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Re-Start of Hobby and 2" eyepiece question

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#1 DonaldW

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Posted 21 April 2017 - 12:34 PM

Hello,

 

I'm dusting off my NexStar 11 GPS which has been boxed up for 8 years. I used to live AZ and belonged to the East Valley Astronomy Club. I'm now in So Cal and have joined the local club. Since I've been out of the hobby for long time, I wanted to know how the viewing is with 2" star diagonal and 2" eye pieces vs 1.25" size that I currently have. Also, what versions and sizes of 2" eyepieces would be be a good selection as a starter set for viewing nebula, Saturn and galaxies?

 

thank you,

 

Don



#2 bobito

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Posted 21 April 2017 - 01:55 PM

I can't imagine using my 12" SCT with just 1.25".  You are only getting about .5 degree FOV max with a 1.25, you get close to 1 degree max FOV with a 2".  There is really no downside (other than the affect on your wallet) to going with 2".  You'll be able to fit some of the larger objects in your FOV (Orion Nebula, Lagoon, most of Andromeda, most of Pleiades...).

 

As far as recommendation, that's largely down to your budget.  The TeleVue EPs are always fantastic, but at a price.  Lots of people like the Explore Scientific EPs (I found the ones I've owned to be very good) so they are a good option.

 

Perhaps just start out with a 55mm Plossl (ranging from $70 to $250 depending on quality) to get you a maximum FOV 2" EP while keeping your costs down.  See what that shows you then fill in the hole between that and your 1.25" EPs as you see fit.

 

Bob



#3 lenrabinowitz

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Posted 21 April 2017 - 02:03 PM

Definitely Televue and Explore Scientific.  Better off getting one of those then half a dozen mediocre ones.  I can't imagine keeping an 11" scope boxed up for 8 years!



#4 DonaldW

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Posted 21 April 2017 - 02:37 PM

Thank you for your input. As far as Tele Vue, there are Nagler, Panoptic, Ethos, Plossl, etc. and if I'm going only get 1, 2 or 3; I am looking for solid recommendation as what to start with. I see a 2" 50mm Plossl is one recommendation. Other suggestions are appreciated.

As far as 8 years out of the hobby, I went thru a layoff, home short sale, divorce and other matters and then found a job in rainy Seattle for several years. I'm now in So Cal with some reasonable clear skies.

Thank you,

Don


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#5 BryanGx

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Posted 21 April 2017 - 02:46 PM

I'm a really big fan of Baader Hyperion eyepieces.  They're extremely versatile because they're specially designed to convert from 1.25" to 2". 

 

You asked about nebulae, Saturn, and galaxies.

 

For example, my 8mm Hyperion can function as a 1.25" eyepiece with an 8mm focal length and 11mm field stop.  That's perfect for viewing Saturn.  But you can simply unscrew the bottom lens elements and turn it into a 2" eyepiece with a 22mm focal length and 30mm field stop.  Perfect for viewing galaxies or smaller nebulae.  Essentially you get two very different eyepieces for the price of one. 

 

Granted, the optics won't be as dazzling as a TeleVue wide angle, but a good Televue would also cost three or four times more than a Baader Hyperion. 



#6 bobito

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Posted 21 April 2017 - 02:56 PM

I have three 2" EPs that I use regularly with my 12" SCT, all TeleVue: 55mm Plossl, 35mm Panoptic, and 22mm Nagler. I decided on these three because of the spread in their FOV and magnification (also eye relief is a concern for me since I wear glasses). As follows:

55 Plossl - .9 Degree FOV @ 55X magnification

35 Pan - .75 Degree FOV @ 87X magnification

22 Nagler - .6 Degree FOV @ 139X magnification

 

So this gives me the ability to cover lots of different sized objects and frame them nicely by having a .15 degree difference between each respective EP.  You'll likely want to do something similar, but as I said in my first post, your budget will dictate any recommendation I would make.  (these three would cost you about $1000 total if purchased new, I got two of three used to save a bunch of money).

 

A tool that helped me was TeleVue's EP calculator.  It will only show you TV eyepieces, but they have so many that you can usually find one that is close in spec to any EP you may be considering.  This will help you pick EPs that complement each other.  For example, you wouldn't want to get a 41 Panoptic and a 31 Nagler because they both give you the same FOV, just at different magnifications.  So you would pick one or the other based on the magnification that best suits you and your EP collection.

 

Bob


Edited by bobito, 21 April 2017 - 02:57 PM.


#7 Taosmath

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Posted 21 April 2017 - 04:01 PM

For my 10" Meade LX200 I routinely use only two EP's - a Televue 35mm Panoptic and a Baader 8-24mm zoom, but then I don't do much planetary.  

 

Your scope is a little longer Focal length so you might want to consider the Televue 55 mm Plossl (51x Mag, 1.0 Degree FOV, 5.5 mm Exit pupil) - this gives you close to the largest FOV you can get.  Then add a Panoptic 27mm or Explore scientific 68 series 28 mm to give you 100x -ish magnification, 0.7 degree FOV, 2.7 mm exit pupil and then the baader zoom to cover 116x magnification (but only 0.4 degree FOV !) up to 350x mag, 0.2 degree FOV, 0.8mm exit pupil.

 

The zoom is good and very convenient for selecting your optimal FOV and magnification, though the narrow FOV at the long end (24mm) is a bit restrictive. However it's close enough to the 27mm pan that if you need a wider view you can just slot the pan back in. (I have a 26mm Meade QX I use for that duty).

 

Just my 2c



#8 lenrabinowitz

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Posted 21 April 2017 - 06:29 PM

+1 on the 55 mm Televue plossl.  Had one for a long time; great eyepiece.  Baaders are good also.



