Quote:Absolutely. The magnification factor of a barlow (M) is determined by:M = 1+e/|b|, where 'b' is the focal length of the barlow and 'e' is the distance from the eyepiece's focal plane to the center of the barlow lens.
10" F/4.7 Modified Skywatcher Reflector, 38mm Orion Q70, 17mm Modified Ultima LX, 10mm TeleVue Delos, 7mm Pentax XL.
15" f/5 Tectron
Mallincam Junior Pro
TMB 40mm Paragon,Leica ASPH zoom,
WO binoviewer w/assorted pairs
"Yeah, well, you know,that's just, like, your opinion, man."
Quote:I have never tried the aforementioned GSO, but it does seem to get high marks.
Vixen 140mm Neo-achro, 2" AP Maxbright diagonal, 50mm Celestron Vixen Silvertop plossl, 35mm, 18mm, and 15mm Ultrascopic/Ultima, 28mm & 20mm ES 68, 19mm TV Panoptic, 5.5mm Meade UWA, 2.4x 2" Dakin barlow (prototype barrel).
Quote:I've read about folks stacking barlows to increase mag, but it would be so much cheaper to just get (or make) extension tubes to do this.Is there some drawback you didn't mention?
The opinions expressed herein are solely mine as an amateur astronomer hobbyist & consumer. Information herein was correlated from experience, discussions with others, & research from multiple sources freely available at time of posting. All reasonable care & skill was used, but no warranty is made as to accuracy, & liability cannot be accepted for errors/omissions. This is for information only and not intended nor implied to be a substitute for professional advice.
Quote: The Barlow does not have an "unlimited" ability to handle increased or decreased distance. For instance, with a 2.7x Barlow I have reducing the distance below that needed to achieve 2.2x introduces off-axis astigmatism and lateral color. So there is an operating range when the image is "best". Go outside the range and your image starts to deteriorate.