Ebay 8' Newts

has anyone bought one of these?

http://cgi.ebay.co.uk/ws/eBayISAPI.d...950259 7&rd=1

I'm obviously not expecting too much, but......?

Too good to be true?

Gaz

Gaz

Your link did not work for me , but I found them easily on ebay.

At least they say the mirror is concave - this is a good start!

Eq mount looks quite nice with alt/az adjusters and polar scope though usually
cheap mounts are wobbly mounts.

Finderscope is likely to be useless.

A good point is that they do not try to sell over-magnification.

Chuck the solar filter - it would be horribly dangerous.

The optics are likely to be pretty mediocre, but probably usable if you are not
fussy. It is certainly not going to be diffraction limited.

If you can take the risk, for the price (£150) it may be worth a punt for an
almost certainly sub-standard, but reasonably high aperture (light bucket)
scope.


Ado


"Gaz" wrote in message
om...
has anyone bought one of these?


http://cgi.ebay.co.uk/ws/eBayISAPI.d...0950259 7&rd=
1

I'm obviously not expecting too much, but......?

Too good to be true?

Gaz

"Ado" wrote in message
...
Gaz

Your link did not work for me , but I found them easily on ebay.

At least they say the mirror is concave - this is a good start!

Eq mount looks quite nice with alt/az adjusters and polar scope though
usually
cheap mounts are wobbly mounts.

Finderscope is likely to be useless.

A good point is that they do not try to sell over-magnification.

Chuck the solar filter - it would be horribly dangerous.

The optics are likely to be pretty mediocre, but probably usable if you
are not
fussy. It is certainly not going to be diffraction limited.

If you can take the risk, for the price (£150) it may be worth a punt for
an
almost certainly sub-standard, but reasonably high aperture (light bucket)
scope.


Ado



Take a look at the width of the spider legs they are HUGE!!!!!! could be the
angle though

http://cgi.ebay.co.uk/ws/eBayISAPI.d...95023 24&rd=1

Col.

IIRC making an f4 mirror is quite a bit more demanding than the usual f6 or
8, so not so good at high mag. The mount looks a bit weedy but you might
remount it as a Dobbo. Still, a cheap bucket. How bad can it be for £150+?
Might have a punt myself.
ben wrote in message
...

"Ado" wrote in message
...
Gaz

Your link did not work for me , but I found them easily on ebay.

At least they say the mirror is concave - this is a good start!

Eq mount looks quite nice with alt/az adjusters and polar scope though
usually
cheap mounts are wobbly mounts.

Finderscope is likely to be useless.

A good point is that they do not try to sell over-magnification.

Chuck the solar filter - it would be horribly dangerous.

The optics are likely to be pretty mediocre, but probably usable if you
are not
fussy. It is certainly not going to be diffraction limited.

If you can take the risk, for the price (£150) it may be worth a punt
for
an
almost certainly sub-standard, but reasonably high aperture (light
bucket)
scope.


Ado



Take a look at the width of the spider legs they are HUGE!!!!!! could be
the
angle though


http://cgi.ebay.co.uk/ws/eBayISAPI.d...em=61095023 2
4&rd=1

Col.

Gaz wrote:
has anyone bought one of these?


http://cgi.ebay.co.uk/ws/eBayISAPI.d...950259 7&rd=1

I'm obviously not expecting too much, but......?

Too good to be true?

Gaz

Andrew Cockburn posted an comprehensive review of the 6-inch eBay scopes a
while back in this ng.

http://www.cockburn.co.uk/astronomy/newton.html

As he points out - it's not much money for something to get you started, but
just be very, very aware of the limitations.

Regards
Chef!

From some of his comments I strongly suspect that the mirror is spherical, a
bit disastrous for an f4. Might do better to stick to good binos and save
up.
Chef! wrote in message
...
Gaz wrote:
has anyone bought one of these?



http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=610950259 7
&rd=1

I'm obviously not expecting too much, but......?

Too good to be true?

Gaz

Andrew Cockburn posted an comprehensive review of the 6-inch eBay scopes a
while back in this ng.

http://www.cockburn.co.uk/astronomy/newton.html

As he points out - it's not much money for something to get you started,
but
just be very, very aware of the limitations.

Regards
Chef!

FWIW, this seems to be a development (improvement ?) of the one I got.
The mount looks slightly sturdier, and the OTA looks a little different
and obviously is 8" instead of 6", but it may just be that it is a
different colour. The accessories however look identical, that is to say
need throwing away from the outset.

Regards,

Andrew

Chef! wrote:
Gaz wrote:

has anyone bought one of these?



http://cgi.ebay.co.uk/ws/eBayISAPI.d...950259 7&rd=1

I'm obviously not expecting too much, but......?

Too good to be true?

Gaz


Andrew Cockburn posted an comprehensive review of the 6-inch eBay scopes a
while back in this ng.

http://www.cockburn.co.uk/astronomy/newton.html

As he points out - it's not much money for something to get you started, but
just be very, very aware of the limitations.

Regards
Chef!

Out of curiosity, how can you tell if a mirror is spherical ? Is there a
simple test you can do with the scope, or do you need measuring tools ?

Regards,

Andrew

Mark Dunn wrote:
From some of his comments I strongly suspect that the mirror is spherical, a
bit disastrous for an f4. Might do better to stick to good binos and save
up.
Chef! wrote in message
...

Gaz wrote:

has anyone bought one of these?



http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=610950259 7
&rd=1

I'm obviously not expecting too much, but......?

Too good to be true?

Gaz

Andrew Cockburn posted an comprehensive review of the 6-inch eBay scopes a
while back in this ng.

http://www.cockburn.co.uk/astronomy/newton.html

As he points out - it's not much money for something to get you started,

but

just be very, very aware of the limitations.

Regards
Chef!

When trying to grind a 6" years ago, I recall a knife-edge test with a point
light source which produced a shadow pattern enabling the figure to be
determined very accurately. Needs the mirror out, I think. Perhaps someone
else here knows more. I'm sure the details must be on the net somewhere.
Andrew Cockburn wrote in message
-service-com...
Out of curiosity, how can you tell if a mirror is spherical ? Is there a
simple test you can do with the scope, or do you need measuring tools ?

Regards,

Andrew

Mark Dunn wrote:
From some of his comments I strongly suspect that the mirror is
spherical, a
bit disastrous for an f4. Might do better to stick to good binos and
save
up.
Chef! wrote in message
...

Gaz wrote:

has anyone bought one of these?




http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=610950259 7
&rd=1

I'm obviously not expecting too much, but......?

Too good to be true?

Gaz

Andrew Cockburn posted an comprehensive review of the 6-inch eBay scopes
a
while back in this ng.

http://www.cockburn.co.uk/astronomy/newton.html

As he points out - it's not much money for something to get you started,

but

just be very, very aware of the limitations.

Regards
Chef!

Andrew Cockburn wrote:
Out of curiosity, how can you tell if a mirror is spherical ? Is there
a simple test you can do with the scope, or do you need measuring tools ?

It's easier to test it out of scope. The tools to test a sphere are
trivially simple: Look up Foucault test or Ronchi test at centre of
curvature. More importantly, to tell if it's been properly corrected,
you can do a Ronchi test at focus, with mirror in situ.

Best,
Stephen

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