choosing televue eyepiece

[DomDubois]

I'm looking into purchasing a new eyepiece soon and have been looking at the Nagler 5mm for my F4.9 dob. I'm curous about which type of televue would be best, what are the main differences between the radian, ethos, nagler and delos lines that televue makes, it seems confusing. They only list a 3mm radian on their website, did they discontinue this line?

Also, will FOV make a planet appear bigger in the eyepiece? I've read that the 82° FOV May make the planet appear small in the eyepiece. I'm not sure if that is accurate. ?

[Druid]

You might find this useful.

http://www.televue.com/engine/TV3b_page.asp?id=212&Tab=#.UyXAhfl_t8E

Pop in the dimensions of your scope and it'll give you the resulting magnification, true field of view and exit pupil size for each.

The magnification determines the size of a planet in the eyepiece, the field of view determines how much space around it is shown. 

[John]

The FoV affects the amount of sky you can see framing the object you are looking at, not the actual apparent size of the object. Sometimes seeing an object with more sky around it can make it appear comparatively smaller, but it's not.

A 5mm eyepiece (any 5mm) will give you 240x magnification which will be useful for Saturn, Mars, the Moon and binary stars but is often a little too much power for Jupiter.

I'd take your time to research the various Tele Vue designs and their competitors as there is a lot of choice available these days depending on your viewing preferences and budget.

[DomDubois]

So if I'm understanding this correctly: the nagler offers a wider FOV than the delos, however the delos has a better eye relief.

The ethos line seems to be a higher grade eyepiece than the others

[DomDubois]

Also, was wondering what some comparable brands to televue might be?

[Daniel-K]

me personally i think you would use a 11,12,13MM nagler more than a 5MM is not all about getting the most power its using the most power available in the conditions available. in my 14 i found that even a 9MM is too much unless the sky is steady. ive just bought a 13MM T6 Nagler which will give me X123 more than enough for to resolve globs and split some doubles i probably will get a 8MM for the planets but i wouldn't go lower than an 8MM 

[Astro Imp]

Everything you need to know about Televue is available on their web site:- http://www.televue.com/engine/TV3b_page.asp?id=27

[rwilkey]

Also, was wondering what some comparable brands to televue might be?

Hi Dom, a 5mm is a little high on power, surely at 8mm or similar would get more use?  On your specific question, yes, comparable brand is the Explore Scientific, I have gone for the ES82 degree series which compare well to Naglers, but a lot cheaper (as the green & blacks were out of my budget).  Main website here, but I buy mine from Agena Astro in the US, as well as s/h: http://www.explorescientific.com/eyepieces/

[DomDubois]

Thanks guys, I took another look at their site and its starting to make more sense now. A lot of people really seem to like the delos design over the naglers, because of the greater eye relief. I am looking for a high power eyepiece for planetary viewing, I currently have a 9mm plossl that came with my scope. Just trying to sort out which design (nagler vs delos) would be better for planetary viewing. Seems to be all personal preference, what experience do you guys have with them?

[Daniel-K]

if its for planetary why not a radian?

[Scooot]

http://stargazerslounge.com/topic/209861-12mm-nagler-or-12mm-delos/

This thread has a lot of good info. I personally would go for a Delos, greater eye relief, the eye relief adjustment mechanism is very good, and I'm not so sure 82° versus 72° AFOV is that important for higher power viewing. Incidentally I did read somewhere that the quality of the Delos is more or less the same as Ethos but for the field of view.

[John]

So if I'm understanding this correctly: the nagler offers a wider FOV than the delos, however the delos has a better eye relief.

The ethos line seems to be a higher grade eyepiece than the others

The Delos sought to replicate the image quality of the Ethos with a more moderate field of view (the Ethos has 100 degrees) and more eye relief and at a lower price. It succeeds very well at this indeed 

I love ultra and hyper wide fields of view so I'm using Nagler and Ethos eyepieces down to 6mm and than Radian's and Pentax XW's (very, very similar to the Delos) in shorter focal lengths.

I also use orthoscopic eyepieces by other brands which cost a lot less and provide great views too albeit at the expense of a much narrower field of view, short eye relief and small lenses to peer into. 

There is just so much choice at all price levels it's well worth spending time over these decisions 

It's taken me years to decide what really suits me and to afford to buy them !

[AlexB67]

 They only list a 3mm radian on their website, did they discontinue this line?

Only the 3mm is sold new these days. They do come up form time to time second hand on here. You need 50 more posts to buy from classifieds though, but you can also buy from here.

http://www.astrobuysell.com/uk/

Typically in the sort of 90 - 120 pound bracket they are good value second hand for half the price of a Delos new if you find 60 degrees FOV enough. Personally I find it plenty for planets at the sort of magnifications needed. The Radians I find are very comfy to use wiith 20mm eye relief. Plenty for glasses or without.

[swamp thing]

me personallyin my 14 i found that even a 9MM is too much unless the sky is steady. ive just bought a 13MM T6 Nagler which will give me X123 more than enough for to resolve globs and split some doubles i probably will get a 8MM for the planets but i wouldn't go lower than an 8MM

Slightly off topic (sorry OP). Man your gonna be wanting to use way higher power than that on globs with a 14" scope, trust me. Your not even starting to exploit its potential down at x123.

Next time your at a dark sky site try M3 at 250x, happy days.

[ollypenrice]

If you really just want planetary views at high power you might do better with fewer glass elements, a far smaller FOV and tight eye relief. This, though, means planetary only, which might be a shame.

TeleVue do all the work, EPs can't be patented successfully, so... reward them with your custom. The rest rip off their work.

Olly

[DomDubois]

I've never felt my 9mm was too much magnification, so I'm thinking maybe a 6mm delos for my high mag. Planetary EP. Just curious, would this be useful for DSO's?

[DomDubois]

If you really just want planetary views at high power you might do better with fewer glass elements, a far smaller FOV and tight eye relief. This, though, means planetary only, which might be a shame.

TeleVue do all the work, EPs can't be patented successfully, so... reward them with your custom. The rest rip off their work.

Olly

Olly what kind of eyepiece would that be, a plossl?

[scarp15]

Plossl's can be excellent at resolving fine planetary detail, yet they can be a little challenging in terms of eye relief and ideally require tracking, with their narrower field of view to retain concentration. As with others, a delos, perhaps 8mm would make a good option, I think that there is currently one for sale on here.  You may determine anyhow to gradually aim to collect a few high power e.p,s, at quite marginal magnification variations.    

[AlexB67]

Slightly off topic (sorry OP). Man your gonna be wanting to use way higher power than that on globs with a 14" scope, trust me. Your not even starting to exploit its potential down at x123.

Next time your at a dark sky site try M3 at 250x, happy days.

Also sorry for the OT but perhaps of use to the OP. I find even in my 10 inch Dob  many globulars take 200x well, M3/M13 seen recently both are both a delight at that magnification in a 6mm, but the scope needs to be well cooled and collimated, at the beginning of a session they just blur out. Conditions need to cooperate also such as how high up near zenith they are, M3 is located very favourably these days at the right hour to push that mag.  

Anyway, I think in a 14 inch scope planetary mags can overlap with many globulars, I like to blow them up as much as I can to see what is in the core    

Also brighter planetary nebulae take that higher mag well also. An 8mm in such a scope would serve more than one purpose besides planets.  

[ollypenrice]

Olly what kind of eyepiece would that be, a plossl?

Not a plossl. I'm not a plossl fan, be it said. Orthoscopic or, if you really want to be a planetary head banger, a monocentric. I did say head banger!!!!

Olly

[AlexB67]

I've never felt my 9mm was too much magnification, so I'm thinking maybe a 6mm delos for my high mag. Planetary EP. Just curious, would this be useful for DSO's?

Do you find the 9mm plossl tight on eye relief or comfortable enough, since you mentioned it in the nagler versus Delos consideration  ?

A nagler will offer about 10mm and up on eye relief depending on focal length. If okay with the plossl the nagler should probably be fine in that case. If you wear glasses for viewing a Delos would be better for eye relief and an orthoscopic of any sort for high mag viewing is not an option, as great as the views they provide, they are tight on eye relief and not comfortable for that.  Something to consider. 

[DomDubois]

Another reason I'm leaning toward a delos is because I think it would make viewing easier for kids/family/friends, with a greater amount of eye relief.

[jetstream]

Another reason I'm leaning toward a delos is because I think it would make viewing easier for kids/family/friends, with a greater amount of eye relief.

Delos are great,really good.I have a similar spec scope as you and have the 8mm and 6mm Delos.During most times the 8mm is the most used,however a recent(short lived) spell of great seeing allowed the 6mm some focuser time.So...the 8mm Delos is the most used on Jupiter/Lunar and as Alex says these higher mags will be great on globs like M13 etc.My seeing here is not that great a lot,so thats why I pick the 8mm.

PS the moon,viewed along the terminator with a 8mm or 6mm Delos is stunning,absolutely stunning