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Equipment Discussions >> Eyepieces

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Ps191
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Reged: 06/17/09

Loc: E.OR.
Time to ask the experts
      #6260106 - 12/18/13 01:22 PM

Hi everyone, first time posting in the eyepiece form. This may be a longer post so please be patience – I can use the help.

Background
I've observed off and on over the years and after recently finishing school (anyone know of an engineering firm looking to hire) and I'm planning on increasing my time enjoying the sky. Because I was in school my astro budget was practically nil but now since I'm out I'd like to consider a few better eyepieces. I've been reading old post that may be of relevance (made it 25 pages back) as well as doing some searches but am quickly finding myself lost.

Current Equipment Observation Choice
I'm currently using a 12” f/4.9 dob. In the future I'll have a 8” f/7.6 when I can finish putting togeather the ota and mount. Long term goals may include a 15” to 17” sub f/4 telescope. At this point I favor Newtonian reflectors and don't have a coma corrector (yet).
I don't find myself gravitating toward one type of observing but enjoy, galaxy's, open and globular clusters, nebula's, double stars and planets. I really enjoy the widefield views but also use some magnification to observe the details, so while I enjoy planets my primary goal for this discussion is to find eyepieces that work best for deep space objects.
My current eyepiece collection are (all are 1.25”):
- Unknown 1 1/8” (I assume this is a 27.6mm eyepiece otherwise no other markings)
- Meade 25mm (I think this the budget eyepiece Meade send with most of their telescopes)
- Parks 20mm Plossl (would be interesting to know more about this eyepiece)
- Edscorp 12.5mm Or. (see note on Parks)
- Meade 9mm (see note on Meade 25)
- Unknown 22-7.4mm zoom (no other markings)
I use the 1 1/8” for finding objects and general viewing but find it frustrating to not be able to see the Pleiades cluster, the double cluster (Per), or the the majority of the Andromeda galaxy. Most of my close up viewing happens with the 12.5mm, as the 9mm sometime feels like to much magnification but then 20mm is not enough.

Now for Questions and Other Thoughts
It seems like the ES 82deg collection is a good value for the money so my current thought would be to get the ES 30mm for widefield views along with the ES14 and ES11 for closer looks. I may consider a 2x Barlow/extender in the future for planetary nebula and double star observing.
I understand that the ES30mm is huge and heavy and the ES24mm a close contender, but will the ES24mm do what I want. Comparing the two it seems the ES24 is a good widefield eyepiece for 10” scopes, is on the fence for 12” scopes but what about larger scopes? Saving $50 on the ES24mm over the ES30mm is also very attractive.
I know the ES14mm has FC and I don't know if it will bother me, but it still gives me pause. I don't know, but the ES11mm may feel short at times thus the ES14mm, or could I get by with only one (and which one)? Should I be considering other ES 82 deg eyepieces?
Any thoughts? As can be seen I don't have much experience with higher quality, wide-field eyepieces so your experience is appreciated (especially the 12” F/4.9 dob users). Is there other eyepiece (brands, makes, models) I should consider? I know some will say get the Televue____ or the ES__mm 100 deg eyepiece, but at “X” time the cost? If I knew exactly what focal lengths best fit my observing I might be able to budget one longer ES 82deg and one shorter shorter length ES 100deg eyepiece but most Televue are out (even at most used prices). Also the 2” barrel of many of these seem to limit its usefulness in certain scopes not to mention doubling the cost of any future Barlow/extenders. $400 is a comfortable budget top and $500 is pushing it, but doable, if it gets me set for my life.

I feel like I have analysis paralysis - maybe I should just go observe (and be thankful) with what I have and forget this whole mess


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gene 4181
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Reged: 11/12/13

Loc: n.e. ohio
Re: Time to ask the experts new [Re: Ps191]
      #6260159 - 12/18/13 01:56 PM

don't worry. you want the widest fov. get the 30. the 24 is nice but for what you want, its the 30. and get the 14. nice field of view, not to high of power, and it will barlow well for a 7 mm. terrence dickson once said about paraylisis. buy it use it and see where you want to go from there. i see the 11 mm being a single use piece. later you can fill in between. i look at eyepieces in terms of exit pupil and my light pollution and what works.

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Starman1
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Reged: 06/24/03

Loc: Los Angeles
Re: Time to ask the experts new [Re: gene 4181]
      #6260221 - 12/18/13 02:29 PM

Well, don't go overboard on eyepieces. The wider the apparent fields of view, the farther apart the magnifications can be because when you step up in power the fields don't get as small. If the field of view of a medium power eyepiece is big enough, you can actually use the same eyepiece for "finding" as you do for "observing".

