August 2010

Star-hopping Tutorial: Lesson Two (M27)

 M27For the second lesson in the star-hopping tutorial series, we’ll star-hop from Albireo (β Cyg) to M27, the Dumbell Nebula. This is a relatively short star-hop—in fact it is shorter than M57, our first lesson. But unlike M57 where we star-hopped using 3rd and 4th magnitude stars, this star-hop will rely on fainter 5th and 6th magnitude stars—stars that are usually invisible in washed-out skies...

Other tutorials in the series:  Lesson 1Lesson 3


Zhumell 10 inch Dobsonian Reflector

Zhumell 10 inch DobsonianSince 2007 my primary telescope has been the Z-10: a Zhumell 10 inch (250 mm) Newtonian reflector on a Dobsonian mount. Many might argue that so much aperture is wasted in washed-out skies, but I found the Z-10 suits my needs quite well. It is sometimes claimed that in light-polluted skies larger apertures only further brighten the background and diminish contrast; that in washed-out skies you can actually see more with smaller apertures. I’ve found that to be simply another urban legend: the Z-10 does quite well in pulling in DSOs from my front yard despite the heavy light-pollution. It consistently shows objects that I can’t see with smaller apertures. The Z-10 also just fits in my car (a VW Passat), allowing me to easily take it to nearby parks or to far-away dark-sites.

I’m reasonably satisfied with the Z-10, although it isn’t a perfect telescope by any means. The optics are okay (but not great) and the mount is reasonably steady. As with all Dobs, I’ve made some modifications to make it better suited to my needs....