#9 DonaldW

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Posted 22 April 2017 - 07:14 PM

All, thank you for your advice. Based on the link that I was sent; the Baader 2" Zeiss Prism seems to be the best for a 2" diagonal. Any idea what additional items I will need to buy to install the 2" star diagonal on the back of NexStar 11 GPS?  Thank you...Don



#10 bobito

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Posted 22 April 2017 - 08:59 PM

You just need a 2" visual back. This one gets great reviews:  http://agenaastro.co...sct-thread.html

 

I've not used a prism diagonal, but my understanding is they are fantastic on axis but can give a soft edge.  I'd search the topics here on CN for more opinions before shelling out that kind of dough. Mirror diagonals are certainly more popular...



#11 DonaldW

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Posted 23 April 2017 - 08:35 AM

Here's the link I was provided for review of the 2" star diagonals and Baader Zeiss prisms come out on top. https://www.cloudyni...omparison-r2877



#12 bobito

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Posted 23 April 2017 - 10:11 AM

OK, sounds like you'll be happy with the prism then. It appears the issues I have heard about prisms were either people that had bad prisms or a very fast scope.  But based on that article your f/10 scope should perform perfectly with the prism.

And I agree with the reviewer on the click lock, I have a baader diagonal and I love the click lock.

 

Bob



#13 Ab Umbra Lumen

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Posted 23 April 2017 - 12:25 PM

Don, you might also want to consider starting the 2" journey with an Explore Scientific 68° Maxvision 40mm (ex Meade rebranded), also known as "the grenade": if you can find it, it's a terrific steal for the price and gives crisp gorgeous views.

Anyway, 2" is the route to go: happy views!

Ab



#14 DonaldW

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Posted 26 April 2017 - 11:10 AM

Part 2 of my move up to 2" eyepiece questions: what are the best current 2" filters to buy?

To refresh, I'm dusting off my Nexstar 11 GPS after years out of the hobby. I'm looking to enter into the 2" eyepiece arena from my current 1.25" basic setup.  Part 2 of my question relates to the current recommended type and brand of filters in the 2" size range. I have 1.25" filters as a basic 10-year old Celestron package and have a moon filter, nebula filter, and light pollution filter. The latter 3 (moon, nebula & pollution) are only ones I recall ever using and I think I paired up the light pollution filter and nebula filter. I have been out of the hobby for years and would like advice on the current 2" filters to investigate for purchase.

Thank you...Don


Edited by DonaldW, 26 April 2017 - 02:33 PM.


#15 jallbery

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Posted 06 May 2017 - 10:18 AM

For Saturn?   You won't need 2" eyepieces.  In planetary, high-power focal lengths there is no advantage provided by the 2" format.  In fact, I believe a c11 is actually optimized for spherical aberration correction with the 1.25 vb and a prism diagonal.  That's definitely the case with the c8.   And with a scope with tracking, I actually prefer narrower apparent fields for planetary.

 

Where 2" eyepieces shine are in the longer focal lengths.   You want something to max out your true field of view, something to give you a max usable exit pupil (max brightness for use with a nebula filter), and then one or two options to bridge the gap between your longest and brightest and your 1.25" eyepieces.

 

For max brightness, a 55-56mm plossl is the obvious choice.  Televue if you want the best.  Meade if you want a bargain.  Russell Optics may also be worth considering. 

 

Now a 55mm plossls also maxes out your tfov, but you will probably want something with more magnification and a wider apparent field of view.   The question is how wide and how much do you want to spend? 

 

You have the 68-70 degree class of eyepieces.  The orion q70 / agena swa eyepieces are the value play.  At f/10, I find them acceptable.  The 40mm gives you max true field and is bright enough that you could skip the 55mm plossl.   And if you want better performance,  the Explorer Scientific 68 40mm is an option.  And if you -want even better, there is the Telescope Vue panoptic 41mm.   If you decide you want the 68-degree class of eyepieces, the 24mm ES 68 (in 1.25") is also a great option to have (or the TV 24mm Panoptic if you have the funds).   So you may want to fill in that the gap between 24mm and 40-ish with something around 32mm.   Oh, and if you choose the budget route, I'd still opt for the 24mm ES 68 over the 26mm Q70/SWA  (I happen to own both).

 

The next step wider is the 82 degree afov.  Here you will look at 30-32mm eyepieceso to max out your view.  The standard in the TV nagler 31mm.  The ES 82 30mm is a more affordable option with still excellent performance.  The celestron luminos 31mm is the bargain contender (still over $200, though).  If you go the 82 route, you'll probably also want something in the low 20s or high teens to complement it.  

 

There are 100-degree options now too.

 

It is also worth noting that the F/6.3 Reduce corrector with a 24mm 68 yields an almost identical field to a 40-41mm 68-degree AFOV eyepiece, and does so at less cost and weight (plus you get the 24mm to use without the R/C).   The same is true with a 32mm plossl and the RC in comparison to the 55-56mm plossl.  A 2" diagonal is not necessary to get the most out of your SCT, if you are willing to put up with the hassle of taking the RC off and putting back on.  On a C8 or smaller, I probably would not bother with 2" eyepieces if I didn't have another scope to use them on.  On a C11, with a full 2" baffle tube, I can see going the 2" route though, but the bargain approach would still be with the R/C.

 

As far as filters, the general consensus is the first filter to buy is a true UHC filter first (Lumicon UHC, Orion Ultrablock, or DGM NBP) , and then an OIII.

See https://www.cloudyni...-nebula-filter/


Edited by jallbery, 06 May 2017 - 10:53 AM.



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