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Equipment Discussions >> Eyepieces

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Darren Drake
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A 30mm 100 degree 3 inch barrel in the works!
      #5507619 - 11/06/12 10:12 PM

Scott Roberts is reporting on FB that he will soon be field testing one of these. There is a pic and it is enormous. Wow now SI or someone is gonna have to start making more 3 inch focusers for dobs....

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Keith
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Reged: 05/14/05

Loc: Costa Mesa, CA USA
Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Darren Drake]
      #5507630 - 11/06/12 10:18 PM

He mentioned that a few years ago, but it I was sworn to secrecy on that. It was at the time being discussed as going with a 3" diagonal for larger SCTs that was also possibly going to be supplied by ES.

Now that the cat is out of the bag, I guess it is ok for me to say "I know"

I hinted about it on the "lowest X for cpc1100" thread recently, but would not say more out of respect to Scott. I am no longer in a position to find out such things anymore anyway, this was a few years ago, guess it was a slow moving process.


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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5507655 - 11/06/12 10:38 PM

I went straight to FB to see...

Edited by Boot (11/08/12 01:28 PM)


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Darren Drake
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5507725 - 11/06/12 11:40 PM

So how much will this go for?? $1500 is my guess....

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Jon Isaacs
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Darren Drake]
      #5507726 - 11/06/12 11:41 PM

Quote:

Scott Roberts is reporting on FB that he will soon be field testing one of these. There is a pic and it is enormous. Wow now SI or someone is gonna have to start making more 3 inch focusers for dobs....




Won't be of much use in a fast Dob until someone makes a 3 inch Coma Corrector... The modern F/3 Dobs are using the 21mm Ethos as the widefield because the 31mm Nagler results in an oversized exit pupil...

Jon


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Darren Drake
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Jon Isaacs]
      #5507737 - 11/06/12 11:52 PM

Right only scopes slower than about f/5 could really benefit from this and perhaps only refractors.

Edited by Darren Drake (11/06/12 11:53 PM)


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SeattleScott
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Jon Isaacs]
      #5507743 - 11/06/12 11:57 PM

The problem with a 3" eyepiece is then you need a bigger secondary, which means lower contrast and light transmission. Maybe for a large aperture scope it would be ok, but there is going to be that compromise. I believe the CO on an 11" SCT is almost 4" already. Do you really want to make it 5" to get a wider field of view? Maybe on an F5 18" dob it would work well. But then you have to balance what looks like a 5-lb eyepiece!

I don't know, I do not see a lot of interest in this outside of observatories that use larger than 2" eyepieces for their huge telescopes. But it is fun to think about!


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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Darren Drake]
      #5507749 - 11/07/12 12:02 AM

scott says $12-1500. And it would probably do well in C11/14 and M10/12/14/16 with proper adapter. Only rub is the c11/14 thread is slightly different than the m10/12/14. It looks like they are planning this mainly for their refractors, but when Scott told me about the idea a few years ago, it sounded like a 3" diag to thread to the 3" thread on the back of the larger SCTs and coma free cats was going to be included with the eyepiece.

As I posted comment on FB, I hope this would lead to other 3"ers, such as a 40mm range 82 or more importantly, a 50mm range 68. Would make the c11 a little more interesting, unless the rear baffle limits it. At f10 there is some leeway, but I think it is about 2.5" clear aperture, but I would have to measure. Either way, a 30mm 100deg is probably not using the full 3" anyway, and I have not ran numbers on any of those theoretical others.

Being f10, I personally would like to see wider 40 and 50mm designs in 3 inch, if a diagonal was available. In the old days, there was a thread on 3" eyepiece for the old 3" c14 diagonal, so I know this has been thought of before, not to mention the pentax 65mmXL.


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Jon Isaacs
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: SeattleScott]
      #5507754 - 11/07/12 12:11 AM

Quote:

The problem with a 3" eyepiece is then you need a bigger secondary, which means lower contrast and light transmission. Maybe for a large aperture scope it would be ok, but there is going to be that compromise. I believe the CO on an 11" SCT is almost 4" already. Do you really want to make it 5" to get a wider field of view? Maybe on an F5 18" dob it would work well. But then you have to balance what looks like a 5-lb eyepiece!

I don't know, I do not see a lot of interest in this outside of observatories that use larger than 2" eyepieces for their huge telescopes. But it is fun to think about!




I could use the added field of view in my 25 inch F/5, the 31mm Nagler without a Paracorr provides about 0.80 degrees, a 30mm 100degree eyepiece would provide about 0.95 degrees... significant but not significant enough to deal with the hassle of balance and adding a 3 inch focuser.

The usefulness of an eyepiece like this is somewhat dubious in the sense that it is not so useful in scopes that are already optimized for a wide field of view. It would be great in my 12.5 inch F/4.06 if there were a Paracorr available but without one, it would not be workable. The beauty of TeleVue products is the integrated solutions, a Paracorr that works with the 31mm Nagler... The NP series that provide wide flat field so that the 31mm nagler can show it's stuff.

Of course the 106 FSQ would provide some amazing views if the eyepiece were sharp at F/5.

Jon


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Rick Woods
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Darren Drake]
      #5507760 - 11/07/12 12:17 AM

Quote:

Scott Roberts is reporting on FB that he will soon be field testing one of these. There is a pic and it is enormous. Wow now SI or someone is gonna have to start making more 3 inch focusers for dobs....




I'm sorry; what are "FB" and "SI"?


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core
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Rick Woods]
      #5507765 - 11/07/12 12:19 AM

FaceBook

StarlightInstruments (feather touch)

Edited by core (11/07/12 12:20 AM)


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Scanning4Comets
Markus
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Reged: 12/26/04

Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: core]
      #5507791 - 11/07/12 12:50 AM

Holy moly! That thing needs a crane just to put it in the focuser.

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Shneor
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Jon Isaacs]
      #5507867 - 11/07/12 02:42 AM

Quote:

Quote:

Scott Roberts is reporting on FB that he will soon be field testing one of these. There is a pic and it is enormous. Wow now SI or someone is gonna have to start making more 3 inch focusers for dobs....




Won't be of much use in a fast Dob until someone makes a 3 inch Coma Corrector... The modern F/3 Dobs are using the 21mm Ethos as the widefield because the 31mm Nagler results in an oversized exit pupil...

Jon



Not necessarily true. The 9mm ES120 shows pinpoint stars from center to edge in my f/4 without any correction needed. It apparently has a quite different design. Unfortunately, as far as I know, only three CN members have one of these, but several observers have viewed through mine. All were amazed by the sharpness across the entire field.

Clears,
Shneor


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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Shneor]
      #5507916 - 11/07/12 04:54 AM

how much for your 9mm ES100? =)

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Mark9473
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5507976 - 11/07/12 07:15 AM

Siebert has been offering large format eyepieces and diagonals for years. I wonder why ES think they will be more successful with it.

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Jon Isaacs
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Shneor]
      #5507990 - 11/07/12 07:44 AM

Quote:

Quote:

Quote:

Scott Roberts is reporting on FB that he will soon be field testing one of these. There is a pic and it is enormous. Wow now SI or someone is gonna have to start making more 3 inch focusers for dobs....




Won't be of much use in a fast Dob until someone makes a 3 inch Coma Corrector... The modern F/3 Dobs are using the 21mm Ethos as the widefield because the 31mm Nagler results in an oversized exit pupil...

Jon



Not necessarily true. The 9mm ES120 shows pinpoint stars from center to edge in my f/4 without any correction needed. It apparently has a quite different design. Unfortunately, as far as I know, only three CN members have one of these, but several observers have viewed through mine. All were amazed by the sharpness across the entire field.

Clears,
Shneor




We have been through this one before with other eyepieces... The 30mm Widescan II comes to mind.

Coma is there to be seen at F/4, the coma free region is 1.4mm, the approximate field stop diameter of the 9mm 120 degree eyepiece is 19mm, that's a lot of room for coma. I have a hard time believing moving a bright star like Rigel to the edge of the field would provide a nice round and still clean primary and secondary.

If an eyepiece truly eliminates coma in an F/4 Newtonian, then the reverse coma necessary to do so would be visible in a coma free telescope...

Jon Isaacs


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Sarkikos
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Jon Isaacs]
      #5508013 - 11/07/12 08:09 AM

So, a 3" eyepiece might make sense in big SCTs which are not yet available, big slow refractors and marginally in 25" Dobs?

Eh... I think I'll pass.

Mike


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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Jon Isaacs]
      #5508020 - 11/07/12 08:17 AM

people's tolerance or ability to detect coma varies greatly. Once the astigmatism found in the more basic designs is gone, most people are happy, and really picky folks start to notice the coma. I also found MANY people like to use the word coma to describe any edge of field abberation, and some even use the word to describe "feild curvature in newtonians". Even fairly knowledgeable guys I have known, maybe they just wanted to make the explanation simple.

In my experience, the elimination of the rest of the abberations, coupled with the barlowing effect of the nagler type eyepieces, makes most people happy, especially when upgrading from eyepieces like said widescan or its cheap chinese clones, to a nagler or more modern chinese nagler clone. At that point, adding the paracorr eeks that extra bit of perfection out of the field. I am kind of bummed that televue only does type II now, because that sucker is expensive. I can understand eliminating the original smaller lens (t-thread) versions and forcing the universal system and it's available tunable top, and T adapters and spacers, but they should have at least kept the universal type 1 in the lineup.

I have owned the original photo-visual version, and then the second to last version of the visual only paracorr. Of course it was vignetting with the 31 that prompted me to get the visual model. At f5, the 31nagler still did very well, and when I was offered a trade I couldn't refuse at a star party for the visual, I let it go figuring I could still use the original for the 22nagler, which totally blew chunks without a paracorr. At f4, the paracorr was a much bigger necessity than it was at f5.

When I sold my 8"f4, I included the photo-visual as a package, because imaging was the main interest of the buyer.

If I get back into dob's, I hope I am lucky enough to get a paracorr at a good price. I am one of the guys who can see the difference, and would not have traded that visual model had I not had the original photo/visual as a backup. It is a non issue for me now being newt free, but I spent a good portion of a decade as a newt guy.


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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Sarkikos]
      #5508025 - 11/07/12 08:26 AM

Quote:

So, a 3" eyepiece might make sense in big SCTs which are not yet available, big slow refractors and marginally in 25" Dobs?

Eh... I think I'll pass.

Mike




wondering what you mean by big scts that are not yet available. Were you just referring to the diagonals not being available? IIRC ES might have been planning a 3"barrel refractor type diagonal (which makes sense since Scott was ref their APO). Even if that is the only diagonal they offer, and they do not offer 3" visual backs for SCTs, OPTEC already does for their 314 and 316 3" .75 reducers, for folks who want the benefit of those reducers (imaging) without having to shell out the big bucks for the TCFS-3 focuser. 3" slide in optics are already on the market in the imaging scene, so getting a visual back for the SCT is not a problem, should ES intend their diagonal only for refractors.

Either way that EP looks to be 10lbs easily, It is one thing to have to slide a CW to rebalance for a 31 nagler, but this would require adding another weight for sure in some cases.


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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5508036 - 11/07/12 08:38 AM

Oh, JMI had a 3" focuser too, so getting them on a dob would have multiple options, but coma would be an issue. My experience with ethos and ES100's in f5 and slower is that they are in the "good enough" range like the 31 nagler. Of course Jon has VERY good points about issues like this being an even bigger field where more intense coma would be, and requiring a bigger secondary. Not to mention trying to balance a dob with an EP that heavy.

I think this EP will be a winner with the BIG cassegrain guys, RC's and CDK's and Classical Cass, and of course the aforementioned big SCTs, where a field that large is actually NEEDED. If I had one of these I would have a 4"-3" sleeve made and take the sucker to the 60" on mt wilson or palomar, but it would have to be very good seeing, IIRC they are f16 and that would be over 800x! This is where it would be sweet if ES considered 40 and 50mm range 3" eyepieces with 82 and 68 degrees. Maybe even less critical designs since they would only be used on f7 or slower scopes. More realistically, the local club has a 21.5" Cass in f8 mode (has f16 secondary as well but never used), last I knew it had a 4" WO focuser on it, so all that would be needed was a 4"-3" sleeve to adapt the diagonal (which ES hopefully includes with the EP or has available at least). I know the 31mm nagler and my widescan III look great on that scope, this sucker would probably be pretty awesome at 146x with a TFOV approx .68 degrees w/3.75mm exit pupil. *BLEEP* now we need a 3" UHC filter!

Just speculating of course, as the market is limited, and I think they will probably stop at the 30 and market it as an uberwide for the APOs with big focusers.


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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: SeattleScott]
      #5508056 - 11/07/12 08:58 AM

Quote:

The problem with a 3" eyepiece is then you need a bigger secondary, which means lower contrast and light transmission. Maybe for a large aperture scope it would be ok, but there is going to be that compromise. I believe the CO on an 11" SCT is almost 4" already. Do you really want to make it 5" to get a wider field of view? Maybe on an F5 18" dob it would work well. But then you have to balance what looks like a 5-lb eyepiece!

I don't know, I do not see a lot of interest in this outside of observatories that use larger than 2" eyepieces for their huge telescopes. But it is fun to think about!




I missed this one earlier. The bigger secondary applies to newtonians, not SCTs, the narrower light cone of the SCT could possibly allow this to work well, especially on 14". Since the 1.5(or 1.75 I forget) inch rear opening on an 8" SCT works well with full field 2" eyepieces, I am sure this sucker will work fine on an 11" with its nearly 3" rear baffle. It might require a low profile thread on diagonal vs one sliding into a visual back as I mentioned earlier, but I am not sure to what degree that would be necessary, if at all.

But "redesigning" the optics of a cassegrain for this eyepiece would not be necessary. What Jon was referring to were newtonians, which are typically optimized for the most acceptable illumination at the edge of a 2" field, typically 70% or better for visual, and 100% or more in an astrograph. A visually optimized newtonian would likely show darker edges with this, and that is where a larger secondary would be needed. On an SCT the secondary is no where near the point of focus, on a newt it is much closer and is an important factor in the design.


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Sarkikos
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5508069 - 11/07/12 09:13 AM

Keith,

Quote:

wondering what you mean by big scts that are not yet available. Were you just referring to the diagonals not being available? IIRC ES might have been planning a 3"barrel refractor type diagonal (which makes sense since Scott was ref their APO). Even if that is the only diagonal they offer, and they do not offer 3" visual backs for SCTs, OPTEC already does for their 314 and 316 3" .75 reducers, for folks who want the benefit of those reducers (imaging) without having to shell out the big bucks for the TCFS-3 focuser. 3" slide in optics are already on the market in the imaging scene, so getting a visual back for the SCT is not a problem, should ES intend their diagonal only for refractors.




SCT's are the only major type of scope that I've never owned, and I don't really plan on owning one ... well, maybe a nice C6 for grab-n-go. And I'm not into AP at all, so I've not really kept up with what is available in both those areas. But just reading this thread I got the impression that 3"-EP-ready SCTs are not out there now. I suppose that was a false impression?

