Celestron Firstscope 80EQ or 114EQ?

Thanks for all the ino. I recently found the club in our area and
picked-up a schedule.

Now, with some background, I'll be more informed when I actually use
some of these scopes.

-Alex

On 05 Jun 2004 11:31:40 GMT, (Jon Isaacs) wrote:

If the 80 is good enough for the planets, some color objects, and
S&T's "111 Deep-Sky Wonders for Light-Polluted Skies," I think I'd be
satisfied.

Please advise.

I think you have chosen a couple of scopes that will provide some some decent
viewing, certainly a cut above the typical Tasco 60mm refractor.

Here's my thinking:

Aperture is pretty much rules the roost in this game but one must always
consider the trade offs between aperture, cost, size, transportability and a
whole bunch of other stuff....

First you need to decide your priorities, if you want to do some terrestial
viewing, then a refractor of some sort is probably best. In that case, you
might consider something with a shorter focal length to give you a wider field
of view and lower magnifications.

Otherwise, if your priority is for astronomy and you are willing to sacrifice
the terrestial for the most part then I think the 114EQ is a better choice and
I thing there are some attractive alternatives that are in a similar price
range.

I do not recommend the 114EQ Short simply because it uses the "short tube"
Newtonian scheme, a fast spherical primary mirror with built-in
barlow/corrector to try to deal with the aberrations. This is a compromise for
price, and results in a scope that does not perform as well as one with the
more proper parabolic mirror.

But the standard 114EQ is an standard F8 Newtonian, should provide
significantly brighter views and sharper views because the mirror is larger and
gathers twice the light of the 80mm. And because of its relatively slow focal
ratio (F8 is slow for a Newtonian), collimation should quite easy.

An alternative to the Firstscope 114EQ is the Orion Space Probe 130ST which
costs $269 plus. This is a fast Newtonian with a parabolic mirror so
collimation will be more difficult, it is slightly larger but will provide a
wider field of view. It also has 30% more mirror area, not huge but
significant. It is also shorter, than the 114EQ, the OTA is only 24 inches
long. I have one of these and have been surprised by the quality of the
optics.

The biggest problem with any of these scopes is the EQ mount. In an attempt to
make them affordable, the mounts are smaller than they really ought to be.
What this means is that they are "shaky" and prone to vibration. This makes
them difficult to use at higher magnifications or in the wind.

The solution to this problem is the DOB mount, no cantilevered weights or
telescopes waiting to shake, just a simple wooden mount that is quite sturdy,
intuitive to use and essentially vibration free. It is also quick to set up.
The down side is that one tracks by hand.

In this price range this is the Orion XT4.5, similar to the EQ-114 but with a
DOB mount, this is $199 and seems to be quite a nice little scope.

At around $250 there are several 6 inch Dobsonian's available, I believe
Celestron's new 6 incher as well as Hardin Optical's 6 inch DOB are $249.
These are essentially the same scope, made by the same manufacturer.

A 6 inch DOB is a serious instrument, it is a simple easy to use mount, enough
aperture to give you some nice views of the planets and brighter DSOs from a
city backyard and something that will "knock your socks off" when you make
those weekend trips to the country side. At F8, these scope have parabolic
mirrors and are easy to collimate.

-----------

So, in my experience, these, including the 80mm F5 "short tube" 80 refractor
are the choices in getting a decent quality telescope in the under $250 price
range.

Which should you choose?

It is really difficult to say, only you can answer that question. If I were in
your shoes, I would probably spring for the 6 inch DOB, the difference will be
significant.

My parting piece of advice is to consider finding your local astronomy club and
going to a star party of viewing session, getting a first hand look at and
through various scopes.

Another option is to find someone who lives nearby who might assist you by
letting you look through a scope or two.

Best wishes, dark skies and good luck...

jon isaacs