A lot to think about. I want at some point to make my own scope and yes, grind my own mirror. See, as a teacher I get these LONG three week breaks throughout the year (one basically in each season) and after getting done with the honey do's and my own do list, I get really bored and have a couple of weeks to kill (I do sub and that pays for this hobby). Anyway, I think this would be a really interesting project to tackle and as others have said, it won't be one the first time I want to do alone. So I'll wait. Good things always result from waiting. Thanks for the advice. Also, when I do it, I want to build it for me, and not go in with others on one scope. I would go in on purchasing materials if it means we got to get going. Guess we or I would need a teacher first. Jay On 2009-01-08 00:53, Chuck Hards wrote:
The wrong ladder in the dark can definitely be hazardous, but that's not exactly a problem with a long-focus telescope; it's the wrong choice of ladder. The right choice might not be easily transported, or even easily used at the eyepiece, so that's one of those choices people make.
I think the original context of the question was short focal- length mirrors as a first effort at mirror grinding. They do take more work and can be more difficult to figure, but it's not out of reach of the average person, given the proper guidance. If, however, one is purchasing a commercially-made mirror, all the caveats of fabrication can be ignored.
I don't agree that deep-sky observing is better at f/4, as a blanket statement. My little RFT is an f/5 and the coma is noticeably less than otherwise identical telescopes I built at f/4, yet the field isn't much smaller using the same eyepiece.
I also don't weigh my equipment choices against their fit at a public star party. I'm kind of selfish with my astro-time- my personal enjoyment is my prime motivation. I'll blow-off being "star-party correct" in a heartbeat if I feel I can get some kind of advantage by doing so. On nights when I'm specifically doing the public outreach job, then convenience and safety will trump imagery out of necessity.
The telescope must be designed for it's intended use. One person's trade-off list will probably not correspond one-for-one with someone elses.
On Wed, Jan 7, 2009 at 1:59 PM, <zaurak@???> wrote:
The narrow steps on a ladder can take a toll on your feet in the course of a night. The classic dobson is long focal length, but there are many companies that do a good job on fast optics in the 4f range. Deep sky observing is better with f 4's.
Tall ladders seem a liability for public star parties.