Jump to content

Banner.jpg.b89429c566825f6ab32bcafbada449c9.jpg

Omni Inconsistencies?


RedSpot

Recommended Posts

Hi All,

I've recently aquired a binoviewer for next to nothing, an AE Binomate.  I realise that this isn't the best BV out there by some margin but I thought that this would be a cheap way to try it out and see if binoviewing was for me before spending a packet on something pricier.  The BV came without any eyepieces, however I already had a 12mm Celestron Omni Plossl kicking about and decided to pick up an additional one to give me a matched pair as a starter for ten.  To this end, I picked up a second hand one from Amazon for £15 which was in mint unmarked condition (in fact it looks brand new).

However, when I compared it to my existing 12mm Omni, the body of the eyepiece is a good bit longer than my existing one and the rubber eyecup is a slightly different design.  I also noticed that the box is a different design too although both carry an identical model number stamp on the box (#93319).  I've attached a couple of pictures to show this.

I realise that manufacturer's change there designs from time to time but does anyone know which of these two is the more modern design and if one is superior to the other in any way?

I thought I'd ask the question more out of curiosity than anything else.  Grateful for any insights or knowledge about Celestron's release history for the Omni EP range.  

Cheers,

Stephen

IMGP4308.JPGIMGP4307.JPG

Link to comment
Share on other sites

Right now, on the Celestron website, the omni appears like this:

white800x600.png&width=800&height=600&co

So it looks like your taller eyepiece  is the newer one. (Unless Celestron forgot to update their website. Then the shorter one is the newer.)

The differences are probably superficial. Possibly most important to you is that the focal lengths are the same, and that the different height eyecups don't interfere too much with the viewing experience.

Plössls have been around since 1860. They consist of two doublets with the convex elements facing each other. In the symmetrical variant, the eye lens and the field lens are identical, in the traditional variant the eye lens is smaller than the field lens.

Vernonscope's Brandon is a Plössl variant from the 1940s. It gathered its fame as the stock eyepiece for the very expensive Questar 3.5" telescope.

Televue introduced a variant which has more pincushion distortion, but less astigmatism. The original Plössl works best in telescopes with a focal ratio of f/6 or slower. The TV variant also performs well in faster telescopes through which it shows sharp stars to the edge of the field.

Meade came up with the super Plössl which has a fifth, convex element between the two doublets. I don't know much about it, except that it really isn't a Plössl. It's more like an Erfle.

Plössl are a scaled design: the longer focal lengths are simply enlarged versions of the shorter focal lengths. If you magnify all dimensions of a 10 mm Plössl, you get a 20 mm one. As a consequence, the eye relief gets longer with increasing focal length. For a Plössl the eye relief is some 70% of the focal length. A 55mm Plössl has more than 38 mm eye relief, and an 8mm Plössl has only 5.6 mm eye relief.

One of my finest eyepieces is a 7.4mm TV Plössl. I don't use it very often because with my eyelashes constantly brushing the glass I have to clean it after every use, but the image quality it delivers is superb.

 

Link to comment
Share on other sites

Thanks Ruud, agree that the TVs are the best around.  I've got a 20mm one myself and it is brilliant, the second Omni was just a cheap way to try out the BVs. 

I think a lot of the images used on supplier websites are out of date although you would hope that Celestron would take more care than others.  I've actually fired off a question directly to Celestron this earlier this morning so I'll see what they come back with and I'll stick the response on here.

 

Link to comment
Share on other sites

I have a 12mm Omni as well. It's a couple of years old but I bought it new. I'm pretty sure it came in an orange box like the one on the right in your picture above. 

