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x2 Barlow Lens, making the view totally blurry


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Hi,

I've tried to focus my x2 Barlow with a 10mm eyepiece (i have a 130mm skywatcher explorer newtonian reflector, 900mm focal length) on jupiter one night, as well as on the moon on another night, and it just comes up as totally blurry, and attempts to focus it are in vein and does not seem to do the trick.

Any advice or help you can supply me with?

Thanks, The Stargazer

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  • 2 weeks later...

I had this same issue when I received my Celestron 2X Optima barlow. In my normal 15 mm and 6mm lenses, I could make out some small but clear detail of Jupiter with my Orion StarBlast 4.5, but when I put the barlow in it's just fuzz fuzz fuzz. Was wondering if this particular one is just poor quality or what.

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That's giving you 180 x magnification... If you consider the 10mm ep that came with the scope is probably not the greatest quality and that the Barlow may not be spectacular... 180 x might be pushing it unless the seeing is perfect and the scope is well cooled and collimated, or it might just not be able to reach focus, try it with the ep slightly out of the Barlow. ?

Good luck :D

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I had a similar problem with a Barlow I bought. The only way I could get it anywhere near focus was to unscrew the bottom lens nearly all the way out, and the mounting collar too. Yes it worked, but it was far from perfect. I believe what I bought was what they call a short focus Barlow?

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As you focus, does the blur ever reach a smallest circle, or do you hit the limit of the focus travel when trying to focus? If the former, other than a poor Barlow or poor eyepiece it could be poor collimation, barely noticeable at low powers but you'll spot it when you crank things up, or it could be the focus "sweet spot" being too small to easily locate with a basic focuser, or it could be spherical aberration reducing the maximum usable power since some examples of the 130 and 130M (but not the 130P) reportedly use a spherical primary mirror.

If you're hitting the limit of the focus travel then that's simpler. Not enough outward focus and you can use an extension tube. Not enough inward focus and the normal resolution is to use a Barlow so I'm not sure what you'd do!

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If you are using the stock 10mm that came with the scope then that is your problem. Its well known that the 10mm EP that comes with the scope is not up to standard. I had the same problem a while back and changed both the 10 and 25mm fairly quickly and the results were amazing. I think they wanted to put all the money into the scope to be honest as the basic EPs can be replaced. Hope this helps

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Neither the barlow or the 10mm are generally much use, and combined they tend to be nototously poor.

Sure that putting in two poor quality items does little for the hobby and that perhaps one decent eyepiece of say 12mm or 15mm would be more useful, but they would then start supplying a poorer quality single eyepiece to save costs. So back to the same situation.

I find it easier to simply expect to buy 2, maybe 3, additional eyepieces and basically ignore the supplied items - the 25mm does seem to operate most of the time.

You scope is I believe the one with the spherical mirror so high magnifications will not be sharp.

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Hi,

I've tried to focus my x2 Barlow with a 10mm eyepiece (i have a 130mm skywatcher explorer newtonian reflector, 900mm focal length) on jupiter one night, as well as on the moon on another night, and it just comes up as totally blurry, and attempts to focus it are in vein and does not seem to do the trick.

Any advice or help you can supply me with?

Thanks, The Stargazer

I have trouble with my 130P parabolic newt with a Celestron LX Barlow combined with my BST EP's. I believe the cause of my problem with focussing with a Barlow in my scope is mainly that it is such a small sweet spot to get the focus right at high power. It does seem much more persnickety when using a Barlow as opposed to using a single powerful EP to achieve the same mag. That's a shame because the Barlow was £££!!! With persistence I can get it most of the time but can be frustrating. If I had a fine adjustment for the focus it would help but cannot see one for sale that would fit anything below an 8" scope. One thing I did do was to slightly tighten the screws at the bottom of the focuser to increase resistance when turning.

I posted regarding my issue and you may find some of the replies helpful. Then again, I don't have a swish collimation tool so my scope might be slightly out. I did check it after getting advice and it still seemed ok but it won't be 100%.

Neither the barlow or the 10mm are generally much use, and combined they tend to be nototously poor.

Sure that putting in two poor quality items does little for the hobby and that perhaps one decent eyepiece of say 12mm or 15mm would be more useful, but they would then start supplying a poorer quality single eyepiece to save costs. So back to the same situation.

I find it easier to simply expect to buy 2, maybe 3, additional eyepieces and basically ignore the supplied items - the 25mm does seem to operate most of the time.

You scope is I believe the one with the spherical mirror so high magnifications will not be sharp.

Given the difficulty I have with good optics, I can only imagine it is even worse with the factory 10mm and Barlow. I'm assuming it is the factory Barlow because the focal length of your tube is a package deal that comes with a supplied Barlow (my 130P package does not). I would recommend you go for a nice high power EP for your repertoire. A 7mm would give you roughly 130x which is a nice power for the SW 130. You need good seeing to realistically exceed that, and we all know how hard that is to come by!! Hope this is helpful.

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