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Explore Scientific 3" 30mm Prototype

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#1 frebie

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Posted 12 December 2012 - 12:45 PM

Scott Roberts of Explore Scientific stopped by the store today with the prototype of the new Explore Scientific 3" 100 degree 30mm eyepiece. The image shows the eyepiece prototype in a prototype 2" to 3" dielectric diagonal being designed for it.

The groove around the barrel is where the knurled rubber grip ring will go. Weight is about 7.5 lbs for the eyepiece. Retail price is pretty firm at $1199 for the eyepiece, as ES production schedules have been set for 2013, with glass quantities and pricing locked in for the year. Eight elements, all multicoated. Argon purged. Roll-down rubber eyecup. Design has been finalized and approved. Deliveries are expected to start in May or June.

The production diagonal will have a deeper eyepiece holder than the one on the prototype and will be threaded for 2" filters. Dielectric coatings. Probably part carbon fiber, as seen in the prototype, to hold the weight down. Pricing to be determined when the design is finalized, but expected to be in the $499 range.

We will have an eyepiece part number up shortly for preorders. The 30mm will be the first in a series of 4 or 5 3" 100 degree eyepieces. ES is contemplating a 40mm as the next in the series and would like CN feedback on what other focal lengths might be desirable. You can post your focal length suggestions on this thread. Scott will monitor the thread regularly to see what focal lengths are the most popular.

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#2 hottr6

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Posted 12 December 2012 - 01:28 PM

The production diagonal .... will be threaded for 2" filters.

Doesn't that mean that the 3" EP will be vignetted? :question:

#3 stevetaylor199

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Posted 12 December 2012 - 01:47 PM

Is ES considering making any models that are wider than 100 degrees? For example, how about a 20mm 120 degree 3" ep?

#4 astro_baby

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Posted 12 December 2012 - 02:15 PM

Wowsa.......

#5 frebie

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Posted 12 December 2012 - 02:32 PM

Is ES considering making any models that are wider than 100 degrees? For example, how about a 20mm 120 degree 3" ep?


You'll have to ask Scott about that. Right now he's just asking for input on a 3" 100 degree series. I'm sure he'll take note of your suggestion.

#6 GeneT

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Posted 12 December 2012 - 02:34 PM

This is very interesting!

#7 frebie

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Posted 12 December 2012 - 02:34 PM

The production diagonal .... will be threaded for 2" filters.

Doesn't that mean that the 3" EP will be vignetted? :question:


As posted elsewhere, Scott did some prototype testing in the ES 80mm apo (480mm focal length) with the prototype 2" to 3" diagonal and did not see any vignetting of the 6.25 degree field of view.

#8 Jim7728

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Posted 12 December 2012 - 03:39 PM

We need a wider angle photo to see just how big that beast is. :o

#9 mgwhittle

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Posted 12 December 2012 - 04:36 PM

I'm interested only if the required diagonal had a high enough quality mirror. I would think that a mirror at this size would be harder to produce a high quality wave front error across the area required by a 3 inch eyepiece.

#10 APM M.Ludes

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Posted 12 December 2012 - 05:05 PM

I looked through the picture combo in Tucson and can attest what we saw is fantastic.
The reson Scotty see no vigneting is the crosswise beam path, still a real 3" stardiagonal is needet

I want one, how do I get it the fastest way ????

clear skies
Markus

#11 rboe

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Posted 12 December 2012 - 05:50 PM

I got to see in Tucson too, I had no idea it was a serious product.

#12 stratocaster

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Posted 12 December 2012 - 05:56 PM

I was wondering what the target market would be for such a beast.

The only thing that makes sense to me would be for large dobs or SCTs with long focal lengths, as it would be a way to increase the tfov for these scopes. Even so, say for a 2000mm f/l scope the increase in tfov is only .25 degrees over a 30mm 82 degree eyepiece - for around three times the weight of a 30mm 82 and the additional weight of a special diagonal.

And I suspect coma would be problem in the dob. So maybe SCTs are really the only market.

I'm thinking FC would be way too apparent for use in a refractor. Could be wrong, though.

I guess I don't get it.

#13 pbsastro

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Posted 12 December 2012 - 06:14 PM

I will buy the ES 30-100 as soon as possible. That is the size and focal length I always wanted.
But I may not need other 3"-100 eyepieces. A 40-100 may be going too far, both in terms of weight and size and in terms of proper field required from the scope (about 70mm circle). But I do not say never. I could be tempted to try it. My APM-LZOS 175 with 3.5"FT would be able to handle it for sure. But shorter refractors, even with big focusers may have too much FC for a 40mm. Remember a refractor has FC=FL/3.
Unless we think about a 40mm-75deg. Given that it provides the same field as the 30-100, not everyone will want both a 30-100 and a 40-75, but it may be a good option for the people not comfortable with 100 deg (specially glass wearers). Also the 40-75, due to smaller magnification, is more forgiving with the FC than the 30-100, so will work well in more scopes then the 30-100.

I will be eternally greatful to ES for the 30-100. However I will not accept a pseudo 3" diagonal. I want a real 3" diagonal with 3" mirror and 3" openings. It is very easy to supply a 3" to 2" adapter to take 2" filters. Also in order to reduce vignetting, the 2" filter should be placed close to the eyepiece, and not in the scope end of the diagonal. So the 2" filter adapter should screw directly in the eyepiece, not the diagonal.

I think that for the new 3" standard, a threaded connection, instead of the barrel-slide-in connection (used by 2" and 1.25" standard) could provide additional safety, given the weight of the 3" eyepieces.

Pedro

#14 pbsastro

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Posted 12 December 2012 - 06:23 PM

So maybe SCTs are really the only market.

I'm thinking FC would be way too apparent for use in a refractor. Could be wrong, though.


Long refractors (>=1200mm) have reasonably small FC (FC=FL/3).
Also some smaller apos are flat field, although expensive (e.g. NP127is).
As someone already said, big refractors, >=6" (specially apos) are the first market for this eyepiece. C11 and C14 Edge HDs, with their flat field, are the second market. Big dobs (>=20") are the third significant market.

#15 SkyscraperJim

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Posted 12 December 2012 - 07:08 PM

This would give me nearly 4 degrees at 26x, which could be a lot of fun sweeping the Milky Way from a dark site. I have the Starlight 3.5" focuser so I'd rather opt for a true 3" diagonal, or just straight through. Funny that no one is talking about the extraordinary mass of this piece--a lot of people are going to have to rethink their mountings before using it.

#16 pbsastro

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Posted 12 December 2012 - 07:22 PM

Funny that no one is talking about the extraordinary mass of this piece--a lot of people are going to have to rethink their mountings before using it.

Big apos (>=6") are front heavy, some even use focuser side dead weights. So eyepiece weight may not be a bad thing.

#17 frebie

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Posted 12 December 2012 - 07:25 PM

We need a wider angle photo to see just how big that beast is. :o


We need a wider angle photo to see just how big that beast is. :o


Here's a little wider shot of the eyepiece on the 6" Explore Scientific 152mm carbon fiber refractor, with Feather Touch 3.5" focuser, on a Celestron CGEM DX mount.

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#18 frebie

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Posted 12 December 2012 - 07:43 PM

Please note that nowhere was it stated that a 2" to 3" diagonal was the only possibility. It happens to be the diagonal configuration that they whipped up to let them try the eyepiece in their current refractor line, which all have 2" eyepiece/diagonal holders on their focusers.

Before they can bring out a pure 3" diagonal, they need to have focusers that can accept 3" diagonals. Give them time. The eyepiece is 6-7 months away, after all.

#19 Jim7728

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Posted 12 December 2012 - 08:42 PM

Thanks Fred. Needs a warning sticker: Beware of falling into eyepiece! :grin:

#20 JayinUT

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Posted 13 December 2012 - 01:06 AM

It use to be beware of heavy scopes on the low back for those with disc issues. Now they will have to label these eyepieces with similar warnings as your back could go out if lifted in correctly.

#21 Cyclop_si

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Posted 13 December 2012 - 04:35 AM

True 3" diagonal is only valid option here.
Why spend almost 2k$ for 2" opening on steroids. And majority of "stock" 2" focusers are not able to support that weight, while FT and similar 3+ inch focusers are capable of this task.



... think about a 40mm-75deg....


You already have (almost) that eyepieces: Pan41, SWA40, XW40...

#22 APM M.Ludes

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Posted 13 December 2012 - 06:12 AM

I forced Scotti to do it, I want one :-)

#23 APM M.Ludes

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Posted 13 December 2012 - 06:13 AM

making a high quality 3" diagonal is no problem, at least not for APM, 3 to 4 weeks delivery time

#24 APM M.Ludes

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Posted 13 December 2012 - 06:15 AM

I asked scotty to make the eyelens bigger so I can look in with 2 eyes :-)

#25 faackanders2

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Posted 13 December 2012 - 09:56 AM

Make the widest TFOV 3" eyepiece possible for 100 AFOV and 82 AFOV and 70 AFOV, to take full advantage of 3". I don't feel I would ever be able to afford a 120 AFOV max TFOV.

P.S. These may be the eyepieces people will build telescope around (3" refractors, 3" reflectors, and 3" SCTs).






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