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 2x Barlow - waste of $?

  • Please log in to reply
26 replies to this topic

#1 Rodex

Rodex

    Lift Off

  • -----
  • topic starter
  • Posts: 19
  • Joined: 15 Oct 2021

Posted 26 October 2021 - 12:05 PM

We just got our first telescope - an XT8i that comes with what sounds like the standard 10mm and 25mm eyepieces. Searching through the forum, it looks like the advice is to choose nicer eyepieces and Barlow combos that make sense for us. That might be a couple of months out for the ole budget.

In the mean time, Amazon has an Omni 2x Barlow for $35, free returns. I’ll probably order it before anyone responds to this since I can return it, but the reviews (the real ones, at least) are not stellar. Is it ever a waste to build a collection of eyepieces, even cheaper ones?

#2 fftulip

fftulip

    Explorer 1

  • *****
  • Posts: 76
  • Joined: 17 Mar 2017

Posted 26 October 2021 - 12:29 PM

I haven't tried it, but the Celestron Omni barlow is probably a decent product.  The problem is don't expect the image to improve, it only magnifies (though the edge of field sharpness may be better with the barlow).

If your eyepiece is not that good, and/or your telescope optics are mediocre, adding a barlow may not improve things.  Also be aware that barlows may affect the in or out focus so when using it, you will probably need to adjust the focus (sometimes dramatically).  One more thing, if using the 10mm eyepiece with a barlow, you are going to need very good seeing (clear steady skies), otherwise the extreme magnification will just result in a very blurry image (probably the cause of some of the reviews).  Please consider upgrading the stock eyepieces also when your budget permits.



#3 MinT

MinT

    Lift Off

  • -----
  • Posts: 5
  • Joined: 17 Sep 2021

Posted 26 October 2021 - 12:39 PM

I got one as part of my starter setup with a 10 inch dob about a month ago.  (Celestron 8-24mm zoom, Celestron 2x Barlow, Orion Q70 32mm). Mostly because it was on sale and seemed like a cheap enough throw in if I wanted to go higher than 8mm with the zoom.  

 

I don't use it a ton, but it has occasionally been useful for giving me some very nice close-ups of the moon when conditions are good.

You can unscrew the bottom and screw it into the back of a 1.25 inch eyepiece to get I think a 1.5x effect, but in practice, I never do this.

I don't really regret buying it, I'll keep it around as I eventually slowly acquire some premium eyepieces, and maybe worry about getting a better Barlow after I have those.

 

tldr: It's fine for the price, but you probably could get away with skipping it too.  


  • Rodex likes this

#4 Sky Muse

Sky Muse

    Cosmos

  • *****
  • Posts: 9,073
  • Joined: 26 Oct 2012
  • Loc: Mid-South, U.S.

Posted 26 October 2021 - 12:50 PM

We just got our first telescope - an XT8i that comes with what sounds like the standard 10mm and 25mm eyepieces. Searching through the forum, it looks like the advice is to choose nicer eyepieces and Barlow combos that make sense for us. That might be a couple of months out for the ole budget.

In the mean time, Amazon has an Omni 2x Barlow for $35, free returns. I’ll probably order it before anyone responds to this since I can return it, but the reviews (the real ones, at least) are not stellar. Is it ever a waste to build a collection of eyepieces, even cheaper ones?

You might like one or both of these better...

 

http://www.scopestuff.com/ss_eba4.htm

http://www.scopestuff.com/ss_eba3.htm

 

I have both myself.  They worked great with my Orion "StarBlast 6", a 6" f/5 Newtonian which is pickier than your 8" at f/6.

 

The kit came with those same eyepieces.  I think I looked through one of them, once...

 

Sirius Plossls.jpg


Edited by Sky Muse, 26 October 2021 - 03:42 PM.

  • Rodex likes this

#5 MrFreeze

MrFreeze

    Sputnik

  • -----
  • Posts: 40
  • Joined: 15 Nov 2020
  • Loc: Bedfordshire, UK

Posted 26 October 2021 - 01:27 PM

I would be a bit wary of Amazon reviews, many of them will not be by people who know what they are talking about. The Celestron Omni barlow is actually rather good. You would need to spend a lot more than this to get something noticeably better.

 

The Sirius Plossl eyepieces that come with your telescope are pretty decent also. They only have a 52degree field of view, but they are good quality eyepieces. They will give magnifications of x48 and x120, with the x2 barlow they would give magnifications of x96 and x240, both of which are well within the capabilities of this scope. The x240 would require pretty good seeing - you certainly won't be able to use this every night.

