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 | (show all)
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
2013 Buyer's Guide to Eyepieces
      #5698730 - 02/24/13 06:13 PM Attachment (4489 downloads)

The attached spreadsheet includes all non-discontinued after-market eyepieces currently available for sale by retailers.

The manufacturers catalogs are larger, but if no retailer is currently selling a particular eyepiece model, I did not include it on my chart.

All the normal information is included and prices are as I found them over the last month.

If I have inadvertently left off a brand or model, please send me a private message and a link to the website where I can find information. I can always update this.

Note that I purposely left off 0.965" eyepieces, Huygenian, Ramsden, and Super Ramsden eyepieces as I do not believe these would be of interest to people reading posts on Cloudy Nights.

I also left in the Pentax XW eyepieces as we just received word these are discontinued but there are a lot in the retail sales bins and will be for a while.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Paraclete
super member


Reged: 01/15/11

Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5698770 - 02/24/13 06:38 PM

Thanks for all the hard work! That is a very helpful spreadsheet... Thank-you.

And especially good-luck with EyepiecesEtc.com --- You have devoted so much to CloudyNights and to this hobby... you deserve the success.


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

Reged: 11/22/11

Loc: Mendon, MA
Re: 2013 Buyer's Guide to Eyepieces new [Re: Paraclete]
      #5698782 - 02/24/13 06:51 PM

Holy cow! And I only have 100! :-)

With all the rebranded Chinese EP, I wonder how many are optically unique? I guess I have some sorting to do :-)


Post Extras: Print Post   Remind Me!   Notify Moderator  
JimMo
I'd Rather Do It Myself


Reged: 01/08/07

Loc: Under the SE Michigan lightdom...
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5698787 - 02/24/13 06:58 PM

Thanks Don. Very cool.

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

Reged: 08/24/11

Loc: Chattanooga, TN
Re: 2013 Buyer's Guide to Eyepieces new [Re: JimMo]
      #5698816 - 02/24/13 07:32 PM

Don, thanks for all you contribute to Cloudy Nights!

Post Extras: Print Post   Remind Me!   Notify Moderator  
DonsDob
member
*****

Reged: 05/21/12

Loc: CT
Re: 2013 Buyer's Guide to Eyepieces new [Re: mgwhittle]
      #5698829 - 02/24/13 07:44 PM

Excellent! Thank you. I've saved it.

Post Extras: Print Post   Remind Me!   Notify Moderator  
ThomasWos
super member


Reged: 02/10/07

Loc: Bellingham WA
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5698835 - 02/24/13 07:49 PM

Great Work Don! Fantastic reference.

Thanks.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Scott in NCAdministrator
80mm Refractor Fanatic
*****

Reged: 03/05/05

Loc: NC
Re: 2013 Buyer's Guide to Eyepieces new [Re: ThomasWos]
      #5698839 - 02/24/13 07:52 PM

Very nice, Don! That obviously took a lot of work. Thanks for compiling this and sharing it with us.

I'm going to make this into a sticky post so it stays at the top of the forum for a while.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013 Buyer's Guide to Eyepieces new [Re: MRNUTTY]
      #5698867 - 02/24/13 08:14 PM

John,
If an eyepiece from one company looks the same as another company, comes in the same focal lengths, has the same eye relief, and the same coatings........well, it could be a copy, but it's probably just a rebranded eyepiece from the same factory.
It's tough, though, to tell who the actual maker is. Some eyepieces appear to be sold by several different factories, and obviously not all of them make the same identical eyepiece.
The eyecups, barrels, and lenses often come from several different sources, though, and there is rarely a prohibition for, say, an eyecup maker to sell to several companies. So an eyepiece that looks alike may indeed be from two different factories and have some of the same parts.

I'm amazed that the count is 625 fewer eyepieces available now than in 2009. So many companies have stopped doing private label or have left the business entirely.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mariner@sg
sage
*****

Reged: 06/28/12

Loc: Little Red Dot
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5698892 - 02/24/13 08:39 PM

Appreciate all the hard work and effort in updating your compilation Don!

Post Extras: Print Post   Remind Me!   Notify Moderator  
audioaficionado
scholastic sledgehammer


Reged: 05/24/12

Loc: Medford, Orygun, USA
Re: 2013 Buyer's Guide to Eyepieces new [Re: Mariner@sg]
      #5700440 - 02/25/13 07:21 PM

Awesome resource. Thanx Don

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

Reged: 12/17/05

Loc: Under the southern horn of the...
Re: 2013 Buyer's Guide to Eyepieces new [Re: audioaficionado]
      #5700475 - 02/25/13 07:48 PM

Wow, Zeiss do a $2000 ortho!

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


Reged: 08/27/12

Loc: Illinois
Re: 2013 Buyer's Guide to Eyepieces new [Re: Sgt]
      #5700510 - 02/25/13 08:14 PM

That was a huge amount of work! Very well done and exceptionally useful. Thanks ever so much!!!

