I have a nice telescope and it came with a barlow lens,, my question is exactly how do you use this lens? i have attepted to use it many times but it seems that i can not focus in on any one star or planet,, can you advise on how to use this lens and what power eye piece should be used with it?
thanks,,
2007-05-18 02:26:15 · 5 answers · asked by SPACEGUY 7 in Science & Mathematics ➔ Astronomy & Space
A Barlow lens is used between the telescope and any eyepiece, and effectively doubles the magnification of the same eyepiece without the Barlow. Unfortunately, the Barlows included free with inexpensive telescopes are almost always total junk, with a plastic lens. They provide way too much magnification and result in dim blurry images. They're put in the package so the manufacturers can advertise ridiculously high magnifications on the box. The same is usually true of the shorter focal length eyepieces provided, typically 4mm focal length. Throw away the Barlow and the 4mm eyepiece, and stick to the 25mm or 20mm eyepiece, which is usually the best. A good Barlow costs at least $80 by itself.
2007-05-18 03:26:09 · answer #1 · answered by GeoffG 7 · 1⤊ 0⤋
Most barlows slide into the focuser tube and you insert the eyepiece in the barlow, but there are other configurations.
In the barlow, insert the lowest powered eyepiece you have. Then slowly turn the focusing knobs until the image is sharp.
Barlows essentially increase the magnification so more often than not you have to zoom out to focus.
2007-05-18 14:55:20 · answer #2 · answered by minuteblue 6 · 0⤊ 0⤋
A Barlow is used in combination with a regular eyepiece. Take the eyepiece out of the focuser, put the Barlow in the focuser, and then put the eyepiece in the end of the Barlow. Now you look in the eyepiece, which is in the Barlow which is in the telescope, and you get more magnification.
2007-05-18 02:49:03 · answer #3 · answered by campbelp2002 7 · 1⤊ 0⤋
After you place the barlow on your telescope, you must also attach one of your standard eyepieces to the barlow. Just looking directly through the barlow, with no other eyepiece there, won't work.
Hope this helps ... good luck!
2007-05-18 02:41:25 · answer #4 · answered by genericman1998 5 · 1⤊ 0⤋
It should work just fine. I believe you need to mount the barlow between the lens and the focus or between the prism (on a refractor) and the focus collar.
You may need extension tubes, but genearlly they work directly.
2007-05-18 03:29:40 · answer #5 · answered by Anonymous · 0⤊ 0⤋