Telescope Reviews: Explore Scientific 3" 30mm Prototype

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frebie
Chief assistant to the assistant chief

Reged: 04/29/08

Loc: Neither here nor there.

Explore Scientific 3" 30mm Prototype
#5567523 - 12/12/12 12:45 PM Attachment (339 downloads)

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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hottr6
Pooh-Bah

Reged: 06/28/09

Loc: 7,500', Magdalena Mtns, NM

Re: Explore Scientific 3" 30mm Prototype new

[Re: frebie]
#5567584 - 12/12/12 01:28 PM

Quote:

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

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

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stevetaylor199
sage

Reged: 09/21/11

Loc: SE Wisconsin

Re: Explore Scientific 3" 30mm Prototype new

[Re: hottr6]
#5567624 - 12/12/12 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?

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astro_baby
scholastic sledgehammer

Reged: 06/17/08

Loc: United Kingdom

Re: Explore Scientific 3" 30mm Prototype new

[Re: stevetaylor199]
#5567680 - 12/12/12 02:15 PM

Wowsa.......

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frebie
Chief assistant to the assistant chief

Reged: 04/29/08

Loc: Neither here nor there.

Re: Explore Scientific 3" 30mm Prototype new

[Re: stevetaylor199]
#5567729 - 12/12/12 02:32 PM

Quote:

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.

Post Extras:

GeneT
Ely Kid

Reged: 11/07/08

Loc: South Texas

Re: Explore Scientific 3" 30mm Prototype new

[Re: frebie]
#5567731 - 12/12/12 02:34 PM

This is very interesting!

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frebie
Chief assistant to the assistant chief

Reged: 04/29/08

Loc: Neither here nor there.

Re: Explore Scientific 3" 30mm Prototype new

[Re: hottr6]
#5567734 - 12/12/12 02:34 PM

Quote:

Quote:

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

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

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.

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Jim7728
Postmaster

Reged: 04/10/05

Loc: Stoop Landing Observatory, NYC

Re: Explore Scientific 3" 30mm Prototype new

[Re: frebie]
#5567847 - 12/12/12 03:39 PM

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

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mgwhittle
scholastic sledgehammer

Reged: 08/24/11

Loc: Chattanooga, TN

Re: Explore Scientific 3" 30mm Prototype new

[Re: Jim7728]
#5567920 - 12/12/12 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.

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APM M.Ludes
Vendor (APM Telescopes)

Reged: 05/01/03

Loc: Germany

Re: Explore Scientific 3" 30mm Prototype new

[Re: mgwhittle]
#5567958 - 12/12/12 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

Post Extras:

rboe

Reged: 03/16/02

Loc: Phx, AZ

Re: Explore Scientific 3" 30mm Prototype new

[Re: APM M.Ludes]
#5568016 - 12/12/12 05:50 PM

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

Post Extras:

stratocaster
sage

Reged: 10/27/11

Re: Explore Scientific 3" 30mm Prototype new

[Re: APM M.Ludes]
#5568024 - 12/12/12 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.

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pbsastro
sage

Reged: 03/21/07

Re: Explore Scientific 3" 30mm Prototype new

[Re: APM M.Ludes]
#5568043 - 12/12/12 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

Edited by pbsastro (12/12/12 06:51 PM)

Post Extras:

pbsastro
sage

Reged: 03/21/07

Re: Explore Scientific 3" 30mm Prototype new

[Re: stratocaster]
#5568056 - 12/12/12 06:23 PM

Quote:

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.

Edited by pbsastro (12/12/12 06:27 PM)

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SkyscraperJim
scholastic sledgehammer

Reged: 07/29/07

Loc: Providence, RI

Re: Explore Scientific 3" 30mm Prototype new

[Re: pbsastro]
#5568107 - 12/12/12 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.

Post Extras:

pbsastro
sage

Reged: 03/21/07

Re: Explore Scientific 3" 30mm Prototype new

[Re: SkyscraperJim]
#5568129 - 12/12/12 07:22 PM

Quote:

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.

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frebie
Chief assistant to the assistant chief

Reged: 04/29/08

Loc: Neither here nor there.

Re: Explore Scientific 3" 30mm Prototype new

[Re: Jim7728]
#5568139 - 12/12/12 07:25 PM Attachment (113 downloads)

Quote:

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

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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frebie
Chief assistant to the assistant chief

Reged: 04/29/08

Loc: Neither here nor there.

Re: Explore Scientific 3" 30mm Prototype new

[Re: frebie]
#5568177 - 12/12/12 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.

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Jim7728
Postmaster

Reged: 04/10/05

Loc: Stoop Landing Observatory, NYC

Re: Explore Scientific 3" 30mm Prototype new

[Re: frebie]
#5568252 - 12/12/12 08:42 PM

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

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JayinUT
I'm not Sleepy

Reged: 09/19/08

Loc: Utah

Re: Explore Scientific 3" 30mm Prototype new

[Re: Jim7728]
#5568550 - 12/13/12 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.

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Cyclop_si
professor emeritus

Reged: 03/13/08

Loc: Slovenia

Re: Explore Scientific 3" 30mm Prototype new

[Re: pbsastro]
#5568667 - 12/13/12 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.

Quote:

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

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

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APM M.Ludes
Vendor (APM Telescopes)

Reged: 05/01/03

Loc: Germany

Re: Explore Scientific 3" 30mm Prototype new

[Re: rboe]
#5568709 - 12/13/12 06:12 AM

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

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APM M.Ludes
Vendor (APM Telescopes)

Reged: 05/01/03

Loc: Germany

Re: Explore Scientific 3" 30mm Prototype new

[Re: pbsastro]
#5568710 - 12/13/12 06:13 AM

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

Post Extras:

APM M.Ludes
Vendor (APM Telescopes)

Reged: 05/01/03

Loc: Germany

Re: Explore Scientific 3" 30mm Prototype new

[Re: JayinUT]
#5568711 - 12/13/12 06:15 AM

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

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faackanders2
Pooh-Bah

Reged: 03/28/11

Re: Explore Scientific 3" 30mm Prototype new

[Re: frebie]
#5568896 - 12/13/12 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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Gord
Carpal Tunnel

Reged: 01/06/04

Loc: Toronto, ON, Canada

Re: Explore Scientific 3" 30mm Prototype new

[Re: JayinUT]
#5568959 - 12/13/12 10:30 AM

The diagonal already has a 3" output and appears as though the mirror would fully support that size. If this is done right, the input size could be swapable (just thread on a new nosepiece) and work with various different scopes focuser sizes.

For example, 2" is the common standard, but there are ones at 2.4" (TV), 2.5" (APM?), 2.7" (A-P & Tak), 3" (FT), 3.25" (Celestron's SCT's), 3.5" (FT), 4" (A-P), etc. You could just have one diagonal design and various different nose pieces. Then people could pick which ones work for their setup (or multiple setups). Some would not offer all the benefits (ex. 2" etc), but it's at least giving options and these would really not be a huge cost to manufacture.

As I said in the thread on the EP forum, I hope we might see some other options in the large format. I'm guessing that some simpler designs (relatively speaking) more along the lines of super or ultra-wides (68-82 deg) would be cheaper than the 100deg so a wider field option in the 50-60mm FL would be possible. The $1200 price option is higher (but not unreasonable for what this is), but something with lower specs (ex. a 55mm 68deg) in the $500 range would be quite paletable and useful to the big cat/refractor owners. Not that much more than the big 2" Plossl's, or the 41mm Panoptic for example.

Clear skies,

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dcoyle
professor emeritus

Reged: 10/11/05

Loc: Turbulent but dark skies, N.M.

Re: Explore Scientific 3" 30mm Prototype new

[Re: faackanders2]
#5568985 - 12/13/12 10:44 AM

I would be concerned about the twisting torque that weight could pose.

It seems to me that if a new standard is established for 3" focusers, it ought to have something like a compression ring lock or splines, not a few #6 screws, to keep that 8 pound baby from rotating. Splines could be at every 20 degrees, so one could set the diagonal at various orientations to facilatate veiwing in different positions.

Dan

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frebie
Chief assistant to the assistant chief

Reged: 04/29/08

Loc: Neither here nor there.

Re: Explore Scientific 3" 30mm Prototype new

[Re: dcoyle]
#5569045 - 12/13/12 11:16 AM

Concerning the weight and safety, Scott thought a lanyard on the eyepiece with a D-ring carabiner on the end for connecting to the scope might be useful to keep the eyepiece from hitting the ground in case of an accident. What say you? It works with DSLR bodies when imaging.

