Posts Made By: Alex McConahay

Howie will certainly get a lot of votes, as will a number of other manufacturers.

If you are looking for something that will always be tight in your focuser, try Hotech. It's 1.25" fits into its own special 2" adapter. Both have a "self centering" mechanism. You turn the centering ring, and a rubber collar centers and locks the collimator in place.

Note, however, that this is no guarantee that the beam will always be in the same place. You have already been told about laser beams that are not in themselves centered. In addition, you may have a problem if your "2" inch inside diameter focusing tube is not the same "2" inch outside diameter as the collimator. Two inches, in other words, is not always two inches when one starts machining. If your focuser itself is not tight, that slop will move the beam from one insertion to another. And if the set screw that you use to hold the collimator tight in the tube is tightened incorrectly, then you may inadvetently adjust where the beam goes.....All collimators are subject to these vissicitudes. Quality collimators overcome them by centering the laser better, having better machining, and such. But, a sloppy focuser will still let the beam vary between insertions.

The real advantage of the Hotech is that it centers itself, and locks without using the setscrew. So, at least it helps overcome some of the problems from mismatch between the focusers 2 inch, and the collimator's ideas 2 inch. It also keeps the collimator locked in place during the collimation. And since you do not use a setscrew, you are not changing the location of the collimator.

But, hey, we may be splitting hairs somewhat here. If you want really good collimation, get yourself a quality laser collimator, yes. (Almost any of the premium quality lasers will work well. And the inexpensive also work pretty darn well, also.)But also get yourself a sight tube/Cheshire, and learn how to use the stars themselves as collimation targets.


Alex

As for the tube:
It depends on how the focuser was "stopped down." If it is just adapters, then take them out. But I suspect it was more than that. I think if you went over to the classifieds here you could find a 2 inch replacement focuser pretty easily.--Although a 1.25 would be sufficient--figure that the secondary would not really fill a 2 incher.

As for the mount:
It depends on whether it is stable enough as it is. If you are generally happy with it, then use it, even if it is EQ instead of Alt-Az. If not, you could make a Dob base for it pretty easily probably.

As for eyepeices. Agree, you probably want to invest in some good quality Plossl's at least--probably $20 each.

Alex

Maybe not--the nearly full earth moon may be in almost the same field of view.....Some five degrees off (Okay, that would be a really big field of view----but there will be lots of skyglow aroung Jupiter).

Moreover--I've been having a problem with this. I like looking at Jupiter and its moons. Why am I excited about seeing the planet without its moons. Its moons are one (okay 4) of the coolest things about Jupiter.

Alex

I checked out the timings on Sky and Tel, and it seemed that my events were happening consistently 5 minutes before listed. (And yes, my UTC clock was set right!!!!)

Also, The Sky did not have Ganymede in the right place. It had several inconsistencies.

I have not thought it out, but are the events location dependent? I do not recall there being any "geographic setting" input request in the Sky and Tel thing--and besides I cannot see why it would be dependent. Wasn't timing the moon's appearances one of the ways to tell longtitude before they invented clocks?

Alex

I've never had any problems with personal messages that I know of.

How are you communicating with this fellow?

Alex

PATS is coming up in a couple of weeks. (September 25-27, Pasadena). The program has been posted at

http://www.rtmcastronomyexpo.org/PATS/patsnew/backProgram.html

Saturday features Wally Pacholka, Rusty Schweickart, Sean Walker, and Arne Henden.
Sunday has Bruce Betts, Sean Walker, and Stephen O'Meara.

Both days also have a number of workshops, demonstrations, and such, in addition to what looks like about fifty or sixty vendor booths full of new goodies for you to look at.

There is also still room in the Imaging WOrkshop on Friday, September 25. Info on that is at:

http://rivastro.org/raw_registrationnew.html


Alex

They are as happy as pie together.

A marriage made in heaven.

Alex

(Can pie be happy? Why would one get married in heaven? I don't know--but I used my G11/ST4 forever and nothing ever blew up.)

Let's hope this starts a trend.

Alex

Flexure is one suspect.....mirror flop could be another.

Does this go on for hours and hours, or does it eventually settle out?

Alex

I do not think you are blocking enough of the sunlight. You risk blindness, but it will come on you slowly, like a sunburn on the beach. Except you cannot get solarcaine to the retina. You should be letting in about 0.0003 percent (shade number 14) of the light, not the .1 per cent your film apparently lets in!

I question whether the black polymer is optically flat.

If you can afford a flourite scope, you can afford $25 worth of Baader solar filter material. And that is about as good as it gets in white light.

Alex