adding a 28mm x 2" eyepiece

[RT65CB-SWL]

Good morning everyone.

Thinking of adding a 28mm x 2" eyepiece to my collection of 1.25" glass and would welcome your thoughts. I have seen on AstroBoot this one made by SkyWatcher.

I read the posts by new and existing members buying their SkyWatcher or other mass produced 'scopes and have been let down with the supplied 1.25" x 10mm. So I was thinking... how well does this perform? ...or do you think it is a waste of money? 

 

 

PS - I am a TeleVue fan with a few Circle T's and other glass.

[alan potts]

I have never actually tried this one even though I did receive one with my Mak 180mm, I gave it away to my dealer friend to pass on with a purcahse. I did at the time own the 28mm Meade SWA and I have to say that was a very good eyepiece and in my view one I should have kept. It would be worth your while to hunt one down or the Ex Sc 28mm which has the same elements.

Alan

[Timebandit]

 

Hi . I have a william optics 28mm in 2" and its a great eyepiece in my opinion. I understand the skywatcher nivana 28mm is in effect the same eyepiece. And from what I have read they are supposed to be very good. Maybe the path to go down if you are in the market for a 28mm in 2" with a 82 d field of view.

I hope the above helps.

[parallaxerr]

Shameless plug - Phil, I have been considering selling my Meade 28mm SWA recently if you're interested? It's a great performer as Alan says, but all my other EP's are 1.25" so I find myself going for the 30mm Plossl instead and sticking with the smaller diagonal. I'll probably go for a 1.25" 24mm 68° to make up for the FOV.

It's just like this, in pristine condition and it's got a bit of green on it too

 

[Ricochet]

I think that the AFoV of that eyepiece is only just enough to warrant it being a 2" eyepiece so you may really be better off using a 24mm 68° or 32mm Plossl and not having to swap between 1.25" and 2" eyepieces. 

As for the quality of the eyepiece I'm sure that the suggestions above will be superior but at £20 it's almost worth a punt for the heck of it if you don't already have something with a similar TFoV. 

[Ben the Ignorant]

I took one apart to blacken it; it's very acceptable, especially when the shiny inside parts are made dull and truly black.

[oobydooby]

Oi! Keep ter 'ands off it.  Been looking at that for a few weeks and was gonna buy it monday when i 'ad a few quid spare!

If you don't buy by Monday I may well get it myself!

[domstar]

I got one free with my ED100. I used it for galaxy hunting but when I turned it on open clusters it was awful. I'm inexperienced with different eyepieces but even I could see this one is a turkey. Any star not in the middle will be badly out of focus (at f9). I love its chunkiness and the way you can just stick your whole face on it and I was really excited about having a 2 inch eyepiece but now I just use a 32mm baader plossl for my low mag needs. I thought about trying to sell it but they are selling for about 10 pounds on ebay so I'm just going to keep it. 

Edit- So in view of Ben the Ignorant's comments I'm going to add that while mine was disappointing, it doesn't mean that others will be.

 

[domstar]

ps The last one went for 10 pounds 50 on ebay and there's one currently with no bids for a fiver. (It's still rubbish though)

[Ben the Ignorant]

The 28mm I blackened for a friend was bought new from TS with a heavy discount and no explanation, turned out it was a bit astigmatic. When I opened it I saw the cemented doublet was glued together while the lenses were not perfectly aligned. Those without this defect must perform well, because the one I worked on was still ok for the price. But others could be worse if the assembly was even less careful, seems it's the case for yours.

[domstar]

@Ben the Ignorant Thanks for the information. Is there anything a clumsy amateur (me) can do with mine?

[Ben the Ignorant]

I'm not sure. If the doublet is cemented well, and only the mounting rings are skewed, you can fix that. The three-lens eyepiece is really two lenses because a pair is glued together, so opening the thing carries no risk of dubious reassembly. You can blacken the lens edges with a felt pen, and paint the inside with blackboard paint (4€ at ACTION stores).

In case the doublet is skewed, and you don't care taking a little risk, try warming the doublet in moderately warm water, 50°c to 60°c. The resin might melt a little, allow you to adjust the lenses, and harden again. Some guy in France did this successfully, but I don't remember where I read that. Could be the doublet is okay but too much play inside the barrel allows the groups to be misaligned; then some shimming will do. These 28's are worth saving. 

[John]

These 28mm 2" Skywatcher LET eyepieces have an apparent field of 56 degrees. It's not going to show any larger true field than a 32mm 1.25" plossl will - slightly less actually. I can't see the point ?

You go for 2" eyepieces to get a larger true field than 1.25" can deliver so you need to go for a 28mm SWA 68/70 or an 82 to make the most of the 2" format

 

[Louis D]

If you want to go cheap and wide around 30mm and don't mind field curvature and edge astigmatism, look for a used 80 degree 30mm KK Widefield clone.  They come up used here in states for $50 to $70.  They're only $90 to $100 new from some places.  They're good to 50% of the way out, so about the same as a 32mm Plossl.  After that, they get progressively worse until by the edges it looks like the Millenium Falcon jumping to hyperspace in fast scopes.  They have 17mm of usable eye relief and a true 80 degree field.  The glass and coatings are actually quite good yielding very dark background skies and sharp stars in the middle.  It really depends on your budget, but for $50, they're worth a look used.  The eyecup even screws off if you want to attach a camera for afocal projection photography.

