Quick question - DSLR mount

[raymo]

If your Newt is a skywatcher you only need the top one [T-ring].
If it is another brand, you could very well need the bottom one
[T- adaptor] as well.
raymo

[omegacrux (David)]

Here you go just screw the 1.25 out exposing the thread an t-ring screws here

David

[ThunderStorm (Alan)]

Originally Posted by raymo

If your Newt is a skywatcher you only need the top one [T-ring].
If it is another brand, you could very well need the bottom one
[T- adaptor] as well.
raymo

Mine is Skywater dob, so will buy the T-ring only then. Thanks.

[ThunderStorm (Alan)]

Originally Posted by omegacrux

Here you go just screw the 1.25 out exposing the thread an t-ring screws here

David

Thanks for the photo, all clear now.

[ThunderStorm (Alan)]

Originally Posted by omegacrux

Here you go just screw the 1.25 out exposing the thread an t-ring screws here

David

Hi David,

I looked at my Skywatcher 10in dob and removed 1.25in eyepiece (and also the 2 inch-to-1 inch adapter) from the focuser, there is no thread for me to screw in the T-ring.

Eidt - is the 2 inch-to-1 inch adapter a single piece? Or can I dis-assemble into 2 pieces?

[omegacrux (David)]

Hi
the 1.25 adapter nosepiece unscrews from that 2in bit that has the two thumbscrews exposing the thread that can be seen at the base of the 1.25 nosepiece

David

[omegacrux (David)]

It looks like a single piece
Care needed with these fine thread made out of alloy make sure you line em up properly , don't want to cross tread them !
See to the right there's the thread you need
Sorry about pic quality I reduce'd it a bit too much

David

[omegacrux (David)]

Here's what to expect
10in flexdob
Lumix gf3
Last night focus is not easy really need a dual speed focuser
I also put up a pic with the ed80 in begginars sec see the difference

David

[raymo]

My Photos and explanation at the beginning of this thread showed quite clearly how to do it. You just unscrew the barrel that the 1.25" eyepieces
slide into from the adaptor that is held in the focuser by the two knurled knobs, and screw the T-ring onto the male thread on the adaptor.
raymo

[Forgey (Paula)]

Hi Alan, if it helps i've taken a pic of how i connect my 600D to the dob. Unscrew the 1 1/2 adapter and and the t-ring screws straight onto that.

[ThunderStorm (Alan)]

I know what's happening:
My 2in-to-1.25in adapter has a "ring" and "eyepiece-like" part.
I unscrewed the eyepiece-like part can see the "ring" that has thread on it.
So finally I think I got it.

What you guys have the 2in-to-1.25in adapter look like? Just the ring or 2-part adapter?

[omegacrux (David)]

Post 11, pic 3-4 of Raymo's post shows what needs to be done just copy and match yours to his pics

David

[ThunderStorm (Alan)]

I found something on eBay, one T2 adaptor is thicker and one other is thinner, not sure if the thinner is the same.

Thinner one:
http://www.ebay.com/itm/M42-Lens-to-...item43b2cec907

Thicker one:
http://www.ebay.com.au/itm/New-T2-T-...item41761f98ae

[raymo]

The first one [thinner] is a different thing altogether; it's purpose is to
let you put Pentax M42 lenses onto your Canon EOS camera.
You need the second [thicker] one, which will screw directly onto the thread you mentioned in your previous post. I had assumed that you already had a basic T-ring.
raymo

[glend (Glen)]

If you have Modular Hyperion EPs you can (using a cheap T-thread adaptor from Baader, product #2958080 available from Agena Astro) screw the EP directly to the camera T-thread adaptor. I have a Hyperion 13mm EP and it attached directly to my Canon 450d. You get the benefit of the magnification from the EP. TO my knowledge this only works with the modular Hyperion EPs.

[MrB (Simon)]

Originally Posted by raymo

The first one [thinner] is a different thing altogether; it's purpose is to
let you put Pentax M42 lenses onto your Canon EOS camera.

To expand on Ray's reply... While both systems are M42, the lens mount version of the M42 thread(by Zeiss but commonly known as Praktica or Pentax mount) has 1.0mm thread pitch, while the T2 thread pitch is 0.75mm.
They will start to screw together for about half a turn, but attempting to force these two systems together will lead to damage.

[ThunderStorm (Alan)]

So I should buy the thicker one?

[astro744]

Originally Posted by MrB

To expand on Ray's reply... While both systems are M42, the lens mount version of the M42 thread(by Zeiss but commonly known as Praktica or Pentax mount) has 1.0mm thread pitch, while the T2 thread pitch is 0.75mm.
They will start to screw together for about half a turn, but attempting to force these two systems together will lead to damage.

The thinner one is called a body mount. They are used to convert a lens of one make for use on a camera of a different make.

When I first started astrophotography I had a Praktica camera that has M42 screw lenses. I bought a Praktica M42 T-ring and T2 adapter. Yes the threads are the same but the pitch is different.

Later I bought a Nikon FE2 and rather than buy a Nikon T-ring, I bought a Praktica M42 to Nikon body mount. This body mount was quite thin and also had a small correcting lens to account for the thickness of the body mount to ensure proper focus (also ensures focus at infinity lines up with the infinity index). The body allowed me to use M42 screw lenses on my Nikon. However, I eventually got some Nikkor lenses and then simply used the body mount with the Praktica T-ring and T2 adaptor when doing astrophotography. I removed the small corrective lens as it was not needed for prime focus astrophotography.

Unless you have use for a body mount, get the thicker T-ring.

[SingleWord]

Thanks for all replies.
I'll go for the thicker one then.