T-adapter without unnecessary wide part?

My local telescope store says that you can't put a camera with a T-mount
on most reflector telescopes because "you can't get the camera close
enough." Well, take a look at a typical T-adapter for a 1.25 eyepiece
tube:

http://www.telescopes.com/telescope-...sal114inch.cfm

It has a thick portion designed to keep the camera about an inch
further away from the telescope than it would otherwise be. It seems
to me that this is a problem easily solved, if someone made a T-
adapter without the thick portion. Is there a reason for this?
What am I missing?

I know I could put a camera on a Cassegrain telescope, but the Newtonians
have much lower f-numbers.


--
Please reply to: | "We establish no religion in this country, we
pciszek at panix dot com | command no worship, we mandate no belief, nor
Autoreply is disabled | will we ever. Church and state are, and must
| remain, separate." --Ronald Reagan, 10/26/1984

On Feb 19, 4:26*am, (Paul Ciszek) wrote:
My local telescope store says that you can't put a camera with a T-mount
on most reflector telescopes because "you can't get the camera close
enough."

Did your local telescope store tell you that you can modify the
(Newtonian) reflector by either replacing the focuser with one of low
profile and/or moving the primary mirror cell forward?

This is advertised as working with a small-chip CCD camera:

http://www.telescope.com/Telescopes/.../19/p/9974.uts

Paul Ciszek:
My local telescope store says that you can't put a camera with a T-mount
on most reflector telescopes because "you can't get the camera close
enough." Well, take a look at a typical T-adapter for a 1.25 eyepiece
tube:


http://www.telescopes.com/telescope-...estrontadapter
universal114inch.cfm

It has a thick portion designed to keep the camera about an inch
further away from the telescope than it would otherwise be. It seems
to me that this is a problem easily solved, if someone made a T-
adapter without the thick portion. Is there a reason for this?
What am I missing?

I know I could put a camera on a Cassegrain telescope, but the Newtonians
have much lower f-numbers.

The Takahashi Epsilon 180ED, a fast Ÿ2.78 Newtonian astrograph, has
very little back-focus. I have two threaded barrels for mine. The
standard barrel mounts an SBIG camera with an internal filter wheel
(i.e., no protrusions on the camera body) or a DSLR. The short barrel
mounts my SBIG with an external eight-position filter wheel. There is
no provision for focal reducers or extenders; such things are not
applicable to this telescope.

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

On Tue, 19 Feb 2013 09:26:55 +0000 (UTC), (Paul
Ciszek) wrote:

My local telescope store says that you can't put a camera with a T-mount
on most reflector telescopes because "you can't get the camera close
enough." ...
It has a thick portion designed to keep the camera about an inch
further away from the telescope than it would otherwise be. It seems
to me that this is a problem easily solved, if someone made a T-
adapter without the thick portion. Is there a reason for this?

I've seen different length T-adapters (the one you show is pretty
short). The thing is, DSLRs often have parts that project forward
(like the prism housing or hand grip), and the T-adapters are probably
designed to ensure clearance with the maximum number of camera/scope
combinations.

People who image with Newts usually do one of two things: switch to a
low profile focuser, or remount the primary mirror a little further up
the tube. Either solution serves to increase backfocus. The reality
is, the majority of Newts are used visually, and their manufacturers
optimize them for that.

On Feb 19, 4:26*am, (Paul Ciszek) wrote:
My local telescope store says that you can't put a camera with a T-mount
on most reflector telescopes because "you can't get the camera close
enough." *Well, take a look at a typical T-adapter for a 1.25 eyepiece
tube:

http://www.telescopes.com/telescope-...aphic/celestro...

It has a thick portion designed to keep the camera about an inch
further away from the telescope than it would otherwise be. *It seems
to me that this is a problem easily solved, if someone made a T-
adapter without the thick portion. *Is there a reason for this?
What am I missing?

I know I could put a camera on a Cassegrain telescope, but the Newtonians
have much lower f-numbers.

--
Please reply to: * * * * | "We establish no religion in this country, we
pciszek at panix dot com | *command no worship, we mandate no belief, nor
Autoreply is disabled * *| *will we ever. *Church and state are, and must
* * * * * * * * * * * * *| *remain, separate." --Ronald Reagan, 10/26/1984

Shift mirror up the tube, use an eyepiece extension tube for visual
use. Simple.

Originally Posted by Paul Ciszek

My local telescope store says that you can't put a camera with a T-mount
on most reflector telescopes because "you can't get the camera close
enough." Well, take a look at a typical T-adapter for a 1.25 eyepiece
tube:



It has a thick portion designed to keep the camera about an inch
further away from the telescope than it would otherwise be. It seems
to me that this is a problem easily solved, if someone made a T-
adapter without the thick portion. Is there a reason for this?
What am I missing?

I know I could put a camera on a Cassegrain telescope, but the Newtonians
have much lower f-numbers.


--
Please reply to: | "We establish no religion in this country, we
pciszek at panix dot com | command no worship, we mandate no belief, nor
Autoreply is disabled | will we ever. Church and state are, and must
| remain, separate." --Ronald Reagan, 10/26/1984

Do you have any pics of your telescope? Just share it

On 19/02/2013 09:26, Paul Ciszek wrote:
My local telescope store says that you can't put a camera with a T-mount
on most reflector telescopes because "you can't get the camera close
enough." Well, take a look at a typical T-adapter for a 1.25 eyepiece
tube:

http://www.telescopes.com/telescope-...sal114inch.cfm

It has a thick portion designed to keep the camera about an inch
further away from the telescope than it would otherwise be. It seems
to me that this is a problem easily solved, if someone made a T-
adapter without the thick portion. Is there a reason for this?v

Usually to avoid bits of the camera that stick out like the pentaprism
hitting the focus wheel.

What am I missing?

Normally the focal plane of the scope is somewhere inside the draw tube
and so it doesn't matter how close you could mount the camera. You can
test this with some tracing paper. If you can get a focussed image of
the moon on tracing paper about 40mm behind the drawtube exit then you
are in luck. Most Newtonians used for photography have either a low
profile focuser that swaps for the eyepiece unit or have tweaked the
mirror to be further up the tube with slight vignetting as a result.

I know I could put a camera on a Cassegrain telescope, but the Newtonians
have much lower f-numbers.

It is a lot easier on an SCT there is huge backfocus - enough to alter
the nominal magnification of matched telephoto multipliers.

Regards,
Martin Brown

In article ,
Tinech wrote:

Do you have any pics of your telescope? Just share it

My intention is to eventually select a telescope based on its ability to
accomodate my camera, sans lens (non of the afocal nonsense). It seems
that Orion sells some Newtonians intended for astrophotography, but I
need to make sure that they are intended for lensless cameras.

--
Please reply to: | "We establish no religion in this country, we
pciszek at panix dot com | command no worship, we mandate no belief, nor
Autoreply is disabled | will we ever. Church and state are, and must
| remain, separate." --Ronald Reagan, 10/26/1984

In article ,
Tinech wrote:

Do you have any pics of your telescope? Just share it

Oh, and it would also be cool to be able to attach my camera to other
people's telescopes with a minimum of fuss.

--
Please reply to: | "We establish no religion in this country, we
pciszek at panix dot com | command no worship, we mandate no belief, nor
Autoreply is disabled | will we ever. Church and state are, and must
| remain, separate." --Ronald Reagan, 10/26/1984

On Feb 22, 6:24*pm, (Paul Ciszek) wrote:
In article ,

Tinech wrote:

Do you have any pics of your telescope? Just share it

My intention is to eventually select a telescope based on its ability to
accomodate my camera, sans lens (non of the afocal nonsense). *It seems
that Orion sells some Newtonians intended for astrophotography, but I
need to make sure that they are intended for lensless cameras.

and also wrote later:

Oh, and it would also be cool to be able to attach my camera to other
people's telescopes with a minimum of fuss.

Yes that would be cool. However, even if you could find a "T-adapter
without unnecessary wide part" there still is no guarantee that your
rig would work on any particular Newt (or refractor) that had not
already been designed or modified for "prime focus" photography.

I do seem to recall mentioning earlier in this thread a product that
might solve your problem. You should contact them for the exact specs
and technical details of their product.