Quick answer
For a DSLR, you need a camera-specific T-ring plus an M42 T-thread adapter or nosepiece; for an Atik 300, 400, or Titan CCD with an EFW2 filter wheel, use the Atik M42 T-Thread Camera Adapter (ATK0098) to join the wheel to the camera body. Check the thread gender and your back-focus budget before ordering.
What the M42 T-thread actually connects
M42 T-thread is a 42 mm screw thread used on many astrophotography adapters, but it is not a universal camera mount. A DSLR body needs its own bayonet T-ring, which then presents an M42 thread to the rest of the chain. The Atik adapter is the opposite case: it is made to connect an EFW2 filter wheel to an Atik 300, 400, or Titan series CCD camera, so it assumes Atik-side hardware rather than a DSLR bayonet.
Thread gender and direction are the usual failure points
Adapters can be male-to-male, female-to-female, or male-to-female, and the catalog entry for ATK0098 does not list which gender each side uses. Before you buy, compare the adapter to the threads on your EFW2 and camera body. Also confirm the thread direction: an adapter that only threads a fraction of a turn before binding is usually the wrong gender or pitch, not a defective part.
Back focus is a budget, not a single number
Every element between the telescope and sensor consumes back-focus distance, and the total must match what your telescope or reducer expects. The Atik adapter's optical thickness is not supplied in the catalog, so treat it as an unknown until you measure it or confirm it with Atik. If you are already close to your telescope's limit, adding an unmeasured adapter can push you past it and prevent focus at infinity.
Step-by-step: connecting a camera through an M42 T-thread adapter
- Identify your camera interface: Look at the camera body: a DSLR has a bayonet mount and needs a matching T-ring, while an Atik 300, 400, or Titan CCD uses the Atik body thread that the ATK0098 adapter is made for. Common mistake: buying an M42 adapter assuming it screws directly onto a DSLR. Write down the camera-side mount before you shop.
- Match thread gender on both ends: Compare the adapter's male or female thread to the EFW2 filter wheel side and the camera side. The ATK0098 catalog entry does not state thread gender, so confirm it against the actual parts. Common mistake: forcing a male thread into another male thread and damaging the first thread. If the adapter binds after a quarter turn, stop and recheck gender.
- Add up your back-focus budget: List every component between the telescope and sensor, including the T-ring, filter wheel, and adapter, and compare the total to your telescope or reducer's required distance. The ATK0098 thickness is not supplied, so measure it or confirm it with Atik before relying on it. Common mistake: forgetting the filter wheel's own thickness. If the total exceeds the requirement, you will not reach focus at infinity.
- Assemble and test in daylight: Thread the adapter onto the EFW2 first, then attach the camera, and check that each joint seats fully without cross-threading. Point at a distant terrestrial target to confirm you can reach focus before a night session. Common mistake: tightening the camera last while the adapter is already cross-threaded. A daylight focus test catches thread and spacing errors before dark.
- Check for play and rotation: With the chain assembled, gently rock the camera and watch for rotation or wobble at each threaded joint. A small amount of play is normal in some adapters, but a loose joint will tilt the sensor and blur stars across the frame. Common mistake: over-tightening to remove play and cracking a thin adapter flange. Fix play with the correct shim or a different adapter, not with force.
Product facts
-
Atik M42 T-Thread Camera Adapter - ATK0098: Atik M42 T-Thread Camera Adapter ATK0098 is listed for connecting an EFW2 filter wheel to an Atik 300, 400, or Titan series CCD camera. It is a targeted Atik-to-Atik link, not a general DSLR T-adapter, so matching it to your camera and wheel is the first check.
Atik M42 T-Thread Camera Adapter - ATK0098
