newbie question

Hi,

I'm considering constructing a telescope for Solar System observation
(especially Mars). I've got all the necessary skills to build one (I think)
but lack the necessary guidance as to what would be the best route to take.
Fundamental questions are, What type, what size, material sources (I'm UK
based), plans?.Is it worth making my own mirror or can I buy mirrors ready
ground? What is going to be a ball park cost for, say, a 6 or 8 inch
reflector?
I have a lot of research to do before I start but some direction would be
appreciated.

Steve

Is it worth making my own mirror or can I buy mirrors ready
ground?
Try Beacon Hill or Orion (UK) for ready made mirrors and DIY
materials. Also SCS Astro.
http://www.beaconhilltelescopes.mcmail.com/main.html

http://www.orionoptics.co.uk/acatalog

http://www.scsastro.co.uk/index.shtml

DIY you learn more, ready made is quicker. Good luck, have you tried
your local Astro society ?
jc


http://mysite.wanadoo-members.co.uk/jc_atm/

UK based? Are you saying your stationed in the UK? Cause if your US
Military stationed in the UK I have a shipping code for US military to
avoid customs charges.

On Sat, 5 Feb 2005 15:38:38 -0000, steve church
wrote:

Hi,

I'm considering constructing a telescope for Solar System observation
(especially Mars). I've got all the necessary skills to build one (I
think) but lack the necessary guidance as to what would be the best route
to take. Fundamental questions are, What type, what size, material
sources (I'm UK based), plans?.Is it worth making my own mirror or can I
buy mirrors ready ground? What is going to be a ball park cost for, say,
a 6 or 8 inch reflector?
I have a lot of research to do before I start but some direction would be
appreciated.

Steve

My last effort was an 8" f/8 with a mirror kit from
Newport Glassworks. (Didn't get to finish, before
giving it away.) Long focal length 8" should be
great for planets.

Start with books:

Build your own telescope - Richard Berry

How to Build a Telescope - Jean Texereau

Amazon.com or Willman-Bell http://www.willbell.com/
if you can't find them locally or at library.
These should give you some ideas.

Cheers,
Larry G.

I'm considering constructing a telescope for Solar System observation
(especially Mars). I've got all the necessary skills to build one (I think)
but lack the necessary guidance as to what would be the best route to take.
Fundamental questions are, What type, what size, material sources (I'm UK
based), plans?.Is it worth making my own mirror or can I buy mirrors ready
ground? What is going to be a ball park cost for, say, a 6 or 8 inch
reflector?

If this is going to be your first telescope, I suggest just buying a
commercial 6" F8 dobsonian. The reason is that: 1) It will take you
less time to save the money than to finish your scope. 2) You'll start
with a good telescope and then know what to expect from one if you
choose to build one 3) If you are building your first telescope alone,
without experience from another telescope maker, you are likely to rush
it and take shortcuts.. so you'll end up with a hacked together scope
and you probably won't save much money.

That said, building a telescope is a rewarding experience. I've built
about 10, and made the mirrors for all of them by both hand and machine.
I bought my first scope (a 10" Meade Dob) and then sold it after
building a few smaller scopes and finally deciding which one was good
enough to use full time. Actually, my 6"F6 beat the Meade 10" hands down
on planets. If you go this route be warned: You will spend more time
building than observing...it's addictive. If you still want to build
one, then buy Jean Texereau's book "How to Make a Telescope" and a
mirror grinding kit from either Newport Glass, Willman Bell (the
publisher), or maybe somewhere over on your side of the pond (sorry
don't know who to suggest).

Grinding a 6" F8 would be the best choice I think (it's the easiest to
figure and test since it can be left spherical) but it will take you
anywhere from 1 month to forever (ie: if you are a gemini)...

Download this software for design help:
http://home.att.net/~dale.keller/atm...t/newtsoft.htm


After 5 years of building scopes and not observing, I finally sold all
of it and bought an LX90, DSI, etc. Call me a sellout if you want to,
but I *love* my LX90 and no longer have the desire to push glass.
Getting outside and observing is more fun these days.

-tom

steve church wrote:
Hi,

I'm considering constructing a telescope for Solar System observation

(especially Mars). I've got all the necessary skills to build one (I
think)
but lack the necessary guidance as to what would be the best route to
take.
Fundamental questions are, What type, what size, material sources
(I'm UK
based), plans?.Is it worth making my own mirror or can I buy mirrors
ready
ground? What is going to be a ball park cost for, say, a 6 or 8 inch
reflector?
I have a lot of research to do before I start but some direction
would be
appreciated.

Steve

Optical quality is the most important factor for planetary viewing but
not the only one. Low obstruction and smooth tracking are also high on
the list.
To ensure high optical quality you should look for a Newtonian longer
than F6. If it is not too large for you consider an F8-F10. As far as
aperture goes you need to balance resolution against seeing. The larger
the aperture the higher the resolution but the fewer instances of good
seeing you will experience. Its hard to say what will be best for you
but since it is your first telescope project I would not recommend
anything over 8".

A long focus Newtonian will have lower obstruction than most other
designs so you shouldn't be too concerned with diffraction.

If you choose an EQ mount you will need at least a Synta EQ6 or a vixen
GPDX. The EQ mount will give you better tracking and make it much
easier to view the planets at high power. A dobsonian base is
inexpensive and rock solid up to about 300 times. I would recommend
starting with a dobsonian base then upgrade to an EQ mount if you feel
you need to.

If you make your own optics they may not be back from the for mars. I
honestly don't know how much of it is tax but Orion optics seem
overpriced. Before shipping a 6" set of high quality is 300 pounds.
The same quality mirror in Canada sells for 127 pounds.

Ian Anderson
www.customopticalsystems.com

On 5 Feb 2005 15:54:20 -0800, wrote:

As far as
aperture goes you need to balance resolution against seeing. The larger
the aperture the higher the resolution but the fewer instances of good
seeing you will experience.

Not true. A larger aperture will always deliver at least as high
resolution view as a smaller one. Always. Perhaps what you meant is that
a larger aperture will be seeing limited more often than a smaller one.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Chris L Peterson wrote:
On 5 Feb 2005 15:54:20 -0800, wrote:

As far as
aperture goes you need to balance resolution against seeing. The
larger
the aperture the higher the resolution but the fewer instances of
good
seeing you will experience.

Not true. A larger aperture will always deliver at least as high
resolution view as a smaller one. Always. Perhaps what you meant is
that
a larger aperture will be seeing limited more often than a smaller
one.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Yes, that is another way to say it.

Ian

Optical quality is the most important factor for planetary viewing but
not the only one. Low obstruction and smooth tracking are also high on
the list.
To ensure high optical quality you should look for a Newtonian longer
than F6. If it is not too large for you consider an F8-F10. As far as
aperture goes you need to balance resolution against seeing. The larger
the aperture the higher the resolution but the fewer instances of good
seeing you will experience. Its hard to say what will be best for you
but since it is your first telescope project I would not recommend
anything over 8".

Whats the meaning of the F number and it's relation to length? Also
aperture?(Yes I really am a newbie)

If you make your own optics they may not be back from the for mars. I
honestly don't know how much of it is tax but Orion optics seem
overpriced. Before shipping a 6" set of high quality is 300 pounds.
The same quality mirror in Canada sells for 127 pounds.

We're holidaying in Canada later this year (25th wedding aniversary treat).
I may end up with excess baggage with
that much glass!

Ian Anderson
www.customopticalsystems.com

Steve Church wrote:
Whats the meaning of the F number and it's relation to length? Also
aperture?(Yes I really am a newbie)

The F number is the focal ratio, and it's equal to the ratio of the
primary mirror's focal length (the distance it takes to bring distant
light rays from a star to converge to a focus) to the mirror's width
or aperture.

For instance, suppose the mirror is 8 inches across, and it has a
focal length of 48 inches. Then the mirror has a focal ratio of f/6.

In Newtonian reflectors, the focal length is typically (but not always)
close to the length of the physical tube.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt