80ed on the way! (1 Viewer)

doublespinss · Mar 19, 2014

Well, I'm about to join the club! Celestron 80ed will be here in 6 days

Not the skywatcher, the discontinued model shown in attachment. I'm using a cannon dslr, so what adapter should I buy? T2 or something like that? Worth mentioning that I also intend to get into cannibalizing lenses for telenegatives if that affects what extension tube/adapter I get. I am a tinkerer big time, so any thoughts on modifications greatly appreciated.
On that note, has anyone here considered using a macro bellows instead of an extension tube so that you can go from very close focus to infinity on the fly? Or maybe even to move a telenegative around for a zoom? I was thinking you might also be able to make the whole rig sturdier that way. Was halfway even toying around with removing focuser all together and replacing with a long bellows. I don't know, just brainstorming.
I also intend to build my own tripod and gimbal head if anyone has thoughts/resources related to that.
Thanks for reading and being a great community!

Tord · Mar 19, 2014

Richard,

I would recommend this adapter: http://www.cncsupplyinc.com/index.htm?true2.htm
With or without undercut, your call. I personally like the undercut, less risk of accidentally camera body slipping.

You will also need ~80mm 2" extension tube. 50mm is too short, your close focus range will be too limited.

I have drilled and threaded extra third holes in the 2" connection, now there are 3 screws at 120 angle. The scope port and extension tube came with two threaded holes only, for some unknown reason. With the third screw I get a perfect alignment, before there was a tendency for slight misalignment and bend caused by the camera and tube weight exercising a torque.

The cheap Crayford focuser that comes with the scope allows for quite fast focusing (at least the single speed one, not sure about the double speed).

Regarding TN, I think you should look at the threads where Paul Corfield has contributed.

Paul Corfield · Mar 19, 2014

I've thought about using bellows in the past but never went anywhere with it. I tended to buy old teleconverters, take out all the insides and be left with what is basically a macro tube. I'd leave some empty and in others I mount my telenegatives. All my stuff is in Pentax mount and old Pentax teleconverters are very cheap. When I switched to Canon I just used a Canon to Pentax adapter. I'm planning to get a Nikon soon so I will just use a Nikon to Pentax adapter and carry on using all my old gear.

Don't know if I'd remove the whole focuser but anything is possible I guess. A lot of my old home made scopes were simple draw tube types mounted straight to the dslr and focusing was just a simple push/pull affair.

T2 is the cheapest option with a simple 2" T2 scope adapter. Or there's the more expensive one piece designs.

Paul.

doublespinss · Mar 19, 2014

Thanks, Tord. I will check out that site.

The 3rd screw makes sense to me, I might end up doing the same thing.

I read through Paul's TN thread months ago, but I need to do it again.

Edit: Thanks for the advice, Paul. I've got a lot to consider here.

Once I start making components and modifying things, I'll keep you guys posted. Looking forward to it!

-Richard

Tord · Mar 19, 2014

I forgot to mention that flocking the inside of extension tube and adapter is recommended in order to reduce/eliminate light reflections.

DanC.Licks · Mar 19, 2014

TNs are THE way to go. Check out my latest moon shot using my Canon 100-200mm TN.

I tried the same thing with the Olympus EC14, a very good 1.4x TC, and it couldn't even come CLOSE!

doublespinss · Mar 19, 2014

Wow Dan, that is a huge difference. Yea, I'll definitely being going for the route that is an order of magnitude cheaper and better. Awesome shot by the way!

DanC.Licks · Mar 19, 2014

Thanks. Took a little doing....

JGobeil · Mar 19, 2014

Tord said:
I forgot to mention that flocking the inside of extension tube and adapter is recommended in order to reduce/eliminate light reflections.

Definitely worth it since it improves the contrast substantially. I also flocked the long focuser tube and the inside of the TN. Everything is flocked except the scope tube.

MPeoples · Mar 19, 2014

Enjoy the Celestron, Richardmg9!!!!

doublespinss · Mar 23, 2014

"T2 is the cheapest option with a simple 2" T2 scope adapter. Or there's the more expensive one piece designs.

Paul."

With the one piece design from cncsupplyinc I still need an 80mm extension tube? Aren't I having 2 pieces of metal between the camera and scope either way? I definitely want to go the cheapest route to start and get a feel for things.
To clarify, T2 ring (or adapter? are these the same thing?) would allow my EOS body to attach to my scope? Then I just need 80mm of tube that goes between the T2 ring and the focuser so that I can focus on closer objects, correct?

Thanks for patience and replies

-Richard

cango · Mar 23, 2014

the extension tube (80mm/60mm etc) and the mount adapter (t2 or not) are usually two different parts.

(I haven't seen (yet) any extension tube with integrated mount)

Enjoy the Celestron! (have enjoyed mine since day 1

)

doublespinss · Mar 23, 2014

Thanks, cango!

Paul Corfield · Mar 23, 2014

Richardmg9 said:
With the one piece design from cncsupplyinc I still need an 80mm extension tube? Aren't I having 2 pieces of metal between the camera and scope either way?

-Richard

With a T-ring you would have 4 pieces of metal. The t-ring itself is two pieces, there are two rings held together with grub screws. Into the T-ring you screw the 2" telescope adapter and then you have the 80mm extension tube.

The CNC adapter does away with three pieces, it's just the adapter and the 80mm extension.

There's nothing wrong with a T-ring, it's what I've always used, just do the grub screws up nice and tight but be aware that they can come loose.

Paul.

Tord · Mar 24, 2014

Richardmg9 said:
"T2 is the cheapest option with a simple 2" T2 scope adapter. Or there's the more expensive one piece designs.

Paul."

With the one piece design from cncsupplyinc I still need an 80mm extension tube? Aren't I having 2 pieces of metal between the camera and scope either way? I definitely want to go the cheapest route to start and get a feel for things.
To clarify, T2 ring (or adapter? are these the same thing?) would allow my EOS body to attach to my scope? Then I just need 80mm of tube that goes between the T2 ring and the focuser so that I can focus on closer objects, correct?

Thanks for patience and replies

-Richard

Richard,

The CNC and T2 adapters do the same thing. They connect the DSLR body to the 2" port. The CNC adapter is manufactured in a single piece, the T2 is in three pieces.

The purpose of the extension tube is to place the camera sensor where the image projected by the scope lens is in focus. That is approximately 600mm behind the front lens of the SW80ED (600mm focal length) for objects at infinity, and further back for closer objects. The length of the scope OTA is shorter than 600mm (maybe 500+mm) so you need to place the camera sensor further back (~10 cm for infinity).

The distance you will need depends on the length of the 2" port, DSLR adapter and distance from camera flange to sensor.

If you use a short tube, the ability to focus on close objects will be impaired.
If you have a too long tube, you will not be able to focus at infinity - but will be able to focus even closer.

On my 4/3 setup I achieve infinity focus with focuser extracted about 1-2 cm. On my m4/3 setup I need to extract the focuser around 4 cm for focus at infinity.

Most people agree that 80mm extension tube is just about right. With 80mm I can focus as close as around 6-7 meters, and infinity is supported. The closest distance depends on the focuser, how far it can be extracted. I personally think the ability to focus at infinity is nice, using the scope at extreme range and observation (although a bit dark).

Hope this helps

doublespinss · Mar 25, 2014

Thanks for the clarification, Tord. I have lot's of DIY in store for this scope, and will be posting my build on DSLR+scope=setup gallery for any that might be interested. It should be here within 24 hours, and I can't wait to get started!

MPeoples · Mar 25, 2014

Tord, Very nice images!!!

Best
Mike

doublespinss · Mar 26, 2014

It's here!

mooreorless · Mar 31, 2014

Hi Richard, I have that exact scope, sold as a spotter. It is lighter than the Orion 80ED and smaller. The only problem I had with mine was the marks the ring mount left, the tube is not perfect for sure, esp. since it had been a demonstrator.
Have fun with it.

80ed on the way! (1 Viewer)

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