[RT65CB-SWL]

Thank you all for your replies. 

I have just been reading a post/topic about the pros & cons of a 2" star diagonal. So after reading your views here and in the other post/topic, I have decided to stick and stay with my 1.25" and a single 0.965" eyepieces for the foreseeable future.

The 2" star diagonal is a definite keeper as I feel that if I decide to attach a camera to either my ETX or C6 it will not flex under the weight.

edit: @parallaxerrI may take up your offer at a later date if I decide to enter the world of 2" glass.

[RT65CB-SWL]

Ok! 

I have now entered the world of 2" glass. Forget about the one I origanally mentioned that started this topic. So what did I end up with?

The TeleVue 13mm Nagler/Type 1 that was advertised by @25585

It maybe over the top with my present 'scopes, but I am sure it will be fine and give the views I dream of. I have read reviews on other astro-forums about 'kidney beaning' near the edges with the 13mm/Type 1's and this has been overcome in newer designs, but that does not worry me.

At £10 per mm this is a nice piece of glass to accompany my other TeleVue e/p's & Ranger.

[Louis D]

2 hours ago, Philip R said:

I have now entered the world of 2" glass. Forget about the one I origanally mentioned that started this topic. So what did I end up with?

The TeleVue 13mm Nagler/Type 1 that was advertised by @25585

Nice way to keep it "Old School".  I just picked up a used smoothie Meade 14mm 4000 UWA for cheap to compare to my modern 12mm to 14mm eyepieces.  It does quite well for a 30+ year old eyepiece.  It's not quite as sharp in the center as a Morpheus, Nagler T4, or Pentax XL, but it has a surprisingly easy to hold 80 degree (measured) AFOV for eyeglass wearers with practically no SAEP.  It does suffer from some glare on the moon.  Perhaps coatings or internal stray light suppression could have been better.  Overall, quite impressive for a 1980s design.

[Timebandit]

2 hours ago, Philip R said:

Ok! 

I have now entered the world of 2" glass. Forget about the one I origanally mentioned that started this topic. So what did I end up with?

The TeleVue 13mm Nagler/Type 1 that was advertised by @25585

It maybe over the top with my present 'scopes, but I am sure it will be fine and give the views I dream of. I have read reviews on other astro-forums about 'kidney beaning' near the edges with the 13mm/Type 1's and this has been overcome in newer designs, but that does not worry me.

At £10 per mm this is a nice piece of glass to accompany my other TeleVue e/p's & Ranger.

 

These are a blast from the past? , will be interesting to see how you get on with this eyepiece. Certainly more magnification that the 28mm you were after.

But I am not sure the 13mm type 1 Nagler is a true 2" glass. If I remember correctly these have 1.25 barrels but with the 2" skirt on them. More of a secure fitting in the 2" focuser with a 2" barrel than the smaller 1.25 handles the size of the eyepiece in the focuser better. I think some of the Ethos use the same design mod. A true 1.25 eyepiece barrel ,but with the 2" skirt. Let us know what you think of it under the stars, clear sky's     ?

 

 

 

[RT65CB-SWL]

10 minutes ago, Timebandit said:

 

These are a blast from the past? , will be interesting to see how you get on with this eyepiece. Certainly more magnification that the 28mm you were after.

But I am not sure the 13mm type 1 Nagler is a true 2" glass. If I remember correctly these have 1.25 barrels but with the 2" skirt on them. More of a secure fitting in the 2" focuser with a 2" barrel than the smaller 1.25 handles the size of the eyepiece in the focuser better. I think some of the Ethos use the same design mod. A true 1.25 eyepiece barrel ,but with the 2" skirt. Let us know what you think of it under the stars, clear sky's     ?

 

 

 

I think my 6mm Radian is also a Type 1... It will be family affair with 2x TV Plossl's and 3-6mm Nagler zoom in the e/p case.

[John]

Type 1 Naglers and first run Radians are different.

There were 2 versions of the Type 1 Nagler, a "smooth side" 1st run and later a 2nd run with rubber eye cups. The former made in Japan and the latter Taiwan I seem to recall. The focal lengths were 4.8mm, 7mm, 9mm and 13mm. These were all 1.25" format eyepieces but the 9mm and 13mm had a 2" "skirt" for mounting security - they are heavy eyepieces.  There were some 1st run 11mm T1 Naglers made as well but that focal length was then dropped from the range before the 2nd run.

The Radians retained the same optical design for both runs but the lens coatings of the 2nd run were improved. The only external difference (apart from the slightly different tint to the coatings) was that the lower barrel section of the 1st run Radians has a rubber grip on it wheras this section is smooth in the 2nd run.

Hope you enjoy your 13mm T1 Nagler

[25585]

Definitely need to use it as a 2 incher. Great ep for globs, planetaries - latter especially with OIII and UHC filters.