SCT to 2" adaptor

[mldee (Mike)]

I recently purchased a Meade 647 2" flip mirror to use with my C8 SCT. I also have a GSO Crayford focusser for the C8. Both obviously with SC screw mounts. Being a good gadget freak, it never occurred to me at the time that I would not be able to use them both together.

I would like to use the 647 in the 2" EP hole of the GSO, so that I get the fine focus, plus switchability between a T-mount 1000d camera and EP using the 647. Why? Just because I can

Does anyone know of an adaptor to convert the standard 647 SCT thread to a 2" barrel suitable for insertion in the GSO focusser? Sort of like a T ring 2" converter but different

[Dennis]

Is this what you are after?

http://www.scopestuff.com/ss_taep.htm

2" Eyepiece Barrel to Schmidt Thread Adapter

Fits in place of a 2" eyepiece, but has male Schmidt threads like a SCT visual back. Adapts SCT visual back devices to 2" backs, focusers, refractors, etc. Male Schmidt threads fit SCT focal reducers, diagonals, turrets, etc. Threaded for 2" filters. No "safety recess" to interfere with compression rings. Black anodized aluminum.

Cheers

Dennis

[Dennis]

Better still, try MyAstro Shop in Brisbane!

http://www.myastroshop.com.au/produc...sp?id=MAS-432C

It looks like the MyAstro (Lumicon) unit has a flange that will prevent the Male SCT thread from screwing in past the end of the Female threads, which is a good idea.

Cheers

Dennis

[mldee (Mike)]

Looks exactly right! Thanks very much for the pointer, I'll contact the shop tomorrow.

Cheers.

[Dennis]

Hi Mike

I notice that the Lumicon model from My AstroShop “appears” to have a relatively short 2inch insertion length and that it also has the undercut for the grub screw(s) that locks the 2” tube in place.

The Scopestuff photo shows a longer 2” barrel and no undercut.

In my Moonlite focuser, the brass compression ring seems to just teeter on the edge of the undercut (of a different make/model adapter) and causes some wobble, so I’ve had to remove the brass compression ring and get a longer 2” barrel for some of my accessories.

Cheers

Dennis

[Dennis]

One thing that I thought of on my morning run today, was the length of your optical train.

C8 – GSO Crayford focuser – Meade 647 2" flip mirror – DSLR camera; this is quite a long focuser train, so just be sure it works and that all the components are rigidly fixed to minimize potential flop.

Cheers

Dennis

[mldee (Mike)]

Originally Posted by Dennis

Hi Mike

I notice that the Lumicon model from My AstroShop “appears” to have a relatively short 2inch insertion length and that it also has the undercut for the grub screw(s) that locks the 2” tube in place.

The Scopestuff photo shows a longer 2” barrel and no undercut.

In my Moonlite focuser, the brass compression ring seems to just teeter on the edge of the undercut (of a different make/model adapter) and causes some wobble, so I’ve had to remove the brass compression ring and get a longer 2” barrel for some of my accessories.

Cheers

Dennis

Thanks for the chins up, seems like it's always hard to get all the goodies in the one package!

Delivered price wise they're about the same, so as I'll have a delicate camera hanging off the 647, probably a good idea to have the undercut, as I'm not the most thorough of grub screw tighteners

[mldee (Mike)]

Originally Posted by Dennis

One thing that I thought of on my morning run today, was the length of your optical train.

C8 – GSO Crayford focuser – Meade 647 2" flip mirror – DSLR camera; this is quite a long focuser train, so just be sure it works and that all the components are rigidly fixed to minimize potential flop.

Cheers

Dennis

Yep, so I decided to go for the Scope Stuff longer model. After I've verified operation, I'll drill a couple of small dimples in it for the grub screw tip to sit in. I'm not worried about the lack of rotation by doing this, but I could drill dimples, say every 60 degrees or so if needed.

The end load will basically just be the 1000d body and a small 12mm illum reticule EP, no big 2" 40mm jobs! Well, at least until I try it

The biggest danger to the focusser train is my colliding with it in the dark.

[Dennis]

Hi Mike

Okay – the focuser port will have the (Scopestuff) SCT to 2 inch adapter, but check your other 647 accessories and adapters. There should be a camera port adapter that offers a T-2 thread for the DSLR and it has 3 long grub screws at 120 degrees to allow for rotation of the camera?

I have a 647 that I haven’t used for a while so my recollection is a bit vague. What does stick in my mind is that the pentaprism on my (old) Pentax *ist DS DSLR used to collide with the cube body of the 647 when I tried to rotate the body by using these 3 long grub screws.

Cheers

Dennis

[mldee (Mike)]

Originally Posted by Dennis

Hi Mike

Okay – the focuser port will have the (Scopestuff) SCT to 2 inch adapter, but check your other 647 accessories and adapters. There should be a camera port adapter that offers a T-2 thread for the DSLR and it has 3 long grub screws at 120 degrees to allow for rotation of the camera?

I have a 647 that I haven’t used for a while so my recollection is a bit vague. What does stick in my mind is that the pentaprism on my (old) Pentax *ist DS DSLR used to collide with the cube body of the 647 when I tried to rotate the body by using these 3 long grub screws.

Cheers

Dennis

Just checked, the 1000d flash assy sits behind the plane of the 3 grub screws, so it's all free to rotate if I wish. My concern there is that the grub screws are quite difficult to grasp, small knobs and sandwiched between the camera body and the 647 body.

BTW, I'm not much of a viewer guy, old lousy eyesight. The 12mm EP is just that I'm embarking on the learning of drift alignment. So far, not much luck due to clouds. Maybe tonight....

Cheers

[Dennis]

Hi Mike

Ahah – yes, those fiddly knobs! I ended up replacing mine with knobs on longer stalks that protrude outside the envelope of the 647 cube. I think they were an American size, something like 8-32?

Let me know if you want further details on this mod and I’ll dig up my unit.

Cheers

Dennis