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Tele Vue Nagler 3mm - 6mm Zoom Telescope Eyepiece for use in 12" Dobsonian

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#1 Colinstar



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Posted 10 August 2018 - 11:30 AM

I am shopping for my next eyepiece for my 12 inch Skywatcher Dobsonian telescope.  I am looking for high power planetary eyepieces.  I was on Orion's site looking at the Tele Vue Nagler 3mm - 6mm Zoom Telescope Eyepiece and it says this is best for short focal length refractors.


Would this also be a good eyepiece to use in my 12 inch dob?


If not, what eyepieces would you recommend as better alternatives?



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#2 Aleko



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Posted 10 August 2018 - 11:36 AM

Assuming around f4-6, you should be fine. Besides my short refractors, on nights of good seeing I can use it in my 15-inch f5 dob.  If you're looking for a planetary zoom, you can't do much better.  

#3 csrlice12



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Posted 10 August 2018 - 11:37 AM

Its useable, but if you don't have tracking then objects will fly by pretty quickly at the below 5mm setting. But it does have nice views and 10mm eye relief.  I normally use wider field eyepieces at high mag.  With trackink...Yum.

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#4 Colinstar



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Posted 10 August 2018 - 11:38 AM

It is F5.

#5 Sam M

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Posted 10 August 2018 - 12:16 PM

Maybe consider a barlowed binoviewer.  I find it much better for planets.  At small exit pupils, using two eyes dramatically reduces problems from floaters.  Also, it's much easier to relax and look for detail while the seeing comes and goes.  Probably, you will need some kind of barlow to reach focus.  A 2x barlow will render much more than 2x, because of the longer light path.  I forget how much more.  There are other barlow options as well.  I use an older model Siebert 1.25x, 2x, 3x OCA.  It's fiddly, but it works very well.  The barlow also tends to improve off axis performance with cheaper eyepieces.

#6 junomike



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Posted 10 August 2018 - 12:17 PM

IMO you're going to need consistant excellent seeing conditions to use even the lowest setting (6mm).

F/L's in the 5mm - 10mm would better suit the F/L of the Dob, at least in my locale and seeing.

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#7 Colinstar



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Posted 10 August 2018 - 12:29 PM

Sam M said:  Maybe consider a barlowed binoviewer.


Thank you, but nope.  I had a couple eye surgeries in my right eye and I do not do much bino viewing as the contacts in each eye are different prescriptions. 

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#8 Astro-Master


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Posted 11 August 2018 - 12:14 PM

I use my TV 3-6 zoom on my 105mm refractor all the time.  Its great for the planets and double stars.  I love that it is parfocal through the whole range of powers.  Its perfect for dialing in the right power for the sky conditions.


On my 18" F4.5 Dob at 6mm the power is 345x and the field of view is only 8.7'.  Not having a drive system on the Dob makes it hard to use, so I just use my Ethos and a barlow for high power.  Its my drive compensator.

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#9 areyoukiddingme



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Posted 11 August 2018 - 02:44 PM

I find that the narrow field of the NZ is too much work for planets in 12.5" F5. Doable, but you will almost certainly be better off with more apparent field. 


Like others say, once you get up to 300x + (which is what I get at 6mm + coma corrector), it's just too much work keeping objects centered for any amount of time.


I typically use a Leica with barlow to get down to 5, and that's a much more comfortable way to go. If I need more power, I can barlow a 6 or 8 Ethos. The 100 degree field is very welcome at those high powers.

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#10 Steve Cox

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Posted 11 August 2018 - 07:51 PM

Depending on your local seeing conditions you should be good down to at least the 4mm setting on the eyepiece.  I know because when I owned a 12" dob many years ago, I regularly used my 8mm Ethos and 2X Powermate for planetary viewing and the whole thing was just idling along at 375X (~1mm exit pupil).  The limiting factor will be seeing conditions.


edit - I should add the other limiting factor is the smoothness of your altitude and azimuth bearings and how easily you can accurately track at high power.

Edited by Steve Cox, 11 August 2018 - 07:53 PM.

#11 Redbetter


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Posted 12 August 2018 - 02:56 AM

It will work, but it might not be the best fit for you and your 12" f/5.  I use 250x or more with a 10" f/5, including a 3-6 zoom at times for planets.  I was just using the zoom at the 6 and 5 settings a few minutes ago for 208x and 250x respectively on Mars, but the seeing was poor so both were too much.  A few nights ago it was doing well enough at 250x in mediocre seeing.  Haven't had particularly good seeing in the backyard with it recently, wrong time of year for it here at lower elevation, but I do go over 300x on the rare nights that allow it. 


The field is going to be narrow even at the 6mm setting for 250x in your scope.  I haven't done any mods to my son's Z10 I am using, so hand tracking with it is less precise than I would like.  I need to ask my son if he wants me to improve the azimuth. 


p.s. If you want a better price than Orion, consider the sponsor of Cloudy Nights, Astronomics.  They give a discount to CN members if you make them aware of your username when you order. 

#12 rowdy388



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Posted 12 August 2018 - 11:28 AM

I agree with those that say it may not be the best choice for a 12" dob. Although

an excellent eyepiece, the power at even the lowest setting is too high for my

conditions most nights and the field of view is too confining for me to be easy to use.

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