Astromaster 130 MD - Barlow Advice

[Andy-T]

Hey guys!

Would a 3 x Barlow be suitable for this scope? After reading various posts i thought i understood that the maximum power would be 2 x your focal width? 2 x 130 = 260. 

The maximum stated on the various retailers websites claims that the maximum is 307.

I have the standard issued eye pieces that are 20mm and 10mm. Would the 10mm still work with a 3 x Barlow. Is it 65 (10mm eye piece) x 3 = 195? Would this be too high for my scope to manage? The Barlow has been bought as a gift, i dont want to open it should it be not be usable.

I am very new to this, its a big learning curve!

Thanks all

[laowho]

We went with 1.5x Barlow because of the Optimum Magnified Visual Angle of Clark for DSOs...and it's a formula cited in many books. Many of the 2x Barlows can be modified to give 1.5 x as well. But 3x? Others will know better, but I'm wondering whether there isn't some relationship between apertures and effective Barlowing? Whether smaller apertures are better suited to less Barlow magnification?

[laowho]

Or whether your aperture can "handle" a 3.3mm eyepiece?

[Andy_E]

260x is an almost unusable magnification for most telescopes apart from the occasional (extremely rare) night of exceptional seeing. Technically the barlow multiplies the focal length of your telescope, so in your case making it a 1950mm (assuming it's a 650mm). Personally I wouldn't bother with a 3x barlow... it will be very rare that you get to use that sort of magnification in your current set up. Much better to go with the standard 2x, or perhaps 2.5 (in the case of the revelation).

Personally I'd rather ditch the barlow idea and go for a dedicated high power EP (something like a 5mm starguider or similar).

I'm assuming you're after this for planetary viewing?

Hope this helps.

[Andy-T]

Thank you for the replies, its a great help!

Truth is i am a complete novice, i am still learning the constellations while trying to build up my knowledge of the sky. I have so far only located Albeiro in the summer triangle and the double cluster above Perseus. I am trying to find targets that are not too difficult to find. Andromeda Galaxy is next, with Hercules cluster. Will these be visible with the 10 mm lens?

I have some 10 x 50 Celestron binos on the way, these i hope will help in learning the sky, im trying to walk first, but its so tempting to run and buy all in sight!

Thanks guys!

[laowho]

Both Andromeda and M13 (your Hercules globular cluster--and while you're there check out another, nearby M92) will be visible in that EP, but for Andromeda you want your widest field EP first. As for the globs, they're custom made for your 10mm EP.

[laowho]

P.s. Congratulations on your new binocular purchase. Everybody should have one!