Jump to content


Photo

Eyepieces for outreach?

  • Please log in to reply
40 replies to this topic

#1 Diana N

Diana N

    Sputnik

  • -----
  • Posts: 45
  • Joined: 10 Jul 2012
  • Loc: Nebraska

Posted 07 August 2012 - 08:55 AM

I'm looking for recommendations for some nice, moderately-priced eyepieces to use at public outreach programs and star parties. Until now I've been using Brandons, but I'm planning in the not-too-distant future to start bringing a larger Dobsonian (either 8" or 10") instead of my small refractor, and I'd really prefer not to use ultra-pricey, super-ultra-premium eyepieces at a public event. Who want to clean fingerprints (or worse!) off of a $400 eyepiece?

So, I'm looking for suggestions for what moderately-priced eyepieces you'd suggest. The 10" dob is an f/5, the 8" dob's an f/5.7, and the refractor's an f/7, so none of the scopes are overly fast. Would some of the Orion plossls be a reasonable choice? What say you all?

#2 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 44751
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 07 August 2012 - 09:54 AM

I'm looking for recommendations for some nice, moderately-priced eyepieces to use at public outreach programs and star parties. Until now I've been using Brandons, but I'm planning in the not-too-distant future to start bringing a larger Dobsonian (either 8" or 10") instead of my small refractor, and I'd really prefer not to use ultra-pricey, super-ultra-premium eyepieces at a public event. Who want to clean fingerprints (or worse!) off of a $400 eyepiece?

So, I'm looking for suggestions for what moderately-priced eyepieces you'd suggest. The 10" dob is an f/5, the 8" dob's an f/5.7, and the refractor's an f/7, so none of the scopes are overly fast. Would some of the Orion plossls be a reasonable choice? What say you all?


First let me welcome you to Cloudy Nights... :jump:

Second... My best eyepieces are a set of Naglers. When I share my scopes with people, I want them to get the best possible views so I use my best.

Finger prints clean off relatively easily but the view of the night sky through a 31mm Nagler, it may last a lifetime.

If I were truly concerned, I would choose eyepieces with more eye relief than Plossls, a 10mm Plossl. Simple widefields...

Jon

#3 tezster

tezster

    Viking 1

  • *****
  • Posts: 817
  • Joined: 14 Jul 2009
  • Loc: Missisauga, Canada

Posted 07 August 2012 - 10:26 AM

Generous eye-relief is the most important consideration for an outreach EP, IMO. Ideally, eyeglass wearers should be able to view through it comfortably, without the need to take their glasses off. This also minimizes the amount of re-focusing needed between observers. Having a set of parfocal EPs also helps, and for manual/undriven scopes, a reasonably wide FOV.

In short, you want EPs that will minimize that amount of 'fiddling' required by either you or the observer.

#4 csrlice12

csrlice12

    Voyager 1

  • *****
  • Posts: 11492
  • Joined: 22 May 2012
  • Loc: Denver, CO

Posted 07 August 2012 - 11:21 AM

I usually just use my Zhummel 8-24mm zoom. If someone is interested, I'll break out my better eyepieces.

#5 Diana N

Diana N

    Sputnik

  • -----
  • Posts: 45
  • Joined: 10 Jul 2012
  • Loc: Nebraska

Posted 07 August 2012 - 11:41 AM

Thanks, everyone! (And thanks, Jon, for the welcome.) Good points about generous eye relief and parfocality being musts. (And as an eyeglass wearer myself, I'll appreciate not having to whip my glasses on and off all evening as I move between the zero-power finder and the eyepiece.)

Time to go look at some manufacturers' and retailers' websites to see what's out there, I guess. There's so much variety in eyepiece design these days, it makes choosing tough! But who can complain about being spoiled for choice? :)

#6 amicus sidera

amicus sidera

    Skylab

  • *****
  • Posts: 4222
  • Joined: 14 Oct 2011
  • Loc: East of the Sun, West of the Moon...

Posted 07 August 2012 - 11:47 AM

Welcome to Cloudynights, Diana!

While it's not ultra-inexpensive at $60, the Edmund Optics 28mm RKE (link here), their stock number NT30-787, is a wonderful eyepiece for public viewing... it comes with its own rubber eyeguard, which is very useful; many people will be wearing eyeglasses, and you don't want them scratching them on your eyepiece. I always use an eyecup when set up in public.

#7 kfiscus

kfiscus

    Vanguard

  • *****
  • Posts: 2296
  • Joined: 09 Jul 2012
  • Loc: Albert Lea, MN, USA

Posted 07 August 2012 - 12:10 PM

My observing buddy and I do outreach with Meade 24.5 Super-Wide Angle EPs (older series 4K). We use these in Orion 10XTs and Zhumell 12s. Decent eye relief, rubber eyecup, affordable, and most important- expansive views.

I know of one currently for sale on the largest buy&sell website.

#8 Pharquart

Pharquart

    Ranger 4

  • *****
  • Posts: 372
  • Joined: 11 Nov 2009
  • Loc: Southwest Minneapolis Metro

Posted 07 August 2012 - 05:15 PM

I second the recommendation on the Edmund RKE 28mm. I use that in my C8 when doing outreach, typically pointed at Saturn. It has a good combination of magnification (in the 2032mm focal length C8) and eye relief. It's generally easy for general public members to find the right spot to put their eyes.

For my 10" Dob, I use one of the 82* Explore Scientific eyepieces. I use a 24mm for widefield views of the moon, then move to a 14mm version for getting closer. Again, it's easy for people to find where to put their eyes.

The RKE is certainly less expensive than the ES eyepieces, but I have the ES for my own use and found they work very well for outreach.

Brian

#9 Diana N

Diana N

    Sputnik

  • -----
  • Posts: 45
  • Joined: 10 Jul 2012
  • Loc: Nebraska

Posted 08 August 2012 - 07:33 AM

Thanks! I'll definitely check out the Edmund RKE (I didn't know they were still making it) and the Meade Super Wide Angle series. I hadn't heard about the Explore Scientific eyepieces; a whole new set of manufacturers seem to have moved into the field since I last went eyepiece shopping.

#10 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 44751
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 08 August 2012 - 09:13 AM

RKEs might work nicely at F/10 but in Diana's Dobs which are likely F/5 and F/6, the are probably pretty rough around the edges.

Jon

#11 Pinbout

Pinbout

    Cosmos

  • *****
  • Posts: 8267
  • Joined: 22 Feb 2010
  • Loc: You can't see me...

Posted 08 August 2012 - 10:30 AM

I usually just use my Zhummel 8-24mm zoom. If someone is interested, I'll break out my better eyepieces.



:waytogo:

#12 amicus sidera

amicus sidera

    Skylab

  • *****
  • Posts: 4222
  • Joined: 14 Oct 2011
  • Loc: East of the Sun, West of the Moon...

Posted 08 August 2012 - 12:03 PM

RKEs might work nicely at F/10 but in Diana's Dobs which are likely F/5 and F/6, the are probably pretty rough around the edges.

Jon


You'd be surprised at how well they work at those focal ratios, Jon... Below f/5 is a different story, of course, but even there they aren't too bad. They were designed in conjunction with, and for use on, Edmund's 6" f/6 and 8" f/5 reflectors of the late 1970's - and I can attest to the fact that they perform very well indeed on those two instruments.

#13 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 44751
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 08 August 2012 - 12:48 PM

RKEs might work nicely at F/10 but in Diana's Dobs which are likely F/5 and F/6, the are probably pretty rough around the edges.

Jon


You'd be surprised at how well they work at those focal ratios, Jon... Below f/5 is a different story, of course, but even there they aren't too bad. They were designed in conjunction with, and for use on, Edmund's 6" f/6 and 8" f/5 reflectors of the late 1970's - and I can attest to the fact that they perform very well indeed on those two instruments.


Back then there were no Naglers, expectations were quite different. I do have a 15mm RKE, I give it a try in my F/5 scopes.

Jon

#14 amicus sidera

amicus sidera

    Skylab

  • *****
  • Posts: 4222
  • Joined: 14 Oct 2011
  • Loc: East of the Sun, West of the Moon...

Posted 08 August 2012 - 01:00 PM

Ah, but remember, this is for the public... if they have any preconceived expectations at all about what they'll see in the eyepiece, it's likely something resembling a Hubble print. A little edge distortion is the least of our concerns... :grin:

Let me know what you think of that 15mm RKE in your 'scope, Jon...

#15 Pharquart

Pharquart

    Ranger 4

  • *****
  • Posts: 372
  • Joined: 11 Nov 2009
  • Loc: Southwest Minneapolis Metro

Posted 08 August 2012 - 04:48 PM

I'm also using the RKE (at times in a scope below F/5) to show an object in the center of the field, like Saturn or the moon. I'm in too light polluted an area (often literally under a streetlight) to show any starfields that would demand precision at the edge.

Experienced astronomers might look through my RKE on a fast mirror without a Paracorr and gag. Relative newbies like me haven't yet graduated to Naglers or other premium eyepieces. We don't know what we're missing, and usually, neither does the public. Ignorance can be bliss (or at least a lot cheaper).

Brian

#16 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 44751
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 08 August 2012 - 05:07 PM

Ah, but remember, this is for the public... if they have any preconceived expectations at all about what they'll see in the eyepiece, it's likely something resembling a Hubble print. A little edge distortion is the least of our concerns... :grin:

Let me know what you think of that 15mm RKE in your 'scope, Jon...


I will give it a try, the NP-101 at F/5.4 is a good test because it is plenty fast capable of perfection.

As I said, preconceived expectations or whatever, I use my best eyepieces at public views, the ones I would use were I alone. I figure I will give them my best, they may notice or maybe not, but I will...

Jon

#17 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 44751
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 09 August 2012 - 10:43 AM

Ah, but remember, this is for the public... if they have any preconceived expectations at all about what they'll see in the eyepiece, it's likely something resembling a Hubble print. A little edge distortion is the least of our concerns... :grin:

Let me know what you think of that 15mm RKE in your 'scope, Jon...


I will give it a try, the NP-101 at F/5.4 is a good test because it is plenty fast capable of perfection.

As I said, preconceived expectations or whatever, I use my best eyepieces at public views, the ones I would use were I alone. I figure I will give them my best, they may notice or maybe not, but I will...

Jon


I spent about 45 minutes last night with the NP-101, the 15mm RKE and a couple of other eyepieces, the only other 15mm I have is my well worn TeleVue 15mm Widefield, the precursor to Panoptic line. Both provide a nominal 36x.

The RKE field stop is 12.2mm, a 47degree effective AFoV. The TV has a 15.5mm field stop, a 59 degree effective AFoV. I mostly looked at M7 and M6 to determine overall sharpness and transmission, M71 and M56 for picking out a small object from a light polluted sky and the double-double to determine on-axis sharpness.

I would say the RKE did about as well as I expected, maybe a little better. In the widefield, the aberrations were quite apparent, a brighter star near the edge was a line, not unexpected. The TV Widefield is only somewhat better in this regard but it does have a noticeably wider field of view, it's edge is considerably further away...

In the center of the field, the RKE was reasonably sharp but did not have quite the contrast at the limit, in a small pattern, there would be one star that I could see in the WF that was not visible in the RKE. Likewise, M56 and M71, both very difficult to detect in the light polluted sky, were more easily seen in the TV. And the double-double showed elongation in the TV, I never got that with the RKE.

Sure, I was comparing a "premium" eyepiece from almost 30 years ago with a non-premium eyepiece and that showed through in the better field correction and better transmission. I could have made it more dramatic and used the 16mm Nagler Type 2 that I would normally use at an outreach event, then the differences would been much greater.

Conclusion:

For a first time observer at the eyepiece, probably the biggest difference would be the narrower field of view combined with the poor off axis correction.

At first glance, neither of these seem important, we think to ourselves, the center is fine, who looks off-axis... For use in an undriven Dob, both field of view and off-axis correction are of primary importance because most of the time, an inexperienced observer will not be looking on-axis, the object will have drifted away from the center of the field and the larger the field, the sharper the field, the more likely it is that inexperienced observer will be getting a nice, clean, sharp view.

In a driven scope, it probably doesn't matter anywhere near as much.

I probably should have dragged out my 16mm Meade Series 5000 SWA, it's a modern eyepiece that is similar to the TV WF but is better corrected off-axis, seems to have better coatings and offers a wider field of view.

Bottom line:

Doing this comparison and writing up this analysis strengthened my belief in importance of using my best eyepieces for outreach. With an undriven scope, one sure thing is that most of the time, the object will not be centered. Eyepieces that offer widefields that are well corrected, these provide the best chance of someone getting that one unforgettable view.

The 9mm Nagler and the 15mm RKE have identical TFoVs, the Nagler is sharp at the edge, the usable field of view, is considerably wider. In doing outreach, I think there are good reasons for giving them your best.

About the only thing that would make me change my mind was if I felt there was a significant risk of theft... finger prints, they clean off, dropped eyepieces, I would be the one doing the dropping, I have some practice, some experience in both. :)

Jon

#18 Pauls72

Pauls72

    Viking 1

  • *****
  • Posts: 626
  • Joined: 28 Oct 2007
  • Loc: LaPorte, IN

Posted 09 August 2012 - 11:16 AM

Do not use any eyepieces with smooth barrels. Make sure there is a step in the barrel so you can lock the eyepiece into the focuser.

I had a lady pull an eyepiece out of the diagonal on my 4" MCT (even though both thumb screws where tightened down). When I said no, no, no you don't need to touch it, she promptly dropped it on the sidewalk and walked away. Fortunately it was just a cheap plossl.

#19 Pharquart

Pharquart

    Ranger 4

  • *****
  • Posts: 372
  • Joined: 11 Nov 2009
  • Loc: Southwest Minneapolis Metro

Posted 09 August 2012 - 11:37 AM

As I said, preconceived expectations or whatever, I use my best eyepieces at public views, the ones I would use were I alone.

Jon


You and I agree, Jon. I want to present the best view to the public, even at some manageable risk of damage to the eyepieces. However, here's where we differ: the RKE and Explore Scientifics are my best eyepieces.

Brian

#20 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 44751
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 09 August 2012 - 11:46 AM

As I said, preconceived expectations or whatever, I use my best eyepieces at public views, the ones I would use were I alone.

Jon


You and I agree, Jon. I want to present the best view to the public, even at some manageable risk of damage to the eyepieces. However, here's where we differ: the RKE and Explore Scientifics are my best eyepieces.

Brian


Touche... Point taken...

In your C-8 and the 90mm F/10, they are probably ideal eyepieces, less so in your 10 inch Dob.

Jon

#21 Scott in NC

Scott in NC

    80mm Refractor Fanatic

  • *****
  • Administrators
  • Posts: 16705
  • Joined: 05 Mar 2005
  • Loc: NC

Posted 09 August 2012 - 03:37 PM

I had a lady pull an eyepiece out of the diagonal on my 4" MCT (even though both thumb screws where tightened down). When I said no, no, no you don't need to touch it, she promptly dropped it on the sidewalk and walked away. Fortunately it was just a cheap plossl.

:ohmy:

#22 GaryJCarter

GaryJCarter

    Messenger

  • *****
  • Posts: 409
  • Joined: 06 Jun 2009
  • Loc: Fairview, Texas

Posted 09 August 2012 - 09:18 PM

I often use an old Televue 8-24mm zoom, ESP. When employing an undriven mount. It has decent eye relief, its easy to center the eye and the eyecup keeps the eyelashes off the glass.

I also use the Type 4 12mm, 17mm, and 22mm Naglers for the same reasons.

#23 csrlice12

csrlice12

    Voyager 1

  • *****
  • Posts: 11492
  • Joined: 22 May 2012
  • Loc: Denver, CO

Posted 10 August 2012 - 08:11 AM

I second the recommendation on the Edmund RKE 28mm. I use that in my C8 when doing outreach, typically pointed at Saturn. It has a good combination of magnification (in the 2032mm focal length C8) and eye relief. It's generally easy for general public members to find the right spot to put their eyes.

For my 10" Dob, I use one of the 82* Explore Scientific eyepieces. I use a 24mm for widefield views of the moon, then move to a 14mm version for getting closer. Again, it's easy for people to find where to put their eyes.

The RKE is certainly less expensive than the ES eyepieces, but I have the ES for my own use and found they work very well for outreach.

Brian


Yea, people see that old mushroom top ES82 on the side of the scope looking like an engorged tick and it scares them. For others its looking thru the big funny looking eyepiece. But once they've looked.....

Like I said, I usually let the people use the zoom as then they can "play" with it. But, if someone is showing a real interest, I will gladly break out my better eyepieces. My first view of saturn was with a toy Tasco scope in the 60s, and I'll never forget that view; but my first view of the Andromeda Galaxy was with a 10" Dob with a 13mm Nagler, and that was just WOW........
It is truely unfortunate that most public viewing nights are located in light polluted cities, where scopes perform about as poorly as they possibly can. It would be great if we could band together and as the governments and people of the world for an International Dark Sky Night, where, all over the world, the streetlights are turned off and people are asked to keep their lights off where possible. We should encourage people to then walk outside and look up....

#24 Jason B

Jason B

    Proud father of 5!!

  • *****
  • Posts: 6590
  • Joined: 21 Jun 2004
  • Loc: Mid-Michigan

Posted 10 August 2012 - 12:04 PM

Since I mostly image, I don't have any "premium" eyepieces so I use my only ones, mostly in my 111mm APO: 19mm AT Flat Field and 12.5mm-3mm AT LER's.

The LER's have been a great hit. Easy to use, 20mm ER give or take, nice field of view at 55 degrees and nice and sharp. I have been extemely pleased in my own personal use and they have worked great for outreach.

When using the big SCT's at Fox, my 30mm Vixen LV is always a crowd pleaser.

#25 Pauls72

Pauls72

    Viking 1

  • *****
  • Posts: 626
  • Joined: 28 Oct 2007
  • Loc: LaPorte, IN

Posted 10 August 2012 - 03:41 PM

It is truely unfortunate that most public viewing nights are located in light polluted cities, where scopes perform about as poorly as they possibly can.


You would think so, but that's not totally true. We did an out reach event in front of a Walmart a couple of years right when the local school year was starting. So we had tons of kids and their parents stop by.

By our standards the viewing was atrocious due to the light pollution. But most of these kids and people had never looked through a telescope before. So when they got to take a peek at our moon or Jupiter & it's moons or a few other bright objects through a large DOB or SCT there was a lot of jaw dropping in amazement. So a lot of them got that WOW factor, even with all the light pollution.






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics