telescope newby question 101

Now before you read further - im new to telescopes... so expect some stupid
questions...

I have a tasco newtonian.
When i look at something - ie planet or star for instance, i get the
reflection of the four stick thingy that sits at the otherend of the tube
always over the centre of the object im trying to look at. The following
link has a picture "similar" to mine that has the offending four stick thing
clearly shown as you view down the tube :-
http://skyandtelescope.com/howto/sco...icle_787_1.asp


Also - what is that 2 part cover that sits over the end of the scope when
im not using it. I notice the small centre circular section comes off as
well as the end that the small centre sphere sits in.
Considering i have very little idea what im trying to convey - i beleive ive
done a good job at explaining the problem. btw - gettin the spottin scope
aligned with the main mirror is a complete pain in the ..well u guess the
rest.

thanks for input.

Hi Troll hunter.

That four stick thingy, is called a spider. It's job is to house a small
mirror that reflect light from the primary mirror into out of the scope and
into your eyepiece. You shouldn't be able to see it when the Telescope is
correctly focussed.
You'll need to learn to correctly focus the scope (sorry if that sounds
blunt). I'd suggest that you pick a bright star. Point the scope at it.
You should be able to be reasonably accurate by looking over the edge of the
tube. (I'm assuming that your finder scope isn't setup correctly yet) Then
tweak the fucus knob until the star becomes a bright dot. As this point
I'd suggest that you spend a little time getting it centered, getting used
to the sky rotation and tracking stars.
Then spend a little time getting your finder scope aligned to your main
scope. This always gives best results when using a real star, and not just
an object down the road ;-)

The 2 part cover is basically a big lens cap. The idea is that it will keep
the optics clean and free from dust. The reason that you can remove the
middle bit is that you can leave the outer ring on the scope whilst obseving
the moon. It's supposed to reduce the glare.

Regards

Colin Dawson
wwww.cjdawson.com


"troll hunter" wrote in message
...
Now before you read further - im new to telescopes... so expect some
stupid
questions...

I have a tasco newtonian.
When i look at something - ie planet or star for instance, i get the
reflection of the four stick thingy that sits at the otherend of the tube
always over the centre of the object im trying to look at. The following
link has a picture "similar" to mine that has the offending four stick
thing
clearly shown as you view down the tube :-
http://skyandtelescope.com/howto/sco...icle_787_1.asp


Also - what is that 2 part cover that sits over the end of the scope when
im not using it. I notice the small centre circular section comes off as
well as the end that the small centre sphere sits in.
Considering i have very little idea what im trying to convey - i beleive
ive
done a good job at explaining the problem. btw - gettin the spottin scope
aligned with the main mirror is a complete pain in the ..well u guess the
rest.

thanks for input.

troll hunter wrote:

Now before you read further - im new to telescopes... so expect some stupid
questions...
I have a tasco newtonian.
When i look at something - ie planet or star for instance, i get the
reflection of the four stick thingy that sits at the otherend of the tube
always over the centre of the object im trying to look at. The following
link has a picture "similar" to mine that has the offending four stick thing
clearly shown as you view down the tube :-
http://skyandtelescope.com/howto/sco...icle_787_1.asp
Also - what is that 2 part cover that sits over the end of the scope when
im not using it. I notice the small centre circular section comes off as
well as the end that the small centre sphere sits in.
Considering i have very little idea what im trying to convey - i beleive ive
done a good job at explaining the problem. btw - gettin the spottin scope
aligned with the main mirror is a complete pain in the ..well u guess the
rest.
thanks for input.

One other thought strikes me.... What is the focal ratio of the scope, and t=what size eyepieces are
you using.

I had an 8" F5, and was unable to use anything larger than a 32mm as I would see the image of the
spider quite clearly in the field of vision.

I dont know what the mechanics of this are, but I believe its something to do with the exit pupil ??

If you could give us more of a description of the scope : lens size, focal length or focal ratio (f
?), we might be able to suss out the problem.. It might be of course that its just very badly out of
focus....

If you look at Jupiter for example, and move the system out of focus, the image of the spider will
be visible on the "out of focus" image of Jupiter (is that right gang ??)

Come on Pete... Stephen..... U know the answers....

DH

"Colin Dawson" wrote in message
...
Hi Troll hunter.

That four stick thingy, is called a spider. It's job is to house a small
mirror that reflect light from the primary mirror into out of the scope
and
into your eyepiece. You shouldn't be able to see it when the Telescope
is
correctly focussed.
You'll need to learn to correctly focus the scope (sorry if that sounds
blunt). I'd suggest that you pick a bright star. Point the scope at it.
You should be able to be reasonably accurate by looking over the edge of
the
tube. (I'm assuming that your finder scope isn't setup correctly yet)
Then
tweak the fucus knob until the star becomes a bright dot. As this
point
I'd suggest that you spend a little time getting it centered, getting used
to the sky rotation and tracking stars.
Then spend a little time getting your finder scope aligned to your main
scope. This always gives best results when using a real star, and not
just
an object down the road ;-)

The 2 part cover is basically a big lens cap. The idea is that it will
keep
the optics clean and free from dust. The reason that you can remove the
middle bit is that you can leave the outer ring on the scope whilst
obseving
the moon. It's supposed to reduce the glare.

Regards

Colin Dawson
wwww.cjdawson.com



thanks ever so much colin, ive been tryin to align the spotter scope with a
telephone poll - altho the pole is probably half a mile away - ive taken
onboard your views - and must say, i like what i see.
As for the spider, yes i did notice the spider image disapear when focused
better, but unless i knew this.. id assume i was doing something wrong -
thanks again.

clear skys

troll hunter wrote:
When i look at something - ie planet or star for instance, i get the
reflection of the four stick thingy that sits at the otherend of the
tube always over the centre of the object im trying to look at.

Are you using an eyepiece (a small lens that goes in the little tube
(focuser drawtube) that sticks out of the side of the scope near the
small mirror (at 10 0'clock in the image on the page you linked to))?

Best,
Stephen

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ohh i have been inserting the eyepiece in the correct fashion, and have
tonight actually managed to focus jupiter and all its 4 moons?
I have however noticed an incredible amount of play on the tripod....money
talks in stargazing i guess
ive lost heart tonight due to the floppyness of the assembly, as for the
details of the lenses etc of the scope in question - i shall do this
tomorrow and post the information. Ive also found using anything other then
one eyepiece, i cant see anything else. I know one is a barlow x2 - i stick
this into the side focus tube thingy (at 10 oclock) cannot see anything,
this coupled with the tube floppyness on the tripod...and well.
But it hasnt all been a disaster - seeing jupiter was great - at first i
thought i had a cracked mirror until i noticed the cracked disolved into the
4 moons of jupiter - i have not lost faith just yet.

post the rest tomorrow - thanks for the input.



"Stephen Tonkin" wrote in message
...
troll hunter wrote:
When i look at something - ie planet or star for instance, i get the
reflection of the four stick thingy that sits at the otherend of the
tube always over the centre of the object im trying to look at.

Are you using an eyepiece (a small lens that goes in the little tube
(focuser drawtube) that sticks out of the side of the scope near the
small mirror (at 10 0'clock in the image on the page you linked to))?

Best,
Stephen

Remove footfrommouth to reply

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+ Stephen Tonkin | ATM Resources; Astro-Tutorials; Astro Books +
+ (N51.162 E0.995) | http://astunit.com +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

Hi Troll hunter.

I think I've used one of these scope a couple of years back. I'm assuming
that it's the same scope that you're using....

It's a 4.5" newtonian Reflector with a Focal Length 1000mm. Possibly
called the Tasco StarGuide 114. If my guess is right I know the scope. For
those not familier with the Tasco's it's almost identical to the Celestron
NexStar 114GT it's just that it's got a smaller object database and is
painting in the Tasco colours.

Here's a link to the NexStar scope for reference.
http://www.celestron.com/prod_pgs/tel/nx114gt.htm

And here's the tasco.
http://sale-depot.co.uk/camera-photo...lesco pe.html

Ok ok, enought with the Guess work.


Now for some helpful hints...

You'll need to do a little math to work out what magnification your
eyepieces *should* give you. When you use an eyepiece in combination with
the Barlow double the magnification. Now you know what the eyepieces give,
you'll need to know how to drive the magnification. The basic rule of thumb
is 50x per Inch of apeture. In the case of your scope that's the diameter
of the main mirror. This should work out to about 225x ish, on a perfect
night. Taking the british weather into account, and sky pollution etc, you
would be extremely lucky to get to over about 180x, and even that is
optimistic. Don't let this put you off though, as a smaller image will be
brighter and with a little practice you'll be ableo to pick out alot of
detail.

The floppyness of the mount is a problem with tripods. Some people add
weight to their tripod to help reduce the shaking effect. I find, on my
scope, that keeping the legs retracted helps to work better. It's worth a
try, as it may help a little.

These is also something that you can do to help recude the shaking. That is
to not touch the scope whilst looking through the eyepiece. This way the
scope can do it's think with you getting in it's way. Also as your detached
from the scope, you'll not be pressing down and possibly causing some
movement in the scope.

You might also be able to come up with some ingenious solution that will tie
the tripod legs together and make them more ridgid.

Hope this helps

Regards

Colin Dawson
www.cjdawson.com

troll hunter wrote:
I have however noticed an incredible amount of play on the tripod.

Some suggestions for improvement at:
http://astunit.com/tutorials/junkscope.htm

Best,
Stephen

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+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

thanks again colin, and as promised here are the specs to this tube :O)

ill start with listing the eyepeices :- f5mm, h20mm,2 x barlow, and also
one that does it all type gizmo -ie it does these magnifications by way of
moving the selector around .. ie 6mm/8mm/12mm/15mm/18mm.

Now ill list the tubes spec which is :- f= 700mm d= 76mm ohh and it says
underneath this data "coated optics" btw - this is not guided by any
computer/electronic means - only by my good judgment , and my olympic size
forearm(they never used to be large but moving a scope about rigorasly does
make one appear more muscular :O)

Colin, i did attempt to align the scope and spotter by lining up the tube
with the target as your goodself recomended...but this coupled with that
tripod..made it rather annoying! but i did get a good look at jupiter and
what looked like a pearl necklace of moons - all 4 of them! however jupiter
itself looked a bright ball - no disearnable detail :O(

over to you sir :O)



"Colin Dawson" wrote in message
...
Hi Troll hunter.

I think I've used one of these scope a couple of years back. I'm assuming
that it's the same scope that you're using....

It's a 4.5" newtonian Reflector with a Focal Length 1000mm. Possibly
called the Tasco StarGuide 114. If my guess is right I know the scope.
For
those not familier with the Tasco's it's almost identical to the Celestron
NexStar 114GT it's just that it's got a smaller object database and is
painting in the Tasco colours.

Here's a link to the NexStar scope for reference.
http://www.celestron.com/prod_pgs/tel/nx114gt.htm

And here's the tasco.

http://sale-depot.co.uk/camera-photo...lesco pe.html

Ok ok, enought with the Guess work.


Now for some helpful hints...

You'll need to do a little math to work out what magnification your
eyepieces *should* give you. When you use an eyepiece in combination with
the Barlow double the magnification. Now you know what the eyepieces
give,
you'll need to know how to drive the magnification. The basic rule of
thumb
is 50x per Inch of apeture. In the case of your scope that's the diameter
of the main mirror. This should work out to about 225x ish, on a perfect
night. Taking the british weather into account, and sky pollution etc,
you
would be extremely lucky to get to over about 180x, and even that is
optimistic. Don't let this put you off though, as a smaller image will be
brighter and with a little practice you'll be ableo to pick out alot of
detail.

The floppyness of the mount is a problem with tripods. Some people add
weight to their tripod to help reduce the shaking effect. I find, on my
scope, that keeping the legs retracted helps to work better. It's worth a
try, as it may help a little.

These is also something that you can do to help recude the shaking. That
is
to not touch the scope whilst looking through the eyepiece. This way the
scope can do it's think with you getting in it's way. Also as your
detached
from the scope, you'll not be pressing down and possibly causing some
movement in the scope.

You might also be able to come up with some ingenious solution that will
tie
the tripod legs together and make them more ridgid.

Hope this helps

Regards

Colin Dawson
www.cjdawson.com

Also - what is that 2 part cover that sits over the end of the scope
....

The larger piece has another use. Get yourself some Baader Astro
solar film, and a roll of double sided tape. Fix pieces of tape to
the underside of the cover, leaving the hole clear. Cut a piece of
the film - large enough to cover the hole plus a bit more - 2-3cm.
Place on the upturned underside of the cover and smooth down. You now
have a safe solar filter. When you have finished with it put the
small cover on. When you want to use the telecope on ordinary astro
objects, take the large cover off (complete with small cover, and put
facing upwards on a flat surface - the film is therefore always
protected from damage.

Roger