Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Eyepieces

Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | (show all)
gatorengineer
Carpal Tunnel
*****

Reged: 02/28/05

Loc: Hellertown, PA
Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: bsim]
      #5676558 - 02/12/13 08:39 PM

reviews on the 25 x 100?, and I have the 9MM 120, and its sharp pretty much to the edge....

Post Extras: Print Post   Remind Me!   Notify Moderator  
leviathan
sage


Reged: 11/29/11

Loc: Azerbaijan
Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: gatorengineer]
      #5676909 - 02/13/13 01:01 AM

Quote:

reviews on the 25 x 100?



Not yet, but here is another topic with discussions about this EP:

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Board/Eyepieces/Num...


Post Extras: Print Post   Remind Me!   Notify Moderator  
Shneor
scholastic sledgehammer
*****

Reged: 03/01/05

Loc: Northern California
Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: leviathan]
      #5677905 - 02/13/13 03:49 PM

I've had a chance to use this eyepiece a couple of times in the field. Both times conditions were mediocre. Coma is evident in the outer 20% of the radius, though maybe less than I'd expect. The field of view is 1.1 degrees for me, which is excellent for large, bright groups (galaxy trios, for example), and also for extended objects like the Rosette (with an H-Beta filter). But contrast is noticeably better in my 20mm ES100°. M42 almost filled the field using an NPB filter. This is not a good finder eyepiece for me, as I often look for relatively faint objects, but there are some objects or groups that it frames better than any other eyepiece I have ever used on my 22". Is it worth the price? Definitely, if you have an SCT, Mak or long focal length refractor. Or if you are an eyepiece junkie...

Post Extras: Print Post   Remind Me!   Notify Moderator  
turtle86
Pooh-Bah Everywhere Else
*****

Reged: 10/09/06

Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: Shneor]
      #5678494 - 02/13/13 10:29 PM

Quote:

I've had a chance to use this eyepiece a couple of times in the field. Both times conditions were mediocre. Coma is evident in the outer 20% of the radius, though maybe less than I'd expect. The field of view is 1.1 degrees for me, which is excellent for large, bright groups (galaxy trios, for example), and also for extended objects like the Rosette (with an H-Beta filter). But contrast is noticeably better in my 20mm ES100°. M42 almost filled the field using an NPB filter. This is not a good finder eyepiece for me, as I often look for relatively faint objects, but there are some objects or groups that it frames better than any other eyepiece I have ever used on my 22". Is it worth the price? Definitely, if you have an SCT, Mak or long focal length refractor. Or if you are an eyepiece junkie...




I'm wondering how much a Paracorr would help with the coma on this eyepiece. A bit, I would suspect...


Post Extras: Print Post   Remind Me!   Notify Moderator  
Fred1
Carpal Tunnel
*****

Reged: 09/19/07

Loc: Somewhere in the Orion Spur
Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: turtle86]
      #5678715 - 02/14/13 02:27 AM

Quote:

Quote:

I've had a chance to use this eyepiece a couple of times in the field. Both times conditions were mediocre. Coma is evident in the outer 20% of the radius, though maybe less than I'd expect. The field of view is 1.1 degrees for me, which is excellent for large, bright groups (galaxy trios, for example), and also for extended objects like the Rosette (with an H-Beta filter). But contrast is noticeably better in my 20mm ES100°. M42 almost filled the field using an NPB filter. This is not a good finder eyepiece for me, as I often look for relatively faint objects, but there are some objects or groups that it frames better than any other eyepiece I have ever used on my 22". Is it worth the price? Definitely, if you have an SCT, Mak or long focal length refractor. Or if you are an eyepiece junkie...




I'm wondering how much a Paracorr would help with the coma on this eyepiece. A bit, I would suspect...





Agreed, my Ethos eps without a Paracorr all show coma in my 18" F/4.3, as does my TV 31NT5. With a Paracorr the views are gorgeous, as they are, also, with my 20mm ES 100°. Note that in the referenced CN thread a few posts back, Don Pensack's (Starman1) post of 1/10/13 says, "...the image was fairly sharp right near the edge" when using it in daytime in a TV NP101 apo at 22x. The TFOV of 4.63° would seem telling but that wasn't on a starfield.
Also, I would expect the 20mm to have better contrast than a 25mm given the greater magnification.


Post Extras: Print Post   Remind Me!   Notify Moderator  
FastMike
sage


Reged: 09/22/10

Loc: Florida 27° 15' N
Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: gatorengineer]
      #5679293 - 02/14/13 11:55 AM

Quote:

reviews on the 25 x 100?, and I have the 9MM 120, and its sharp pretty much to the edge....




I had the ES25 out a few times in various scopes.

For edge of field sharpness I rank it as follows:

1. 21 Ethos
2. 31 Nagler
3. 25 ES

The 25ES was very good near the field stop but the 21E and 31N were both better.

I also noted no problems with the edge of field illumination of the 25ES. Using a defocued star, the ES25 was comparable to the 31N.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Shneor
scholastic sledgehammer
*****

Reged: 03/01/05

Loc: Northern California
Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: turtle86]
      #5679777 - 02/14/13 03:47 PM

Quote:

Quote:

I've had a chance to use this eyepiece a couple of times in the field. Both times conditions were mediocre. Coma is evident in the outer 20% of the radius, though maybe less than I'd expect. The field of view is 1.1 degrees for me, which is excellent for large, bright groups (galaxy trios, for example), and also for extended objects like the Rosette (with an H-Beta filter). But contrast is noticeably better in my 20mm ES100°. M42 almost filled the field using an NPB filter. This is not a good finder eyepiece for me, as I often look for relatively faint objects, but there are some objects or groups that it frames better than any other eyepiece I have ever used on my 22". Is it worth the price? Definitely, if you have an SCT, Mak or long focal length refractor. Or if you are an eyepiece junkie...




I'm wondering how much a Paracorr would help with the coma on this eyepiece. A bit, I would suspect...



Yhis is a pretty heavy eyepiece, weighs at least 2.2 pounds. Using a Paracorr adds more weight and has the eyepiece sticking out about 7 or 8 inches. That makes it a bit difficult to use. Worth it, I guess, if coma bothers you.


Post Extras: Print Post   Remind Me!   Notify Moderator  
turtle86
Pooh-Bah Everywhere Else
*****

Reged: 10/09/06

Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: Shneor]
      #5680392 - 02/14/13 11:14 PM

Quote:

Yhis is a pretty heavy eyepiece, weighs at least 2.2 pounds. Using a Paracorr adds more weight and has the eyepiece sticking out about 7 or 8 inches. That makes it a bit difficult to use. Worth it, I guess, if coma bothers you.




Seems there are always tradeoffs. I don't mind using the Paracorr with the 21mm Ethos or 31mm Nagler, so I probably wouldn't mind it with the 25mm ES. But that's about my limit--a while back I tried observing with a Paracorr + Powermate + Ethos but quickly found that trio to be quite unwieldly. Of course dropping the Powermate meant getting more Ethos...


Post Extras: Print Post   Remind Me!   Notify Moderator  
PolarBearCO
member


Reged: 01/25/13

Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: Jeff Black]
      #5682119 - 02/15/13 06:32 PM

Quote:

There are quite a few 2" EPs over 21mm. I have a TeleVue 35mm Panoptic. I have 42mm and 50mm 2" EPs ordered and on the way now.




I was considering ordering a few EPs over 30mm but read a thread about exit pupil and someone suggested to that person that they exit pupil would be too big to be "favorable."

I have a Zhumell Z10. 1250mm. I don't the forula for figuring exit pupil, but the thread was for a similar scope.

What do you think?


Post Extras: Print Post   Remind Me!   Notify Moderator  
PolarBearCO
member


Reged: 01/25/13

Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: Darenwh]
      #5682124 - 02/15/13 06:35 PM

Quote:

Actually the 5.5mm will be out close enough to my wife's birthday that I could buy it for her!!




That reminds me of a Simpsons' episode where Homer wanted a new bowling ball, so he bought one for his wife, Marge, for her birthday knowing she wouldn't want it. He already had drilled it for his hands and had "Homer" enscribed on it, so she was able to see through his thoughtless and selfish gift. Hahaha.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Dick Jacobson
scholastic sledgehammer


Reged: 12/22/06

Loc: Plymouth, Minnesota, USA
Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: PolarBearCO]
      #5682227 - 02/15/13 07:39 PM

Quote:

I was considering ordering a few EPs over 30mm but read a thread about exit pupil and someone suggested to that person that they exit pupil would be too big to be "favorable."

