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Trouble focussing barlow

ejp

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ejp

ejp

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Hi guys,

Hope someone can help me with this. I've been scoping now for a little over a month, so I'm fairly new to this. Whenever I use the 3x barlow that came with my Powerseeker 70eq I have difficulty focussing on Jupiter. The moon is no problem. I can almost see the dust in any crater on the moon, when I use the 4mm lens + 3x barlow. However, when I point the 3xbarlow + 4mm combination on Jupiter I can't seem to get a clear image. No matter how I turn the focus knob, the view of Jupiter and its moons is blurry at best. (Also, I find it annoying that turning the focus knob on my powerseeker makes the view shift.)

Am I doing something wrong? Or is this due to light pollution? Should I not be looking over rooftops? Or is this because of the chemtrails conspiracy (yes, I have bad sense of humor)? The 3xbarlow + 20mm combination is just fine.

Thanks, Eric.

PS English is my second language so please don't be annoyed by any mistakes.

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Peter Drew

Peter Drew

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Hello Eric. I suspect that the magnification produced by the combination of the 3x Barlow and 4mm eyepiece is too high for a clear view of Jupiter, the Moon is far more forgiving. Small movements of the Barlow lens rapidly changes the focus so more care is needed to adjust this. As with most things, practice will be a big help in due course.  :smiley:

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ejp

ejp

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Hi Peter and Paul,

Thanks for replying so quickly. So far this forum has been a great way of communicating. I'm glad that I found it.
I believe the English expression is "practice makes perfect", right? I have found that patience is a great asset when it comes to stargazing. I will try your suggestion, Paul. I'm really curious what kind of image this combination will provide.
Also, I like what you said Peter. "The moon is more forgiving." How poetic. :)

Thanks guys.

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LukeSkywatcher

LukeSkywatcher

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" the Moon is far more forgiving".

Yes it is, but is it so forgiving in a 70mm scope using a 4mm ep and a 3x barlow. I cant imagine so. Ive obsrved the Moon once with a 4mm EP on a perfect night. Never used the same 4mm EP since. I certainly could not imagine adding a 3x barlow to the equation for observing purposes, maybe imaging though.

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LukeSkywatcher

LukeSkywatcher

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Hi Peter and Paul,

Thanks for replying so quickly. So far this forum has been a great way of communicating. I'm glad that I found it.

I believe the English expression is "practice makes perfect", right? I have found that patience is a great asset when it comes to stargazing. I will try your suggestion, Paul. I'm really curious what kind of image this combination will provide.

Also, I like what you said Peter. "The moon is more forgiving." How poetic. :)

Thanks guys.

There is a website which will show you how the planets should look in most scopes and using any eyepiece. I just cant remember it right now but i know someone else will post a link. It really is a pretty true representation (under perfect conditions). 

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ejp

ejp

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Thanks Sirius and Luke for your replies and the kink to the website. That website is really genius.

The reason for using the 3x Barlow + 4mm was that I hadn't done it yet. I was curious what it would result to. Turns out I have to learn more about using the right equipment. But thanks again guys. This stuff really helps me getting better at stargazing.

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RLWP

RLWP

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" the Moon is far more forgiving".

Yes it is, but is it so forgiving in a 70mm scope using a 4mm ep and a 3x barlow. I cant imagine so. Ive obsrved the Moon once with a 4mm EP on a perfect night. Never used the same 4mm EP since. I certainly could not imagine adding a 3x barlow to the equation for observing purposes, maybe imaging though.

Somewhere on this international thingy, I found a website that explained not only the magnification you get with a particular objective/eyepiece combination but also the diameter of the image at your eye. IIRC this combination produces a high magnification image that isn't very wide, making it hard to see

I must go find that site again

Richard

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