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Jobryant
sage

Reged: 01/13/09

Re: Explore Scientific 3" 30mm Prototype new

[Re: frebie]
#5569659 - 12/13/12 05:52 PM

More info here http://www.youtube.com/watch?v=nnjlmxHQfmw

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pbsastro
sage

Reged: 03/21/07

Re: Explore Scientific 3" 30mm Prototype new

[Re: frebie]
#5569728 - 12/13/12 06:32 PM

Quote:

Concerning the weight and safety, Scott thought a lanyard on the eyepiece with a D-ring carabiner on the end for connecting to the scope might be useful to keep the eyepiece from hitting the ground in case of an accident. What say you? It works with DSLR bodies when imaging.

What about a parachute on the eyepiece, plus an air-bag for the landing? I would drop it on purpose often to enjoy the ride

Sorry couldn't resist

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pbsastro
sage

Reged: 03/21/07

Re: Explore Scientific 3" 30mm Prototype new

[Re: Jobryant]
#5569747 - 12/13/12 06:46 PM

Quote:

More info here http://www.youtube.com/watch?v=nnjlmxHQfmw

What a beauty. Can't wait to get one.
The field lens is bigger than I expected, which is a good sign that we will get a totally unvignetted, 100% illuminated, field of view.
ES rules!

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pbsastro
sage

Reged: 03/21/07

Re: Explore Scientific 3" 30mm Prototype new

[Re: Cyclop_si]
#5569766 - 12/13/12 07:13 PM

Quote:

Quote:

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

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

You may be right. I already have the XW40, which I find perfect by the way. I just usually prefer the 100 deg views of the 17 Ethos.
The XW40 has about 46mm field stop, about same as Pan41. So 52mm of the 40-75 may not be a big enough step to justify it.
However I think a smaller AFV eyepiece allows to use more of the eyepiece barrel, so it should be possible to fit a larger 75 deg eyepiece in the 3" barrel than what is possible with 100 deg. Say 62mm. That would translate to a 54mm-70deg or a 50mm-75deg.
But 50mm may be too much focal length for me.
So I think my preferred companion to the 30-100 would be a 20mm-120deg (or 17-120), weighting about the same as the 30-100, so that the scope would keep balance when changing eyepiece. The perfect pair!

Post Extras:

pbsastro
sage

Reged: 03/21/07

Re: Explore Scientific 3" 30mm Prototype new

[Re: pbsastro]
#5569780 - 12/13/12 07:20 PM

The 30-100 is getting famous. One of these days we may get to see it on TV.
Sorry couldn't resist again.

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Jim7728
Postmaster

Reged: 04/10/05

Loc: Stoop Landing Observatory, NYC

Re: Explore Scientific 3" 30mm Prototype new

[Re: pbsastro]
#5570471 - 12/14/12 08:46 AM

From the video: 6.25 degrees TFOV with the ES 80ED!

I think I want one

or at least check out in person at NEAF.

Post Extras:

EFT
Vendor - Deep Space Products

Reged: 05/07/07

Loc: Phoenix, AZ

Re: Explore Scientific 3" 30mm Prototype new

[Re: pbsastro]
#5570523 - 12/14/12 09:33 AM

Quote:

Quote:

Concerning the weight and safety, Scott thought a lanyard on the eyepiece with a D-ring carabiner on the end for connecting to the scope might be useful to keep the eyepiece from hitting the ground in case of an accident. What say you? It works with DSLR bodies when imaging.

What about a parachute on the eyepiece, plus an air-bag for the landing? I would drop it on purpose often to enjoy the ride

Sorry couldn't resist

Something a kin to what the Spirit and Opportunity rovers used when they bounced onto Mars would probably do the trick.

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junomike
Pooh-Bah

Reged: 09/07/09

Loc: Ontario

Re: Explore Scientific 3" 30mm Prototype new

[Re: EFT]
#5570804 - 12/14/12 12:50 PM

One important thing! Filters? I guess we all have to replace our Filters with 3" versions? Can't put a 2" Filter on a 3" eyepiece!

Mike

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dscarpa
Carpal Tunnel

Reged: 03/15/08

Loc: San Diego Ca.

Re: Explore Scientific 3" 30mm Prototype new

[Re: frebie]
#5570914 - 12/14/12 02:10 PM

It would be wise to wear steel toed boots when using it. David

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coopman
Carpal Tunnel

Reged: 04/23/06

Loc: South Louisiana

Re: Explore Scientific 3" 30mm Prototype new

[Re: dscarpa]
#5571475 - 12/14/12 08:16 PM

Just what the Dr. ordered - an eyepiece that will turn any scope into a diving duck.

Post Extras:

APM M.Ludes
Vendor (APM Telescopes)

Reged: 05/01/03

Loc: Germany

Re: Explore Scientific 3" 30mm Prototype new

[Re: junomike]
#5572031 - 12/15/12 05:19 AM

CHROMA Filters in USA makes UHC, O-III, Deep Sky and other filters in big sizes, they made my full 150 mm size for the big Fuji :-)

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mclewis1
Thread Killer

Reged: 02/25/06

Loc: New Brunswick, Canada

Re: Explore Scientific 3" 30mm Prototype new

[Re: APM M.Ludes]
#5572349 - 12/15/12 10:56 AM

Suggestions/Options:

How about one of those Medic Alert things ... just in case the eyepiece/diagonal combo pulls a small refractor over on it's side? - "help I've fallen and can't get up".

An airbag in case it's dropped - you could probably incorporate one around the outside edge without it changing the size and shape at all.

An arrow indicating which end to look into - because it's not going to be obvious when this thing is used on a small refractor.

Handles to hang onto so you don't fall into that big black hole.

Long term financing, something on the order of a small bank bail out.

Name and number of a good divorce attorney - because you're gonna need one when the CFO finds out you spent over $1000 on "another eyepiece".

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faackanders2
Pooh-Bah

Reged: 03/28/11

Re: Explore Scientific 3" 30mm Prototype new

[Re: faackanders2]
#5573062 - 12/15/12 07:38 PM

Quote:

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).

Anybody know what would be the theoretical widest TFOV eyepiece focal length for a 3" diameter 70 AFOV, 82 AFOV, 100 AFOV, and 120 AFOV eyepiece? Also what would be their exit pupils?

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Starman1
Vendor (EyepiecesEtc.com)

Reged: 06/24/03

Loc: Los Angeles

Re: Explore Scientific 3" 30mm Prototype new

[Re: faackanders2]
#5573139 - 12/15/12 08:20 PM

OK, 3" is 76.2mm.
It's likely an eyepiece barrel for that large and heavy an eyepiece will be 2mm thick, maybe 2.5mm thick counting threads.
That means the maximum field stop would be 71.2mm.
With a negative/positive design, that might result in vignetting, so I'll go with a more conservative maximum of 70mm.
With NO distortion (of course unlikely), that would mean
an apparent field of:
99 degrees in 30mm
90 degrees in 35mm
82 degrees in 40mm
75 degrees in 45mm
70 degrees in 50mm
With a little distortion at the edge, the apparent fields could be slightly larger than that in each focal length. For example, the 24mm 1.25" widefield eyepieces would have a field of 59 degrees instead of 68 were it not for some distortion.
Which means 100 degrees for the 30mm 3" is entirely plausible, even if the effective field stop is less than 70mm.

Post Extras:

edwincjones
Close Enough

Reged: 04/10/04

Re: Explore Scientific 3" 30mm Prototype new

[Re: Starman1]
#5573707 - 12/16/12 07:58 AM

oh no
I went from 1.25" to 2",
back to 1.25" for binoviewers
now I have to go to 3"

Post Extras:

Thomas Karpf
Pooh-Bah

Reged: 02/09/09

Loc: Newington, CT

Re: Explore Scientific 3" 30mm Prototype new

[Re: edwincjones]
#5582309 - 12/21/12 11:26 AM

Should we expect that Explore Scientific will soon be selling refractors with 3" focusers (and 2" inserts and 1.25" inserts)?

Post Extras:

faackanders2
Pooh-Bah

Reged: 03/28/11

Re: Explore Scientific 3" 30mm Prototype new

[Re: Starman1]
#5584975 - 12/23/12 12:56 AM

Quote:

OK, 3" is 76.2mm.
It's likely an eyepiece barrel for that large and heavy an eyepiece will be 2mm thick, maybe 2.5mm thick counting threads.
That means the maximum field stop would be 71.2mm.
With a negative/positive design, that might result in vignetting, so I'll go with a more conservative maximum of 70mm.
With NO distortion (of course unlikely), that would mean
an apparent field of:
99 degrees in 30mm
90 degrees in 35mm
82 degrees in 40mm
75 degrees in 45mm
70 degrees in 50mm
With a little distortion at the edge, the apparent fields could be slightly larger than that in each focal length. For example, the 24mm 1.25" widefield eyepieces would have a field of 59 degrees instead of 68 were it not for some distortion.
Which means 100 degrees for the 30mm 3" is entirely plausible, even if the effective field stop is less than 70mm.

If I got a 3" focuser, I would probably be most interested in a 50mm 70 AFOV for widest TFOV, folo

wed by either 40mm 82 AFOV or 30mm 100 AFOV.

Post Extras:

faackanders2
Pooh-Bah

Reged: 03/28/11

Re: Explore Scientific 3" 30mm Prototype new

[Re: Thomas Karpf]
#5584976 - 12/23/12 12:58 AM

Quote:

Should we expect that Explore Scientific will soon be selling refractors with 3" focusers (and 2" inserts and 1.25" inserts)?

If you build it, they will come.

Post Extras:

faackanders2
Pooh-Bah

Reged: 03/28/11

Re: Explore Scientific 3" 30mm Prototype new

[Re: faackanders2]
#5584980 - 12/23/12 01:00 AM

What is the AFOV of this ES 3" 30mm prototype?

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Astrojensen
Post Laureate

Reged: 10/05/08

Loc: Bornholm, Denmark

Re: Explore Scientific 3" 30mm Prototype new

[Re: faackanders2]
#5585070 - 12/23/12 03:49 AM

100°

Clear skies!
Thomas, Denmark

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Cyclop_si
professor emeritus

Reged: 03/13/08

Loc: Slovenia

Re: Explore Scientific 3" 30mm Prototype new

[Re: frebie]
#5588196 - 12/25/12 08:32 AM

Quote:

.... 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...

I agree that it would be smart move for ES to offer 35-40mm 100° eyepiece next, since I think this would maximize 100° potential in 3" format. Also, I think many APO and SCT users would prefer this focal length over 30mm, since difference between existing 30-31 mm 82° and new 3" 30mm 100° eyepiece might not be beneficial enough for potential customers to mess with bulk and weight of new system. Contrary, 35-40mm 100° eyepiece would give them significantly increased TFOV to deal with related cost, bulk and weight. This eyepiece would give reasonably small exit pupil for most APOs (f/7 and slower) and SCT users of course.

For large SCT users, I think 3" eyepiece with 45-50mm 82° and also 55-60mm 70° would be interested as well.

Post Extras:

faackanders2
Pooh-Bah

Reged: 03/28/11

Re: Explore Scientific 3" 30mm Prototype new

[Re: Cyclop_si]
#5590544 - 12/26/12 11:47 PM

Quote:

Quote:

.... 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...

I agree that it would be smart move for ES to offer 35-40mm 100° eyepiece next, since I think this would maximize 100° potential in 3" format. Also, I think many APO and SCT users would prefer this focal length over 30mm, since difference between existing 30-31 mm 82° and new 3" 30mm 100° eyepiece might not be beneficial enough for potential customers to mess with bulk and weight of new system. Contrary, 35-40mm 100° eyepiece would give them significantly increased TFOV to deal with related cost, bulk and weight. This eyepiece would give reasonably small exit pupil for most APOs (f/7 and slower) and SCT users of course.

For large SCT users, I think 3" eyepiece with 45-50mm 82° and also 55-60mm 70° would be interested as well.

30mm 120 AFOV, 40mm 100AFOV, 50mm 82AFOV, 60mm 70AFOV really would be pushing the limit of maximum TFOV for given power. They probably would all require a paracorr coma correcttor.
But hopefully they would allow 2" filters to be screwed in the eye side of the eyepiece also; till we have enough 3" eyepieces to upgrade filters also.

Post Extras:

gatorengineer
Carpal Tunnel

Reged: 02/28/05

Loc: Hellertown, PA

Re: Explore Scientific 3" 30mm Prototype new

[Re: faackanders2]
#5591037 - 12/27/12 11:36 AM

Well, I just pre-ordered mine. With the reason being, is that with the 25 F5, I will now have 105x at 1 degree with a 6mm exit pupil.

A E21 in a 25 F3.3 gets you .86 with a 5.5mm exit pupil, an E21 in an F3.7 gets you .77, at a 5mm exit both requiring paracorrs

So now I can get wider field of view then the fast scopes, still have the ladder, but am about 15k less invested....

Next step will be the 3" feathertouch.

In this regard, as there is not a standard for 3" eyepices, would it be possible for Astronomics (who I ordered through), to ask what the exact interpretation of 3" is and what the taper is... Thanks.

BTW I dont expec the eyepiece until 14, but hey its on order....

Post Extras:

Starman1
Vendor (EyepiecesEtc.com)

Reged: 06/24/03

Loc: Los Angeles

Re: Explore Scientific 3" 30mm Prototype new

[Re: gatorengineer]
#5591267 - 12/27/12 02:18 PM

Quote:

Well, I just pre-ordered mine. With the reason being, is that with the 25 F5, I will now have 105x at 1 degree with a 6mm exit pupil.

A E21 in a 25 F3.3 gets you .86 with a 5.5mm exit pupil, an E21 in an F3.7 gets you .77, at a 5mm exit both requiring paracorrs

So now I can get wider field of view then the fast scopes, still have the ladder, but am about 15k less invested....

Next step will be the 3" feathertouch.

In this regard, as there is not a standard for 3" eyepices, would it be possible for Astronomics (who I ordered through), to ask what the exact interpretation of 3" is and what the taper is... Thanks.

BTW I dont expec the eyepiece until 14, but hey its on order....

Just a note about Coma and Paracorr:

It is not the exit pupil or true field that determines whether coma is visible in a field of view, it is the apparent field of the eyepiece.

I'll explain.

Take two eyepieces of 25mm--one of 50 degree field and 1 of 100 degree field. Since the field of the 100 degree eyepiece is twice as wide, coma at the edge (a linear feature) is twice as wide a star image in the 100 degree field as it is in the 50 degree field.

Now, use a 12.5mm 100 degree eyepiece. The field is 1/2 as wide, so the comatic star image at the edge is 1/2 as wide--the same width as the comatic star at the edge of the 50 degree field in the 25mm eyepiece.

BUT, the magnification is now twice as great. That increase in magnification makes the apparent size of the comatic star image at the edge exactly the same as it appeared in the 25mm 100 degree eyepiece.

And so it is with all magnifications--the apparent size of the comatic star image will be the same at all magnifications in 100 degree eyepieces.

So what eyepiece seems to present a comatic star image at the edge of the field is determined by the apparent field. Don't like coma? Stick to scopes longer than f/5 or apparent field eyepieces of 50 degrees or less.

Or, use a scope not known to have visible coma: refractor, Maksutov, etc. The SCT does have coma unless it is corrected (such as the Meade ACF or the Celestron Edge, both of which are corrected to eliminate coma). The standard f/6.3 reducer does a pretty good job of that in a standard SCT (it is a reducer/corrector).

Post Extras:

faackanders2
Pooh-Bah

Reged: 03/28/11

Re: Explore Scientific 3" 30mm Prototype new

[Re: gatorengineer]
#5591555 - 12/27/12 06:05 PM

Quote:

Well, I just pre-ordered mine. With the reason being, is that with the 25 F5, I will now have 105x at 1 degree with a 6mm exit pupil.

A E21 in a 25 F3.3 gets you .86 with a 5.5mm exit pupil, an E21 in an F3.7 gets you .77, at a 5mm exit both requiring paracorrs

So now I can get wider field of view then the fast scopes, still have the ladder, but am about 15k less invested....

Next step will be the 3" feathertouch.

In this regard, as there is not a standard for 3" eyepices, would it be possible for Astronomics (who I ordered through), to ask what the exact interpretation of 3" is and what the taper is... Thanks.

BTW I dont expec the eyepiece until 14, but hey its on order....

I can just see it now; 3" focuser soon to become the new standard for large dobsonians. Many may feel it is time to upgrade their scope or buy a new one.

Post Extras:

Astrojensen
Post Laureate

Reged: 10/05/08

Loc: Bornholm, Denmark

Re: Explore Scientific 3" 30mm Prototype new

[Re: faackanders2]
#5591569 - 12/27/12 06:15 PM

And why not? Rafael Benner has a 4" focuser on his 30". It has 5" of travel, allowing to change from a single eyepiece to a binoviewer without fumbling with extension tubes or use barlows. On a 30" this is of course similar to a 2" with 2.5" travel on a 15"... Nothing ordinary. A 4" focuser doesn't look all that big on a 30". In Rafael's case, there's no need to worry about balance issues, when using a 30mm/100° eyepiece. It takes some real muscle power to track that huge dob.

Clear skies!
Thomas, Denmark

Post Extras:

gatorengineer
Carpal Tunnel

Reged: 02/28/05

Loc: Hellertown, PA

Re: Explore Scientific 3" 30mm Prototype new

[Re: Astrojensen]
#5591657 - 12/27/12 07:24 PM

Well long focus big dobs are a dying breed, Until they come up with a Paracorr X in 3", I dont expect to see many of these in todays generation F5 big dob..... For me its a worthwhile investment. I love my 9 120.... The next problem is the near $700 focuser from feathertouch. The other thing not to be discounted for me, is going from this thing to a small Nagler will be a heck of a balance change.... But fun...

Post Extras:

Astrojensen
Post Laureate

Reged: 10/05/08

Loc: Bornholm, Denmark

Re: Explore Scientific 3" 30mm Prototype new

[Re: gatorengineer]
#5592148 - 12/28/12 04:51 AM

Quote:

Until they come up with a Paracorr X in 3",

But these already exist! Well, sort of...:

http://www.astrooptik.com/sonstiges/Newton4Inch/NewtWynne.htm

Not really plug 'n play, but it exists!

Clear skies!
Thomas, Denmark

Post Extras:

faackanders2
Pooh-Bah

Reged: 03/28/11

Re: Explore Scientific 3" 30mm Prototype new

[Re: Astrojensen]
#5593415 - 12/28/12 09:52 PM

Quote:

Quote:

Until they come up with a Paracorr X in 3",

But these already exist! Well, sort of...:

http://www.astrooptik.com/sonstiges/Newton4Inch/NewtWynne.htm

Not really plug 'n play, but it exists!

Clear skies!
Thomas, Denmark

This is for a 4" coma corrector. It would be even a bigger leap from 2" to 4", but the cost would likely be out of reach for many; so 3" (or 2") may be the limit for most.

P.S. Moderator, Could this be moved to the eyepiece forum so it is easier to find?

Post Extras:

Astrojensen
Post Laureate

Reged: 10/05/08

Loc: Bornholm, Denmark

Re: Explore Scientific 3" 30mm Prototype new

[Re: faackanders2]
#5593750 - 12/29/12 02:52 AM

Quote:

This is for a 4" coma corrector.

Oops!

Well, it will fully illuminate a 3" eyepiece, that's for sure.

Let's try again:

http://www.astrosysteme.at/images/Corr_3Zoll_Wynne.pdf

Clear skies!
Thomas, Denmark

Post Extras:

gatorengineer
Carpal Tunnel

Reged: 02/28/05

Loc: Hellertown, PA

Re: Explore Scientific 3" 30mm Prototype new

[Re: Astrojensen]
#5596607 - 12/30/12 05:30 PM

Well the issue with the Wynn is that it may not work visually. I dont know that it will or wont, but I was interested in buying one a few years back before the Paracorr 2 for an F3.5 scope. I called the US distributor and frankly he laughed at me on the phone.... Needless to say this vendor will never get a dime from me, it would be interesting to know if the wynns work visually. There are a bunch of F3ish dobs out there that arent fully illuminated with a 2" P2....

Post Extras:

Astrojensen
Post Laureate

Reged: 10/05/08

Loc: Bornholm, Denmark

Re: Explore Scientific 3" 30mm Prototype new

[Re: gatorengineer]
#5596702 - 12/30/12 06:39 PM

Why shouldn't it work visually??? The 3" Wynne corrector from Philipp Keller has ~55mm working distance and the 4" around 60mm. I would email Keller directly and ask. I am pretty sure he could also design something with greater working distance, if the edge correction tolerances are relaxed a bit, as would be perfectly possible in visual observing.

Clear skies!
Thomas, Denmark

Post Extras:

AlienRatDog
Carpal Tunnel

Reged: 07/15/05

Loc: Ann Arbor

Re: Explore Scientific 3" 30mm Prototype new

[Re: JayinUT]
#5596801 - 12/30/12 07:32 PM

I am interested in a 40mm eyepiece...would be nice to make an adapter for larger SCT visual backs (I have a 12" SCT, I believe the back is like 3" or something like that)...so special 3" diagonals with large SCT adapter (11,14" celestron scts and >10"Meade SCTs)...I would be all over that!

Post Extras:

rboe

Reged: 03/16/02

Loc: Phx, AZ

Re: Explore Scientific 3" 30mm Prototype new

[Re: Astrojensen]
#5597005 - 12/30/12 10:04 PM Attachment (80 downloads)

This should help....

Post Extras:

herrointment
Carpal Tunnel

Reged: 03/12/11

Loc: North of Hwy. 64

Re: Explore Scientific 3" 30mm Prototype new

[Re: rboe]
#5597243 - 12/31/12 12:38 AM

Ron, I looked at your photo and swore I heard wheels turning.

Post Extras:

faackanders2
Pooh-Bah

Reged: 03/28/11

Re: Explore Scientific 3" 30mm Prototype new

[Re: herrointment]
#5621481 - 01/13/13 07:21 PM

Will ES be bringing this to NEAF or any of the shows?

Post Extras:

frebie
Chief assistant to the assistant chief

Reged: 04/29/08

Loc: Neither here nor there.

Re: Explore Scientific 3" 30mm Prototype new

[Re: faackanders2]
#5622454 - 01/14/13 10:50 AM

I would certainly assume so, but you'd need to check directly with them to be sure.

Post Extras:

GeneT
Ely Kid

Reged: 11/07/08

Loc: South Texas

Re: Explore Scientific 3" 30mm Prototype new

[Re: frebie]
#5659078 - 02/02/13 10:59 PM

For some, OK--for me, no thanks.

Post Extras:

Bart
Carpal Tunnel

Reged: 05/28/06

Loc: Somewhere near Charlottesville...

Re: Explore Scientific 3" 30mm Prototype new

[Re: GeneT]
#5663325 - 02/05/13 10:44 AM

I think the point of ridiculous has been reached!

Post Extras:

DaveJ
Pooh-Bah

Reged: 01/07/05

Loc: NE Ohio

Re: Explore Scientific 3" 30mm Prototype new

[Re: Bart]
#5663337 - 02/05/13 10:50 AM

Quote:

I think the point of ridicules had been reached?

If you mean "ridiculous" I completely agree with you!

Post Extras:

Bart
Carpal Tunnel

Reged: 05/28/06

Loc: Somewhere near Charlottesville...

Re: Explore Scientific 3" 30mm Prototype new

[Re: DaveJ]
#5664060 - 02/05/13 05:52 PM

Yes, and I see I made two other mistakes as well.

Post Extras:

Clif
member

Reged: 07/19/06

Loc: Perrineville New Jersey

Re: Explore Scientific 3" 30mm Prototype new

[Re: JayinUT]
#5667278 - 02/07/13 03:16 PM

I figured out by scaling the photograph (taking perspective into account) that the OD of the widest part of the eyepiece is 4.22 inches. Unless you have REALLY widely separated eyes, don't even think of buying two for a binocular.

Post Extras:

faackanders2
Pooh-Bah

Reged: 03/28/11

Re: Explore Scientific 3" 30mm Prototype new

[Re: Clif]
#5673216 - 02/10/13 10:37 PM

Quote:

I figured out by scaling the photograph (taking perspective into account) that the OD of the widest part of the eyepiece is 4.22 inches. Unless you have REALLY widely separated eyes, don't even think of buying two for a binocular.

Most 2" eyepieces can not be used for binoviewing either.

Post Extras:

aa6ww
sage

Reged: 10/23/11

Loc: Sacramento, Calif.

Re: Explore Scientific 3" 30mm Prototype new

[Re: faackanders2]
#5728964 - 03/12/13 08:52 PM

I think its awesome. Once all the bugs are worked out with adapting it to scopes, I'll get me a set. Good thing I paid off my house last year!!
I have a TOA with a 2.7" focuser, and an APM with with a 2.5" focuser, so at least that ones easy to upgrade, Better still, it should be awesome in my C11 and C14!!!
Bring um on with the big diagonal also!! a 40mm 100deg eyepiece would never stay on the shelfs, even with a $2k pricetag!!

...Ralph

Post Extras:

pbsastro
sage

Reged: 03/21/07

Re: Explore Scientific 3" 30mm Prototype new

[Re: aa6ww]
#5738095 - 03/17/13 07:10 AM

Ralph, a 40-100 will not work in a C11 or C14, as they are limited to a 53-55mm illuminated field. The 30-100 has a 52mm field. A 40-100 will have a 70mm field. Even refractors with 1200+ focal length will start to show field curvature and other aberrations at the edge. You will have to go with 1600+ focal length.
If you want 40mm for the C14/C11, with the same 52mm field, that would be 40-75, but close to that we already have the XW40 and Pan41 with field of 46mm.
That said, the 30-100 will be awesome in the C14HD or C11HD.

Edited by pbsastro (03/17/13 07:12 AM)

Post Extras:

gatorengineer
Carpal Tunnel

Reged: 02/28/05

Loc: Hellertown, PA

Re: Explore Scientific 3" 30mm Prototype new

[Re: faackanders2]
#5758787 - 03/26/13 06:13 PM

I bino view Ethos 17's.... with a Siebert 2" binoviewer. The explore 9 120 is too big, as is a terminagler.

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