 

You've got yourself a rather nice scope there, I'm quite envious. I hope you enjoy it.

 

David


  • SteveG, BFaucett, vtornado and 1 other like this

#6 Rodex

Rodex

    Lift Off

  • -----
  • topic starter
  • Posts: 19
  • Joined: 15 Oct 2021

Posted 26 October 2021 - 02:22 PM

I would be a bit wary of Amazon reviews, many of them will not be by people who know what they are talking about. The Celestron Omni barlow is actually rather good. You would need to spend a lot more than this to get something noticeably better.

The Sirius Plossl eyepieces that come with your telescope are pretty decent also. They only have a 52degree field of view, but they are good quality eyepieces. They will give magnifications of x48 and x120, with the x2 barlow they would give magnifications of x96 and x240, both of which are well within the capabilities of this scope. The x240 would require pretty good seeing - you certainly won't be able to use this every night.

You've got yourself a rather nice scope there, I'm quite envious. I hope you enjoy it.

David


Looking at Jupiter and Saturn the other day, I was impressed with the image quality, albeit the image was small. A little bit of magnification would seem to go a long way so I went ahead and ordered the Omni and we will see how it comes out.
  • Jon Isaacs likes this

#7 vrodriguez2324

vrodriguez2324

    Explorer 1

  • *****
  • Posts: 83
  • Joined: 11 Sep 2020
  • Loc: San Diego, CA

Posted 26 October 2021 - 02:43 PM

I have the Celestron Omni 2x Barlow. 

 

I found it slightly vignettes longer focal length eyepieces but I still use it with them.

 

I am happy with the performance and nice spartan build. 

 

+1 on unscrewing the front lens and using it as 1.5X barlow. 


Edited by vrodriguez2324, 26 October 2021 - 02:51 PM.

  • Jon Isaacs likes this

#8 CeleNoptic

CeleNoptic

    Surveyor 1

  • *****
  • Posts: 1,830
  • Joined: 20 Dec 2007
  • Loc: Mid-Atlantic, Bortle 7

Posted 26 October 2021 - 02:48 PM

Looking at Jupiter and Saturn the other day, I was impressed with the image quality, albeit the image was small. A little bit of magnification would seem to go a long way so I went ahead and ordered the Omni and we will see how it comes out.

 

If you're saying about the views showed by your 10mm Plossl, no surprise that at 120x and eye pupil of 1.7mm the image is sharp. If you add a 2x Barlow (get ready it'll work as a 2.1-2.2x) than at 240x and with the eye pupil of 0.8mm you'll depend mostly on your seeing conditions, rather than on any other factors. The views won't be that sharp and you need the steady atmosphere that is the seeing above average, especially on Jupiter. And if you observe from the Northern Hemisphere keep in mind that these planets are too low above the horizon and going lower every night which worsen the views due to atmospheric refraction. For high magnifications you need planets rising above ~30-35°. So for better views wait for next summer or even better for 2023. And watch for twinkling stars, they indicate the poor seeing conditions.  Don't blame your equipment first, if you're not satisfied with the results, the seeing is king for planetary observations. In addition to the Barlow you may want to consider a decent Zoom eyepiece which would be very helpful for planetary, IMO.


  • Rodex likes this

#9 Second Time Around

Second Time Around

    Viking 1

  • -----
  • Posts: 656
  • Joined: 08 Oct 2019
  • Loc: Rural Kent, UK

Posted 27 October 2021 - 09:27 AM

The option to use a Barlow at 1.5x is extremely handy.  Indeed, from the UK where seeing conditions are often pretty poor I use it far more than 2x or higher.  1.5x with your 10mm eyepiece will you 180x, a very useful magnification indeed.


  • Jon Isaacs, CeleNoptic, spaceoddity and 1 other like this

#10 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 96,039
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 27 October 2021 - 11:32 AM

Looking at Jupiter and Saturn the other day, I was impressed with the image quality, albeit the image was small. A little bit of magnification would seem to go a long way so I went ahead and ordered the Omni and we will see how it comes out.

 

Hi:

 

Congratulations on your new XT-8i.. It's a good one.

 

I believe my two Celestron Shorty Barlows are earlier version of the 1.25 inch Omni 2X Barlow.  I have Barlows include the 3 elements versions like the Antares as well as a 2X TeleVue. 

 

I use the Shorty's a lot.  The TeleVue has slightly less scatter but the Shorty's are very good and the 1.5x-2x ability that makes them more versatile. With your 10mm Plossl, that would give you magnifications of 180x and 240x, a nice range of magnifications for higher power observations.  

 

When using a Barlow, one has to be aware that increasing the magnification may make the image less sharp, this is not due to the quality of the Barlow, it's the result of increasing the magnification.  Increasing the magnification tends show the effects of atmospheric turbulence, more.  Increasing the magnification also dims the views of the planets and other extended objects.  This is just simple geometry, the light in the image is spread out more.

 

I say go for it. At some point you will want to buy some more eyepieces but I think a good Barlow is always a good thing to have.

 

Jon


  • CeleNoptic and vtornado like this

#11 vtornado

vtornado

    Aurora

  • *****
  • Posts: 4,545
  • Joined: 22 Jan 2016
  • Loc: 42N 88W

Posted 27 October 2021 - 02:18 PM

I have had multiple $30-$50 barlows none were head an shoulders over the other.

Removable lens elements is a plus. (orion, celestron, meade, gso ...) 

 

So far my favorite is the gso 2x, 2 element barlow. It seems a touch sharper,

however I am sure that this tiny bit of extra sharpness can be overriden

by variance in the sample.

 

A lot of low priced eyepieces are improved by a barlow.

They make the light cone more shallow which helps with edge correction.

And they lengthen the eye relief, which for a 10mm plossl is very welcome.

 

I also use my 2x barlow to collimate my scope.

 

*** there is a celestron 2x barlow in the classified for $25.00 shipped.


Edited by vtornado, 27 October 2021 - 02:22 PM.

  • CeleNoptic and Rodex like this

#12 YeloSub

YeloSub

    Vostok 1

  • *****
  • Posts: 163
  • Joined: 16 Aug 2020

Posted 27 October 2021 - 04:26 PM

Can't find the thread right now, buy for the price, the GSO 2.5x ED barlow (many say its only 2.1-2.2x though) is one of the best in the price range, without jumping up to TV and other pricey offerings. I have one and it does great! Better than the old meade #126 and similar older offerings from orion IMO. Never tried the omni though. The GSO comes with a brass compression ring which is nice too for its price.
  • AhBok, davelpg and Rodex like this

#13 CeleNoptic

CeleNoptic

    Surveyor 1

  • *****
  • Posts: 1,830
  • Joined: 20 Dec 2007
  • Loc: Mid-Atlantic, Bortle 7

Posted 27 October 2021 - 05:25 PM

Links to older threads discussing Barlows which are not "waste of $" smile.gif

 

https://www.cloudyni...s-best-barlows/

https://www.cloudyni...e-3x-tv-barlow/

https://www.cloudyni...for-your-money/

https://www.cloudyni...-advice-needed/

https://www.cloudyni...s/#entry9150978

https://www.cloudyni...for-refractors/

https://www.cloudyni...t-a-new-barlow/

https://www.cloudyni...-shorty-barlow/

https://www.cloudyni...1-which-barlow/

https://www.cloudyni...60-best-barlow/

https://www.cloudyni...nce-difference/


  • Rodex likes this

#14 Rodex

Rodex

    Lift Off

  • -----
  • topic starter
  • Posts: 19
  • Joined: 15 Oct 2021

Posted 27 October 2021 - 07:57 PM

I have had multiple $30-$50 barlows none were head an shoulders over the other.

Removable lens elements is a plus. (orion, celestron, meade, gso ...) 

 

So far my favorite is the gso 2x, 2 element barlow. It seems a touch sharper,

however I am sure that this tiny bit of extra sharpness can be overriden

by variance in the sample.

 

A lot of low priced eyepieces are improved by a barlow.

They make the light cone more shallow which helps with edge correction.

And they lengthen the eye relief, which for a 10mm plossl is very welcome.

 

I also use my 2x barlow to collimate my scope.

 

*** there is a celestron 2x barlow in the classified for $25.00 shipped.

Thanks for the heads up! Messaged the seller about that and a filter set. 



#15 Rodex

Rodex

    Lift Off

  • -----
  • topic starter
  • Posts: 19
  • Joined: 15 Oct 2021

Posted 27 October 2021 - 08:10 PM

 

I use the Shorty's a lot.  The TeleVue has slightly less scatter but the Shorty's are very good and the 1.5x-2x ability that makes them more versatile. With your 10mm Plossl, that would give you magnifications of 180x and 240x, a nice range of magnifications for higher power observations.  

This 1.5-2x ability, is that the same as the other posts where the lens can be removed? We have those ThorLabs lens tubes with the threaded retaining rings that take a spanner wrench - is that how these removable lenses come out? 



#16 BFaucett

BFaucett

    Mercury-Atlas

  • *****
  • Posts: 2,516
  • Joined: 12 Jul 2014
  • Loc: Houston, Texas 29.78° N

Posted 27 October 2021 - 09:15 PM

This 1.5-2x ability, is that the same as the other posts where the lens can be removed? We have those ThorLabs lens tubes with the threaded retaining rings that take a spanner wrench - is that how these removable lenses come out? 

 

1.jpg

 

2.jpg

 

3.jpg

Photos from: https://agenaastro.c...arlow-lens.html

 

GSO 1.25" 2x "Shorty" Achromatic Barlow Lens # GS2BL

"Barlow element can be separated from main tube and threaded directly into a 1.25" eyepiece for approximately 1.5x increase in magnification"

https://agenaastro.c...arlow-lens.html

 

You just unscrew the lens cell from the Barlow's tube (using your fingers) and then screw it onto an eyepiece just like attaching an eyepiece filter.  My Orion Shorty 1.25" 2x Barlow Lens works the same way. Note that not all Barlows have this feature / capability.

 

Cheers! Bob F.


Edited by BFaucett, 27 October 2021 - 09:17 PM.

  • Jon Isaacs, spaceoddity, vtornado and 1 other like this

#17 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 96,039
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 27 October 2021 - 09:24 PM

You just unscrew the lens cell from the Barlow's tube (using your fingers) and then screw it onto an eyepiece just like attaching an eyepiece filter.  My Orion Shorty 1.25" 2x Barlow Lens works the same way. Note that not all Barlows have this feature / capability.

 

goodjob.gif

 

It takes maybe 10 seconds.  You have to rack the focuser outwards quite a bit but other than that, it works very nicely.  

 

Jon


  • BFaucett likes this

#18 Thomas_M44

Thomas_M44

    Apollo

  • -----
  • Posts: 1,033
  • Joined: 14 Feb 2020
  • Loc: Modesto, CA USA

Posted 27 October 2021 - 09:57 PM

We just got our first telescope - an XT8i that comes with what sounds like the standard 10mm and 25mm eyepieces. Searching through the forum, it looks like the advice is to choose nicer eyepieces and Barlow combos that make sense for us. That might be a couple of months out for the ole budget.

In the mean time, Amazon has an Omni 2x Barlow for $35, free returns. I’ll probably order it before anyone responds to this since I can return it, but the reviews (the real ones, at least) are not stellar. Is it ever a waste to build a collection of eyepieces, even cheaper ones?

I wouldn’t. Instead…

 

The GSO 2-inch ED Barlow (includes a 1.25-inch eyepiece adapter) is only $65 USD, and *very* good Barlow —in fact, IMO about the best deal available today in a quality Barlow.

 

If you buy that Celestron Barlow, you may likely loose interest in it the minute you look through a better quality Barlow.

 

 

I have a number of Premium Barlows and Powermates by TeleVue, Nikon etc, and so I have a good base of comparison.

 

 

Even if you don’t presently envision using the Barlow with 2-inch eyepieces, it would be a good idea to have that capability ready.


Edited by Thomas_M44, 27 October 2021 - 10:01 PM.

  • Brent Campbell, PKDfan and Rodex like this

#19 Rodex

Rodex

    Lift Off

  • -----
  • topic starter
  • Posts: 19
  • Joined: 15 Oct 2021

Posted 27 October 2021 - 10:30 PM

I wouldn’t. Instead…

The GSO 2-inch ED Barlow (includes a 1.25-inch eyepiece adapter) is only $65 USD, and *very* good Barlow —in fact, IMO about the best deal available today in a quality Barlow.

If you buy that Celestron Barlow, you may likely loose interest in it the minute you look through a better quality Barlow.


I have a number of Premium Barlows and Powermates by TeleVue, Nikon etc, and so I have a good base of comparison.


Even if you don’t presently envision using the Barlow with 2-inch eyepieces, it would be a good idea to have that capability ready.


Would that GSO be something to pair with better eyepieces as well, besides the 10 and 25 that came with the scope? Just planning on the next several purchases!

#20 vtornado

vtornado

    Aurora

  • *****
  • Posts: 4,545
  • Joined: 22 Jan 2016
  • Loc: 42N 88W

Posted 27 October 2021 - 10:37 PM

I had both the 2x gso barlow and the 3 element gso 2.5x barlow. (1.25 inch)

 

I went back and forth on Jupiter with a 100mm ED scope.