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013 Buyer's Guide to Eyepieces new [Re: Sgt]
      #5700546 - 02/25/13 08:48 PM

Quote:

Wow, Zeiss do a $2000 ortho!



1539 Euros before conversion to dollars (1.36:1) and freight.


Post Extras: Print Post   Remind Me!   Notify Moderator  
MAURITS
scholastic sledgehammer


Reged: 09/22/09

Loc: Belgium
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5701070 - 02/26/13 07:08 AM

Thanks Don for all the useful information!

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


Reged: 11/29/11

Loc: Azerbaijan
Re: 2013 Buyer's Guide to Eyepieces new [Re: MAURITS]
      #5701126 - 02/26/13 08:10 AM

Great work !

Post Extras: Print Post   Remind Me!   Notify Moderator  
Mark9473
Postmaster
*****

Reged: 07/21/05

Loc: 51°N 4°E
Re: 2013 Buyer's Guide to Eyepieces new [Re: leviathan]
      #5703422 - 02/27/13 12:25 PM

Don, your list is a great resource and like many others I've saved a copy immediately.

You have commented repeatedly over the last few weeks how many eyepieces you've had to delete because they've been discontinued.
I was thinkling that it would actually be very useful if you could include a second worksheet with the data of the discontinued models. We are all still using them, and besides they are often traded on the second hand market. It's very useful to be able to compare basic specs such as eye relief, weight, field stop diameter etc.

Many thanks.


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

Reged: 12/27/06

Loc: Boise Idaho
Re: 2013 Buyer's Guide to Eyepieces new [Re: Mark9473]
      #5705169 - 02/28/13 11:42 AM

This is very helpful. Thanks Don!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013 Buyer's Guide to Eyepieces new [Re: Mark9473]
      #5705250 - 02/28/13 12:27 PM

My 2009 version of the Buyer's Guide is still on CN, under:
Eyepieces Forum>>"Best of" Eyepieces Forum>>2nd Post:"Buyers Guide to Eyepieces and Accessories">>2nd post attachment

It would be a simple matter to save that version to look up info on discontinued models.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mark9473
Postmaster
*****

Reged: 07/21/05

Loc: 51°N 4°E
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5705431 - 02/28/13 02:16 PM

Thanks for the pointer Don. Turns out I also had your 2005 version already on file.

Post Extras: Print Post   Remind Me!   Notify Moderator  
rgm40
sage
*****

Reged: 04/15/08

Loc: Western Kentucky
Re: 2013 Buyer's Guide to Eyepieces new [Re: Mark9473]
      #5706084 - 02/28/13 07:48 PM



Post Extras: Print Post   Remind Me!   Notify Moderator  
steveyo
super member


Reged: 03/13/12

Loc: Upstate NY
Re: 2013 Buyer's Guide to Eyepieces new [Re: Mark9473]
      #5707411 - 03/01/13 04:02 PM

Thank you for this amazing list. Are the little TV Zooms (2-4mm and 3-6mm) discontinued? I ask because they're still widely available from retailers.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013 Buyer's Guide to Eyepieces new [Re: steveyo]
      #5707478 - 03/01/13 04:51 PM

Quote:

Thank you for this amazing list. Are the little TV Zooms (2-4mm and 3-6mm) discontinued? I ask because they're still widely available from retailers.



They're in the list between the Ethos and Nagler Type 4's as "Nagler Zooms".
Still made and stocked everywhere.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pollux556
Pooh-Bah
*****

Reged: 12/14/08

Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5707541 - 03/01/13 05:40 PM




Post Extras: Print Post   Remind Me!   Notify Moderator  
steveyo
super member


Reged: 03/13/12

Loc: Upstate NY
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5707715 - 03/01/13 07:57 PM

Quote:

Quote:

Thank you for this amazing list. Are the little TV Zooms (2-4mm and 3-6mm) discontinued? I ask because they're still widely available from retailers.



They're in the list between the Ethos and Nagler Type 4's as "Nagler Zooms".
Still made and stocked everywhere.




Doh! Don't know how I missed'em. Thank you.


Post Extras: Print Post   Remind Me!   Notify Moderator  
faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5710578 - 03/03/13 12:43 PM

Thanks Don!

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

Reged: 12/05/09

Loc: Streetlight Archipelago
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5720388 - 03/08/13 12:04 PM

Don,

Between this and your "Best of Deep Sky" list, it's amazing that you have time for anything else! Keep up the good work!


Post Extras: Print Post   Remind Me!   Notify Moderator  
droidModerator
rocketman
*****

Reged: 08/29/04

Loc: Conneaut, Ohio
Re: 2013 Buyer's Guide to Eyepieces new [Re: uniondrone]
      #5720404 - 03/08/13 12:12 PM

Thanks Don; must have taken a while to put this together.

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

Reged: 08/22/09

Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5751885 - 03/23/13 01:17 PM

Don - Thanks for putting this together. It's a nice presentation of EP's ..... Tony

Post Extras: Print Post   Remind Me!   Notify Moderator  
whiskers1978
member


Reged: 04/15/12

Re: 2013 Buyer's Guide to Eyepieces *DELETED* new [Re: Starman1]
      #5793306 - 04/11/13 09:28 PM

Post deleted by whiskers1978

Edited by whiskers1978 (04/11/13 09:32 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013 Buyer's Guide to Eyepieces new [Re: whiskers1978]
      #5793639 - 04/12/13 12:37 AM

My earlier version of the spreadsheet had calculated columns for magnification, exit pupil, and true field. You just posted your telescopes focal length and f/ratio at the top of the column and the spreadsheet automatically filled everything in.
I'll post instructions for how to add those columns to the spreadsheet tomorrow.


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

Reged: 07/07/10

Loc: Davison, Michigan
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5793698 - 04/12/13 01:38 AM

Thanks a lot Don, this will help plenty of people.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013 Buyer's Guide to Eyepieces new [Re: buddyjesus]
      #5794211 - 04/12/13 11:24 AM Attachment (467 downloads)

OK, I am attaching the 2013 Buyer's Guide to Eyepieces again.

This new version has calculated columns for:
*magnification
*exit pupil
*true field in degrees (you can convert to minutes by multiplying by 60)
All you have to do is insert your telescope's focal length and f/ratio in the two top cells with red lettering.

*NOTE* this will not work with eyepieces that have a range of focal lengths or a range of magnifications. In those fields you will see errors.

Edited by Starman1 (04/12/13 11:29 AM)


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

Reged: 04/05/13

Loc: Desierto de Sonora
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5794613 - 04/12/13 02:21 PM

Thank you Don! Very helpful.

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


Reged: 01/23/12

Loc: Greensboro NC
Re: 2013 Buyer's Guide to Eyepieces new [Re: dpippel]
      #5820985 - 04/24/13 10:32 PM

From one Don to another - thanks

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

Reged: 03/23/11

Loc: smack dab in the middle of the...
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5822976 - 04/25/13 08:18 PM

My Sage Calculus/Photography/Astronomy Instructor from High School....yes small town, but this man is exemplary in all mentioned fields. He uses several film and DSLR 35mms, Also has a Hassleblad 2.25x2.5, and a Linhof Technica 4x5. He has had an extensive color and black and white darkroom since I met him in 1978, and has a 10" Newt that I first saw Saturn, Jupiter and Andromeda through.

I place all of that ahead of what he has recently told me, to establish his "bona fides" in the world of optics, both near, and at great distance. I had always told him from waaaaay back that I wanted a Contax 35mm, because they came with Zeiss lenses, which he always sang the praises of. I believe after that, in the camera world, Rodenstock and Sinar were his Choices...oh and Pentax, though their camera lenses aren't as highly prized as their telescope oculars.

Anyways, He told me just this last fall that Zeiss quality has fallen through the floor. I cannot remember if he said they were bought out, or what happened, and how long they've been sub par. I will contact him this evening or tomorrow to get his insight, but he told me that the people buying newer Zeiss lenses are wealthy impressionable amateurs. If true, it is indeed a shame that the greatest name in lenses has fallen away into the pack....yet still with winner's circle prices.

More to come as I learn, or others contribute.


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

Reged: 12/14/06

Loc: Montreal, Canada
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5914255 - 06/10/13 10:57 PM

Quote:

The attached spreadsheet includes all non-discontinued after-market eyepieces currently available for sale by retailers.

The manufacturers catalogs are larger, but if no retailer is currently selling a particular eyepiece model, I did not include it on my chart.

All the normal information is included and prices are as I found them over the last month.

If I have inadvertently left off a brand or model, please send me a private message and a link to the website where I can find information. I can always update this.

Note that I purposely left off 0.965" eyepieces, Huygenian, Ramsden, and Super Ramsden eyepieces as I do not believe these would be of interest to people reading posts on Cloudy Nights.

I also left in the Pentax XW eyepieces as we just received word these are discontinued but there are a lot in the retail sales bins and will be for a while.




Great stuff
thanks !!


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

Reged: 07/08/04

Loc: New York City
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5923977 - 06/16/13 03:26 PM

Very kool. Thanks for the effort.

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


Reged: 05/13/13

Loc: Michigan
Re: 2013 Buyer's Guide to Eyepieces new [Re: thesubwaypusher]
      #5928833 - 06/19/13 09:07 AM

Great information. I am finding this information very useful. Thanks for sharing.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Maverick199
Postmaster
*****

Reged: 02/27/11

Loc: India
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #5985968 - 07/23/13 12:21 PM

Thank you, very helpful indeed!

Post Extras: Print Post   Remind Me!   Notify Moderator  
wags1
member
*****

Reged: 05/23/13

Loc: PA, USA
Re: 2013 Buyer's Guide to Eyepieces new [Re: Maverick199]
      #5986306 - 07/23/13 03:44 PM

Don,
Just stumbled on this..incredibly useful! Thank you!


Post Extras: Print Post   Remind Me!   Notify Moderator  
GregLee1
professor emeritus


Reged: 07/21/13

Loc: Waimanalo, HI
Re: 2013 Buyer's Guide to Eyepieces new [Re: wags1]
      #5990050 - 07/25/13 06:17 PM

Wanting to try a wide angle EP but being pretty tight, I ordered a "UW80[deg]" (shown on photo) from a Chinese seller on Ebay. It is called "New 1.25" Multi-coated F16mm Untra Wide Angle 80 Degree Telescope Eyepiece". It matches pretty well entry #482 in the spreadsheet: KnightOwl, $44.95 (I paid $68.68, free shipping). I wonder if it is this exact EP.

If it turns out to be really wonderful, I'll post. Otherwise, I might not get back to you.


Post Extras: Print Post   Remind Me!   Notify Moderator  
JustaBoy
Post Laureate
*****

Reged: 06/19/12

Re: 2013 Buyer's Guide to Eyepieces new [Re: GregLee1]
      #5990258 - 07/25/13 08:46 PM

Please tell us that you are just kidding...?

Post Extras: Print Post   Remind Me!   Notify Moderator  
AllanStaib
journeyman


Reged: 10/15/12

What's the difference between planetary and plossl new [Re: Starman1]
      #5999906 - 07/31/13 11:38 AM

Thanks Starman1 for the excellent spreadsheet. I'm curious about the listing of the Meade HD 60 series as "planetary" type eyepieces and the series 4000 Meade eyepieces as plossls. What defines an eyepiece as a planetary? I the the HD series are also plossls so there must be another feature which earns the planetary designation. Thanks for all the information and posts!

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: What's the difference between planetary and plossl new [Re: AllanStaib]
      #6000150 - 07/31/13 02:46 PM

The HD series was billed by both the manufacturer and distributor (Meade) as "planetary" eyepieces. The HD-60s are a 6-element design and may be identical internally to the Celestron X-Cel LX and similar or identical to the Astrotech Paradigms and its 4 or 5 clones (from Orion, Teleskop Service, etc.).
They may be considered general use eyepieces. There is no specific name for the design that I know of. They may all be copies of the TeleVue Radian, which is now discontinued. I used the "planetary" moniker out of convenience.

A Plössl has 4 elements in 2 groups (2 doublets). There are at least 4 different configurations for these 4-element eyepieces, called Plössls or Super Plössls. Unfortunately, there are also some 5-element designs, in a 2:1:2 configuration that are also called Plössls or Super Plössls. They are not Plössls, but more closely resembling Erfles, and may be designed similarly to a WWII design of Carl Zeiss, called the Astroplanokular. And the actual symmetrical design we now call Plössls are not the original design (the "original" may have come from König, it has been argued).

Confusion reigns in design names. Partly, it's that many designers live a long time and have many designs. Albert König had 28 patents for different designs. At least 6 or 7 have been sold as telescope eyepieces, and many more used in binoculars. Eyepieces of 3, 4, 5 and 6 elements have been sold that were designed by König, so what is a König eyepiece?


Post Extras: Print Post   Remind Me!   Notify Moderator  
AllanStaib
journeyman


Reged: 10/15/12

Re: What's the difference between planetary and plossl new [Re: Starman1]
      #6000597 - 07/31/13 09:33 PM

Thanks! You've really gotten me interested in the details of eyepiece design. Are there any publications that go into detail on the various designs? Thanks again!

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: What's the difference between planetary and plossl new [Re: AllanStaib]
      #6000946 - 08/01/13 03:00 AM

Lots!
Start here:
http://www.brayebrookobservatory.org/BrayObsWebSite/BOOKS/EVOLUTIONofEYEPIECE...


Post Extras: Print Post   Remind Me!   Notify Moderator  
GregLee1
professor emeritus


Reged: 07/21/13

Loc: Waimanalo, HI
Re: 2013 Buyer's Guide to Eyepieces new [Re: JustaBoy]
      #6009530 - 08/06/13 01:51 PM

Quote:

Please tell us that you are just kidding...?



No, not kidding. The UW80 eyepiece arrived from China on schedule -- seems fine to me for terrestrial viewing. Stars have to wait for clouds to dissipate (perhaps left over from tropical storm Flossie). Anyhow, relevance to the Guide is that it tells me I probably overpaid by $25 or so. Useful to know.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: GregLee1]
      #6019434 - 08/11/13 06:03 PM Attachment (128 downloads)

I attach the 3rd version of the spreadsheet, with a couple hundred new eyepieces and oddballs I missed the first time around.
So many resellers are selling BST (Barsta) eyepieces that I added those as well.


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


Reged: 07/10/13

Loc: Switzerland
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: Starman1]
      #6020568 - 08/12/13 11:21 AM

Thanks for sharing, great job!

Post Extras: Print Post   Remind Me!   Notify Moderator  
LDW47
scholastic sledgehammer


Reged: 03/04/12

Loc: North Bay,Ontario,Canada
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: Starman1]
      #6105603 - 09/28/13 10:02 AM

What happened to the # in the calculated Field Stop column in the third version or am I missing them on my iPad copy ??

Post Extras: Print Post   Remind Me!   Notify Moderator  
LDW47
scholastic sledgehammer


Reged: 03/04/12

Loc: North Bay,Ontario,Canada
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: LDW47]
      #6105612 - 09/28/13 10:08 AM

Also how we're the various Field Stops calc.? By actual physical measurement with a tape, inside callipers etc. ?

Post Extras: Print Post   Remind Me!   Notify Moderator  
LDW47
scholastic sledgehammer


Reged: 03/04/12

Loc: North Bay,Ontario,Canada
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: LDW47]
      #6105651 - 09/28/13 10:30 AM

If not physically measured the calc. Field Stop could be significantly different ( probably much less ) based on the actual design of, shall we call it the Field Stop Ring, in the barrel of each individual manufacturers EP !?

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: LDW47]
      #6105719 - 09/28/13 11:05 AM

Quote:

What happened to the # in the calculated Field Stop column in the third version or am I missing them on my iPad copy ??



That column automatically populates when you enter your telescope's focal length in the red-letter field at the top of column N.
Other fields populate when you put your telescope's f/ratio in the red letter field at the top of column O.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: LDW47]
      #6105731 - 09/28/13 11:11 AM

Quote:

Also how we're the various Field Stops calc.? By actual physical measurement with a tape, inside callipers etc. ?



The manufacturer's field stop field is the one to look at first. But I wanted to figure out a way to calculate a field stop that would yield the apparent field in your scope if the manufacturer didn't quote a field stop. So, a formula in the field takes into account the focal length of the eyepiece, the manufacturer's claim for apparent field, and the focal length of your scope to calculate an "effective" field stop. It could be off by a few tenths of a millimeter.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: LDW47]
      #6105743 - 09/28/13 11:18 AM

Quote:

If not physically measured the calc. Field Stop could be significantly different ( probably much less ) based on the actual design of, shall we call it the Field Stop Ring, in the barrel of each individual manufacturers EP !?



If you use the calculated field stop for the eyepiece, you can derive the manufacturer's apparent field figure and a true field for the eyepiece. So the calculated figure does work back to the apparent field that is quoted by the manufacturer. As you know, when such things are actually measured, the apparent fields are rarely exact, so in those examples where the calculated field stop differs from the manufacturer's field stop quote, it is likely the manufacturer's claim for the apparent field is off by a couple degrees.
In such a case, you can adjust the apparent field figure until the calculated field stop and the actual field stop are the same. That would work for apparent fields of view smaller than about 50 degrees. It won't work for widefield eyepieces, though, since distortion at the edge of the field changes the amount of apparent field that will fit within a particular field stop diameter.


Post Extras: Print Post   Remind Me!   Notify Moderator  
LDW47
scholastic sledgehammer


Reged: 03/04/12

Loc: North Bay,Ontario,Canada
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: Starman1]
      #6107056 - 09/29/13 08:36 AM

I don't understand what distortion has to do with the amount of apparent field that will fit within the field stop for a given widefield and/or 2" EP ? As well, other than in an odd case, why don't the EP manufacturers clearly identify the Field Stop spec.for their product, why make the buyer do the leg work as I think it is a fairly important # to have when buying an EP or am I wrong in my thoughts ? This is a learning experience for me as I gain knowledge in this hobby !

Post Extras: Print Post   Remind Me!   Notify Moderator  
LDW47
scholastic sledgehammer


Reged: 03/04/12

Loc: North Bay,Ontario,Canada
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: Starman1]
      #6107068 - 09/29/13 08:46 AM

I am having a hard time accessing the columns to enter my data as I get no response from my iPad when I hit the data line !? What's the secret as I have tried it several times ! Also I am going to physically measure the Field Stop as a comparison on my 2" and 1.25" EP's

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: LDW47]
      #6107332 - 09/29/13 11:56 AM

Quote:

I don't understand what distortion has to do with the amount of apparent field that will fit within the field stop for a given widefield and/or 2" EP ? As well, other than in an odd case, why don't the EP manufacturers clearly identify the Field Stop spec.for their product, why make the buyer do the leg work as I think it is a fairly important # to have when buying an EP or am I wrong in my thoughts ? This is a learning experience for me as I gain knowledge in this hobby !




I'll try to come up with a decent analogy.

You're in space, looking at a globe. As a city comes around the edge of the planet, it seems to move sideways, relative to you, very slowly (because a lot of its motion is toward you, not laterally). When it crosses underneath you, it seems to move fast. When it nears the other edge, it appears to slow down.

What we've just described is similar to how angular magnification distortion works in an eyepiece. The star may enter the field moving very slowly, speed up as it crosses the center, and slow down again as it nears the edge. This is because, in my example, magnification is lower at the edge of the field than it is in the center.

So let's say we time the passage of a star to see how large the true field of view is. We would get a larger true field than the size of the apparent field would predict, i.e. the apparent field would be smaller than it should be for that large a true field. If we knew the apparent field, could we predict the true field? No. If we knew the true field, could we predict the apparent field? No.

So, let's say we know the field stop of the eyepiece. Can we predict what the true field or apparent field will be from that figure? Only if there is zero distortion.

To get around that, some manufacturers quote a "derived" field stop. It's not an actual field stop like an iris, but it is a field stop size that can be plugged into formulae to calculate the true field of the eyepiece. In the example I gave of the eyepiece with significant AMD, the field stop size we'd quote would actually be larger than a true field stop inside the eyepiece because the true field stop size would lead you to predict a smaller true field than you would actually measure.

As to manufacturers quoting a field stop size, some do. But many manufacturers don't because they are not aware of the spec (their engineers certainly are), or don't care, or think it would hurt the sales, or be confusing to the customer. As I discovered when doing the buyers guides over the years, some manufacturers quote nothing more than the diameter of the eyepiece and the focal length--they tell you nothing about elements inside, or apparent field, or weight, or any other characteristic. How do they expect to make sales? I haven't a clue.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: LDW47]
      #6107351 - 09/29/13 12:04 PM

Quote:

I am having a hard time accessing the columns to enter my data as I get no response from my iPad when I hit the data line !? What's the secret as I have tried it several times ! Also I am going to physically measure the Field Stop as a comparison on my 2" and 1.25" EP's



Your iPad is an Apple computer and the spreadsheet format is Microsoft Excel (xlsx). Can you normally read Microsoft programs? Do you have Excel on the iPad? Perhaps you only have a "Reader" for Excel and don't actually have the Microsoft Office program on the iPad.
If that's the case, you can download OpenOffice from openoffice.org and have a fully-functioning program to read and modify Word, Excel, PowerPoint, pdf, etc.

As to field stops, a lot of today's eyepieces have negative lenses in the bottom and a positive group in the top. On these eyepieces, the field stop is between the lenses, and not directly measurable. Besides, as I implied in my previous post, even if you measured it, it would only lead to the actual true field if the eyepiece had zero distortion. You're better off deriving a "effective field stop" size for the eyepiece by timing the passage of a star on the Celestial Equator and back-calculating the field stop that would yield that true field.


Post Extras: Print Post   Remind Me!   Notify Moderator  
LDW47
scholastic sledgehammer


Reged: 03/04/12

Loc: North Bay,Ontario,Canada
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: Starman1]
      #6107373 - 09/29/13 12:20 PM

I would have thought that the amount of distortion is so minute that it would have virtually been unmeasurable or insignificant !? My thoughts were that it was, somehow, just a straight line measurement between the narrowest part of the EP at the lenses but I now see there is a lot more to it once you add in how the lense(s) function ! It's just amounts to getting all these little goodies straight in your mind !

Post Extras: Print Post   Remind Me!   Notify Moderator  
LDW47
scholastic sledgehammer


Reged: 03/04/12

Loc: North Bay,Ontario,Canada
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: Starman1]
      #6107385 - 09/29/13 12:26 PM

That is exactly what my problem is so I will access it on my Microsoft desktop ! Measuring it would be strictly eyeballing as you are correct in saying you can't actually get to it ! You would probably be within a mm or so if it actually means anything based on your other answer !?

Post Extras: Print Post   Remind Me!   Notify Moderator  
JustaBoy
Post Laureate
*****

Reged: 06/19/12

Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: LDW47]
      #6107583 - 09/29/13 02:00 PM

It actually is a bit more complicated than just what we would think.

In an eyepiece that has an internal field stop, it is always placed after the negative lower group, and before the upper positive group. – Now just for the sake of simplicity let’s call this lower negative group a ‘barlow’, as it does produce diverging rays like a Barlow, but because it may be designed just to complement the specific upper group in in use , then I suppose that it is more correctly called a Smyth lens. – But please; for our purpose here, ‘barlow’ it is, with a small ‘b’ out of respect for Peter Barlow, capital ‘B’.

Now a ‘barlow’ is usually considered to be part of the telescope’s optical train rather than the eyepiece’s, but in this case we are making it part of the eyepiece, as is certainly the case with the negative lens being before a field stop in all eyepieces that use them.

Now for an example, let’s do something easy, a 32mm 50° Plossl, which has a easily measured field stop of very close to 27mm (please, lets not nit-pick here).

Now let’s attach a 2x ‘barlow’ to the bottom of it so that we can no longer get to the field stop to measure it... Now we have what appears to be a 16mm Plossl, still with a 50° AFOV, so the field stop ‘must be’ 13.5mm, to get the 16mm and 50° field.

But, when we open this hybrid to gain access to the internal field stop we see it is indeed 27mm.

So, the moral of this story is that measuring the internal field stop by disassembling the eyepiece tells us nothing if the focal length of the upper group (used as a stand alone unit), is not known. How much amplification is our ‘barlow’ providing to arrive at the resultant focal length as a whole eyepiece?