Quote:

Either way that EP looks to be 10lbs easily, It is one thing to have to slide a CW to rebalance for a 31 nagler, but this would require adding another weight for sure in some cases.




Yes, the weight could be a deal breaker for many observers. I had a hard enough time balancing my scopes for my 2 lb ES 82 30mm, much less some 10 lb monster.

Overall, I don't see 3" eyepieces having a big market among consumers of astro gear. Barely a notch in a niche.

Mike


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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Sarkikos]
      #5508144 - 11/07/12 10:18 AM

C11/14 and Meades 10/12/14 all have a 3" thread on the rear cell. Hence the peterson eye opener option. On a standard LX200 with microfocuser, there is a step down ring to standard 2" threads that has about 1.5" clear aperture, so widefield 2" eps get light loss at the edges. Taking off that step down ring, and attaching a visual back or focuser directly to the 3" rear cel, opens the aperture to the full 2" and then some. So all it takes is a 3" visual back and diagonal (not common) and theoretically this could work. Since the 11" and the 14" celestron both use the same thread, it is already possible to add a 3" JMI or optec focuser to the scope, so all that would be needed was the diagonal. I would be interested to see a field lens pic of that monster 30, to see how much of the 3" field it is using. Since the light cone is a narrow f10, I have a feeling this could work well on even a c11.

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Darren Drake
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5508162 - 11/07/12 10:39 AM

Keith
I would estimate based on the 31 nagler being what it is that the field lens is about 2.4 inches across but that's just an educated guess. I'm pretty sure its not the full 3 inches.


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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Darren Drake]
      #5508191 - 11/07/12 11:03 AM

a full 3" in 82deg or 68deg would be pretty sweet though, or even 42mm82 and 55mm68, even if they are not full 3" (I think the pentax 60mm XL was 65deg at full 3" thread on)

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Darren Drake
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5508200 - 11/07/12 11:14 AM

Yes and if I'm not mistaken that Pentax goes for over $3000.

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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Darren Drake]
      #5508211 - 11/07/12 11:27 AM

so the ES is quite a bargain!

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Sarkikos
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5508219 - 11/07/12 11:30 AM

Always! ... except for that ES 82 14mm. Too much FC for my eyes at any price.


Mike


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Junn Chavez
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Darren Drake]
      #5508489 - 11/07/12 02:53 PM

I guess I have to start saving money to purchase two for binoviewing

Clear skies.


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pbsastro
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Sarkikos]
      #5508504 - 11/07/12 03:02 PM

One is already sold! It will be perfect in my 175/1400 APM-LZOS with FT35 fcouser. Small apos with FL below 1000mm may have FC issues, although that is dependent on the individual eye capability to adjust. From 1000mm and longer FL will be OK I think. So the TEC140 will be the starting apo for this eyepiece. A TV 102 with 2.4" focuser may work as well for many people.

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Starman1
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Shneor]
      #5508529 - 11/07/12 03:19 PM

Quote:

Quote:

Quote:

Scott Roberts is reporting on FB that he will soon be field testing one of these. There is a pic and it is enormous. Wow now SI or someone is gonna have to start making more 3 inch focusers for dobs....




Won't be of much use in a fast Dob until someone makes a 3 inch Coma Corrector... The modern F/3 Dobs are using the 21mm Ethos as the widefield because the 31mm Nagler results in an oversized exit pupil...

Jon



Not necessarily true. The 9mm ES120 shows pinpoint stars from center to edge in my f/4 without any correction needed. It apparently has a quite different design. Unfortunately, as far as I know, only three CN members have one of these, but several observers have viewed through mine. All were amazed by the sharpness across the entire field.

Clears,
Shneor



A little reality, here:
At f/4, your coma free field is only 1.4mm wide. The field stop of the 9mm 100 degree ES is over 14mm. This eyepiece produces significant visibility of coma at the edge of the field of view in my f/5 dob. At f/4, comatic star images would be significantly larger than the 3' resolution of the eye less than half way to the edge.
The 9mm 120 degree is wider still.
Only in a coma-corrected field could you have no coma at the edge of the field.
So what you suggest is not physically possible.

It is, however, psycho-physiologically possible to not be aware of coma, and while I won't go into the multiple reasons why that is, the noticeability of coma varies significantly from person to person. I see coma in 82 degree eyepieces at f/6, and the math says I'm only seeing what's really there. It's not too bad, so I could live with it. By f/5, I can't live with it and need to correct it. By f/4, I must have coma correction to even make the scope usable.
Others blissfully use f/4-f/4.5 scopes without any coma correction at all and are not bothered by it.

So, perhaps a better way to state your case would be to say that YOU don't notice any coma at the edge in that eyepiece.

The only alternative, and I have not heard this to be the case, is that the 120 degree eyepiece has built-in coma correction like the old Praetoria eyepieces did.


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GeneT
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Darren Drake]
      #5508580 - 11/07/12 03:43 PM

For me, probably not a buy.

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star drop
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Jon Isaacs]
      #5508604 - 11/07/12 03:53 PM

Quote:

Quote:

Scott Roberts is reporting on FB that he will soon be field testing one of these. There is a pic and it is enormous. Wow now SI or someone is gonna have to start making more 3 inch focusers for dobs....




Won't be of much use in a fast Dob until someone makes a 3 inch Coma Corrector... The modern F/3 Dobs are using the 21mm Ethos as the widefield because the 31mm Nagler results in an oversized exit pupil...

Jon



Where is Ron Popeil and his 3" pocket coma corrector when you need him?


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GlennLeDrew
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: star drop]
      #5508639 - 11/07/12 04:11 PM

I find the concept of this eyepiece intriguing. Being one who uses the outer field to illuminate my poor-in-resolution outer retina, additional aberration out there is not so objectionable. I don't tend to gaze at or near the field edge, instead striving to place the bits of interest closer to the field center. With this tactic, I enjoy the benefits of the uber fields without becoming hung up on off-axis unsharpness. My own (and your) eye's off axis performance is in some ways already horrid, and so big field eyepieces should be utilized in the way that mates them best to the eye; using the extra field to more fully fill the more sensitive outer retina.

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maroubra_boy
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: GlennLeDrew]
      #5508808 - 11/07/12 06:15 PM

If TV started to make a 3" eyepiece, there would be an almighty rush on. No question about it. Just hint at it an these forums will be abuzz.

Explore Scientific, Sieberts, these aint TV.

So, Al, when's it due?

Very interesting reading. Will be needing to redesign the entire structure and bearings of existing dobs to accomodate a 3" focuser, not just a CW. A 10lb EP, and a focuser not less than 3, maybe even 6 or 7. That's a lot of dead weight that's leavering off the secondary cage.

Edited by maroubra_boy (11/07/12 06:16 PM)


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pbsastro
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: maroubra_boy]
      #5508823 - 11/07/12 06:28 PM

Quote:

If TV started to make a 3" eyepiece, there would be an almighty rush on. No question about it. Just hint at it an these forums will be abuzz.



Agree completely.

Quote:

Will be needing to redesign the entire structure and bearings of existing dobs to accomodate a 3" focuser, not just a CW. A 10lb EP, and a focuser not less than 3, maybe even 6 or 7. That's a lot of dead weight that's leavering off the secondary cage.




I don't think this eyepiece is for dobs. For small dobs (usually slow) it is too expensive. For large dobs (usually fast) 30mm is too much focal length.

