Barlow recommendations

[2Karl]

Hi all,

I'm planning on buying a barlow for my celestron 130SLT, and as with eyepieces there seems to be a bewildering amount of choice and more than a whiff of "emperor's new clothes" lingering over the more expensive options. My budget is limited in the short term (perhaps £50-£100), but I'm willing to spend more and not eat for a few weeks if it means getting a quality barlow which will last until my untimely death or the heat death of the universe (whichever comes first). Having said that, forking over 200 quid for something which provides a negligible improvement over a £100 offering is a mug's game, and I'd need a compelling reason to do so.

To whit: I am seeking personal recommendations with justifications beyond "This is what I have and it's good" (what makes it good?, what are the benefits/drawbacks? how does it compare to other barlows?), or links to objective reviews (ie not thinly veiled sales pitches).

Now, I have tried out a celestron X-Cel 3x barlow and it worked very well with the 25mm and 9mm eyepieces I got bundled with my telescope, but I want to get a few options before I splash out. On my list of "possibles" are the X-Cel 2x or 3x (I'm leaning towards a 3x rather than 2x as I plan to use it with a meade 4000 zoom as well as my bundled eyepieces and any other eyepieces I buy in the future, and the 3x would give a greater range than 2x, ie less "duplication" of power levels with/without the barlow), the celestron Omni 2x, Orion TriMag and Baader Classic 2.25x.

As mentioned, I have tried the X-Cel out personally; The omni got good customer reviews, although some people have suggested that it's worth spending extra on something else; the TriMag seems to get a lot of love on forums; the baader seems good value from what I can tell. It's worth noting that I've not really be able to find reviews of these lenses beyond forum posts and amazon reviews etc.

Any help or useful opinions would be appreciated. I'm not really interested in hearing about how I "shouldn't get a barlow", or how it would be better to "get higher power eyepieces instead"- I've made very careful consideration and decided a barlow is something I want to buy, I just need to decide which one.

If it's important in your considerations, my aperture is 130mm, focal length 650mm giving a f/5 focal ratio. Also if it makes any difference I'm interested in branching into astrophotography at some distant point in the future, but that's a long way off right now.

Many thanks!

[johninderby]

The Explore Scientific focal extenders are very good. Very close  to the Televue ones in performance. I prefer extenders to plain barlows.

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

https://www.telescopehouse.com/explore-scientific-3x-barlow-focal-extender-1-25.html

I have the 3x version and it simply gets out of the way so to speak. By that I mean except for the increased mag you don’t notice any other effect and barely need to refocus after adding it. That’s what I particularly like compared to a true barlow. Eyepiece  eye relief doesn’t change either which is great for glasses wearers. An extender usualy works better with wide angle eyepieces which can have vignetting problems with a barlow. 

            John

 

[2Karl]

That's interesting, I had made the assumption that "focal extender" was just another name for Barlow. What's different about them?

[johninderby]

The achieve similar things but the designs are quite different. The extenders are a more expensive design though and a bit bigger and heavier. which is why there are still a lot of barlows around. 

Usefull info here

 

[2Karl]

Much appreciated.

[2Karl]

OK so it seems that the ES 3x FE is front runner. How much does it weigh? I've heard tell that they're pretty heavy and might not play well in my 130mm newtonian

[25585]

On 26/06/2018 at 12:05, johninderby said:

The achieve similar things but the designs are quite different. The extenders are a more expensive design though and a bit bigger and heavier. which is why there are still a lot of barlows around. 

Usefull info here

 

Interesting read. So TEs are like Petzval refractors design in a loose sense?

[Nyctimene]

9 minutes ago, 2Karl said:

How much does it weigh? I've heard tell that they're pretty heavy and might not play well in my 130mm newtonian

If weight is an issue, the Baader 2,25x Barlow (67 g) could be a solution:

https://www.teleskop-express.de/shop/product_info.php/info/p5503_Baader-1-25--Q-Turret-Barlow-and-photo-converter---2-25x-und-1-3x.html

This small and lightweight Barlow works quite well with my Skywatcher Heritage 130 P Flextube (130/650 - the same optics as yours), and gives very sharp views, e.g. with the Seben Zoom 8-24 mm. It's my most used grab-and-go combination at the moment.

Stephan

[2Karl]

The baader is indeed in my shortlist.

 

EDIT: I don't actually know if weight would be a concern - I don't know what the limits are

[johninderby]

2 hours ago, 2Karl said:

OK so it seems that the ES 3x FE is front runner. How much does it weigh? I've heard tell that they're pretty heavy and might not play well in my 130mm newtonian

246 grams

[Ricochet]

3 hours ago, 2Karl said:

OK so it seems that the ES 3x FE is front runner. How much does it weigh? I've heard tell that they're pretty heavy and might not play well in my 130mm newtonian

I would be inclined to go for the 2x model instead. In an f5 Newtonian you're unlikely to see any benefit in going past the equivalent of a 4mm eyepiece. This means with a 3x barlow you will be using the 24-12mm part of your zoom's range which is the part where the AFoV is narrowest while with a 2x barlow you will use the 16-8mm range which gives the wider views. 

[2Karl]

Many many thanks to all the help and advice on this thread. The Baader came close to being my top pick, as did the ES, but in the end I went for a Revelation Astro 2.5 - some reviews I read on this site and elsewhere put it in a good class especially for the price. I also bought a lens cleaner and a set of filters, so I'm all set to view Mars!