12mm Omni custom.jpg

I dug it out recently and swapped the aluminium draw with an undercut for this chromed brass smooth draw tube (originally from a 12.5mm orthoscopic). Since this picture was taken it has been cleaned again and I've replaced the rubber eyeguard as the original one (pictured) was torn slightly. I have a feeling that the red boxed 12mm is older, I also believe they were originally manufactured in Taiwan with smooth draw tubes. Some of these earlier 12mm Omnis were in fact 12.5mm apparently. At some stage they seem to have changed the smooth chromed draw tubes for GSO-style aluminium ones equipped with undercuts. I don't know who actually make the Omni series, maybe Synta and GSO both have at some time, or anyone for that matter. Oddly I was using my 12mm Omni today to look at a twilight Mars and I'm sure I saw fleeting surface detail at 167x (the Mare Erythraeum is actually facing Earth at the moment). I know many people don't rate the Omni Plossls, especially in comparison to TeleVue Plossls. I have the 11mm TV Plossl, and although I think it is superb, the Omni 12mm holds its own in comparison considering it's a quarter of the price. I use a pair of 15mm TV Plossls for binoviewing, but I nearly bought another 15mm Omni instead of the TV as it has longer eye relief and a slightly larger eye lens. In my experience the Omni Plossls seem to perform slightly better than the standard Celestron Plossls which are almost certainly GSO. They have many similarities however and some of the casing parts could be sourced from the same manufacturer. 

omnis.jpg

I've slightly customised the above Omni Barlow and eyepieces. They're still useful for using on very light scopes like my 90mm Mak. In my experience, pictures/artwork on the Celestron website are perpetually out of date.

Link to comment
Share on other sites

Hello all.

Stephen, I purchased two Celestron Omni eyepieces just a few months ago - the 12mm and 9mm. They definitely match the style on the right, being shorter than the left photo (in the case of the 12mm) and both having the same eyeguard. I also swapped out the barrels on both with brass smooth types which are sold by a fellow on ebay, scopehead1.

Using both with a 2x TV Barlow, they work well. Anything shorter than the 9mm in a Plossl design I find to have an uncomfortable eye relief.

Thank you!

joe

 

Link to comment
Share on other sites

I'm fairly convinced most 'Celestron' kit Plossls are made by GSO. The Eyeopener Kit almost certainly has GSO Plossls. Synta have marketed a few eyepieces under the Celestron name though. 

6mm pair side.jpg

These two 6mm Celestron Plossls are from kits  (Eyeopener and AstroMaster respectively). The Eyeopener 6mm (left) has silk screened lettering and a standard aluminium draw tube with undercut. The one on the right has painted lettering and a chromed brass tube. The dimensions of the housings are slightly different. It's a distinct possibility that the EP on the right is Synta made, possibly in Taiwan. Although ostensibly both decent Plossls, the brass draw tubed eyepiece has a brighter and sharper image I think.

Link to comment
Share on other sites

With Celestron now being owned by Synta I wonder how much choice they now have over sourcing things ?

I guess I'd be a little surprised if the Celestron brand was still able to use a competitor to Synta such as GSO for their items :icon_scratch:

 

Link to comment
Share on other sites

As far as the source of the eyepieces are concerned, who knows!  There is that much inter-trading and re-branding going on between manufacturers and suppliers that it is anybody's guess. 

Joe, I suspect that the shorter barrel is probably the more modern one.  From my own limited testing of the two eyepieces in the picture, they don't show any differences whatsoever in the quality of image so I'm guessing that any enhancements are marginal.

No word back from Celestron yet but I'll post it as soon as it arrives.


Stephen

Link to comment
Share on other sites

10 minutes ago, John said:

With Celestron now being owned by Synta I wonder how much choice they now have over sourcing things ?

I guess I'd be a little surprised if the Celestron brand was still able to use a competitor to Synta such as GSO for their items :icon_scratch:

 

I think that's just it though. Celestron is a brand name. The Celestron eyepiece kits and some eyepieces may simply be made for Synta by other manufacturers to market as Celestron. I'm pretty sure some of the 'Celestron' kits are marketed under other names. 

Link to comment
Share on other sites

Hot from the Inbox, the reply from Christopher at Celestron!

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Hi Stephen,

Thank you for emailing into Celestron. I would be happy to help you out with your question. The two eyepieces are identical. The main differences between the two are the rubber eyeguard and the silver barrel (one being longer than the other). There are no advantages between the two as they have the same optical design and field stop. I hope this helps.

Best Regards,
Christopher
Celestron Technical Support
 
-----------------------------------------------------------------------------------------------------------------------------------
Link to comment
Share on other sites

10 minutes ago, Mak the Night said:

I think that's just it though. Celestron is a brand name. The Celestron eyepiece kits and some eyepieces may simply be made for Synta by other manufacturers to market as Celestron. I'm pretty sure some of the 'Celestron' kits are marketed under other names. 

I thought Synta was a manufacturer ?

Nothing to stop them outsourcing certain items to others though, if thats more efficient / profitable.

Mind you, apparently the Celestron branded SCT's that are now made in China are consistently as good or a little better than the older USA made ones.

 

 

Link to comment
Share on other sites

14 minutes ago, John said:

I thought Synta was a manufacturer ?

Nothing to stop them outsourcing certain items to others though, if thats more efficient / profitable.

Mind you, apparently the Celestron branded SCT's that are now made in China are consistently as good or a little better than the older USA made ones.

 

 

'Suzhou Synta Optical Technology Co., Ltd. is Chinese company located in Suzhou, Jiangsu, China, the primary manufacturing subsidiary of Synta Technology Corporation of Taiwan. It produces telescopes and astronomical equipment like mounts and eyepieces for the amateur astronomical market.' ~ Wikipedia

Suzhou Synta Optical Technology is a manufacturer, but all of the products marketed by Synta may not actually be manufactured by them. They may own Celestron now but sell some products marketed as Celestron as the name is so famous. I'm guessing 'Celestron' eyepieces and kits are sold under the brand name but may be actually outsourced to other manufacturers, or in some cases merely outsourced/repackaged/rebranded as Celestron as in their generic GSO Plossls. 

Possibly ... lol

Link to comment
Share on other sites

I think "may" is the opertative word. :icon_biggrin:

I guess all we can do is to judge the end products :dontknow:

When I had a couple of Celestron Omni's they did seem very, very like Revelation plossls (which GSO make) in their weight, build coatings etc but it's quite likely that the manufacturer of them has varied a number of times over the years so it's probably not surprising that the original poster has two that are not quite identical. I've seen a number of variations of the Meade 4000 series over the years as well, different body and barrel lengths particularly.

Apparently Meade have tried to buy the Celestron brand a couple of times over the years but their move was blocked by regulators.

 

Link to comment
Share on other sites

2 minutes ago, John said:

I think "may" is the opertative word. :icon_biggrin:

I guess all we can do is to judge the end products :dontknow:

When I had a couple of Celestron Omni's they did seem very, very like Revelation plossls (which GSO make) in their weight, build coatings etc but it's quite likely that the manufacturer of them has varied a number of times over the years so it's probably not surprising that the original poster has two that are not quite identical. I've seen a number of variations of the Meade 4000 series over the years as well, different body and barrel lengths particularly.

Apparently Meade have tried to buy the Celestron brand a couple of times over the years but their move was blocked by regulators.

 

Yes, it's all guess work really. I think the Omni EP's are a lot like the GSO Plossls but sometimes I'm not so sure. I think Synta made some eyepieces as Celestron in Taiwan and later on the Chinese mainland. The first Omni eyepieces were supposedly manufactured in Taiwan. I have a feeling that old 6mm Celestron Plossl I have is Taiwanese made, possibly not GSO either. It could be that many of the housings and draw tubes are from the same source even if the internal parts aren't.

Link to comment
Share on other sites

Just to round off this thread then.  Picked up a new shorter version Omni 12mm so job done, pictures attached.  All I need now is for the cloud to clear up and I can have a go.  The day time test looks promising though.

Thanks to all for their input, including Celestron for their response.

Clear Skies (I wish),

Stephen

IMGP4338.JPG

IMGP4340.JPG

Link to comment
Share on other sites

9 hours ago, RedSpot said:

Just to round off this thread then.  Picked up a new shorter version Omni 12mm so job done, pictures attached.  All I need now is for the cloud to clear up and I can have a go.  The day time test looks promising though.

Thanks to all for their input, including Celestron for their response.

Clear Skies (I wish),

Stephen

IMGP4338.JPG

IMGP4340.JPG

Looks great! Good luck.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.