This eyepiece is ideal for refractors from 1000mm FL up and for flat field (Edge HD) SCTs 10" up.
The eyepiece virtual field stop should be about 52mm, which is exactly the clear aperture of my Meade 12" SCT baffle tube. Issue here is it is not flat field. So as soon as get this eyepiece I will be swapping my 12" SCT for a 11" or 14" Edge HD.

Edit: Oh, it will be perfect also for flat field small refractors, like Televue NPs with 2.4" focuser, the irony...

Edited by pbsastro (11/07/12 06:45 PM)


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johnnyha
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Mark9473]
      #5508841 - 11/07/12 06:44 PM

Quote:

Siebert has been offering large format eyepieces and diagonals for years. I wonder why ES think they will be more successful with it.



Better web page?


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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: maroubra_boy]
      #5508957 - 11/07/12 08:03 PM

Quote:

If TV started to make a 3" eyepiece, there would be an almighty rush on. No question about it. Just hint at it an these forums will be abuzz.

Explore Scientific, Sieberts, these aint TV.

So, Al, when's it due?

Very interesting reading. Will be needing to redesign the entire structure and bearings of existing dobs to accomodate a 3" focuser, not just a CW. A 10lb EP, and a focuser not less than 3, maybe even 6 or 7. That's a lot of dead weight that's leavering off the secondary cage.




Siebert and ES not in the same catergory. ES is literally taking the televue inspired designs and using a state of the art factory in china, to replicate near TV quality at lower prices. Siebert is not making eyepieces that are literally nagler , panoptic and ethos clones. So before comparing ES to TV, it helps to look through both, not counting the 14mm 82 which didn't quite live up to its japanese series 4000 UWA predecessor. Meade was the first to copy TV with good results in the early 90s, and then in the early 00's the 5000 series came out from china, and that is the embryo which ES matured from. Quite different from Siebert's boutiqe machine shop style (and Siebert has not come out with any exotic widefields with edge correction coming close to televue, where most ES perform 90% as good as the televue, especially in the 100's)


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aa5te
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: johnnyha]
      #5509047 - 11/07/12 09:10 PM

Quote:


Better web page?



I LOL'd and received funny looks. Sorry, carry on.


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gezak22
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5509310 - 11/08/12 01:46 AM

The real question here is how are we going to use these in bino mode?

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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: gezak22]
      #5509322 - 11/08/12 02:03 AM

Admiral Ackbar of Mon Calimari has 3" binoviewers, but he also has eyes on the side of his head.

IT'S A TRAP!


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BillP
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: gezak22]
      #5509854 - 11/08/12 12:14 PM

Quote:

The real question here is how are we going to use these in bino mode?




Easy...one eye at a time


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Shneor
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5510045 - 11/08/12 02:12 PM

Quote:

how much for your 9mm ES100? =)



Not selling that yet - I can still use it in my 6" f/5 reflector; the 120 is too heavy for that telescope.

Clears,


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Shneor
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Jon Isaacs]
      #5510048 - 11/08/12 02:18 PM

Quote:




Jon



Not necessarily true. The 9mm ES120 shows pinpoint stars from center to edge in my f/4 without any correction needed. It apparently has a quite different design. Unfortunately, as far as I know, only three CN members have one of these, but several observers have viewed through mine. All were amazed by the sharpness across the entire field.

Clears,
Shneor




We have been through this one before with other eyepieces... The 30mm Widescan II comes to mind.

Coma is there to be seen at F/4, the coma free region is 1.4mm, the approximate field stop diameter of the 9mm 120 degree eyepiece is 19mm, that's a lot of room for coma. I have a hard time believing moving a bright star like Rigel to the edge of the field would provide a nice round and still clean primary and secondary.

If an eyepiece truly eliminates coma in an F/4 Newtonian, then the reverse coma necessary to do so would be visible in a coma free telescope...

Jon Isaacs



Sorry Jon, it's the same result in a 4" f/5 refractor. You can complain as much asyou wish, but the results are clear. I don't know how they did it, but they did...I believe Sixela has suggested how they might have accomplished this - see this thread: http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/4866855/page...

Clears,


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Starman1
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Shneor]
      #5510292 - 11/08/12 05:23 PM

Alexis talked about angular magnification distortion versus rectilinear distortion, not coma. Coma is an aberration of the paraboloidal mirror, and is more visible and severe the wider the apparent field, so if this eyepiece has built-in coma correction, and you imply it does, then it is unusable in refractors and catadioptrics.
That seems strange for JOC to do that, but it's certainly possible to do it.

Edit: One other user used this in a Paracorr with good results. I have a hard time believing it has built-in coma correction. therefore.

Edited by Starman1 (11/08/12 05:25 PM)


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sixela
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5510319 - 11/08/12 05:40 PM

Quote:

C11/14 and Meades 10/12/14 all have a 3" thread on the rear cell. Hence the peterson eye opener option. On a standard LX200 with microfocuser, there is a step down ring to standard 2" threads that has about 1.5" clear aperture, so widefield 2" eps get light loss at the edges. Taking off that step down ring, and attaching a visual back or focuser directly to the 3" rear cel, opens the aperture to the full 2" and then some. So all it takes is a 3" visual back and diagonal (not common) and theoretically this could work. Since the 11" and the 14" celestron both use the same thread, it is already possible to add a 3" JMI or optec focuser to the scope, so all that would be needed was the diagonal. I would be interested to see a field lens pic of that monster 30, to see how much of the 3" field it is using. Since the light cone is a narrow f10, I have a feeling this could work well on even a c11.




You can physically fit it, but given the diameter of the central baffle I doubt the outer field is going to be very well illuminated. Yes, the clear aperture is larger than the field stop but the baffle (especially the front) is also a lot closer to the secondary and the entry pupil...

But it might still be "good enough", of course; we Newt folks use 31T5s without batting an eyelid when the outer field is illuminated 70%, and I was using a FrankenBlast with 2" focuser in which the edge of a 26T5 was only 50% illuminated with pleasing results.


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pbsastro
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: sixela]
      #5511942 - 11/09/12 04:24 PM

The 3" diag will also be good for 2" eyepieces with big field stop, such as XW40, Pan 41 or Nag31, because those eyepieces cannot be fully illuminated by a 2" diag in refractors even with large focusers.

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johnnyha
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5512055 - 11/09/12 05:50 PM

A 3" eyepiece also has the potential, depending on the size of the eye lens, to be naturally "binoviewed" with both eyes, simply due to the large size of the optic.

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Starman1
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: johnnyha]
      #5512091 - 11/09/12 06:13 PM

Quote:

A 3" eyepiece also has the potential, depending on the size of the eye lens, to be naturally "binoviewed" with both eyes, simply due to the large size of the optic.




They have a big 4" eyepiece at Mt. Wilson they call their "binocular" eyepiece.
Of course, unless the exit pupil is 3" wide (!), even these behemoths are mono-vision eyepieces.


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Grava T
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Starman1]
      #5512122 - 11/09/12 06:35 PM

Is that even possible? For example; (and I'm just having fun here) an eight inch ocular with a six inch exit pupil for both eyes! Or is that physically impossible?

.965", 1.25", 2", 3", 4", 5",... 8" I see a progression here for our future.


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faackanders2
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Jon Isaacs]
      #5512380 - 11/09/12 10:08 PM

Quote:

Quote:

Scott Roberts is reporting on FB that he will soon be field testing one of these. There is a pic and it is enormous. Wow now SI or someone is gonna have to start making more 3 inch focusers for dobs....




Won't be of much use in a fast Dob until someone makes a 3 inch Coma Corrector... The modern F/3 Dobs are using the 21mm Ethos as the widefield because the 31mm Nagler results in an oversized exit pupil...

Jon




I'll bet a 3" paracorr is in the works. And probably a 40mm 82 AFOV, and a 50mm 70 AFOV too.


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faackanders2
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: gezak22]
      #5512399 - 11/09/12 10:27 PM

Quote:

The real question here is how are we going to use these in bino mode?




Just move your eyes wider apart.


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faackanders2
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Grava T]
      #5512405 - 11/09/12 10:32 PM

Quote:

Is that even possible? For example; (and I'm just having fun here) an eight inch ocular with a six inch exit pupil for both eyes! Or is that physically impossible?

.965", 1.25", 2", 3", 4", 5",... 8" I see a progression here for our future.




Hmmm. Would an 8" eyepiece be an eyepiece or a small telescope?


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faackanders2
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Darren Drake]
      #5512409 - 11/09/12 10:34 PM

Can someone please post an image?

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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: faackanders2]
      #5512507 - 11/09/12 11:55 PM

I got in trouble for posting an image

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faackanders2
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5512524 - 11/10/12 12:14 AM

Is there a website to look at?

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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: faackanders2]
      #5512569 - 11/10/12 12:49 AM

scott roberts posted it on his facebook feed, and since I mentioned that, I got in trouble and the pic was taken down.

I can't seem to win, and one of these days I am going to finally stop trying


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ThreeD
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5512603 - 11/10/12 01:33 AM

The picture is still there... In fact, here is the FB posting. Note it is public so you shouldn't need a FB account to see it.

Yup, it's big all right. That's a 2" 18mm on the left and a 1.25" 11mm on the right. Seems to be Argon purged by the little sticker on it.

Edited by ThreeD (11/10/12 01:38 AM)


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GlennLeDrew
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: ThreeD]
      #5512628 - 11/10/12 02:21 AM

To answer the question of two-eyed viewing if the exit pupil is large enough. Sure, it can be done, but your tiny pupils will stop down the system aperture accordingly. Suppose the exit pupil is 80mm, the objective is 800mm, and one's eye pupils are 6mm. The entrance pupils will be near opposite sides of the objective, and their aperture would be 6/80 * 800 = 60mm. Not at all efficient use of that 800mm aperture!

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faackanders2
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: ThreeD]
      #5513217 - 11/10/12 01:44 PM

Humongous. I wonder how many pounds (or Kg) that is?
I know a 3" focuser (& filters) is required, but would it also require a larger secondary mirror. I currently have a 17.5 f4.1 discovery and a 10.1" f4.5 coltour oddessy dobsonians. I look forward to uberwide TFOVs 3" eyepieces would bring. I assume it would be great for M45, M44, M42, North American, Viel, M31/M32/M110, Markarians Chain, and lots of other multiple objects and conjunctions.

Who is the innovator now? Hope I'll be able to afford one.


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avenger
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: faackanders2]
      #5513247 - 11/10/12 02:13 PM

Quote:

Humongous. I wonder how many pounds (or Kg) that is?
I know a 3" focuser (& filters) is required, but would it also require a larger secondary mirror. I currently have a 17.5 f4.1 discovery and a 10.1" f4.5 coltour oddessy dobsonians. I look forward to uberwide TFOVs 3" eyepieces would bring. I assume it would be great for M45, M44, M42, North American, Viel, M31/M32/M110, Markarians Chain, and lots of other multiple objects and conjunctions.

Who is the innovator now? Hope I'll be able to afford one.




I was talking with Scott two nights ago. He states the weight of the eyepiece and diag. will be around 8 pounds. He also stated that the eyepiece is for use in refractors. If the optics testing turns out good, than it will be about 6 months before the eyepiece and diag. hit the market. He also stated that JOC (the optics company that made the proto type), does not think there will be a big calling for such an eyepiece from the amateur astronomers. But Scott thinks there will be.


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pbsastro
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: avenger]
      #5513368 - 11/10/12 03:55 PM

Quote:

I was talking with Scott two nights ago. He states the weight of the eyepiece and diag. will be around 8 pounds. He also stated that the eyepiece is for use in refractors. If the optics testing turns out good, than it will be about 6 months before the eyepiece and diag. hit the market. He also stated that JOC (the optics company that made the proto type), does not think there will be a big calling for such an eyepiece from the amateur astronomers. But Scott thinks there will be.




Scott is the man!


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Arizona-Ken
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5513760 - 11/10/12 10:19 PM Attachment (61 downloads)

A picture of Scott today at the Tucson show:


Arizona Ken


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faackanders2
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Arizona-Ken]
      #5514085 - 11/11/12 08:32 AM

Now that's an eyepiece!

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REC
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: faackanders2]
      #5514106 - 11/11/12 08:56 AM

Holy Molly.....look at the size of that thing!

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Shneor
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: REC]
      #5514486 - 11/11/12 01:28 PM

Yes, it's massive! And beautiful! Also saw a 3" diagonal.

Clears,


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Blake Andrews
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: BillP]
      #5514581 - 11/11/12 02:33 PM

Quote:

Quote:

The real question here is how are we going to use these in bino mode?




Easy...one eye at a time




Nagh,

You just put your face up to the eyepiece and open both eyes. Like taking a shower with all those photons. No need for binoviewers anymore!

Cheers!
Blake


Edited by Blake Andrews (11/11/12 02:58 PM)


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Shneor
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Starman1]
      #5514809 - 11/11/12 05:11 PM

Quote:

Alexis talked about angular magnification distortion versus rectilinear distortion, not coma. Coma is an aberration of the paraboloidal mirror, and is more visible and severe the wider the apparent field, so if this eyepiece has built-in coma correction, and you imply it does, then it is unusable in refractors and catadioptrics.
That seems strange for JOC to do that, but it's certainly possible to do it.

Edit: One other user used this in a Paracorr with good results. I have a hard time believing it has built-in coma correction. therefore.



Ok, then ES has achieved the impossible. I plan to observe at Lake Sonoma this winter, you are welcome to see for yourself.
Clears,


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pbsastro
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Shneor]
      #5515012 - 11/11/12 08:09 PM

Quote:

Yes, it's massive! And beautiful! Also saw a 3" diagonal.

Clears,




I have been dreaming over that eyepiece for two years now, since I saw a picture of it from the manufacturer lab. The day is getting closer!

The 3" diag another dream, finally will be able to use my XW40 as it should, fully illuminated to the edge.

The weight is not necessarly a bad thing. Tipically apos from 5" up, specially from 6" up, are front heavy. My 175 apo is held near the lens although it has a 3.5" FT focuser.

No picture of the 3" diag?

Edited by pbsastro (11/11/12 08:20 PM)


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pbsastro
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5515028 - 11/11/12 08:22 PM

The importance of these eyepieces (9-120, 25-100, 30-100) to ES is not profit. It is the same as F1 for car manufacturers. It is a statement of tecnological superiority. ES is leaving TV behind. And in the way it is creating standards, like the 3" size.

Meanwhile TV is inovating with the Delos, which is a huge leap from the XWs...


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MrGrytt
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5515063 - 11/11/12 08:49 PM

Quote:

The importance of these eyepieces (9-120, 25-100, 30-100) to ES is not profit. It is the same as F1 for car manufacturers. It is a statement of tecnological superiority. ES is leaving TV behind. And in the way it is creating standards, like the 3" size.

Meanwhile TV is inovating with the Delos, which is a huge leap from the XWs...




Yes, their technological superiority over Tele Vue is evident.

Harvey


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pbsastro
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: MrGrytt]
      #5515133 - 11/11/12 09:41 PM

Quote:

Yes, their technological superiority over Tele Vue is evident.



According to TV yes, they said they could not make those.
I will not go into watertight, that ES shares with Nikon and Pentax, because TV may allow us to get extra nebulas inside the eyepiece, for free.
TV has been superior, that is a fact, but the tide is turning. The past is full of ex-superiors that chose to rest on their superiority.


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Happy Birthday Achernar
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Scanning4Comets]
      #5515621 - 11/12/12 08:47 AM

That thing looks more like a depth charge than an eyepiece......

Taras


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rtomw77
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Achernar]
      #5515655 - 11/12/12 09:26 AM

We saw that monster at ASAE.

Tom


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pbsastro
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5516592 - 11/12/12 07:39 PM

Quote:

Quote:

Yes, their technological superiority over Tele Vue is evident.



According to TV yes, they said they could not make those.
I will not go into watertight, that ES shares with Nikon and Pentax, because TV may allow us to get extra nebulas inside the eyepiece, for free.
TV has been superior, that is a fact, but the tide is turning. The past is full of ex-superiors that chose to rest on their superiority.




To avoid misinterpretation: A 25-100 from TV may be better than a 25-100 from ES, and a 30-100 from TV may be better than a 30-100 from ES.
But I am 100% sure that the 9-120, 25-100 and 30-100 from ES are much better than the non-existent counterparts from TV.


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csa/montana
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5516972 - 11/12/12 10:44 PM

Here it is, along side the ES30

http://www.cloudynights.com/ubbthreads/showthreaded.php/Number/5516901/


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M44
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: csa/montana]
      #5517186 - 11/13/12 01:42 AM

It looks like Jeff Bridges's prototype iron man suit next to Robert Downey's suit.

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ThreeD
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5517591 - 11/13/12 10:03 AM

Quote:


To avoid misinterpretation: A 25-100 from TV may be better than a 25-100 from ES, and a 30-100 from TV may be better than a 30-100 from ES.
But I am 100% sure that the 9-120, 25-100 and 30-100 from ES are much better than the non-existent counterparts from TV.


Where can I buy one of these 25-100s? Oh, that's right, it doesn't exist as a product for sale from ES either... (I'm not interested in the others but don't think I could get my hands on them right now either.)

When/if they do become available, I hope they are great and sell well but did it ever dawn on you that TV stopped where they did because they wouldn't want to put their name on EPs that would compromise aspects which they felt didn't meet their standards? Again, if ES puls them off and they are great EPs that's awesome but to assume that because EP designs are produced that they will be great EPs is a bit of stretch. If it turns out that they are less than great would that be a signal that TV is technologically superior because they know the real limitations?

Note, I'm not taking sides here or suggesting anything other than one should wait and see rather than get tied up in the hype.


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ManuelJ
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: ThreeD]
      #5517599 - 11/13/12 10:10 AM

A nice marketing campaign.

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csa/montana
Den Mama
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: M44]
      #5517600 - 11/13/12 10:11 AM

Here I thought my ES30 was a monster!

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Starman1
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: ThreeD]
      #5518001 - 11/13/12 01:56 PM

Quote:

Quote:


To avoid misinterpretation: A 25-100 from TV may be better than a 25-100 from ES, and a 30-100 from TV may be better than a 30-100 from ES.
But I am 100% sure that the 9-120, 25-100 and 30-100 from ES are much better than the non-existent counterparts from TV.


Where can I buy one of these 25-100s? Oh, that's right, it doesn't exist as a product for sale from ES either... (I'm not interested in the others but don't think I could get my hands on them right now either.)

When/if they do become available, I hope they are great and sell well but did it ever dawn on you that TV stopped where they did because they wouldn't want to put their name on EPs that would compromise aspects which they felt didn't meet their standards? Again, if ES puls them off and they are great EPs that's awesome but to assume that because EP designs are produced that they will be great EPs is a bit of stretch. If it turns out that they are less than great would that be a signal that TV is technologically superior because they know the real limitations?

Note, I'm not taking sides here or suggesting anything other than one should wait and see rather than get tied up in the hype.



I've been told by ES that the 25x100s are coming near the end of this month.


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rockethead26
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: ThreeD]
      #5518158 - 11/13/12 03:33 PM

Quote:

Where can I buy one of these 25-100s? Oh, that's right, it doesn't exist as a product for sale from ES either... (I'm not interested in the others but don't think I could get my hands on them right now either.)

When/if they do become available, I hope they are great and sell well but did it ever dawn on you that TV stopped where they did because they wouldn't want to put their name on EPs that would compromise aspects which they felt didn't meet their standards? Again, if ES puls them off and they are great EPs that's awesome but to assume that because EP designs are produced that they will be great EPs is a bit of stretch. If it turns out that they are less than great would that be a signal that TV is technologically superior because they know the real limitations?

Note, I'm not taking sides here or suggesting anything other than one should wait and see rather than get tied up in the hype.




Sounds like the same words being thrown around when ES announced their 9mm 120. It couldn't/wouldn't be any good because TV didn't do it first.

First reports have proven otherwise. Now we just have to see if ES can be as successful with the 25mm 100 design. I have a feeling that they will.


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pbsastro
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: ThreeD]
      #5518364 - 11/13/12 05:30 PM

Quote:

Quote:


To avoid misinterpretation: A 25-100 from TV may be better than a 25-100 from ES, and a 30-100 from TV may be better than a 30-100 from ES.
But I am 100% sure that the 9-120, 25-100 and 30-100 from ES are much better than the non-existent counterparts from TV.


Where can I buy one of these 25-100s? Oh, that's right, it doesn't exist as a product for sale from ES either... (I'm not interested in the others but don't think I could get my hands on them right now either.)

When/if they do become available, I hope they are great and sell well but did it ever dawn on you that TV stopped where they did because they wouldn't want to put their name on EPs that would compromise aspects which they felt didn't meet their standards? Again, if ES puls them off and they are great EPs that's awesome but to assume that because EP designs are produced that they will be great EPs is a bit of stretch. If it turns out that they are less than great would that be a signal that TV is technologically superior because they know the real limitations?

Note, I'm not taking sides here or suggesting anything other than one should wait and see rather than get tied up in the hype.




You are obviously ignoring the 9-120 is available and got very favorable opinions from people whose opinion I trust very much.
The 25-100 is two weeks from availability.
Unfortunately these eyepieces were not announced by TV...

BTW, I have 3 Ethos, 2 Naglers and none ES eyepieces. I love all my TV eyepieces. So not real a ES fanboy.

Everyone knows there are 3 issues with a 30-100 eyepiece: size, weight and it will not work well with many telescopes (due to scope CA and scope FC). TV decided they did not not want to make such eyepiece. I want such eyepiece. ES is making such eyepiece. My deep thanks to ES.
The argument of optical compromise is just a false excuse. It will be a dream eyepiece in the right scopes.

Edited by pbsastro (11/13/12 06:23 PM)


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Dave Ittner
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5518468 - 11/13/12 06:37 PM

Looks like a perfect eyepiece for .... Cyclops
http://oldmanfoltz.com/wp-content/uploads/2009/06/cyclops2.jpg


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Scott99
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Arizona-Ken]
      #5518546 - 11/13/12 07:15 PM

This is a great idea! The eyepiece looks awesome. I'm not sure how much it's going to offer around f/8. At f/8 you can use a 40mm eyepiece to get the larger field and still have a manageable exit pupil. this would offer a 2.5 degree field in my refractor vs. 2.33 with Pentax XW40mm.

Of course the XW is not the same as the 100 degree ES field. This 30/100 will be perfect for f/5 super-scopes, or anyone who can't give up their ultimate 100 degree field.

regarding needing a 3-inch diagonal to use a 40mm Pentax or TV eyepiece - the eyepiece still has a 2-inch wide barrel, I would not expect a different result.


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ThreeD
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5518563 - 11/13/12 07:23 PM

Whoa! Where did I say that the ES EPs wouldn't be any good? Two people who've taken exception to what I've said even quoted me and NO WHERE do I say in my post that they won't be good. I simply stated that I'd wait to see and I even stated that if they turn out great then that's awesome.

The person to whom I was responding seemed to assume that they would be the greatest thing since sliced bread. Come on, I don't even assume EPs with green letters will be good. (I've read of people who were a little disappointed with some aspect of their Delos, for example. Blackout problems if I recall correctly.) I'm a native Californian but I'll borrow something from Missouri -- show me. (And that applies regardless of the maker.)

I made a point of stating that the only one of the bunch that might interest me is the 25-100 so I'm not ignoring the 9-120. I'm pretty happy with my Naglers and BGOs and although I have no problem seeing to the edge of the 100s I've looked through, I'm in no rush to part with that much cash. The only reason the 25-100 might be interesting is if it could replace my 31T5 as it would have a more favorable exit pupil. I read enough dob owners who said they shouldn't have sold their 31T5 when bought their E21 that I opted for the 31 - that and the E21 didn't really fit the budget. A 25-100 should have pretty much the same TFOV as 31T5 so I'd need to look at it. I have no use for the 30-100 but more power to them for making it and to those who can make use of it.


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MrGrytt
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5518651 - 11/13/12 08:34 PM

Quote:


BTW, I have 3 Ethos, 2 Naglers and none ES eyepieces. I love all my TV eyepieces. So not real a ES fanboy.





For the record, I have had a ES 14-100 since the first month they were available and think it's a decent enough eyepiece for the cost. If they actually do something on their own and are successful at it the more power to them.

I know that Tele Vue had reasons for not going longer than 21mm with the 100 degree AFOV in 2 inch format so I'm also anxious to see how the 25-100 performs.

To be totally honest I simply don't see a need for the 120 degree AFOV. Didn't really understand going wider than 100 degrees with the 3.7 and 4.7mm Ethos either. It's my most unused area with anything I observe.

Don't know what to say about the big 30mm. Just have to wait and see how it works out.

Harvey


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Scanning4Comets
Markus
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: MrGrytt]
      #5518909 - 11/13/12 11:34 PM

Way too big and heavy & expensive !!! You can have it!

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Zamboni
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Scanning4Comets]
      #5518982 - 11/14/12 01:24 AM

I saw the thread title and thought this was a joke.

Then I pooped myself.


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FlorinAndrei
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5520102 - 11/14/12 08:27 PM

Quote:

The importance of these eyepieces (9-120, 25-100, 30-100) to ES is not profit. It is the same as F1 for car manufacturers. It is a statement of tecnological superiority.




That rings true for some reason. Although I'm sure the bragging rights are not the sole motivation for the 3" eyepiece project. Perhaps Scott just wanted to see all of M31 at once in his refractor.


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edl
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Scanning4Comets]
      #5520212 - 11/14/12 09:47 PM

Quote:

Way too big and heavy & expensive !!! You can have it!



Hi Mark,
LOL! You say that now...

Best,
Ed L.


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Scanning4Comets
Markus
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: edl]
      #5520406 - 11/15/12 12:26 AM

Quote:

Hi Mark,
LOL! You say that now...

Best,
Ed L.




Hi Ed! @ almost $1500.00 a pop and prob over 5 pounds, I say that now because I mean it !!! I can find a lot better ways to spend the imaginary $1500.00 I have. Even if I had a money tree in my backyard, for me it would mean spending that kind of cash for a finder eyepiece that would need a CRANE to put in the focuser, LOL.

No thx.


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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Scanning4Comets]
      #5520517 - 11/15/12 03:18 AM

Most people in the market for this will have $6-10k+ APO optical tubes, on $4k-20k mounts, $1500 is a drop in the bucket for these guys. I know, I used to sell stuff to them all the time.

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pbsastro
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5521507 - 11/15/12 04:20 PM

Quote:

Most people in the market for this will have $6-10k+ APO optical tubes, on $4k-20k mounts, $1500 is a drop in the bucket for these guys. I know, I used to sell stuff to them all the time.




Absolutely right. Some C14HD owners may be tempted as well.


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Alvin Huey
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5521542 - 11/15/12 04:35 PM

I think Shneor might end up with one of these. Just need a larger secondary and a new focuser.

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MitchAlsup
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5522085 - 11/15/12 10:59 PM

Quote:

Most people in the market for this will have $6-10k+ APO optical tubes, on $4k-20k mounts, $1500 is a drop in the bucket for these guys. I know, I used to sell stuff to them all the time.




Guys with 20"+ DOBs with larger than necessary secondaries will like htis EP also.


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George N
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: MitchAlsup]
      #5522928 - 11/16/12 01:26 PM

Maybe ES will *include* this eyepiece with their 6-inch APO. That prototype has been shown with a 3-inch r&p focuser since NEAF 2011 and Scott has talked about 3-inch field-flattener and reducer lenses for the scope. I would not be surprised to see it at least coming with a 3-inch diagonal.

So what if this EP does not work with Dobs. They will sell plenty to SCT and refractor owners. I see nothing wrong with aiming an EP at those scopes.


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Shneor
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Alvin Huey]
      #5523010 - 11/16/12 02:42 PM

Quote:

I think Shneor might end up with one of these. Just need a larger secondary and a new focuser.




Thanks for the confidence, Alvin! But my upper ring won't take the weight of a larger secondary, and I'd have to shorten the struts, not to mention a new, heavier focuser. Too much for me, I'm afraid. But there's a lot to like about the 9mm "120" ES. Wish there was a way to optically demonstrate how they eliminated coma. By the way I do like the 8mm Delos.

Clears,
Shneor


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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5523336 - 11/16/12 07:17 PM

Quote:

Quote:

Most people in the market for this will have $6-10k+ APO optical tubes, on $4k-20k mounts, $1500 is a drop in the bucket for these guys. I know, I used to sell stuff to them all the time.




Absolutely right. Some C14HD owners may be tempted as well.




probably will work on standard C11/C14s too. When Scott first mentioned this a couple years ago, the possibility of a diagonal to thread directly to the 3.25" threads on the rear cell was mentioned. OLD C14s had a 3" diagonal that had a thread on 2" reducer, and there was an eyepiece that threaded directly to the diagonal. I've never seen one, but I assume it was a longer FL erfle or something similar.

The problem with big 20"+ dobs is exit pupil, fine on F5, but many of these are f4, some down to F3, would be better off waiting for a 25-100, and if willing to go to a 3" focuser, only going wider, like a 3" 20-120, would make any sense. That is why the 21mm Ethos makes more sense than the 31 nagler to many fast dob owners. The 25-100 is going to be a hit if it is as good as the 14 and 20's. Good thing I have a 31 nagler to sell if it does. 4.6deg at 21.6x in the TV101, .89deg at 112x in C11 and 1.25deg at 80x in 8" ACF does sound appealing with 4.6mm and 2.5mm exit pupils respectively. Still slightly less field than 31 nagler (4.7deg in 101, .91 in C11 and 1.27 in 8"). Before anyone slams me on this math, I used simple AFOV vs Mag calculations, not taking into account actual effective field stop or magnification distortions, because we don't have that info for the 25-100 yet, and I didn't want to look up the equations and field stops. In my world the simple formula works well enough.

When it comes to pushing the edge of the barrel, it sounds like the 30-100 is not even close to the 3", and the 25-100 has room to spare as well (as does the 31nag). I wish someone would push the whole 2" field in a well corrected 82deg design, but nobody seems up to the challenge. In fact, when ES came out with the 20mm just before televue announced the E21, it was believed by the optical designers, that 20mm was as wide as could be done in a 2" barrel with acceptable performance. This makes me want to try before I buy a 25-100. Of course a few years have gone by, who knows what they could have figured out by now, and I hope TVs answer is to push the envelope with a 27mm, or whatever the max 46.5mm effective field stop allows in a 100deg design. It is times like this that I regret selling my 40XW, which really used the whole 2" field. I am pretty sure my 50 axiom does too, so it is not the end of the world. With the C11 I like the option to get as much field as possible, selling the 40XW was a "bad move Ripley, bad move!" (the field advantage of 31n vs 25-100 makes me hesitant to have to pick one or the other, but SOMETHING would have to be sacrificed financially for me to take on another $600 eyepiece, let alone a $1500 setup to go to 3" that would only work on one of my scopes... I better check my lottery ticket from yesterday's 300k drawing!


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panhard
It's All Good
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: pbsastro]
      #5526932 - 11/18/12 09:56 PM

That looks like the bomb known as fat boy.

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faackanders2
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: panhard]
      #5531110 - 11/20/12 09:43 PM

Would it be possible to make a 40+mm 100 degree 3inch eyepiece for even wider TFOV? What would be the upper limit where TFOV is maxed out with a 3" barrell?

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rmollise
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: panhard]
      #5531774 - 11/21/12 09:29 AM

Who you callin' "boy"? That baby was Fat MAN.

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Shneor
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: faackanders2]
      #5532407 - 11/21/12 02:40 PM

Quote:

Would it be possible to make a 40+mm 100 degree 3inch eyepiece for even wider TFOV? What would be the upper limit where TFOV is maxed out with a 3" barrell?



The field lens on the 3" did not look as though it left much room for an even wider field lens.

Clears,


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Keith
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Shneor]
      #5536951 - 11/24/12 10:05 AM

field lens size is not always an indicator in that type of eyepiece, but holding it up to the light and looking at the size of the field from the bottom, is a good indicator of how much room is left, since the field stop is inside the eyepiece, and is usually smaller than the field lens.

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faackanders2
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: faackanders2]
      #5537621 - 11/24/12 06:11 PM

Quote:

Would it be possible to make a 40+mm 100 degree 3inch eyepiece for even wider TFOV? What would be the upper limit where TFOV is maxed out with a 3" barrell?




Or 50mm 82 AFOV, or 60mm 68-70 AFOV. What would be the theroretical wideest TFOV configuration with a 3" barrel?


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Starman1
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: faackanders2]
      #5537804 - 11/24/12 08:30 PM

It would depend on how much vignetting to put up with.
You would think a field stop of 72mm would be possible, but what if that meant the lenses in the upper body had to be 150mm in diameter?
I'm not saying they would, but at some point focuser technology would have to keep up with the weight of eyepiece and correctors used, and if the load exceed ten pounds? Then, a rethinking of the design of the 3" to 2" reducer to adequately hold that 3 lb 2" eyepiece.
I think it can be done, but lets assume a 4000mm focal length 16" SCT for starters. A 72mm field stop yields a field of a little over 1 degree.
But if you did it just for the FOV, a 16" f/4.5 dob could do the same thing with a 21 Ethos and a Paracorr and provide an even bigger field with a 31 Nagler.
And the mount for the 16" SCT would have to be redesigned to handle the extra weight and clearance needed.
It could be done, but would the manufacturers want to do all the necessary re-engineering to accommodate a visual observer?
I'm dubious.


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faackanders2
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Starman1]
      #5537856 - 11/24/12 09:13 PM

Just a visual observer who loves looking at Multiple objects. Currently have a 17.5" f4.1 Dob; but if I got a larger one I think I would like a 3" eyepiece to provide wider TFOVs (as an option to the great higher powered views).

I think of it as the fifference from goning from 0.995 to 1.25" or 1.25" to 2".

Now many will say just get a smaller scope for wide views (and I do have many binos up to 25x100), but I would only want to take one scope out and use it to the max full range limits.


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Starman1
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: faackanders2]
      #5537970 - 11/24/12 10:33 PM

Do you need 3", though?
Let's say you have a 28", f/3.6 (it's a size I've looked through).
A 21 Ethos yields a true field of 42' That's not overly large, but there are entire nights I don't use a larger field than that on my 12.5", interestingly, at the same magnification.
Would I get a 28" scope to try to see a true field of 1.5 degrees?
No, why bother? The objects you'd look at don't require 28" of aperture to view them.
Out of the more than 11,000 objects in my log, only 79 of them are larger than that 42' field. Admittedly, it's fun to see groups of objects in one field, like M65/66/N3628 or M81/82 or N6939/6946, etc. But I recognize that this is not what you get a truly large scope to do. You get it to see things you cannot see in smaller scopes, and to see deeper into the universe--to see all the Abell planetaries or the Shakbazian galaxies.
And you don't need a 3" eyepiece to do that.


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faackanders2
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Starman1]
      #5538781 - 11/25/12 02:02 PM

Quote:

Do you need 3", though?
Let's say you have a 28", f/3.6 (it's a size I've looked through).
A 21 Ethos yields a true field of 42' That's not overly large, but there are entire nights I don't use a larger field than that on my 12.5", interestingly, at the same magnification.
Would I get a 28" scope to try to see a true field of 1.5 degrees?
No, why bother? The objects you'd look at don't require 28" of aperture to view them.
Out of the more than 11,000 objects in my log, only 79 of them are larger than that 42' field. Admittedly, it's fun to see groups of objects in one field, like M65/66/N3628 or M81/82 or N6939/6946, etc. But I recognize that this is not what you get a truly large scope to do. You get it to see things you cannot see in smaller scopes, and to see deeper into the universe--to see all the Abell planetaries or the Shakbazian galaxies.
And you don't need a 3" eyepiece to do that.




But supposed you would like to do both with the same scope?
I already have 40mm 70 AFOV, 30mm 82 AFOV, 20mm 100 AFOV 2" eyepieces; and although I can see M31/M32/M110 in the same FOV; I still cant see all of M44 nor M45, viel nor North American, nor more of Marakains chain, etc. The wider the FOV the more multiple objects you can see.

The larger scope would be to see dimmer objects, but I probably would still like to see the wider/multiple objects also without having to carry a second scope (although I would likely be willing to also bring my 25x100 and smaller binos since these don't take as much room nor weight of another Dob.


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Starman1
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: faackanders2]
      #5538873 - 11/25/12 02:46 PM

You just gave the best reason for having 2 scopes.

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Shneor
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Reged: 03/01/05

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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Keith]
      #5539242 - 11/25/12 06:49 PM

Quote:

field lens size is not always an indicator in that type of eyepiece, but holding it up to the light and looking at the size of the field from the bottom, is a good indicator of how much room is left, since the field stop is inside the eyepiece, and is usually smaller than the field lens.




Assuming the same proportionality is required between the field lens and the field stop, the field lens is the limiting factor in this case.

Clears,
Shneor


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faackanders2
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Starman1]
      #5539641 - 11/25/12 11:42 PM

Quote:

You just gave the best reason for having 2 scopes.




Perhaps if I had an observatory, and didn't need to transport scopes to a dark site.


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watcher
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Re: A 30mm 100 degree 3 inch barrel in the works! new [Re: Starman1]
      #5539759 - 11/26/12 02:35 AM

Sounds like a great eyepiece for something like this.

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