So Uncle Al uses what is really a derived figure for the size of the field stop for the eyepieces that can’t be measured directly.

If you don’t believe any of this, just take your $500 Nagler apart and measure the field stop directly (NOT recommended), and you will find your measurement to be quite a bit different than what AL is trying to tell you. – He is only telling you the derived figure to help you in your field calculations, so trust him on this.

Now, like Don has mentioned the TFOV and AFOV will not compute because of the eyepiece’s distortion, but will typically vary only about 5% in a Nagler design, Perhaps more in a T1, T5, and approaching nil in a T4.

I think I need another cup of coffee, and then I will wake up and discover once again, that everything that I thought I knew was all wrong

Good day,

-Chuck


Post Extras: Print Post   Remind Me!   Notify Moderator  
LDW47
scholastic sledgehammer


Reged: 03/04/12

Loc: North Bay,Ontario,Canada
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: JustaBoy]
      #6107665 - 09/29/13 02:46 PM

With so many different EP 's out there with differing specs, are all these numbers ever going to be truly indicative of anything in real life or are they just a good, average guide of what you have in your particular EP set ? It seems that with the number of manufacturers / designs / performance characteristics for each that to arrive at anything truly accurate would be difficult because of this complicated nature !? If that is how the results is to be taken ie.a really good set of numbers to be used, then I have no problems with that as long as we all know ! I have just been wondering how accurate / meaningfully this issue is !! Very interesting and kind of what I thought but thanx for all of your help and considerable knowledge !

Post Extras: Print Post   Remind Me!   Notify Moderator  
JustaBoy
Post Laureate
*****

Reged: 06/19/12

Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: LDW47]
      #6107698 - 09/29/13 03:03 PM

Try a eyepiece and see how it works for you, in your scope. - See if it's what you want.

Here's a little trick... Multiply the focal length of the eyepiece by it's quoted AFOV. - If we are talking 1.25" eyepieces, then the number you are looking for to max out the TFOV is around 1600 - For 2" you want 2700.

As you can see there are many ways you can end up with the number you want with all of the different AFOV's you will find.

Bottom line is; see the top line of this post:-)

Have fun
-Chuck


Post Extras: Print Post   Remind Me!   Notify Moderator  
LDW47
scholastic sledgehammer


Reged: 03/04/12

Loc: North Bay,Ontario,Canada
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: JustaBoy]
      #6107746 - 09/29/13 03:31 PM

The top line is exactly correct ! Like with everything else it's just nice to have a number for reference / comparison and to take it for what it is worth !

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: LDW47]
      #6107755 - 09/29/13 03:39 PM

Quote:

The top line is exactly correct ! Like with everything else it's just nice to have a number for reference / comparison and to take it for what it is worth !



Which is one of the reasons why, though it is a little less accurate than the field stop calculation, the standard TF=AF/M works just fine [true field = apparent field/magnification]. Just keep in mind your actual true field will be slightly smaller than the calculated one from that formula, and you're fine.
Because what we don't really know is the EXACT focal length of our scopes, or the EXACT focal lengths of the eyepieces (they're usually rounded off).
And, really, how important is the EXACT magnification? I almost always round off the magnification of my eyepieces when people ask me what power I'm using, and that's close enough.
And you can always time a star to yield the correct true field for the eyepiece.
With TF and M and approximate AF, you're set.


Post Extras: Print Post   Remind Me!   Notify Moderator  
LDW47
scholastic sledgehammer


Reged: 03/04/12

Loc: North Bay,Ontario,Canada
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: Starman1]
      #6107841 - 09/29/13 04:44 PM

I agree ! Thanx again for all of your expertise !!

Post Extras: Print Post   Remind Me!   Notify Moderator  
LDW47
scholastic sledgehammer


Reged: 03/04/12

Loc: North Bay,Ontario,Canada
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: LDW47]
      #6107886 - 09/29/13 05:10 PM

Your 01/09/06 article Eyepiece Qualities & Aberrations explains a lot !

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: LDW47]
      #6107909 - 09/29/13 05:26 PM

Quote:

Your 01/09/06 article Eyepiece Qualities & Aberrations explains a lot !



Thanks. Here are some more essays I've written in recent years:
Informational Articles


Post Extras: Print Post   Remind Me!   Notify Moderator  
LDW47
scholastic sledgehammer


Reged: 03/04/12

Loc: North Bay,Ontario,Canada
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: Starman1]
      #6112664 - 10/02/13 09:14 AM

I have them bookmarked !

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013v.3 Buyer's Guide to Eyepieces new [Re: LDW47]
      #6116060 - 10/03/13 09:03 PM Attachment (138 downloads)

I attach the 2013.5 Buyer's guide to eyepieces.

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


Reged: 05/09/13

Loc: Dallas Texas
Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #6259038 - 12/17/13 09:47 PM

Post deleted by Scott in NC

Edited by Scott in NC (12/24/13 12:45 PM)


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


Reged: 03/06/12

Loc: Durban, South Africa
Re: 2013 Buyer's Guide to Eyepieces new [Re: MatthewG]
      #6260119 - 12/18/13 01:34 PM

Sometimes (amateur) astronomy -or should I say optics- can become a leeeeettllle bit overwhelming.

Kudos to Don who -as it turns out- is either single, or has a very accommodating (another optometrical term) wife...

Just kidding.

Well done and great work Don,
Like I mentioned in my article.. you are truly the telescope guru!!!

Edited by Scott in NC (12/24/13 12:45 PM)


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


Reged: 03/06/12

Loc: Durban, South Africa
Re: 2013 Buyer's Guide to Eyepieces new [Re: michaeldurban]
      #6260125 - 12/18/13 01:39 PM


Yes, ..for the discerned scientists..
I did make up the word optometrical...

just fitted the context I guess..



Edited by Scott in NC (12/24/13 12:46 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013 Buyer's Guide to Eyepieces new [Re: michaeldurban]
      #6260154 - 12/18/13 01:54 PM Attachment (131 downloads)

Quote:


Sometimes (amateur) astronomy -or should I say optics- can become a leeeeettllle bit overwhelming.

Kudos to Don who -as it turns out- is either single, or has a very accommodating (another optometrical term) wife...

Just kidding.

Well done and great work Don,
Like I mentioned in my article.. you are truly the telescope guru!!!



No, I have a great wife, who, while professing little interest in astronomy, can find all the Messier objects in Sagittarius without star charts. She, like many women, has somewhat of a shoe-collecting hobby. Periodically she feels guilty about spending so much money on shoes and says to Me, "Don't you need an eyepiece or something?"
It's how I collected a suitcase full of Ethos eyepieces over the last 5 years.


As for the 2013 Eyepiece Buyer's Guide, I hereby attach the latest version with all recent updates.

Edited by Scott in NC (12/24/13 12:46 PM)


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


Reged: 11/14/13

Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #6424994 - 03/23/14 04:32 PM

This got lost in the brief 2.0 version, but I had some emails with Don, and once he finished up the 2014 updates/additions, I am going to take the data and make it into a searchable database. I have a preliminary version working, but it isn't ready for primetime.

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


Reged: 10/13/12

Re: 2013 Buyer's Guide to Eyepieces new [Re: MPD]
      #6470166 - 04/16/14 05:38 PM

Thanks, very kind of you to share.

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


Reged: 04/16/14

Re: 2013 Buyer's Guide to Eyepieces new [Re: Mark9473]
      #6506027 - 05/04/14 02:32 PM

this may sound like a terrible newbie question, but why can't I use my 1.25 Barlow with a 10 mm to get a closer look at Jupiter or Mars? They simply don't appear and I'm sure I've got them in my finder.

Thanks. From a newbie. By the way, I use an Orion 90mm refractor and a 6 inch Newtonian Star Blast, also from Orion.

What I really want from Santa is a 12 inch Dobsonian.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013 Buyer's Guide to Eyepieces new [Re: Moses]
      #6506461 - 05/04/14 06:24 PM

Quote:

this may sound like a terrible newbie question, but why can't I use my 1.25 Barlow with a 10 mm to get a closer look at Jupiter or Mars? They simply don't appear and I'm sure I've got them in my finder.

Thanks. From a newbie. By the way, I use an Orion 90mm refractor and a 6 inch Newtonian Star Blast, also from Orion.

What I really want from Santa is a 12 inch Dobsonian.



Your finder is not lined up with the main scope. This won't matter much at low power, when the field in the eyepiece is large, but it will matter at high power, when the field of view in the eyepiece is small.
So, use your 10mm eyepiece on Polaris and line up your finder exactly on Polaris.
Add your barlow and repeat, lining up Polaris perfectly with your finder (center Polaris in the eyepiece first, then adjust your finder).
Then, you'll find your target will still be in the field when you add the barlow on any other target. just remember to be quick, because the turning of the Earth will take the object out of the field in only a short time.


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


Reged: 11/14/13

Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #6548438 - 05/27/14 02:51 PM

Did this get unpinned on purpose?

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: 2013 Buyer's Guide to Eyepieces new [Re: MPD]
      #6548459 - 05/27/14 03:08 PM

Quote:

Did this get unpinned on purpose?



Bookmark a link to the thread. That way you can refer others to it.
I am almost ready with a 2014 version.
I hope it was not unpinned simply because I am a vendor. After all, there is nothing in the spreadsheet which could be construed as commercial promotion other than, perhaps, for the entire industry.


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


Reged: 11/14/13

Re: 2013 Buyer's Guide to Eyepieces new [Re: Starman1]
      #6552877 - 05/29/14 09:31 PM

Yup, I have a bookmark now.

I'm ready to import the new data to a searchable database when you have the new version ready.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | 5 | (show all)


Extra information
18 registered and 30 anonymous users are browsing this forum.

Moderator:  ausastronomer, droid, Scott in NC 

Print Thread

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


Thread views: 13236

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics