Need help choosing Barlow

[AstroMuni]

Hi,

I am a newbie to astronomy and I have a Celestron Astromaster 130EQ (The scope is f/5 and accepts 1.25" eyepieces) which I had bought for my daughter but is now my hobby 🙂.

I wish to buy a Barlow (perhaps a 2x?) that will stand by me long term. I have read reviews which say that Powermates are the best (but expensive) and many other reviews that suggest that the Omni, Celestron, BST barlows are good/great and this has confused me. I am not about to commit to the Powermate just yet, so looking for advice on which of these other barlows are worth investing in.

So would be interested in your advice please.

[johninderby]

The Televue Powermates are excellent but the Explore Scientific equivelents are 95% as good but much, much cheaper and well worth considering.

 https://www.firstlightoptics.com/explore-scientific-eyepieces/explore-scientific-2x-3x-5x-barlow-focal-extender-125.html

[AstroMuni]

1 hour ago, johninderby said:

The Televue Powermates are excellent but the Explore Scientific equivelents are 95% as good but much, much cheaper and well worth considering.

 https://www.firstlightoptics.com/explore-scientific-eyepieces/explore-scientific-2x-3x-5x-barlow-focal-extender-125.html

Thanks John.

I have read that these ES Focal extenders need longer in-travel of the focusser. Has anyone on this forum used the ES Focal extender with the Celestron 130EQ?

[rockinrome]

Hi John
Getting a really high-end barlow with this telescope *may* not be the best idea as it is likely to show up imperfections in the telescope build (mirror) itself and indeed the supplied eyepieces.
Sure, if you are looking to keep long term and upgrade the scope then I would possibly agree.
Like all these things small steps are the best so that you don't get disappointed early on.
Of course this is only my take on your situation. I have always been disappointed by the view with a barlow (the Moon aside!)
I know that you can't really afford to get a whole host of eyepieces, but you can get 3/4 in a suitable range.

Clear skies
Matthew

 

 

[Ricochet]

1 hour ago, M55_uk said:

Thanks John.

I have read that these ES Focal extenders need longer in-travel of the focusser. Has anyone on this forum used the ES Focal extender with the Celestron 130EQ?

I think that is only in comparison to powermates rather than generic barlows. 

With regards to the barlow, what are you looking to get from it and which eyepieces do you already own? 

[Cosmic Geoff]

57 minutes ago, rockinrome said:

Getting a really high-end barlow with this telescope *may* not be the best idea as it is likely to show up imperfections in the telescope build (mirror) itself and indeed the supplied eyepieces.

Too right. The eyepieces bundled with scope kits are often very poor (especially those of ~10mm) and they should be the first target for replacement.

To put this into context, the whole outfit was on sale for £149.99, the cost of three decent eyepieces, and apparently came with a 20mm erecting eyepiece (shudder) and a 10mm, but no Barlow.

"The supplied eyepieces are cheap, and ok to begin with, but your viewing experience will benefit from some Celestron Plossl's, and a Barlow." - reviewer on FLO.

A Powermate would apparently cost about as much as the whole scope outfit did in the first place.

[AstroMuni]

21 minutes ago, Ricochet said:

I think that is only in comparison to powermates rather than generic barlows. 

With regards to the barlow, what are you looking to get from it and which eyepieces do you already own? 

I have just the standard eyepieces that came with the scope - 10mm & 20mm celestron.

I am hoping to be able to get better view of planets and moon to start with. My reading tells me that Barlow may not be as useful for DSO. Is that right?

[AstroMuni]

15 minutes ago, Cosmic Geoff said:

To put this into context, the whole outfit was on sale for £149.99, the cost of three decent eyepieces, and apparently came with a 20mm erecting eyepiece (shudder) and a 10mm, but no Barlow.

"The supplied eyepieces are cheap, and ok to begin with, but your viewing experience will benefit from some Celestron Plossl's, and a Barlow." - reviewer on FLO.

And that is what I am trying to make a start with 🙂 i.e buy a Barlow & decent Plossls. FYI, the finderscope was rubbish, so bought a Telrad and that has made it a breeze.

 

Edited July 8, 2019 by M55_uk

[Cosmic Geoff]

3 minutes ago, M55_uk said:

I have just the standard eyepieces that came with the scope - 10mm & 20mm celestron.

I am hoping to be able to get better view of planets and moon to start with. My reading tells me that Barlow may not be as useful for DSO. Is that right?

As I wrote, upgrading the eyepieces first will improve planetary views. A Barlow will be more useful for planets and double stars.  Other deep-space targets may require lower power or widefield eyepieces.

[Louis D]

I would pick up a used 1990s Meade 140 2x barlow like this one.  I've A/B compared it with my Televue 2x barlow, and the two are basically identical.  The only low cost barlow I've found that's cleaner is the 1990s Orion Deluxe 2x fully baffled barlow, but it is a monster at 6 inches in length and much more difficult to find.

I like the Meade so much that I've picked up a total of three of them.  One for regular use, one as a backup in case I drop one on cement, and one for reaching focus with a binoviewer.  The fact that the optical nosepiece is threaded in the standard 1.25" eyepiece thread means it can be threaded onto eyepieces or onto the front of binoviewers or star diagonals.

[Cosmic Geoff]

I have a Sky-watcher x2 Barlow that I got with my Startravel OTA.  It is highly unlikely to be the best Barlow in the world (some retailers offer a similar one for 25 pounds) but I have used it for planetary observing with the Startravel and, with a binoviewer on a couple of my other scopes, and not seen anything obviously wrong with it. 

[Ricochet]

On 08/07/2019 at 14:49, M55_uk said:

I have just the standard eyepieces that came with the scope - 10mm & 20mm celestron.

I am hoping to be able to get better view of planets and moon to start with. My reading tells me that Barlow may not be as useful for DSO. Is that right?

A barlow may or may not be useful for DSOs depending on the focal lengths of the eyepieces used with it. For observing DSOs you will want to pay attention to the exit pupil produced by your telescope-eyepiece combination. From a light polluted area you probably don't want to have an exit pupil greater than 5mm, but you might want to go a bit larger to max out your field of view with a 30/32mm Plossl, and you can go as low as 1mm for DSOs that resolve into point sources (i.e. star clusters) if they fit within the field of view. For extended objects (galaxies, nebulae) the acuity of your eye makes a 2-3mm exit pupil ideal. To find the exit pupil simply divide the focal length of your eyepiece by the focal ratio of your telescope (5). If you use a 2x barlow then you effectively halve the focal length of the eyepiece so both your 10mm eyepiece and your 20mm eyepiece plus a 2x barlow will give you an exit pupil of 2mm, which is ideal for DSOs. On the other hand, your 10mm plus a 2x barlow will give a 1mm exit pupil, which is at the limit of usefulness for some DSOs but in the right ballpark for planetary observing. 

With regards to your current eyepieces, I would be looking at replacing both with better alternatives in addition to your planned barlow purchase . A 23mm Aspheric can be found cheaply on eBay and is an optically sound eyepiece. For higher magnifications I would suggest either:

• 10mm Aspheric, 7mm Skywatcher Planetary, 2x barlow
• 12mm Plossl or Starguider, 8mm Starguider, 2x barlow

Which I think would have you quite well covered. Higher priced options are available if your budget stretches either now or later. I think any of the barlows previously mentioned will be optically similar so it comes a bit more down to construction. One with a removable lens cell that can be screwed directly to the filter threads of the eyepiece would give about 1.5X so you could skip the higher power (lower focal length) eyepiece in my suggestions initially. Otherwise I would look for a decent size thumbscrew that is easy to use with gloves and a compression ring to prevent damaging the eyepiece barrels, unless you're more concerned about price in which case the one @Cosmic Geoff mentions is very nice optically and available direct from China very cheaply (without the "Skywatcher" branding).

[Nyctimene]

With my 5.1" Skywatcher Heritage 130 P Flextube (f/5, like yours), I'm using the shorty Baader 2.25x Turret Barlow, and it works very well with the Seben Zoom 8-24, the ES 26mmf/62° LER, a 6mmf Skywatcher UWA, and several orthos. Moderate price, excellent optical quality, lightweight; very recommendable; have a look here:

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p5503_Baader-1-25--Q-Turret-Barlow-und-Foto-Konverter---2-25x-und-1-3x.html

Stephan

 

Edited July 9, 2019 by Nyctimene

[jetstream]

1 hour ago, Nyctimene said:

I'm using the shorty Baader 2.25x Turret Barlow, and it works very well

Excellent recommendation Stephan

 

On 08/07/2019 at 08:52, M55_uk said:

i.e buy a Barlow & decent Plossls.

I would seriously look at the Baader  2.25x that Nyctimene recommends and also a couple of decent plossls, the GSO come to mind which  can be bought at Teleskop Service- I think their brand of plossls are GSO's.

A 25mm and a 10mm would be fantastic and would be great with the Baader Q 2.25x/1.3x barlow. Might as well look at an OIII for down the road too, great for nebula like M42. Ask around on here as there are many brands that give sub par performance.

https://www.teleskop-express.de/shop/product_info.php/info/p3960_TS-Optics-1-25--Ploessl-Eyepiece---25-mm-focal-length--50--apparent-field-of-view.html

 

This will give 25mm,19mm,11mm,10mm,8mm,4.5mm- all very useable in your scope.

Edited July 9, 2019 by jetstream

[John]

I'm another happy owner and user of the Baader Q-Turret 2.25x barlow. Simply designed and made but optically excellent for it's cost

[cletrac1922]

I use Celestron 2 X Barlow with my 10" Flex Dob

Also has screw thread, for filters

Some of the cheaper Barlows, do not have this feature

John

[SIDO]

I own several barlows both cheap and more expensive models, the Meade #126 2x is very good and is optically the best lower cost Barlow I have ever come across...Mine is  like 30 years old now and still competes well even against my Q-Turret and even prefere it to that Barlow.

       You don't have to spend a lot to get a good Barlow but if you want a good Barlow with a compression eyepiece holder then some extra funds are definitely needed.

Best of Luck and Clear Skies of course...

                          Freddie.

 

[AstroMuni]

Thanks for all the tips. All roads seem to lead me to the Baader Barlow 🙂 Will keep you posted once I purchase one.

BTW, Has anyone bought from AliExpress? Some of their prices are quite low ; for example this ES eyepiece - AliExpress ES 4.7mm 68deg eyepiece

 

[John]

32 minutes ago, M55_uk said:

Thanks for all the tips. All roads seem to lead me to the Baader Barlow 🙂 Will keep you posted once I purchase one.

BTW, Has anyone bought from AliExpress? Some of their prices are quite low ; for example this ES eyepiece - AliExpress ES 4.7mm 68deg eyepiece

 

I think you will end up paying import duty on that as its not in the EU. You need to allow around 25% on top of the listed price to cover duty plus handling charges.

 

 

 

 

[AstroMuni]

I think it would be a good idea to have a section on this forum that lists good lesser known vendors (eg: cheaper Chinese ones etc. selling unbranded but decent products). Is there a discussion thread already that I have missed?

[John]

29 minutes ago, M55_uk said:

I think it would be a good idea to have a section on this forum that lists good lesser known vendors (eg: cheaper Chinese ones etc. selling unbranded but decent products). Is there a discussion thread already that I have missed?

There are so many of them and they are changing quite frequently as well. I think it would be impossible to maintain with any accuracy.

 

[Alfian]

As someone who cut my astronomical teeth on a Celestron 130eq I can only strongly reinforce the need to upgrade the supplied EPs as soon as possible. The difference will be  very noticeable THEN get a barlow if desired or another EP for higher magnification. A 2x or 2.25x barlow with a 24 or 25 mm EP will give views not so much different from a 10mm in a 650mm scope, so a 5 or 6mm EP may be better. With the 130EQ the collimation needs to be pretty much spot on to get decent higher magnification views.  I found with the seeing in my location that 150x was the practical maximum. In terms of barlows I can also endorse the Baader QTurret 2.25x. I once had a Revelation 2.5x ED and that was pretty good too.

Edited July 23, 2019 by Alfian

[Louis D]

On 23/07/2019 at 08:16, Alfian said:

As someone who cut my astronomical teeth on a Celestron 130eq I can only strongly reinforce the need to upgrade the supplied EPs as soon as possible.

Never having bought an entry level telescope kit, and for the edification of future readers, could you expand upon what eyepieces come with the 130EQ and what makes them so bad?

[Alfian]

The 130EQ that I had 10 years ago came with 2 eyepieces. The first was a 20mm erecting image eyepiece which by design is already compromised for astronomical use. With the 20mm I assume that Celestron tried to market the 130EQ as both an astronomical and a terrestrial scope which was not a good idea in my opinion.  The second was a 10mm EP that I am guessing was a Kellner. It had poor eye relief and felt like I was looking down a tunnel so I'm guessing it had quite a narrow field of view.  When you are starting out in this hobby  and are looking through a scope for the first time and having had no experience of what to expect, a magnified image of the moon , for example, is quite satisfying.  For me this early "honeymoon" quickly faded and it wasn't until I bought  25mm, 15mm plossls and a 9mm WA EP that I realised how much better things could be even with this relatively humble telescope. Strangely I still have a 9mm Celestron EP that came as standard equipment with another 'scope and although its not the  bees knees its quite usable and Skywatchers standard issue 25mm is similarly usable, yet  another Celestron standard issue EP,  a 3mm, was a plastic lensed abomination.  Such variations are a shame as budding new astronomers need something usable and adequate to start with otherwise enthusiasm can easily fade.

[AstroMuni]

On 23/07/2019 at 14:16, Alfian said:

As someone who cut my astronomical teeth on a Celestron 130eq I can only strongly reinforce the need to upgrade the supplied EPs as soon as possible. The difference will be  very noticeable THEN get a barlow if desired or another EP for higher magnification. A 2x or 2.25x barlow with a 24 or 25 mm EP will give views not so much different from a 10mm in a 650mm scope, so a 5 or 6mm EP may be better. With the 130EQ the collimation needs to be pretty much spot on to get decent higher magnification views.  I found with the seeing in my location that 150x was the practical maximum. In terms of barlows I can also endorse the Baader QTurret 2.25x. I once had a Revelation 2.5x ED and that was pretty good too.

Thanks. I have placed a 'donut' on the primary and done a bit of basic collimation. I also got rid of the erecting prism on the 20mm so its improved a little bit. I took a punt and procured a Svbony 23mm and that has opened a better vista for me. Now contemplating purchasing a Skywatcher Planetary UWA eyepiece 4 or 6mm and the Baader barlow.