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Explore Scientific 82 24mm vs. 30mm

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#1 citrite_y


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Posted 20 January 2013 - 08:45 PM

Hey all,

Now that I've had a chance to observe with my ES 82 24mm I'm curious as to what I missed by not going with the 30mm. Originally I was looking at both of these EPs before purchasing the 24mm last week.

After trying the 24mm I think I prefer the heavier 2" EPs on my XT8 rather than the lighter 1.25" ones; the scope just seems to move better and doesn't require a counterweight as others have mentioned in their posts. Ultimately I'd like to end up with 3-4 ES 82 EPs or maybe even a 100 somewhere in the mix.

Another poster (I believe his name was Jim) was talking about just needing 3 total EPs and that seems pretty realistic for my needs. At the low power end I could see having either the 30mm or the 24mm, an 11mm (which most posters seems to rave about) and then perhaps a 4.7mm for high power.

I like seeing the complete Orion nebula with the 24mm and I would imagine that Andromeda would frame nicely in this EP as well. Hopefully I will get a chance to vet this out in the next week or so.

So does anyone have both the 24mm and 30mm ES 82 EPs that could comment on the differences and whether or not they think I would be better off exchanging the 24mm for the 30mm or was the 24mm a good choice to begin with? Even though I'm on an acre in a neighborhood without streetlights, I have a couple of neighbors that insist on putting on their outside lights at night which can be a bummer and my thinking was that the 24mm would capture less light pollution. Any thoughts or comments would be greatly appreciated.


#2 bherv


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Posted 20 January 2013 - 09:32 PM

The 30 would give you a 2 degree FOV while the 24 gives you a 1.6 degree field.40X for the 30 50X for the 24.

#3 Dave Ittner

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Posted 20 January 2013 - 09:46 PM

IMHO the 30 is a beast and too much eyepiece for the XT8 scope. The 24 provides a 1.64 TFOV at 50x. It weighs a lot less and will not require you to add a ton of counter balance weights.

#4 stratocaster



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Posted 21 January 2013 - 12:59 AM

I originally was attempting to determine to go with the 24mm vs the 30mm myself. I went with the 24 because I didn't want to spend the extra $50. On my 10" f5 dob, the 24 couldn't completely frame M31 and I had to poke around the Veil and Pelican nebula with the 24. I wanted a larger afov to frame these larger objects, so I ended up buying the 30 eventually anyway.

They're both great eyepieces. The 30 does get a tad heavy and balancing can be an issue. During more light polluted viewing the 24 gives a darker background.

I just sold my 24 because I went with a ES 20mm 100; otherwise, I would have kept both eyepieces.

#5 Achernar



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Posted 21 January 2013 - 08:31 AM

Probably you already have the best possible choice right now, because the 30mm is right up there with the TeleVue 31mm "Terminagler" in terms of size and weight. Both are the size and weight of a can of vegetables. In other words, it weighs two and a half pounds. That would probably be a major balance problem for your Dob, even though you would get a true field of view two degrees across. I find the 1.5 degree field of view it gives for my 10-inch and a one degree field of view for my 15-inch more than adequate. If you stay with the 24mm, a 14 and a 8.8mm ES 82 degree eyepiece will handle most deep sky objects, while a 6.7mm will be a good high power eyepiece. The 4.7mm does vey well as a high power eyepiece, when the seeing permits, in the 15-inch I get 425X, far more than the atmosphere in coastal Alabama permits.


#6 JayinUT


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Posted 21 January 2013 - 10:09 AM

I own the following EP's:

Pentax XW 5mm, 7mm, 10mm, 14mm,

27mm Panoptic

ES 82 degree: 24mm and 30mm

ES 68 degree: 20mm

I just got the 24 so I haven't used it in my 10 inch dob or in the 14 inch dob. I have used the 30mm in both and yes, it requires a counterweight. On the 14 inch dob that is a simple 2.5 lb ankle weight attached to the bottom of on of my front struts. No biggie. and I can leave it on to help balance out other items as the scope likes it there since I use a Paracorr Type I (sometimes I add a second weight, sometimes I don't). On my XT10 dob I have a Harbor Freight welder's magnet that I use as a counter weight and that works great on the back end of the tube.

The 30mm frames all my large objects well, and for me it is a speciality eyepiece when I want to see big objects like M42, or the Veil in summer, the Double Cluster, M31 and friends, or a triage of spring galaxies that will soon be in the early night sky in one field of view. My 27mm Panoptic has been my go to finder eyepiece as I love the size, the weight and the FOV when in my Type I Paracorr. The 24mm was an impulse buy to compare the 30mm to it and to see if its wider FOV is preferable to my 27mm Panoptic as a finder eyepiece. I can't sell the 27mm Panoptic as my daughter bought it for me as a gift and it has sentimental value, and I got it for $270 in the day, but it should make for an interesting comparison. The 24mm ES 82 degree gives me 69x with a 1.19 degree FOV. The 27mm Pan. gives me 61x with a 1.11 degree FOV. We'll see which I use more of.

I also use the 20mm ES 68 degree as a finder depending on where I am at and what I am doing and if I want to keept the 1 1/4 inch adapter in. My goal is to take off my 9x50 finder and just use eyepieces to view since I do that about 80% of the time anyway. Taking off the finder scope I find does more for resolving balance issues with the ES 30mmand 24mm than anything. In the end, all I want on my scope is my Telrad, my eyepiece and Paracorr.

#7 csrlice12


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Posted 21 January 2013 - 12:46 PM

Have both, use the 24mm a LOT more then the 30mm in my 10XTi. The 30mm in my dob is 40X, but it also has a 6.4mm exit pupil, which isn't like looking thru a portal, it's like being thrown out the airlock. Love the eyepiece though. Like I said, I use the 24mm more as it has a 5mm exit pupil and frames the lagoon nebula and the clusters in Hercules nicely. I only use the 30mm for real wide-field stuff like the Veil and Andromeda...Both of these eyepieces are nice hunks of glass....If your scope has the teflon bearings, balance won't be a problem, if you have the spring system, you may need some counterweights.

#8 Igor


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Posted 21 January 2013 - 06:13 PM

...Both of these eyepieces are nice hunks of glass....If your scope has the teflon bearings, balance won't be a problem, if you have the spring system, you may need some counterweights.

...but at the same time, especially when using 30mm, you don't need finder anymore so balance is retained ;)

#9 citrite_y


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Posted 21 January 2013 - 09:50 PM

I'm fairly certain my scope has teflon pads that the OTA rests on--it definitely has the springs.

#10 csrlice12


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Posted 22 January 2013 - 08:56 AM

If you have springs, you may need some counterweights. The XTi and XTg both have teflon bushings that create the friction that hold the scope in place (like the Zhummels) rather than the spring system (on the XT classics). The spring system is still a good system, but just isn't as capable of balancing weight as the teflon bearing system is. I'd recommend maybe getting some magnets and using them as counterweights. After a few tries, you'll know how much extra counterweight you need.

#11 faackanders2



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Posted 24 January 2013 - 12:25 AM

30mm 82 AFOV will give you widest TFOV at 30mm power.

If you ever binoview you would like 24mm 68mm 1.25" panoptic.

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