I have a Zhumell Z10. 1250mm. I don't the forula for figuring exit pupil, but the thread was for a similar scope.

What do you think?



One way to figure the exit pupil is to divide the focal length of the eyepiece by the focal ratio of the telescope. If your Zhumell Z10 is f/5 focal ratio, then a 30mm eyepiece would have an exit pupil of 30/5 = 6 mm. Since most people middle-aged or older have pupil sizes of around 5 mm, some light would be wasted in this case. The eyepiece might still be useful for its wide field of view despite the stars being a little dimmer. Tele-vue recommends not using an exit pupil over 7.5 mm.


Post Extras: Print Post   Remind Me!   Notify Moderator  
rodster
newbie


Reged: 01/08/09

Re: 25mm ES 100* confirmed? sale date? preorder? [Re: star drop]
      #5683116 - 02/16/13 10:07 AM

Just had first light last night (between clouds & moon) using a 18 UC Obsession with paracorr. Conditions were not great but allowed time to compare the ES 25 and the Nagler 31, the ES 25 is very comfortable to use, the eye lens is like a movie screen providing a very immersive view, field stop is well defined but I would stop short calling it crisp. Compared to the nagler the field of view was ery similar. The best part was the contrast was much better on the ES 25 (smaller exit pupil). my nagler was giving me a washed out appearance probably due to my aging (64) year old pupils. So objects like the double cluster and galaxies were popping out and much more detailed (same FOV and greater magnification). Stars were crisp of axis basically the same ad the 31 nagler. I also have the ES 20 and the ES 25 views are similar as far as of axis goes, not perfect but very useable, I can focus on a star out on the peripheral view and not loose much focus as the same star is moved to the center. Very similar to all my naglers and ES eyepieces. The only time I felt I was missing the 31 nagler was on the rosette nebula using a filter, here the greater light gathering power of the nagler produced a brighter rendering if the nebulous area but the FOV was similar. I am not a professional, but my viewing was much enhanced using the ES 25 over the nagler 31, the ES 25 is very easy to view through, even relaxing & it will for sure be in my focuser a good share of the time. I highly recommend this EP! Nice work ES!

Post Extras: Print Post   Remind Me!   Notify Moderator  
Fred1
Carpal Tunnel
*****

Reged: 09/19/07

Loc: Somewhere in the Orion Spur
Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: rodster]
      #5684079 - 02/16/13 07:05 PM

Welcome to Cloudy Nights, rodster. I very much appreciate your post as I've had my eye on the ES 25mm 100° for the exact reasons that you described in your comparison with the TV31NT5. I had presumed that if the ES25mm was designed correctly that it would be a very nice complement to the 82° AFOV and longer focal length of the 31. You've helped keep it on my short list for new purchases.
Clear and dark skies.


Post Extras: Print Post   Remind Me!   Notify Moderator  
turtle86
Pooh-Bah Everywhere Else
*****

Reged: 10/09/06

Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: rodster]
      #5684373 - 02/16/13 10:46 PM

Thanks for your post, Rodster, and welcome to Cloudy Nights. The 25mm ES 100 sounds promising indeed. I was just curious about which Paracorr setting works best for the 25mm ES 100. I know that the 31mm Nagler and 21mm Ethos perform best with the tunable top all the way in...

Post Extras: Print Post   Remind Me!   Notify Moderator  
bleep
super member
*****

Reged: 08/06/12

Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: turtle86]
      #5684884 - 02/17/13 10:15 AM

I just noticed there is one on eBay from high point scientific for $599 plus $5.90 shipping actually says 2 available much to much for me just throwing it out there in case some are interested

Post Extras: Print Post   Remind Me!   Notify Moderator  
Fred1
Carpal Tunnel
*****

Reged: 09/19/07

Loc: Somewhere in the Orion Spur
Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: bleep]
      #5685152 - 02/17/13 12:46 PM

Quote:

I just noticed there is one on eBay from high point scientific for $599 plus $5.90 shipping actually says 2 available much to much for me just throwing it out there in case some are interested




Skip ebay and buy directly from Highpoint's website for free shipping.


Post Extras: Print Post   Remind Me!   Notify Moderator  
careysub
Carpal Tunnel
*****

Reged: 02/18/11

Loc: Rancho Cucamonga, CA
Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: Dick Jacobson]
      #5685771 - 02/17/13 07:14 PM

Quote:

Quote:

I was considering ordering a few EPs over 30mm but read a thread about exit pupil and someone suggested to that person that they exit pupil would be too big to be "favorable."

I have a Zhumell Z10. 1250mm. I don't the forula for figuring exit pupil, but the thread was for a similar scope.

What do you think?



One way to figure the exit pupil is to divide the focal length of the eyepiece by the focal ratio of the telescope. If your Zhumell Z10 is f/5 focal ratio, then a 30mm eyepiece would have an exit pupil of 30/5 = 6 mm. Since most people middle-aged or older have pupil sizes of around 5 mm, some light would be wasted in this case. The eyepiece might still be useful for its wide field of view despite the stars being a little dimmer. Tele-vue recommends not using an exit pupil over 7.5 mm.




I am 55 and measured my pupils with the hex key method and found it was between 5.5mm and 6.5mm, roughly 6mm.

Other sources indicate that 6mm is common in older people:
http://www.intechopen.com/books/electroretinograms/electroretinograms-and-nor...
http://www.intechopen.com/source/html/17263/media/image2.png

http://calgary.rasc.ca/telescopes/index.htm

It seems the the average approaches 5mm as a limit with increasing age.


Post Extras: Print Post   Remind Me!   Notify Moderator  
rodster
newbie


Reged: 01/08/09

Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: turtle86]
      #5686195 - 02/17/13 11:37 PM

I have the paracorr with tunable top but it is not the newest model, paracorr 1? Anyway I noticed inserting the 25 ES fully into the paracorr would not allow the paracorr travel all the way in, which is my preferred setting for my 31 nagler & the 20mm ES. I just used a setting near the middle of travel and it seemed to work out ok. I would like to try the newest paracorr & see if I can get full range of travel. I will experiment with this next tome out as I only had a couple of hours before it clouded up. Funn EP, can't wait for decent night. Clear skies

Post Extras: Print Post   Remind Me!   Notify Moderator  
leviathan
sage


Reged: 11/29/11

Loc: Azerbaijan
Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: rodster]
      #5686454 - 02/18/13 05:34 AM

Quote:

Just had first light last night (between clouds & moon) using a 18 UC Obsession with paracorr. Conditions were not great but allowed time to compare the ES 25 and the Nagler 31, the ES 25 is very comfortable to use, the eye lens is like a movie screen providing a very immersive view, field stop is well defined but I would stop short calling it crisp. Compared to the nagler the field of view was ery similar. The best part was the contrast was much better on the ES 25 (smaller exit pupil). my nagler was giving me a washed out appearance probably due to my aging (64) year old pupils. So objects like the double cluster and galaxies were popping out and much more detailed (same FOV and greater magnification). Stars were crisp of axis basically the same ad the 31 nagler. I also have the ES 20 and the ES 25 views are similar as far as of axis goes, not perfect but very useable, I can focus on a star out on the peripheral view and not loose much focus as the same star is moved to the center. Very similar to all my naglers and ES eyepieces. The only time I felt I was missing the 31 nagler was on the rosette nebula using a filter, here the greater light gathering power of the nagler produced a brighter rendering if the nebulous area but the FOV was similar. I am not a professional, but my viewing was much enhanced using the ES 25 over the nagler 31, the ES 25 is very easy to view through, even relaxing & it will for sure be in my focuser a good share of the time. I highly recommend this EP! Nice work ES!



Thanks for comparison !


Post Extras: Print Post   Remind Me!   Notify Moderator  
JMW
Pooh-Bah


Reged: 02/11/07

Loc: Nevada
Re: 25mm ES 100* confirmed? sale date? preorder? new [Re: leviathan]
      #5686890 - 02/18/13 12:12 PM

I have done 3 dark sky public outreach events with the 25mm 100* eyepiece. It is an easy to use eyepiece that is great for showing larger objects with a good deal of magnification. It is nice to not have to nudge the scope as often for the public. I have used it on a TEC 140 and C11 EdgeHD. I plan on buying a Paracorr II before the GSSP this summer. I will be using it in an 20 inch F5 Obsession. I will be curious to compare the Nagler 31T5 to the ES25mm 100* in a large dob.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | (show all)


Extra information
15 registered and 31 anonymous users are browsing this forum.

Moderator:  ausastronomer, droid, cbwerner, kkokkolis 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 20283

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics