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Explore Scientific 24mm 68deg bargain

F15Rules

By F15Rules
in Discussions - Eyepieces

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John

John

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Posted
....Looking at what we were asked to pay for any half decent eyepieces in the late 80s/90s, it really is amazing the quality of kit we can now buy for very modest cost. As an example I remember in the early 90s seeing ads for the Vixen SP102M 4" frac on a GP mount (truly great bit of kit) at a price of approaching £1000, which was a LOT of cash to most of us then. Now, you can buy a bigger Bresser 5" F9.5 frac on an EQ5 class mount for c £500 (http://www.telescopehouse.com/acatalog/new_bresser_messier_refractor_ar_127l_on_exos_2_mount.html)

which, taking into account real terms inflation etc is a remarkable difference. We're lucky to have so much choice.. :p

Dave

We must have been looking at the same brochures back then Dave :smiley:

I seem to recall the eyepiece choices were kellners, orthos, plossls or erfles. Naglers were exotic and way out of reach.

When I see the Bresser 127L for a few hundred quid it makes be think how much a 5" achromat would have cost back in the late 1980's and how hard it would be to actually get one. Now it's just a couple of clicks and a decent 5" refractor is on it's way to you :smiley:

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F15Rules

F15Rules

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We must have been looking at the same brochures back then Dave :smiley:

I seem to recall the eyepiece choices were kellners, orthos, plossls or erfles. Naglers were exotic and way out of reach.

When I see the Bresser 127L for a few hundred quid it makes be think how much a 5" achromat would have cost back in the late 1980's and how hard it would be to actually get one. Now it's just a couple of clicks and a decent 5" refractor is on it's way to you :smiley:

Yes, I remember that Sir Patrick had a long focus 5" achromat and I used to dream of being rich and famous enough to ever afford such an instrument. Funnily enough he also had a 12.5" reflector, and I remember thinking how that "half inch" on the 12 inch seemed significant somehow... and yet I never coveted the Newtownian in the way I coveted that 5" frac. I guess I was born with "refractorglobin" in my DNA!

BTW..The latest version AR127l can be had from a UK supplier for the princely sum of £250 with new Hexafoc (is that a "meet the Fockers" type inspired name?) focuser, complete with decent finder and some less decent "bits".. it's a really nice lens, and for the money is outstanding value.

Dave

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Chris

Chris

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Blimey! That's a proper bargain! My Mrs would approve :D

I was hoping they would have more available, but when I returned to the site it wasn't listed anymore. Shame, It would have been nice if others could have grabbed one for that price, as they are 20 quid more than that second hand usually!

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Chris

Chris

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My 6.7mm ES82 has landed. Not that it makes a difference I know but I was kind of expecting it to be old N2 stock, not the newer AR purged funky magnetic box version. Thumbs up Bresser!

I'm looking forward to testng this against my Luminos 7mm which is also excellent for the money.  

post-16129-0-26618000-1443006907.jpg

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Thonolan

Thonolan

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Cloudy nights and lack of observing time prevented me from testing the eyepieces in faster scopes but still have some updates about the ES100 25mm performance.

Since I guess it's not really worth looking for eyepiece aberrations in a f/15 Mak 180 I tried different things. Some comparisons don't need fast scopes, light transmission being one of them. So, having my previously purchased ES68 24mm, I wondered if its 6 element design would bring more light into my eyes than the 10 element design of the ES100 25mm. I decided to use Messier 11 as a target for this. Being a favourite object of mine I can say I know it pretty well as I just have to look at it everytime it's above the horizon. I just can't help it and tend to finish all my observing nights with its glorious vision at this time of the year. I also thought it would be a good target for a comparison like this as many of its stars can be seen only with averted vision. Star patterns make it easy to recall which stars are threshold objects. The fact that both eyepieces are close to being parfocal made it easier.

I observed carefully for several minutes, switching between both eyepieces every 30-60 seconds until the image of the cluster and some of its specific "threshold stars" was fixed in my memory. As both eyepieces deliver almost the same magnification/exit pupil the results may be accurate. What happened? To my surprise, there wasn't a single faint star observed with the 6 element eyepiece that couldn't be seen with the 10 element one. To my eyes light transmission was virtually the same for both pieces of glass. Honestly I felt really happy about this and I guess it speaks good things about the coatings and glasses used. I kind of expected a dimmer image with the 100 degree monster but that wasn't the case :smiley:

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F15Rules

F15Rules

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My 6.7mm ES82 has landed. Not that it makes a difference I know but I was kind of expecting it to be old N2 stock, not the newer AR purged funky magnetic box version. Thumbs up Bresser!

I'm looking forward to testng this against my Luminos 7mm which is also excellent for the money.  

Hi Chris,

I have one of these and love it. I'll be interested to see what you make of it in your shorter scopes :laugh:.

I also had a 7mm Axiom (very similar to Luminos) and liked it, however I felt that the ES had it beaten by some margin in my scopes.

Great build too!

Dave

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Chris

Chris

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Hi Chris,

I have one of these and love it. I'll be interested to see what you make of it in your shorter scopes :laugh:.

I also had a 7mm Axiom (very similar to Luminos) and liked it, however I felt that the ES had it beaten by some margin in my scopes.

Great build too!

Dave

Hi Dave, this is a very good question because as already mentioned the 24mm ES68 didn't hold up very well in my short frac. I'll give the 6.7 ES82 a whirl in my ED70 at the weekend if it's clear and report back.

I tried the 8.8, 11, and 14mm Es82's in my old 200p Dob a couple of years ago and they were excellent at the edges, but never tried them in anything shorter or faster.

I'll add the 6mm SLV to the head to head and I'll only be keeping two out the three. The Luminos is looking a bit nervous!   

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AndyWB

AndyWB

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I'll give the 6.7 ES82 a whirl in my ED70 at the weekend if it's clear and report back. ... I'll add the 6mm SLV to the head to head and I'll only be keeping two out the three. The Luminos is looking a bit nervous!   

Please do, I'd be curious to hear the result.

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Chris

Chris

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Hi Chris,

I have one of these and love it. I'll be interested to see what you make of it in your shorter scopes :laugh:.

I also had a 7mm Axiom (very similar to Luminos) and liked it, however I felt that the ES had it beaten by some margin in my scopes.

Great build too!

Dave

Please do, I'd be curious to hear the result.

I managed a bit of cloud dodging last night with the Starwave ED70 mounted on an horizon tripod, so I got the chance to see how the 6.7 ES82mm performed.

The only targets I managed to see with intermittent cloud and no RDF were M45 and the double cluster but this was enough for some EP testing :)

So with the 6.7mm ES82 the first thing I looked for was edge sharpness which was way better than the 24mm ES68 in this particular scope. I would say it was tack sharp 70 degrees out, and only degraded mildly compared to the 24mm ES68. Infact, at a glance you'd probably say the 6.7mm ES82 was fully sharp right across the FOV, it's only when you looks close at the edges you see any aberration.

This kind of isn't a problem either because seeing the edge is very difficult, you really need to peer right around the corner to see the edges, and I'm not 100% sure I like this so I'm starting to remember why I sold my last ES82's. I'd say looking straight ahead you can see about 60 degrees. The field stop is formed by the eyecup. Eyecup rolled down isn't an option if you want to keep the eyelens free from eyelash marks.

Contrast was very good, there was no edge of field brightness, and the view was fairly flat although I didnt really check for pin cushioning, although I didn't notice any significant amount.

I briefly tried the ES68 24mm again but I can't hack it in this scope, mushy 2/3rds out :(

The best views of the night were with my WO binoviewers and a simple pair of 25mm Plossls! Very engaging views but balancing such a short scope with BV's was impossible, very back heavy.

Also tried my cheap Seben Zoom. I sometimes forget to use this EP but it really is surprisingly nice to use. 

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Roy Challen

Roy Challen

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Chris,

I fully agree with you regarding having to 'peer round the corner', but I've noticed that sometimes with the eyecup down and your eye in exactly the right position, the eyepiece almost seems to disappear.

The Maxvision 24mm 68 behaved exactly the same when I had an Altair 70ED.

And the ES 6.7mm 82 is great in all my scopes, even down to f/5.4

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John

John

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Personally I don't spend much time looking at the edge of the field stop. The "limitless pool of stars" is the effect that I'm looking for, but I do like as much of it as possible to be sharp :smiley:

This is where personal preferences come into eyepiece choice though. Some folks like a delimited field of view and some are not so bothered.

I have eyepieces from 50 to 100 apparrent degrees so have a foot in both camps, so to speak. :smiley:

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F15Rules

F15Rules

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Hi Chris,

Interesting report:-)

I'm an interested bystander in this as my fastest scope is F9.5: however there are a couple of parallels in my experience too.

I can also see in my scopes that the 6.7 has better edge sharpness than the 24. I've now also got the Maxvision 20 68, the ES28 68, and the ES34 68 and in my scopes all of these best the 24 as well. That said, in my scopes the 24/is still a very fine eyepiece and delivers great, high contrast views.

My absolute favourite is the ES 34 68. This is a simply stunning eyepiece and the 68 degree field and long fl deliver pinpoint, uber sharp stellar points right across the field. I have had my best ever views of the double cluster with this EP. It is a real "grenade" of a unit but in a decent 2" focuser it works a treat.

On balance I do definitely prefer the 68 degree fields, I just find them the most comfortable and immersive.

Dave

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