In a 12" (about the same size and f/ratio as my 12.5" f/5), you could use the 1X/2X/3X protocol to pick some reasonable wide field eyepieces.
In your size scope, that would be 70x, 140x, 210x and then either add a good barlow for 280X and 420X or think about another eyepiece.

In your instrument, with its 1500mm focal length, that would be eyepieces of
21mm, 10-11mm, 7-8mm, and a good 2X Barlow.

Let's come up with some possibles:
Economy widefields:
--ES 24mm x 82
--ES 11mm x 82
--ES 8.8mm x 82
--ES 2X 1.25" Focal Extender

Medium price widefields, choice 1:
--ES 20mm x 100
--ES 14mm x 100
--ES 9mm x 100
--ES 2X, 2" Focal Extender

Medium price widefields, choice 2:
--TeleVue Nagler T5 20mm x 82
--TeleVue Nagler T6 11mm x 82
--TeleVue Nagler T6 7mm x 82
--TeleVue 2X, 1.25" Barlow.

Medium price widefields, choice 3:
--ES 20mm x 100
--TeleVue Delos 10mm x 72
--TeleVue Nagler T6 7mm x 82
--TeleVue 2X, 1.25" Barlow or TeleVue 2.5X, 1.25" PowerMate

High price widefields
--TeleVue Ethos 21mm x 100
--TeleVue Ethos 10mm X 100
--TeleVue Nagler 7mm x 82
--TeleVue 2X, 2" PowerMate

I put a 2" Powermate in the last selection because it is easier to use with a Paracorr, which you might want with the 12" and definitely will need on the larger scopes planned.
Note that, at f/5, all the above eyepieces will work great. At f/4 and below the edge of field issues begin to show with most eyepieces and you will want to move to eyepieces fully corrected at short f/ratios.

I'm sure other posters will quickly chime in about what you need.


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JustaBoy
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Re: Time to ask the experts new [Re: gene 4181]
      #6260231 - 12/18/13 02:34 PM

"$400 is a comfortable budget top and $500 is pushing it, but doable, if it gets me set for *my life*"


You're kidding, right?

Sorry, but this is the Eyepiece Forum:-)


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howard929
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Reged: 01/02/11

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Re: Time to ask the experts new [Re: Ps191]
      #6260250 - 12/18/13 02:44 PM

Price verses performance appears to be on a per case basis. From a 100 degree ES being tromped by a Delos, a ES 82 being only as good as 80 percent of a Nagler to I couldn't tell the difference. Buy one eyepiece in the more expensive class, just one, use it and find out what you think of it.

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JustaBoy
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Reged: 06/19/12

Re: Time to ask the experts new [Re: howard929]
      #6260254 - 12/18/13 02:47 PM



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Lorence
scholastic sledgehammer


Reged: 09/15/08

Re: Time to ask the experts new [Re: Ps191]
      #6260263 - 12/18/13 02:50 PM

Quote:

I really enjoy the widefield views but also use some magnification to observe the details, so while I enjoy planets my primary goal for this discussion is to find eyepieces that work best for deep space objects.




Take a look at what some people are doing with their astro video cameras before you spend more on eyepieces.

http://www.nightskiesnetwork.com/

I have a collection of eyepieces that are better than adequate. The only thing they are collecting now is dust.

That collection was over fifty years in the making. I have seen and enjoyed observing more in the few years I have used my Mallincams than I have in all the years before.


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Jeff Morgan
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Reged: 09/28/03

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Re: Time to ask the experts new [Re: JustaBoy]
      #6260265 - 12/18/13 02:52 PM

Quote:

"$400 is a comfortable budget top and $500 is pushing it, but doable, if it gets me set for *my life*"


You're kidding, right?

Sorry, but this is the Eyepiece Forum:-)






But seriously, if you are looking to be set "for life" then buy the best for DSO work (Tele Vue Delos or Pentax XW) immediately and avoid the transaction costs of trading up later.

The key is not falling for the trap of buying the whole set, or having to have it all now. Buy one or two of the best, and perhaps a barlow and be patient for more available budget. Your existing eyepieces can supplement the range of focal lengths short term.

Utilizing the used market can help greatly in this - used XW and Delos are in the $225-$275 range currently.

