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MarcusE
member

Reged: 02/06/11

Loc: Iowa

2 inch or not 2 inch? - that is the question new

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#5246661 - 05/30/12 12:52 AM

Hello,

I've had my telescope (LXD-75 f/5 6" newt) for almost two years and am working on upgrading my eyepieces. I was able to get the Meade 4000 eyepieces set for free as a promo, but am ready for some better stuff. My only splurge to date is an ES82* 11mm. I mostly like to look at deep space stuff - globs, open clusters, galaxies, etc. I haven't spent too much time on the planets and so far, very little on the Moon.

With the Explore Scientific sale about to end, I am looking at the 2" ES 68* 28mm to replace the Meade 4000 32MM plossl as my wide field eyepiece. However, with that come some questions.

With my current 32mm eyepiece, I get 24 power and a field of view of 2.06 degrees (using the Astronomics telescope eyepiece formula on their website). If I bought the ES68* 28mm, I get 27 power and a FOV of 2.5 degrees - a huge difference. If I buy the ES68* 24mm I get 32 power and a FOV of 2.14 degrees - larger than my 32mm piece AND $30 cheaper than the 28mm. (no the $30 dollars won't break the bank, but still....)

Either one will be an upgrade. I am not sure how much work (and time) it will be to change from the 2" to the 1.25" eyepieces. I do not want to spend a lot of extra money on a "quick change" adapter, are there solutions to this too?

So is a 2" eyepiece worth it for my wide field eyepiece, knowing I will need to change over to 1.25" to view at higher magnifications? Or am I making too much of it?

Thanks,

Marcus

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daniel_h
Carpal Tunnel

Reged: 03/08/08

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Re: 2 inch or not 2 inch? - that is the question new

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[Re: MarcusE]
#5246803 - 05/30/12 05:40 AM

If it were me I'd get the 24, I prefer slightly more mag.

I leave the higher power I'm gonna use in the 2-1.25" adapter, swap the 2" ep with the adapter-ep together. Or do all cruising at 2" then re-visit with 1.25"

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Jon Isaacs
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA

Re: 2 inch or not 2 inch? - that is the question new

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[Re: MarcusE]
#5246872 - 05/30/12 08:02 AM

Marcus

I think you should also be considering a 2 inch Widefield around 30mm, in my f/5 Newtonians this is a real workhorse, you would get a TFoV of about 3 degrees.

As far as swapping between 1.25 and 2 inch eyepieces, I find its not an issue, it takes a moment but it'd easy

Jon

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archer1960
sage

Reged: 07/26/11

Re: 2 inch or not 2 inch? - that is the question new

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[Re: Jon Isaacs]
#5246878 - 05/30/12 08:13 AM

I only have one 1.25" eyepiece I use with any regularity on my AT6RC, and I just leave it in the 2" to 1.25" adapter on nights that I'm using it, so swapping doesn't take any longer than changing any other eyepiece. Finding focus again is an entirely different matter, however; that 1.25 is nowhere near parfocal with my 2" eyepieces.

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HCR32
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Reged: 08/27/10

Loc: Australia

Re: 2 inch or not 2 inch? - that is the question new

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[Re: archer1960]
#5246900 - 05/30/12 08:38 AM

I'm not a fan of changing 2inch to 1.25inch while observing, but if you had to choose I'd pick the ep that had the widest field with the highest mag.

TV 31mm I reckon is the best wide field ep for a wow factor!

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Jon Isaacs
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Re: 2 inch or not 2 inch? - that is the question new

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[Re: HCR32]
#5246927 - 05/30/12 08:59 AM

Quote:

I'm not a fan of changing 2inch to 1.25inch while observing, but if you had to choose I'd pick the ep that had the widest field with the highest mag.

TV 31mm I reckon is the best wide field ep for a wow factor!

I swap back and forth many times during an evening... It's definitely worth the effort.

The 31 mm Nagler is my favorite but it is expensive and heavy, over 2 pounds. There are other similar focal length eyepieces that are more practical.

Jon

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MarcusE
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Reged: 02/06/11

Loc: Iowa

Re: 2 inch or not 2 inch? - that is the question new

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[Re: Jon Isaacs]
#5247220 - 05/30/12 12:25 PM

From the several responses so far, it looks like a draw on whether to use a 2” or not. I am getting the idea that swapping out is not too big of a deal… and I like the idea of just leaving it in the 2” ep adapter for the night.

- So what percentage of time do you use your 2” eyepieces?
- Is this a frivolous purchase right now? Or would my money be better spent on something else? (see below)
- What should I expect from a 2” over a similar focal length 1.25” eyepiece? (besides FOV? Can I get that with the 1.25”? Or is that why you want a 2” ep?)

Unfortunately, the Televues are out of my current price range (which is why I’m considering the sale items)… and I think I would be better served in the long run to save up for a better, and of course, bigger ‘scope.

Thanks for your thoughts so far!

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craytab
Carpal Tunnel

Reged: 06/10/11

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Re: 2 inch or not 2 inch? - that is the question new

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[Re: MarcusE]
#5247363 - 05/30/12 02:04 PM

I'm assuming your scope has a 2" focuser with a 1.25" adapter in it. If not, this whole conversation would be moot in that you should go for the 24mm ES 68.

I think everyone should have at least one 2" low mag widefield EP. I have 2, the ES 82 24mm and a Meade 5k SWA 40mm (same as the ES 68 series). I use both frequently. Switching back and forth is no different than switching between different FL 1.25" EPs and is absolutely worth it.

I am with Jon in that you may want to go a little lower in mag. Perhaps the ES 68 34mm or the ES 82 30mm, though the 68 28mm would probably do just fine.

With a 2" EP you can achieve a wider FOV compared to a similar FL 1.25". Further, when comparing 2" and 1.25" EPs with similar FOVs, if the 2" is a widefield the magnification can be higher which will result in a smaller Exit Pupil often making the background sky darker which will make faint fuzzies pop out a little more.

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David Knisely
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Re: 2 inch or not 2 inch? - that is the question new

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[Re: MarcusE]
#5247574 - 05/30/12 04:12 PM

Quote:

From the several responses so far, it looks like a draw on whether to use a 2” or not. I am getting the idea that swapping out is not too big of a deal… and I like the idea of just leaving it in the 2” ep adapter for the night.

- So what percentage of time do you use your 2” eyepieces?
- Is this a frivolous purchase right now? Or would my money be better spent on something else? (see below)
- What should I expect from a 2” over a similar focal length 1.25” eyepiece? (besides FOV? Can I get that with the 1.25”? Or is that why you want a 2” ep?)

Unfortunately, the Televues are out of my current price range (which is why I’m considering the sale items)… and I think I would be better served in the long run to save up for a better, and of course, bigger ‘scope.

Thanks for your thoughts so far!

I have three 2" barrel eyepieces and use them about half of the time in my 14 inch Newtonian. The 2" eyepiece that probably gets the most use is my 14mm ES100, followed by my 2" 36mm Hyperion Aspheric and then my 1.25" 24mm Panoptic (although if I had a 24mm wide-field 2" barrel eyepiece, I would use that instead of the 24 Pan). For higher powers (focal lengths under 14mm), I would go with my 1.25" barrel eyepieces. Clear skies to you.

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Tony Flanders
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Re: 2 inch or not 2 inch? - that is the question new

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[Re: MarcusE]
#5247824 - 05/30/12 06:41 PM

Quote:

From the several responses so far, it looks like a draw on whether to use a 2” or not. I am getting the idea that swapping out is not too big of a deal… and I like the idea of just leaving it in the 2” ep adapter for the night.

Swapping in and out certainly isn't a big deal. I always leave the adapter on the last 1.25-inch eyepiece that I used -- which often as not is also going to be the next one that I use. But it takes just a few seconds to swap from one 1.25-inch EP to another.

Quote:

So what percentage of time do you use your 2” eyepieces?

On my 7-inch f/5.4 and 12.5-inch f/5 Dobs, I'm swapping back and forth constantly. I really like low-power views a lot! Total percentage of time spent with the 2-inch eyepieces is undoubtedly small, well under 20%. But it's a very important 20%.

Quote:

Is this a frivolous purchase right now?

I would say that it is neither frivolous nor essential. You absolutely will see a lot more than a 24-mm widefield than a 32-mm Plossl due to the higher magnification. And the extra field of view of a wide-field in the 28- to 40-mm range opens up whole new worlds. Nonetheless, a 32-mm Plossl is a mighty nice eyepiece!

For what it's worth, I use a 30-mm Ultima (almost the same as a 32-mm Plossl) on my 70-mm refractor, which doesn't take 1.25-inch eyepieces. I keep thinking of getting a 24-mm wide-field to replace it, and keep deciding it's not worth the money.

That's partly because a 27-mm Panoptic is the workhorse on my 12.5-inch f/5 Dob. And I just can't justify owning two eyepieces so similar as the 24-mm and 27-mm Panoptics.

Quote:

What should I expect from a 2” over a similar focal length 1.25” eyepiece?

Field of view -- that's all. There's no inherent difference between 1.25-inch and 2-inch eyepieces except physical size. As far as optical quality is concerned, barrel size is totally irrelevant.

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csrlice12
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Reged: 05/22/12

Loc: Denver, CO

Re: 2 inch or not 2 inch? - that is the question new

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[Re: Tony Flanders]
#5247860 - 05/30/12 07:15 PM

You might consider the ES68 24mm, which now comes in 1.25" format and save going to 2" altogether, believe they were less than $125 at the NEAF sale.

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Matt2003
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Reged: 04/22/10

Re: 2 inch or not 2 inch? - that is the question new

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[Re: csrlice12]
#5247872 - 05/30/12 07:25 PM

I have a 2 inch Q70 EP from Orion, switching it out from the 1.25 adapter is a piece of cake. It gets a lot of use in the Summer, as the central Milky Way draws nigh. I can hardly wait! LOL
Oh btw, its 32mm. I would say get at least one just for sweeping starfields. Nothing is more fun that doing that with the Q70 in my 8 inch Dob.

Clear Skies,
Matt

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SeattleScott
scholastic sledgehammer

Reged: 10/14/11

Re: 2 inch or not 2 inch? - that is the question new

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[Re: Matt2003]
#5248252 - 05/31/12 12:13 AM

Just remember his Dob is an F6 which will work better for the Q70. Not that I haven't seen people use these ep's with F5's before but the ES will work better in the faster scope. And the ES are better quality than the Meade 4k plossls (I would know). One consideration is that over time you could replace your other plossls with Hyperions or other ep's that have both barrel sizes, giving you more eye relief and wider FOV and eliminating the need to use the adapter. You won't want to ditch the ES 11 but you could just leave your adapter on that eyepiece.

The ES 24mm 82 would be a fine ep for that scope, giving good mag with a wide FOV while not being terribly heavy. But it may not be on sale now. Nice thing about getting a 24mm is then you could skip straight to the ES 11mm since it would be roughly 2x the magnification. The ES24 68 wouldn't even require an adapter.

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archer1960
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Reged: 07/26/11

Re: 2 inch or not 2 inch? - that is the question new

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[Re: MarcusE]
#5248440 - 05/31/12 07:46 AM

Quote:

...

- So what percentage of time do you use your 2” eyepieces?

...

Unfortunately, the Televues are out of my current price range (which is why I’m considering the sale items)… and I think I would be better served in the long run to save up for a better, and of course, bigger ‘scope.

Thanks for your thoughts so far!

Most of the time I have my camera attached to the scope. When I am using eyepieces, the 2" ones are on it probably 80% of the time. The single 1.25" EP is just too much mag for the scope in most conditions.

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MarcusE
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Reged: 02/06/11

Loc: Iowa

Re: 2 inch or not 2 inch? - that is the question new

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[Re: archer1960]
#5248857 - 05/31/12 01:09 PM

Wow, this has been very interesting with lots of good ideas and advice. Thanks!
I am going to go for the 2” ES68 - 28mm.

Here’s another can of worms – how do the Hyperions perform in an F/5 telescope? I like the idea of their longer eye relief (I wear glasses) combined with their 1.25” and 2” barrels. Do other eyepieces exist which have both barrel sizes?

On a side note, it is interesting that wider AFoV eyepieces have a larger FoV and greater magnification in shorter focal lengths than the Plossls.

Cheers!

Marcus

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spaceoddity
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Re: 2 inch or not 2 inch? - that is the question new

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[Re: MarcusE]
#5248995 - 05/31/12 02:37 PM

Are you not staisfied with the 32 plossl? 2.06* is a pretty big chunk of the sky and large enough to fit the pleiades and pretty much any object other than a few large extended nebulae. Switching between 2" ep and 1.25 isn't a big deal. The ES68 28 would be a modest upgrade over a 32 plossl. Is it worth it? Well that's up to the buyer.

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craytab
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Reged: 06/10/11

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Re: 2 inch or not 2 inch? - that is the question new

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[Re: MarcusE]
#5249093 - 05/31/12 03:32 PM

Quote:

Here’s another can of worms – how do the Hyperions perform in an F/5 telescope? I like the idea of their longer eye relief (I wear glasses) combined with their 1.25” and 2” barrels. Do other eyepieces exist which have both barrel sizes?

I had a Hyp 21mm. Please note that this is not the best of the group (those would be the 17mm and 13mm I believe). It was not near as sharp to the edge as my ES EPs at F/4.7. There was also some slight brightening at the edges. These are common complaints with these EPs though many don't see these things and like the line quite well, especially if glasses are needed for viewing. Also, I could not achieve focus when using it as a 2" in my XT10i. Don't know why and I didn't fiddle with it to see what was up.

In general, I think if you can get away with less ER the ES EPs will be a much better value. YMMV.

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Jon Isaacs
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Re: 2 inch or not 2 inch? - that is the question new

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[Re: spaceoddity]
#5249117 - 05/31/12 03:45 PM

Quote:

Are you not staisfied with the 32 plossl? 2.06* is a pretty big chunk of the sky and large enough to fit the pleiades and pretty much any object other than a few large extended nebulae. Switching between 2" ep and 1.25 isn't a big deal. The ES68 28 would be a modest upgrade over a 32 plossl. Is it worth it? Well that's up to the buyer.

The Pleiades barely fit in a 2 degree field of view, they are much better to my eye in a larger field of View.

But the advantages of a larger field of view come if you move away from the viewing a single object paradigm and look at multiple objects as well as the details of star fields and fields of nebulosity such as the Milky Way. That is when 2 inch widefields with a longer focal length are at their best.

Jon

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Gary Riley
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Re: 2 inch or not 2 inch? - that is the question new

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[Re: Jon Isaacs]
#5249634 - 05/31/12 10:15 PM

I have the 21mm, 13mm, 8mm and the 5mm Hyperions and I enjoy them quite a lot! I use the 21, 13, & 8 most of the time. I find them to work quite well in my 12 inch f/5 dob.

When using them in the 2inch mode you may have to leave them approx. 1/4 inch out of the focuser to be able to bring the object to proper focus. But overall I think they are a good quality eyepiece for the price.

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PhilCo126
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Re: 2 inch or not 2 inch? - that is the question [Re: Gary Riley]
#5251940 - 06/02/12 12:04 PM

After 20 years of observing I only have 6 eyepieces: 4 1.25 inch and 2 2.0 inch... So yes You should invest in 1 or 2 good 2.0 inch eyepieces

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