The same can be said of your "central star" statement. From what I've been reading, now stellar evolutionists believe that the white dwarf stage isn't clearly reached until the planetary nebula has ceased to exist- an incredibly short lifespan of only a few tens to a hundred thousand years is typical for a planetary nebula. Central stars of visible planetaries are considered pre-white dwarf stars. The knowledge base continues to be refined as time passes. It may be that Bishop knows this but wanted to point out examples of stars unambiguously settled in the white-dwarf stage. Firmly in the stellar grave yard, with no evidence of recent nuclear reactions in the immediate environ. Bishop never made an absolute statement such as you imply; he mentioned no apertures at all. A 10" telescope isn't considered a small telescope by the general public- or with many serious amateurs. It's pretty big to me, and I've been doing this since 1968. Hair-splitting, semantic games can always be played with someone's words trying to communicate astronomy to a wide audience. Only a tiny fraction of people would jump on a soapbox and find issue with Bishop's exact choice of words. I wholeheartedly approve of Bishop's piece, and your statement does nothing to provide contrary evidence. On Sun, Jan 25, 2009 at 3:36 PM, daniel turner <outwest112@yahoo.com> wrote:
The problem comes when someone writes with a voice of authority about what "can't be done". This causes people to immediately try to prove them wrong. Bishop may regret his choice of words but it's best to remember that just because you haven't seen something, doesn't mean the other people haven't either or that next year they might be able to.
I look at dozens of planetary nebula every year, and a large fraction of these have an easily seen central star. Most can be seen with a 10" which is no longer considered a particularly large telescope anymore. The standards for an "amateur" or "backyard" or "average" telescope may continue to change change with time.