOV and (gnat's whisker) difference in transmission and neutrality clinched it. XW vs Radian is a bit like P51 Mustang vs Me109. According to a German pilot the P51 could do everything the Me109 could, but for two hours instead of 30 minutes (given this big difference in range, the analogy might fit an XW/Ortho comparison more accurately).

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People also forget that the eye's got auto-colour-balance.

Thirty seconds of looking through an eyepiece and any minor colour cast will have disappeared.

Very good point. This is why you have to compare them side by side. The eye corrects rapidly for these very slight colour casts.

However, transmission is another matter. The transmission of the XW, XF and Delos range appears to be a touch better than the Radians. The eye cannot really correct for that. Not at all important on planets, of course.

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