Selling a few (eventually all) of your starter eyepieces can help you stretch a bit further. Getting hired into your profession will help quite a bit more, best of luck on that!


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JustaBoy
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Re: Time to ask the experts new [Re: Jeff Morgan]
      #6260274 - 12/18/13 02:55 PM



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gene 4181
Pooh-Bah


Reged: 11/12/13

Loc: n.e. ohio
Re: Time to ask the experts new [Re: Ps191]
      #6260451 - 12/18/13 04:24 PM

you said you'd like to see the pleides and andromeda and double cluster . 30 mm the rest, i'll defer to my esteemed collegues

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Starman1
Vendor (EyepiecesEtc.com)
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Reged: 06/24/03

Loc: Los Angeles
Re: Time to ask the experts new [Re: gene 4181]
      #6260553 - 12/18/13 05:23 PM

True field in the 30mm ES will be 1.64 degrees. That's large enough for most large targets--not quite large enough to see ALL of the Pleiades or North America Nebula or California nebula or Veil nebula, etc., but certainly large enough for just about everything else. And large enough to see major portions of the really big things.

A note to consider, however, is that just about every object in the sky is a degree in diameter or smaller. Purchasing an eyepiece just for the 10-20 objects that are a bit larger seems like it would be a "supplemental" purchase for later, when filling in the "in-between" sizes and magnifications.
The 24mm x 82 ES would yield a true field of 1.28 degrees, which is still very large, and the magnification would be better for a much larger number of objects.


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gene 4181
Pooh-Bah


Reged: 11/12/13

Loc: n.e. ohio
Re: Time to ask the experts new [Re: Starman1]
      #6260800 - 12/18/13 07:31 PM

well then, i would say to get yourself a small refractor then to see all the pleides, those huge sprawling star clouds thru cygnus, and andromeda galaxy. i guess a 12 dobs not the best for huge swaths of sky.

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JustaBoy
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Re: Time to ask the experts new [Re: gene 4181]
      #6260804 - 12/18/13 07:35 PM

I have larger scopes, but I could not get along well without my ST-80. - My most used by far!

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SeattleScott
Pooh-Bah


Reged: 10/14/11

Re: Time to ask the experts new [Re: JustaBoy]
      #6261105 - 12/18/13 11:48 PM

Vixen LVW series are reported to be the best series for observing down to F4 without a coma corrector. Sub F4 and there is probably no getting around a Paracorr. Used LVW prices are about $150 to $175 which is significantly cheaper than Pentax XW or Delos, the two competing brands. In astronomy you end up paying real money for minute differences in performance with the top of the line stuff. ES may be the best value in terms of coming close to the top brands and being quite a bit less, and ES will work fine at F4.9. But if you go much lower, LVW or a Paracorr will work better.

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ibase
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Reged: 03/20/08

Loc: Manila, Philippines 121*E 14*N
Re: Time to ask the experts new [Re: Ps191]
      #6261136 - 12/19/13 12:12 AM

One thing immediately noticed is that the current EP arsenal lacks widefields (68-70-deg. AFOV up). Just a suggestion, leapfrog over 70 & 80-deg widefields and get your feet wet with a 14mm ES-100, that way, you'll be avoiding the FC dilemma in the 14mm 82-deg. too.



The majestic expansive view the 100 yields on a big scope is an unforgettable wow moment.

Best,


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TechPan6415
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Reged: 07/29/12

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Re: Time to ask the experts new [Re: Lorence]
      #6261283 - 12/19/13 03:18 AM

Quote:

Take a look at what some people are doing with their astro video cameras before you spend more on eyepieces.




That's like saying "Take a look at what some people are doing with Garage Band on their computers before you spend money on a Martin Acoustic."


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csrlice12
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Loc: Denver, CO
Re: Time to ask the experts new [Re: TechPan6415]
      #6261453 - 12/19/13 08:31 AM

Regarding your other question; the Denver, CO area has lots of company's looking/hiring engineers. We have Lockheed Martin, CH2M Hill, Ball, Raytheon, and numerous other smaller firms in the area. Not a bad place to live either...we've had a bad last year of viewing though, but who hasn't.....we also have something many places don't....a brick and morter astronomy store, not just a camera store with a couple of scopes, but a real telescope shop will very knowledeable people, who are also active astronomers.....

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Ps191
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Reged: 06/17/09

Loc: E.OR.
Re: Time to ask the experts new [Re: csrlice12]
      #6262028 - 12/19/13 02:18 PM

Wow, thanks everyone for the great thoughts, suggestions and help. I was gone most of yesterday so I'll try and catch up. I've been using N.A.A. Telescope Math Calculator to find the true field of view and Stellarium to compare what these fields of view would look like with different objects, this has been helpful.

@ gene4181 - Thanks for the reminder to buy used, almost all of my equipment has been purchased used and I'll certainly plan for more used equipment in the future. Would you mind clarifying the thought of "the 11 mm being a single use piece".
@ Starman1 - Thanks for assembling those list and for clarifying why you suggest the 24mm over the 30mm. This has been good food for thought and very helpful.
@ JustaBoy - I know this is the eyepiece forum, but I tend to be a minimalist with the thought that "less is more (manytimes)" and "if I don't used it, lose it". I've been interested in the night sky for over 20 years, about half of that time using a star wheel and binoculars (with an occasional borrowed C8), of the remaining time most of it was happily spent with only 3 eyepieces. I suspect that a few of the eyepieces from my list will find a new home if I get anymore.
@ howard929 - Thanks, so it sounds like used is the preferred way to go, while figuring out what will work best. Is ES considers the expensive class or are you thinking of TV?
@ Lorence - I've thought about astro video cameras and I would like to see one someday, but at this time I appreciate the simplicity of my dob with its few power requirements. Also if I'm going to be using electrons to create an images why not jump in all the way in AP with a dedicated CCD?
@ Jeff Morgan - Thanks I don't few pushed to buy complete sets which is why I'm asking here before buying the ones that will work the best. Also considering I spent years with simple eyepieces so most any choice will be an upgrade that should keep me happy for a vary long time, or is this a slipper slop? Maybe the key is not to look through more expensive eyepieces?
@ SeattleScott - Thanks I'll have to read more about the Vixen LVW, either way I'm leaving the future open to a Paracorr.
@ ibase - If you took that picture then you would have both the 100 and 82 deg. Would you care to share your thoughts comparing the two?
@ csrlice12 - Thanks for the ideas. I've looked for jobs in Denver area in the past, but it may be time to revisit the possibilities.

I did remembered I have one more eyepiece that should be somewhere on the way, a Lunt 10mmm - 70deg. I don't know how I'll like this eyepiece but it should be better then much of what I have.
So now I'm considering the ES 24mm-82 and the ES 14mm-82 (preferably used) with a 2x barlow/extender in the future.
If the ES 30mm-82 would be available used before the ES24mm-82 should I still consider it?
Howabout a used ES14mm-100 instead of the ES14mm-82? The ES14mm-100 would have a 0.94deg true field and the ES24mm-82 would have 1.3deg true field, is this too close of overlap?
Finally with the Lunt 10mm in the mix should I skip the 14mm rang and thing about something in the 6mm to 8mm range?

As always I appreciate the great suggestions and thoughts.


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Ps191
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Reged: 06/17/09

Loc: E.OR.
Re: Time to ask the experts new [Re: Ps191]
      #6262090 - 12/19/13 02:47 PM

I should add that while I enjoy the wide field views I'm not looking for a rich field view from a 12" F/4.9. Rich field views will have to remain the domain of my binoculars or another telescope.

Concerning my quest for a better eyepiece, I don't have an AM account but maybe I'll post a wanted add here on CN and see what comes. This is by no means the end, so keep the thoughts and suggestions coming.


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Starman1
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Reged: 06/24/03

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Re: Time to ask the experts new [Re: Ps191]
      #6262104 - 12/19/13 02:54 PM

Kevin,

The html code behind that calculator uses the formula:
1) TF = AF/M to calculate True Field.
AF = Apparent Field
M = Magnification.

This will result in very slightly larger than actual true fields when calculated.

You may have read that a slightly more accurate formula to use is:
2) TF = (FSEP/TFL) * 57.296
where FSEP = field stop of eyepiece
and TFL = Telescope focal length.

How much difference does it make?

Let's see:

My Telescope has an effective focal length of 1825.6mm
If I use a 21 Ethos, the magnification is 86.93 and the field stop of that eyepiece is 36.2mm.

Using formula 1, the true field is 100/86.93 = 1 degree 9 minutes
Using formula 2, the true field is (36.2/1825.6)*57.296 = 1 degree 8 minutes.

That difference is really small.

The only point I'd make is that IF you know the field stop diameter, use formula 2. Otherwise, use formula 1.


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