My 2x seemed just a wee bit sharper than the 2.5.

I did try different eyepieces to nullify the difference in the magnification factor.

I sold the 2.5 and kept 2x.  The 2x  has the bonus of having the removable lens assembly.

The 2.5 does not.

 

The difference was so small it could be sample variation.

Could it be I was at f/9 and not f/4.7, 5 or 6 the f ratio of most dobs?


Edited by vtornado, 28 October 2021 - 08:00 AM.

  • Jon Isaacs, BFaucett, YeloSub and 1 other like this

#21 CeleNoptic

CeleNoptic

    Surveyor 1

  • *****
  • Posts: 1,830
  • Joined: 20 Dec 2007
  • Loc: Mid-Atlantic, Bortle 7

Posted 28 October 2021 - 01:38 AM

Would that GSO be something to pair with better eyepieces as well, besides the 10 and 25 that came with the scope? Just planning on the next several purchases!

 
First, I'd check its weight, almost 14oz. Ask yourself if you want this in your focuser. IMO, bulky and inconvenient, I had it and sold, no regret. Optically, nothing special, just ordinary budget Barlow, works good not with every eyepiece, that was my experience. Do you really plan on getting 2 or 3 2" eyepieces that you'll need to Barlow? They are heavy themselves plus the heavy Barlow. IMO, a 1.25" Barlow would be preferrable for planetary, lightweight and convenient with 1.5x option like Jon Isaacs suggested above. And no 1.25"/2" adapter necessary. Of course, your mileage may vary.


Edited by CeleNoptic, 28 October 2021 - 01:40 AM.

  • SteveG and Rodex like this

#22 Rodex

Rodex

    Lift Off

  • -----
  • topic starter
  • Posts: 19
  • Joined: 15 Oct 2021

Posted 28 October 2021 - 09:50 AM

I had a spare microscope eyepiece (Nikon C-W20x) laying around and popped it in last night just to see what happened. Seemed to be equivalent or better than the Sirius Plössl 10mm, albeit the interface diameter must be a little smaller on the Nikon. I would imagine the microscope eyepiece wouldn’t be as coaxial with the image, but I couldn’t tell much. I run into high quality microscope eyepieces every now and then, is anyone collecting these as well? I usually pass them up blush.gif



#23 YeloSub

YeloSub

    Vostok 1

  • *****
  • Posts: 163
  • Joined: 16 Aug 2020

Posted 28 October 2021 - 11:05 AM

I had both the 2x gso barlow and the 3 element gso 2.5x barlow. (1.25 inch)

I went back and forth on Jupiter with a 100mm ED scope.
My 2x seemed just a wee bit sharper than the 2.5.
I did try different eyepieces to nullify the difference in the magnification factor.
I sold the 2.5 and kept 2x. The 2x has the bonus of having the removable lens assembly.
The 2.5 does not.

The difference was so small it could be sample variation.
Could it be I was at f/9 and not f/4.7, 5 or 6 the f ratio of most dobs?

I have the 2.5x and recently acquired the 2x to play with the 1.5x barlow cell. This makes me want to do a more detailed comparison between the two as I probably don't "need" to keep both. Thanks for the review!
  • vtornado likes this

#24 vtornado

vtornado

    Aurora

  • *****
  • Posts: 4,545
  • Joined: 22 Jan 2016
  • Loc: 42N 88W

Posted 28 October 2021 - 11:42 AM

I have the 2.5x and recently acquired the 2x to play with the 1.5x barlow cell. This makes me want to do a more detailed comparison between the two as I probably don't "need" to keep both. Thanks for the review!

Let us know what you see.

 

VT



#25 RLK1

RLK1

    Surveyor 1

  • -----
  • Posts: 1,638
  • Joined: 19 Apr 2020

Posted 28 October 2021 - 01:27 PM

I used a Celestron Omni 2x barlow last night with my binoviewer in my 16" f4.5 dob while viewing Jupiter and Saturn with 32mm plossl eyepieces and the views were excellent. No issues with the barlow itself although I had more eye relief than I needed but the images were clear, contrasty and sharp. There's nothing wrong with the barlow although the 2" GSO versions that come up on sale on amazon or elsewhere from time to time offer a bit more versatility if you move into acquiring 2" eyepieces. I purchased a 2" 2x ED barlow on sale via amazon under the meoptrix name recently for around $40.00 and it provides superb views with my 10mm ethos eyepiece. It's likely produced by GSO and I have an earlier version of it, a non-ED GSO,  that I had repurposed for another application but it works well, too...




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






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics