5mm eyepiece or 2.5x barlow?

[johncbradley1]

Can someone help me decide which one of these I should buy: Revelation Astro 2.5x Barlow Lens 1.25" or Ostara 5mm 1.25" Plossl HR Telescope eyepiece | eBay

I have a Celestron 130EQ and the standard low quality 20mm & 10mm eyepieces that came with the scope. I want to use it for viewing everything, nothing pacific. Only can afford one item.

Any help is welcome! Thanks!

[Grotemobile]

Hi, i would go for the 5mm EP.This is one of the most EP i use. I have a 102mm Vixon refactor, i always end up using this.Good for everthing .Hardly use my barlow.

Steve.

[JBadger]

To be honest, I think a 5mm eyepiece will just be dissapointing and you'll regret buying it.

Personally, I would get a 2x barlow. You'll then get the equivalent of a 5mm eyepiece using you 10mm, which will be 130x in that scope.

[jkwhinfrey]

You're scope is an f5 Newtonian like mine, and they're a bit sensitive to cheaper EPs, and short focal lengths make the problem worse in my opinion.

Personally I'd probably go for a 2x Barlow as has been suggested.

You could take a look at this thread, apologies if you've already seen it, there are some good comments from people using the same scope facing a similar dilemma.

http://stargazerslounge.com/beginners-help-advice/77827-celestron-astromaster-130eq-eyepiece-help.html

[dag123]

Hi JohnBradley1,

I have the same scope as you and I would advise you to think carefully about getting a 5mm EP. I have the Celestron X-Cel ED 5mm which I got from FLO (it seems they still some available with the same discount).

First Light Optics - Celestron X-Cel ED eyepiece

Now I am very happy with it, but it is not what I would call a general-use item. I note you specifically say you want to use it for everything!

I have used it for viewing Jupiter but I found that it was pushing the limit of the scope and the image in my 10mm Celestron X-Cel ED was showing clearer detail, albeit a smaller image. I get most use of it splitting doubles (e.g the double-double next to Vega) and for my star-tests for checking collimination.

If your 130EQ, like mine, is not motor driven, things will not stay in view very long when using any 5mm EP.

With the 2x barlow from my EP kit, I can get the mag. up to 260 which is way past what is useable for the scope.

In my opinion, if you want a general-purpose EP that you will end up using a lot, you probably don't want to be looking at anything less than 8mm (maybe-even 10mm). In fact you might consider looking at the other end of the scale. My 32mm EP from my Celestron kit is my most-used, it makes things so easy to find.

I hope this helps

dag123

[datman]

Hi

I have a C130 and was very disappointed with the view through a balow lens. Have you looked at the BST Explorer dual ED from Skys the Limit

I was very pleased with these and use them in the C130 & SW200P.

At £41 they won't break the bank either.

5mm is about the limit for both IMO and only when the seeing is good.

Any more and you just get a bigger but fuzzier image.

8mm or 12mm would be a good start if you are looking for Planets.

With 8mm I could see the bands on Jupiter quite clearly.

[sulaco]

I have a SW 130p and prefer the view with a Televue 11mm plossl or 15mm Vixen NPL and my 2.5X Reveletion Barlow than that of the smaller ep, The aperture is just too small on that size EP.

[jkwhinfrey]

I've find that my 9mm Meade 5000 is nice and sharp with my f5 130P, and I can 2x Barlow this EP with some success, making it similar to a 4.5mm with better eye relief.

The image is really tricky to get sharp, after all it's a fast scope and 144x might be pushing it, though I'm not entirely convinced.

I think I get more use from this EP in this combined configuration than I would from a dedicated high mag EP.

Having said that I'm considering a 6mm EP to just breach the 100x barrier. A single millimetre of focal length makes a big difference to the magnification at this end of the size scale.

[michael.h.f.wilkinson]

A good barlow on a good EP is OK, but a poorer barlow with a poorer EP may not be a good way to go on a fast scope. Something like the TMB planetary EPs (or the clones) could be OK, and they are not expensive. As others have said, such magnifications work mainly for planets and the moon. Getting better, low magnification EPs gets you much better views of a wide variety of objects.