ICEINSPACE
Most Read Articles
Moon Phase
CURRENT MOON Waning Gibbous
97.5%
The Sun Now
Time Zones
Sydney
1:43 am
Perth
11:43 pm
Auckland
3:43 am
New York*
11:43 am
Paris*
5:43 pm
GMT
3:43 pm




Go Back   IceInSpace > Equipment > Eyepieces, Barlows and Filters

Reply
 
Thread Tools Rate Thread
  #1  
Old 16-02-2018, 03:53 AM
AstroStudentUSQ (Mark)
Registered User

AstroStudentUSQ is offline
 
Join Date: Sep 2017
Location: Adelaide
Posts: 63
Orion LHD Lanthanum 80 degree UWA Eyepieces

Does anyone have first hand experience with the Orion LHD Lanthanum 80 degree UWA eyepieces?

Cannot find an independent review of these eyepieces anywhere!

Claims I am keen to see if they live up to are long eye relief (with large surface lenses - I hate squinting through pin head sized lenses!) and their claim for the Lanthanum eliminating colour fringing (or rather, not unduly introducing it).

Do share your thoughts!

Cheers,
Mark
Reply With Quote
  #2  
Old 16-02-2018, 12:33 PM
Wavytone (Nick)
BigBanger

Wavytone is online now
 
Join Date: Jul 2008
Location: Killara, Sydney
Posts: 3,146
Another type well worth trying are the Vixen SSW, I have 3, all with 20mm eye relief. Much overlooked IMHO and 60% of the price of the LHD ones.
Reply With Quote
  #3  
Old 16-02-2018, 12:37 PM
MortonH's Avatar
MortonH
Deprived of starlight

MortonH is offline
 
Join Date: Nov 2006
Location: Sydney
Posts: 3,041
According to the specs I've seen the SSW have 13mm eye relief.
Reply With Quote
  #4  
Old 16-02-2018, 01:46 PM
Wavytone (Nick)
BigBanger

Wavytone is online now
 
Join Date: Jul 2008
Location: Killara, Sydney
Posts: 3,146
Quote:
Originally Posted by MortonH View Post
According to the specs I've seen the SSW have 13mm eye relief.
Ah yes you're right. Actually doing the maths I don't think anyone makes eyepieces with 80 degree AFoV and 20mm ER, the eye lend would have to be ginormous.
Reply With Quote
  #5  
Old 16-02-2018, 03:11 PM
AstroStudentUSQ (Mark)
Registered User

AstroStudentUSQ is offline
 
Join Date: Sep 2017
Location: Adelaide
Posts: 63
https://www.bintel.com.au/product/or...ide-eyepieces/

20mm Eye relief and 30mm lens diameter for the Orions.


Wavytone, have you noticed any CA in the outer 10% or so of those Vixens? I did read one review that mentioned this, keen to hear of users views on them as this is one of the brands I am closely looking at.

Cheers,
Mark
Reply With Quote
  #6  
Old 16-02-2018, 04:13 PM
Wavytone (Nick)
BigBanger

Wavytone is online now
 
Join Date: Jul 2008
Location: Killara, Sydney
Posts: 3,146
Mark, I acquired a 14mm secondhand and found it to be excellent and bought the 7 and 10mm as well.

I don’t think any eyepiece is perfect and any comparison depends on the eye of the beholder and the specific scope you’re using.

IMHO they’re well worth the outlay. I just wish vixen made one more at about 25mm.

Last edited by Wavytone; 16-02-2018 at 04:25 PM.
Reply With Quote
  #7  
Old 16-02-2018, 05:34 PM
bigjoe (Joe)
Registered User

bigjoe is offline
 
Join Date: Nov 2010
Location: sydney
Posts: 1,143
Quote:
Originally Posted by AstroStudentUSQ View Post
Does anyone have first hand experience with the Orion LHD Lanthanum 80 degree UWA eyepieces?

Cannot find an independent review of these eyepieces anywhere!

Claims I am keen to see if they live up to are long eye relief (with large surface lenses - I hate squinting through pin head sized lenses!) and their claim for the Lanthanum eliminating colour fringing (or rather, not unduly introducing it).

Do share your thoughts!

Cheers,
Mark
If the original Long Perng version comes out it should be much cheaper..they do makes quality gear for sure.

http://www.longperng.com.tw/goods.ph...atId=34&page=1

Also make the lenses for other manufacturers..
Including lenses for 120mm SW ED and ESPRIT line..Quite extraordinary indeed!
bigjoe.
Reply With Quote
  #8  
Old 16-02-2018, 07:10 PM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Location: Lake Macquarie, NSW
Posts: 4,706
Is it actual Lanthanum glass or a Lanthanum coated regular glass, there is a difference. Given the high cost and very limited availability of Lanthanum glass i suspect its just coated.
Reply With Quote
  #9  
Old 16-02-2018, 11:17 PM
Wavytone (Nick)
BigBanger

Wavytone is online now
 
Join Date: Jul 2008
Location: Killara, Sydney
Posts: 3,146
ED elements have to be solid lanthanum glass to be effective - coating is pointless.

And hence the price of the LHD series. Ditto TV Panoptics which also use it, and FWIW the Vixen LVW42 which is huge lump of glass.
Reply With Quote
  #10  
Old 23-02-2018, 10:01 AM
Don Pensack's Avatar
Don Pensack
Registered User

Don Pensack is offline
 
Join Date: Aug 2006
Location: Los Angeles
Posts: 351
Quote:
Originally Posted by AstroStudentUSQ View Post
https://www.bintel.com.au/product/or...ide-eyepieces/

20mm Eye relief and 30mm lens diameter for the Orions.


Wavytone, have you noticed any CA in the outer 10% or so of those Vixens? I did read one review that mentioned this, keen to hear of users views on them as this is one of the brands I am closely looking at.

Cheers,
Mark
80 requires a minimum of 33.6mm of eye lens diameter for 20mm of eye relief
30mm of eye lens diameter and 20mm of eye relief means a maximum of 73.7 apparent field.
If these eyepieces do indeed have an apparent field of 80 then the eye relief is really 17.9mm. That's still pretty long for an 80 eyepiece.

If you want to work the math for yourself:
tan0.5ApparentField = 0.5lens diameter / eye relief

One adjustment to that: the depth of the concavity of the eye lens is added to the eye relief so calculated. If the LHD has an eye lens that is 1mm concave, then eye relief could be 18.9mm.
If the eye lens is convex, the convexity amount is subtracted from the calculated eye relief.
Reply With Quote
  #11  
Old 23-02-2018, 10:05 AM
Don Pensack's Avatar
Don Pensack
Registered User

Don Pensack is offline
 
Join Date: Aug 2006
Location: Los Angeles
Posts: 351
Quote:
Originally Posted by Wavytone View Post
ED elements have to be solid lanthanum glass to be effective - coating is pointless.

And hence the price of the LHD series. Ditto TV Panoptics which also use it, and FWIW the Vixen LVW42 which is huge lump of glass.
Well, coating isn't pointless, but it isn't lanthanum glass, either.
I'm sure these are broadband anti-reflection coating (BBAR)
For coatings to be effective, they do have to match the refractive index of the glass, however.
Reply With Quote
  #12  
Old 23-02-2018, 02:57 PM
AstroStudentUSQ (Mark)
Registered User

AstroStudentUSQ is offline
 
Join Date: Sep 2017
Location: Adelaide
Posts: 63
Excellent points and very useful info re-equation, thank you Don!

Cheers,
Mark


Quote:
Originally Posted by Don Pensack View Post
80 requires a minimum of 33.6mm of eye lens diameter for 20mm of eye relief
30mm of eye lens diameter and 20mm of eye relief means a maximum of 73.7 apparent field.
If these eyepieces do indeed have an apparent field of 80 then the eye relief is really 17.9mm. That's still pretty long for an 80 eyepiece.

If you want to work the math for yourself:
tan0.5ApparentField = 0.5lens diameter / eye relief

One adjustment to that: the depth of the concavity of the eye lens is added to the eye relief so calculated. If the LHD has an eye lens that is 1mm concave, then eye relief could be 18.9mm.
If the eye lens is convex, the convexity amount is subtracted from the calculated eye relief.
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 01:43 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Advertisement
SkyWatcher WiFi Adaptor
Advertisement
Lunatico Astronomical
Advertisement
Atik Horizon
Advertisement
SkyWatcher 2018 Catalogue
Advertisement
Interest Free Finance
Advertisement
OzScopes Authorised Dealer
Advertisement
NexDome Observatories
Advertisement
Bintel
Advertisement
FLI Cameras and Imaging Accessories
Advertisement
Astronomy and Electronics Centre
Advertisement