Dob ease-of-use?

I've had a telescope on a german equatorial mount but just sold it. I'm considering a dobsonian, but I'm wondering about the practical limitations due to its lack of tracking. How high can you go with the magnification before keeping it centered gets impractical? Does it get old having to constantly move the scope when observing? In all the articles I've read, nothing has addressed this subject; I'd appreciate some real-world opinions from those of you who have used them. Aperture is not the question here -- I'm just looking at an 8 or 10, which can be had in either configuration, but the dob is more portable and quicker to set up. Thanks.

It's interesting how a great deal of the dicussion with reflectors is directed to the optics and little is said about mechanics.

In general, most dobs in the size you are looking at will not be of a "premium" pedigree. Consequently they can all use some tweaking and puttering to make them more of a joy to use. Tweaking the movement is one of the items most considered. There are many good discussions on this topic on the yahoo group Skyquest-Telescopes.

I have a premium truss Dob and the movement is sublime. I also have a Discovery Premium 8" and it works OK, but planetary viewing at 450x shows the mechanics could use some tweaking. I have no experience with the current crop of Asian scopes, but everyone has a different level of tolerence for nudging the scope. The short focal length Naglers begin to look a whole more inviting for planetary viewing however.

Gary Weber

The only time I've really missed the tracking is when I'm at a star party and have to keep jumping in to adjust for the kids looking through the 'scope (I've got a 12.5" truss-Dob). On the other hand, it's kinda nice to be able to actually LOOK once in a while! BTW, I (fairly) routinely go to about 300X. It's not a big deal - you just have to "lead" what you're looking for and let it drift across. In some ways it's actually a little better as movement seems to bring out contrast (at least for me). The only real drawback is not being able to do photography, but my Digital Rebel won't come to focus without double-barlowing anyway! I really don't think you'll be disappointed in a Dob - the convenience outweighs the tracking, in my opinion.

Pat

Personally I don't have much trouble with tracking a DOB. It does take a bit of practice.

The typical Asian DOB has adequate action when new but as someone else pointed out, with a bit of tweaking (read that Ebony Star and Teflon) things will be very good. Some attention is necessary every so often is necessary to keep things nice and smooth, no biggie.

One thing I like about DOB mounts is that are more stable and vibration free than non=premimium EQ mounts. Focusing in real time is a real pleasure.

Bottomline: Some folks like DOBs for their simple elegence. Some like more gizmos.

Star parties-club outings, try before you buy.

jon

Craig,

I bought an Orion XT10 and worked endlessly to get to the panacea of motion. My bar was set very high. No kidding finger light touch with a predictable motion (no "stiction"). I tried everything. Every lubricant, every type of pad, lazy susans, zen, incense, incantation. Nothing got it to where I thought it was perfect. I thought my level of perfection was not achieveable until I went to a star party and tried a couple of premium dobs. Ahhh, now that was nudging nirvana. If you gotta nudge, it should be with the precise predictable motion of a Starmaster (or equivalent). No kidding, one finger, onces of pressure, predictable motion. My XT10 got close, but I never achieved what my Starmaster currently offers with respect to motion.

http://www.tomhole.com/Motion%20Tips%20and%20Tricks.htm

But, having said all that, I hate nudging. I started hating it after I didn't have to do it and realized how much I hated it without knowing it. Is that really hate? I built an eq platform for $130 that worked for my XT10 and now works for my Starmaster.

http://www.tomhole.com/EQ%20Platform.htm

Now that I have it, I can't live without it. I know folks say nudging isn't hard, and it isn't. But most of my nights involve bad seeing with fleeting moments of good or (eeegads!) great seeing. Missing those moments because I am in the middle of a nudge was irritating. Combine a good dob with an eq platform, a comfortable observing chair and binoviewers and you have an experience that is so comfortable you may fall asleep at the ep(s). It's like you are in the view rather than looking at it. I will spend hours on just Jupiter or the moon and never tire of the viewing. All of my equipment just gets out of the way and I spend all my time just sitting there looking at stuff. And the bonus is star parties where you just center up Saturn at 405x and let it track for many minutes as folks step up and ask "Is that a picture?"

Anyway, that is my concept of observing perfection. Doesn't mean that it's everyone else's, though. Nudging is easy and painless until you don't have to do it anymore.

Clear skies,

Tom

Tracking platforms with a dob will give you all the tracking you need for visual observing at a fraction of the bulk of a GEM.

My not-so-premium dob's motion, even unaltered, was and is perfectly fine for 90% or more of my viewing. For showing people stuff at public events, or at high power planetary viewing when I want to also sketch, the lack of tracking is a bit of a bother. I borrowed a tracking platform one evening for a public event, and it was a dream! I haven't yet been compelled to scrape up the funds for my own personal platform, though.

Thanks very much to all for your replies -- excellent info, just what I needed. Now to make the decision ....