Re: Starter scope for 9 year old: StarBlast or SkyQuest?


LurfysMa wrote:
On Thu, 14 Dec 2006 02:31:24 -0700, W. H. Greer <sendnomail@xxxxxxxx>
wrote:

LurfysMa wrote:

I'm not sure I fully understand the difference between the StarBlast
and the StarBlast EQ. The magnifications are different (26x, 75x vs
39x, 75x) but I think that's because they come with different
eyepieces (Explorer II 17.0mm, 6.0mm vs 3-Element 15.0mm, 6.0mm).

Ah-ha! You caught something I missed.

I just did a search (on the Orion website) for "StarBlast" then
checked the "compare" box for the two StarBlast and then clicked on
Compare. I got a side-by-side comparison chart. From there, it was
easy to spot the differences.

The Expanse eyepieces that the
EQ comes with provide wider fields of view and better (at least with
the 6mm) eye-relief. Such eyepieces are easier for beginners to use
with any telescope.

But I can buy other eyepieces for either scope, no?

The big difference seems to be the mount type (altazimuth vs
equatorial). According to Wikipedia, the altazimuth mount is simpler
to build and use, but more difficult for tracking moving objects
because tracking must be done on two axes. The equatorial mount is
more complex, but eliminates the earth's spin as a variable. It then
goes on to say that altazimuth are more appropriate for dobsonian
scopes.

The differences you mention are accurate.

A Dobsonian is (by definition) essentially a low-budget Newtonian on
an inexpensive, altaz mount. A Newtonian on an EQ mount is no longer
(by most definitions) a Dobsonian.

Would you only get the EQ if a sturdy platform is NOT available?

That was my original intent. My reasoning had to do with the use of
the standard (non-EQ) StarBlast. Without some kind of solid, raised
platform (picnic table, etc.) to rest it on, a child would end up
having to lie on the ground in order to use it. The EQ version is on
a raised tripod -- placing the eyepiece at a more convenient height.

The Expanse eyepieces make the EQ a bit more attractive; but if a
sturdy platform is available for the other scope, the final decision
would depend heavily on the specific child. I suggest using both
scopes (actually pointing them at a variety of targets) with their
supplied eyepieces while at the Orion store so that you can better see
the differences in the mounts as well as the eyepieces.

OK. Will I be able to tell how well these things will work at night on
celestial objects by looking at telephone poles from the store in the
day?

I suspect
that most 9-year olds would be more comfortable using the alt-az
version; but both are good first telescopes.

I going to the store today.

--

I'll toss in my $0.02 (and it's worth about that much)....

An EQ mount is really only useful (all other things being equal) if you
are going to be doing some long exposure astrophotography. As far as
just 'looking at the stars' an Alt-Az will work just fine.
Personally, I like a motorized (not computerized) EQ mount over a
computer controlled one in either Alt-Az or EQ, but that's just my
personal preference.

I've seen some great scopes go unused at star parties because the
computers were acting up. A computerized mount will have him finding
interesting objects, but in many cases getting the alignment right can
be time-consuming and tricky, and the scope won't operate correctly
until that's done. Some of the newer computers with more bell$ and
whi$tle$ will make that easier.

Perhaps you should look for a scope that has an 'upgrade path' where
you can buy an add-on wedge down the road. (A wedge will allow sky
tracking like an EQ mount on an Alt-Az scope).

After he's gotten his scope, invite him to come to one of the public
viewing nights at the local astronomy clubs (there are several in the
SF Bay Area) where he will find lots of helpful dedicated amateurs who
will gladly help him use his scope, find interesting objects, and teach
him the sky.

I am a member of the Fremont Peak Observatory Association
(http://www.fpoa.net) and you're welcome to bring him down to Fremont
Peak on one of our public viewing nights (March through October).

--
Bill Hudson - http://astrogeek.wordpress.com

.

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