Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Celestron Omni 32mm and 40mm

Eyepieces Celestron
  • Please log in to reply
15 replies to this topic

#1 Daniel Wood83

Daniel Wood83

    Sputnik

  • -----
  • topic starter
  • Posts: 33
  • Joined: 11 Oct 2021

Posted 16 October 2021 - 08:10 AM

Tried searching the site but didn't find any direct links. If this has been beat like a dead horse, please point me to thread. We are newish still wearing some green. Started in October 2020 with my daughter getting a Gskyer 70400. We had a blast with it. We bought a full line of Celestron Omni 40, 32, 15, 12, 9, 6, 4. All have been good but the 32 and 40.

 

Question is am I doing something wrong or are these just hard to use? There is only one very specific place you see the field otherwise the sides blur bad and almost cover the whole FOV. If you are patient enough the views are nice but it's hard to keep eye in one exact spot. We have used them in 70400 refractor Gskyer, a 70700 refractor Celestron power seeker, a 127x700 Celestron power seeker reflector, and a Celestron Omni 150 reflector.

 

Thanks,

 

Also if the eyepiece is the problem is the Tele Vue 32mm plossl a good one that won't do this. This price is $150 is top of my budget for a fix.


Edited by Daniel Wood83, 16 October 2021 - 08:40 AM.

  • DAG792 likes this

#2 Daniel Wood83

Daniel Wood83

    Sputnik

  • -----
  • topic starter
  • Posts: 33
  • Joined: 11 Oct 2021

Posted 16 October 2021 - 08:40 AM

We don't have this issue with the higher magnification EPs



#3 DAG792

DAG792

    Ranger 4

  • -----
  • Posts: 332
  • Joined: 21 Mar 2020

Posted 16 October 2021 - 08:47 AM

Hello and welcome here,

 

The issue you are facing is because the Plossl eyepiece is a very simple eyepiece. Its eye relief is proportional to its focal length. This means that for longer focal length Plossls, you will have to place your eye quite far away from the eye-lens and still remain along the line of the exit pupil. This can be quite hard and frustrating at times, and I remember suffering from it too when I was a beginner.

 

To be honest, I don't think a Televue 32 mm Plossl will be any different. You will have to change your eyepiece design if you want to solve this immediately. If you want to go this route, then I suggest a Explore Scientific 24 mm(see if you can find any used examples) although it will be pricey. 

 

Although, if you are a bit patient and continue to observe through the telescope; in a small amount of time, your subconscious will get used to the proper eye-placement distance and you will not even have to think about it.


Edited by DAG792, 16 October 2021 - 08:48 AM.

  • Jon Isaacs and Sarkikos like this

#4 Migwan

Migwan

    Mercury-Atlas

  • *****
  • Posts: 2,867
  • Joined: 24 Jul 2017
  • Loc: Meeechigan

Posted 16 October 2021 - 08:47 AM

Eye relief in plossl eyepieces lengthen as the focal length of the eyepiece lengthens.   The eye relief on the 32 is 22mm and the 40mm 31mm.  This can cause difficulties in keeping the exit pupil centered and likely what you are experiencing.

 

The best resolve is to have a good adjustable height viewing chair.  That will help you hold still when you have the exit pupil in view. 


  • Sarkikos and havasman like this

#5 Daniel Wood83

Daniel Wood83

    Sputnik

  • -----
  • topic starter
  • Posts: 33
  • Joined: 11 Oct 2021

Posted 16 October 2021 - 09:47 AM

So the Omni 32mm has a 22mm eye relief, the 15mm has 13mm ER, the Celestron Xcel lx 25mm has ER of 15mm.

Would the Celestron Xcel lx 25mm be a good choice for my budget?
  • Jon Isaacs and bdcmd like this

#6 Daniel Wood83

Daniel Wood83

    Sputnik

  • -----
  • topic starter
  • Posts: 33
  • Joined: 11 Oct 2021

Posted 16 October 2021 - 09:48 AM

I will try some more practice and see if it's any better before jumping on a new EP

#7 SeattleScott

SeattleScott

    Voyager 1

  • *****
  • Posts: 12,414
  • Joined: 14 Oct 2011

Posted 16 October 2021 - 09:52 AM

The Celestron Xcel LX also has an adjustable height eye guard so you can reduce eye relief more if it helps.

In general practice helps with learning eye placement, but yes the Xcel LX should be easier to view through.

Scott
  • Dobs O Fun likes this

#8 Daniel Wood83

Daniel Wood83

    Sputnik

  • -----
  • topic starter
  • Posts: 33
  • Joined: 11 Oct 2021

Posted 16 October 2021 - 10:12 AM

Thanks all for all the input

#9 Mike W

Mike W

    Surveyor 1

  • *****
  • Posts: 1,995
  • Joined: 30 Apr 2006
  • Loc: Upstate NY

Posted 16 October 2021 - 12:00 PM

Tried searching the site but didn't find any direct links. If this has been beat like a dead horse, please point me to thread. We are newish still wearing some green. Started in October 2020 with my daughter getting a Gskyer 70400. We had a blast with it. We bought a full line of Celestron Omni 40, 32, 15, 12, 9, 6, 4. All have been good but the 32 and 40.
 
Question is am I doing something wrong or are these just hard to use? There is only one very specific place you see the field otherwise the sides blur bad and almost cover the whole FOV. If you are patient enough the views are nice but it's hard to keep eye in one exact spot. We have used them in 70400 refractor Gskyer, a 70700 refractor Celestron power seeker, a 127x700 Celestron power seeker reflector, and a Celestron Omni 150 reflector.
 
Thanks,
 
Also if the eyepiece is the problem is the Tele Vue 32mm plossl a good one that won't do this. This price is $150 is top of my budget for a fix.


If you get the TV eye guard extender with the TV32 plossl the problem will go away.

#10 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 96,161
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 16 October 2021 - 12:44 PM

I will try some more practice and see if it's any better before jumping on a new EP

 

:goodjob:

 

Practice and experience can help with sorting out eye placement issues.. an adjustable height observing chair can be a help because your upper body is steady and the eyepiece can be at the exact right height.

 

Jon


  • Sarkikos and vtornado like this

#11 GGK

GGK

    Viking 1

  • *****
  • Posts: 517
  • Joined: 04 Jan 2021
  • Loc: Southwest Florida

Posted 16 October 2021 - 02:21 PM

Tried searching the site but didn't find any direct links. If this has been beat like a dead horse, please point me to thread. We are newish still wearing some green. Started in October 2020 with my daughter getting a Gskyer 70400. We had a blast with it. We bought a full line of Celestron Omni 40, 32, 15, 12, 9, 6, 4. All have been good but the 32 and 40.

 

Question is am I doing something wrong or are these just hard to use? There is only one very specific place you see the field otherwise the sides blur bad and almost cover the whole FOV. If you are patient enough the views are nice but it's hard to keep eye in one exact spot. We have used them in 70400 refractor Gskyer, a 70700 refractor Celestron power seeker, a 127x700 Celestron power seeker reflector, and a Celestron Omni 150 reflector.

 

Thanks,

 

Also if the eyepiece is the problem is the Tele Vue 32mm plossl a good one that won't do this. This price is $150 is top of my budget for a fix.

Daniel Woods83,

 

All good comments above.  I'm guessing that it's simply the longer eye relief that's giving you a challenge. I use a 40mm Omni Plossl and 32mm TeleVue and Denkmeier Plossls.  The typical problem with these is getting too close or weaving from side to side which moves your eye out of the proper position.

 

The eye relief of a Plossl is about 2/3rds the focal length of the eyepiece.  So the 15mm Omni you use has about a 10mm eye relief, which means your eye is close to the eyepiece, and that's helping you with positioning.  Your eye is even closer using the 12 through 4mm.  

 

On the other hand, the 32mm and 40mm Plossls have 22mm and 27mm eye relief and your eye will not be close to the eyepiece, so you have no physical guide for positioning.  Buying a different 32mm Plossl will probably not help, regardless of the brand unless it has some sort of extension that brings a physical eyecup/guard up to your eye.  That's what the TeleVue Extender does for the TV32 and 40mm Plossls. But that's expensive and you can get the same result with your Omni with some creativity.

 

Some people wrap the eyepiece in a piece of black felt or some other soft material to raise the eyecup enough to contact your face.  This can really help teach / maintain good eye position.  Don at EyePieces, Etc - Starman1 on CN - wrote a procedure to use a piece of a bicycle innertube to make a soft extending eyecup.  Search for that or contact Don.

 

My guess is that you'll earn to use the long eye relief Plossls with a little practice and end up liking them very much.  Also, as said above, good body position helps keep your head still so the observing chair mentioned above by Jon is a good accessory.

 

Gary


  • vtornado likes this

#12 Daniel Wood83

Daniel Wood83

    Sputnik

  • -----
  • topic starter
  • Posts: 33
  • Joined: 11 Oct 2021

Posted 28 October 2021 - 10:27 AM

Made a sleeve from black construction paper that fits up to the grip and protrudes above eyepiece 22mm. The view is perfect now. My 7 year old can use it too. Wrapped the outside of paper only with mailing tape
  • izar187, BFaucett, vtornado and 2 others like this

#13 sportsmed

sportsmed

    Viking 1

  • *****
  • Posts: 545
  • Joined: 01 Aug 2012
  • Loc: Hot Springs, AR

Posted 28 October 2021 - 10:10 PM

I have the Omni 32mm and X-Cel LX 25mm, the Omni is sharp but suffers from black out and eye positioning problems. The X-Cel LX 25mm is a good eyepiece for the price if you dont mind the 60o FOV. I use both in my 127mm Mak since I can only use 1.25" EP's with it and they do the job. The 25mm is nice because of the adjustable eye cup though. 



#14 Sarkikos

Sarkikos

    ISS

  • *****
  • Posts: 33,303
  • Joined: 18 Dec 2007
  • Loc: Right Coast of the Chesapeake Bay

Posted 01 November 2021 - 05:33 PM

Tried searching the site but didn't find any direct links. If this has been beat like a dead horse, please point me to thread. We are newish still wearing some green. Started in October 2020 with my daughter getting a Gskyer 70400. We had a blast with it. We bought a full line of Celestron Omni 40, 32, 15, 12, 9, 6, 4. All have been good but the 32 and 40.

 

Question is am I doing something wrong or are these just hard to use? There is only one very specific place you see the field otherwise the sides blur bad and almost cover the whole FOV. If you are patient enough the views are nice but it's hard to keep eye in one exact spot. We have used them in 70400 refractor Gskyer, a 70700 refractor Celestron power seeker, a 127x700 Celestron power seeker reflector, and a Celestron Omni 150 reflector.

 

Thanks,

 

Also if the eyepiece is the problem is the Tele Vue 32mm plossl a good one that won't do this. This price is $150 is top of my budget for a fix.

You must be patient.  You must keep your eye in one exact spot.  :grin:

 

Are you sitting while you observe?  Sitting can help steady your gaze.

 

Mike



#15 kklei940

kklei940

    Vostok 1

  • *****
  • Posts: 129
  • Joined: 04 Aug 2017
  • Loc: Wisconsin

Posted 02 November 2021 - 09:45 AM

So the Omni 32mm has a 22mm eye relief, the 15mm has 13mm ER, the Celestron Xcel lx 25mm has ER of 15mm.

Would the Celestron Xcel lx 25mm be a good choice for my budget?

 

I currently use the Celestron Xcel Lx as my 1.25" finder eyepiece. It gives really nice views and sits in a case with 4 Televue DeLites and a powermate. I will say though it's hard to believe the ER is listed at 15mm. I twist the eyecup all the way down and view very comfortably with my glasses on. The ER feels very similar to my DeLites.

 

Also, I had both the Omni 32mm and Televue 32mm plossl's at the same time and compared them. Both the eye placement and views seemed pretty similar to me. Not sure if you'll gain a whole lot by purchasing the Televue.


  • sportsmed likes this

#16 GGK

GGK

    Viking 1

  • *****
  • Posts: 517
  • Joined: 04 Jan 2021
  • Loc: Southwest Florida

Posted 02 November 2021 - 02:58 PM

Made a sleeve from black construction paper that fits up to the grip and protrudes above eyepiece 22mm. The view is perfect now. My 7 year old can use it too. Wrapped the outside of paper only with mailing tape

That’s fantastic. Thanks for the note of success. 


  • BFaucett likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics





Also tagged with one or more of these keywords: Eyepieces, Celestron



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics