More reports on Televue eyepieces

[alan potts]

I am thinking of writing another few reports for site. I was thinking of the 10mm and 21mm Ethos against the nearest Naglers. So that is either 9mm or 11mm and 20mm.

I am looking for some ideas for targets and scopes from members to include, it will make it more interesting for me. I could of course just review the eyepieces on their own or if people would like me to review something else post that.

I am open to ideas.

Alan

[ronin]

Personally I am never going to buy one of either type so fairly irrelevant to me, other thought is they cost so much that if you happened to get a poor one you complain, send it back immediatly and either get a replacement that is good or get a refund. The result being you are only looking through a very good (expensive) eyepiece.

I cannot see a result other then "It is an excellent eyepiece" coming out. I cannot see a conclusion of "Buy a GSO plossl. they are better, wider views and sharper across the view" coming out.

[jetstream]

There is a big interest in the eyepiece reports & tests as evidenced by the number of people viewing them.Your reports are objective and to the point and give everyone a chance to here how they are before buying them. TV's are all "excellent" in their individual ways and customer service from Mr Nagler is top notch I hear,but this is to be expected from such a reputable company.It seems like Televues marketing strategy is paying off....with the customers winning.I am extremely interested in Ethos vs Naglers Alan,& if you can find the time to do this,it wil benefit many here.Thanks

[ramstar]

I agree with Jetstream - the eyepiece reports make interesting reading even though I can never see me spending the sort of cash an Ethos would need. Having said that, based on similar reports and comments, I did invest in a 10mm Delos and am more than pleased with it.

han happy with my purchase.

Reports as far as I'm concerned provide enthusiasts of all levels of experience with information and yes, they will be one individuals' point of view, it is up to each reader to disseminate the content and do what they want with it.

[Stu]

Hi Alan

I'm actually wondering if it may be of value to the forum to review the best eyepieces against some of the less expensive ones?

The trouble with putting Delos vs Nagler vs Pentax vs Ethos is that under our sorts of skies it is pretty hard to see much difference as they are all excellent.

I've know idea how you could do that as you don't have any of the value brands to compare with, but its just a thought.

I love reading your reviews by the way, keep then up either way!

As to suggestions? Not too sure, perhaps splitting tight doubles and seeing how they fair across the whole fov? How about comparing eps with different mags but similar fov to show the effect of mag in sky background darkness and contrast. This would show the value of Ethos vs Delos for example. The things I am interested in are Orthos vs Widefield which I think you've covered but might bear repeating when skies are darker. Also TV Plossls versus Orthos, although I should be able to do this myself, again once skies get darker.

Just a few rambling thoughts.....

Cheers,

Stu

[alan potts]

Stu,

A very good point, 20mm Nagler against 21mm Ethos, apart from the fact they beyond many to take Ronins point and I am only going to say something along the lines of what he suggested. I never really looked at it that way though if they were poor I would say.

To come back to what you said, if i compared with a cheaper band I would then have to buy one. I could do something that has been on my mind for some time now, 24mm Meade UWA against 26mm Nagler, I don't think they are a million miles apart focal length wise.

I will give the tight double idea some thought, though with a wide spread of scopes it would be different eyepieces to get anywhere near matching powers.

Alan.

[Stu]

Actually I was thinking more along the lines of 22 Nagler vs 17mm Ethos or similar combination. That would give relatively similar fov with higher mag in the Ethos for darker background showing the benefit of the extra afov.

Meade vs TV also sounds interesting

Stu

[Pig]

Alan, I for one think it will be great to read another review, I find them very helpful.

Its a good idea, and very considerate, for anyone to perform a comparison between eyepieces and then share the findings with others.

I personally would like to see some eyepiece comparisons between a selection of craters on the moon.

Another point is the reviewer can only compare the eyepieces they have in their collection, what else can anyone expect.

I also think its natural for people (not OEM's) to compare similar eyepieces for 2 reasons:-

1) You have to compare apples with apples,

2) The likelihood is the eyepieces will be of a similar cost or some factor / reasoning to do with cost as we only buy what we can afford.( well maybe not all the time )

Please fire away Alan and review as much as you can

[alan potts]

Pig,

I will give the Moon some thought, but I will have to do some study first.

Stu,

I have the 20mm Nagler but not the 22mm. Another I could do is the 41mm Panoptic and the 40mm SWA Meade. I guess I could do some comparisons with my BGO's as well. Your old 7mm Nagler v the BGO 7mm, bit of a FOV difference though. Likewise I have both 9mm as well.

Alan.

[swamp thing]

Reckon you need a nice fast scope to make some of these comparisons Alan.

Maybe you should post your eyepiece collection over to me

[John]

Reckon you need a nice fast scope to make some of these comparisons Alan....

Thats my thoughts, with lots of respect to Alans reports of course

The point about comparing expensive eyepieces to less expensive ones of similar specifications is valid too. It's not easy to arrange though, I appreciate that.

[Pig]

An interesting area the moon to test and compare eyepieces could be:-

EXODUS - Forms a remarkable couple with Aristoteles. Circular. Very steep and tormented slopes. Very high walls with terraces.Tormented floor. Central mountains and hills.

Position - Quadrant: North-East

Area: Just North of Mare Serenitatis region

[alan potts]

This is one time where I wish I were still in England, for a fairly small outlay you could swap eyepieces, though I have to say many of you seem to live miles from where I did up in Hull.. I accept my scopes are not really fast enough, one reason why I didn't bother with the 14mm's and the 13mm E in the F15 Mak, I imagine most eyepiece will look good in that.

To some degree you come back to Ronins point that writing about Televues is only going to end in a comment, of my what a super eyepiece.

I think there is a point to the Meade 24mm and the Nagler 26mm and the two 40mm combatant as well, they are like for like and at least they are different manufacturers.

Alan

[Moonshane]

I'd be interested in some views on the moon too. I must be the only person in the world that hates looking though my 13mm Ethos at the moon as I get weird chromatic effects off axis with that and my 26mm Nagler. I never use them on the moon though and prefer plossls and orthos. maybe you could try the 26mm Nagler and 21mm Ethos.

I don't get these effects with my 16mm T2 Nagler or my Radians.

[estwing]

Reckon you need a nice fast scope to make some of these comparisons Alan.

Maybe you should post your eyepiece collection over to me

..no me...mines faster

[estwing]

I'd be interested in some views on the moon too. I must be the only person in the world that hates looking though my 13mm Ethos at the moon as I get weird chromatic effects off axis with that and my 26mm Nagler. I never use them on the moon though and prefer plossls and orthos. maybe you could try the 26mm Nagler and 21mm Ethos.

I don't get these effects with my 16mm T2 Nagler or my Radians.

...using shanes 26mm last week was a pleasure..but my heart is set on a 21mm Ethos

[alan potts]

I have said before on forum, I would love a Dob, maybe a 16 inch of one type or the other, the LB 16 has always caugth my eye. I don't think there is much in the mirros from all the main players, OO look to be better but are a lot more money, well here anyway. They also take a long time to get.

It is just too close to my last big spend to risk it, yes I have made the barn waterproof but there is no heating in there and winter nigths are not far away.

So for the time being it will just have to be the M/N 190mm at F5.26 and that is not really quick enough to distory all but the cheaper eyepieces.

Just a thought here, If I use the focal reducer in the LX will that act exactly like a true F6.3 scope?

Alan.

[John]

Actually I'd forgotten that the MN190 was as fast as that. Mak-newts make pretty good eyepiece test beds because they produce only 30% or so of the coma that a normal newtonian does. That makes it easier to see the outer field aberrations in eyepieces.

My fastest scope is now F/5.3 so you are better equipped for eyepiece testing than I am Alan. More access to better skies I'll warrant too

I have used a focal reducer with an 8" Celestron SCT but I don't know if it produced a "true" F/6.3 scope in every respect.

[bingevader]

...if I compared with a cheaper band I would then have to buy one.

How about a star party at yours!

I've always fancied a holiday in Bulgaria.

We bring our EPs for you to compare.

Cheers

[Dunkster]

What is "true" focal length anyway? Are the characteristics of physical focal lengths different from folded designs? Even then, reducers seem to quite prevalent with refractors too... Isn't it about the mirror(s) and/or glass elements bending the light cone?

[Naemeth]

What is "true" focal length anyway? Are the characteristics of physical focal lengths different from folded designs? Even then, reducers seem to quite prevalent with refractors too... Isn't it about the mirror(s) and/or glass elements bending the light cone?

Surely focal length is just focal length. Most SCTs have a primary with a focal ratio of F/3 or F/2, it's the secondary mirror that adds most of the focal length.

Another example would be using a x2 powermate - it doesn't add anything except magnification. More precisely, it doesn't do anything other than increase the focal length of the scope.

A Star Party in Bulgaria sounds great .

The Moon does test eyepieces, so I too would be interested in more reviews with the Moon as one of the main objects .

[alan potts]

A star party here, I just turned the field over too.

John.

A point that you makes about coma on a Mak/Newt, I think the adverts say coma free, I have never seen any and the stars at the very edge are sharp. My understanding of coma is you get a comet sort of shape, if that is so I have never seen it on any magnification with any FOV, could it be going faster than this could cause it. The scope is sold mainly as an astrograph and photos I have seen from others show very good star shape (though croping could be in the mix). I seem to make a habit of using scopes designed for photography for visual..

Going back to the focal reducer, I guess if the scope speed is 6.3 then it is a 6.3 scope but it would be interesting to know if the other unwanted baggage invites itself along for the ride.

I will learn some of the crater on the Moon as it seems popular. At the moment with it being close to full I don't observe even though it is clear most of the time. Oh how I recall my first large scope up in Hull, it was 3 months before I could use it after it was finished.

Alan

[John]

I find this illustration of aberrations quite useful. It's exaggerated but gets the point across:

http://www.umich.edu...dscobel.27.html

I've seen the MN190 described (by vendors) as having "coma-suppressed optics". Which sounds more or less correct. Perhaps we ought to start describing ED doublet refractors as having "chromatic aberration suppressed optics" rather than "apos"

[Naemeth]

I find this illustration of aberrations quite useful. It's exaggerated but gets the point across:

http://www.umich.edu...dscobel.27.html

I've seen the MN190 described (by vendors) as having "coma-suppressed optics". Which sounds more or less correct. Perhaps we ought to start describing ED doublet refractors as having "chromatic aberration suppressed optics" rather than "apos"

+1 for that website and the article ('Got Aberrations?'). I've had it bookmarked for ages

[bingevader]

A star party here, I just turned the field over too.

I see no question mark!

Dates please?

Cheers