Hi. I have an Orion Optics Ultranewtonian CT8, 203mm X 900mm. It has an ACU-2S 2” (50.8mm) Crayford focuser, with 31.7mm adaptor fitted.
I would like to replace it with your Baader Diamond Steeltrack focuser (BDS-NT).
I need help to know how to fit you focuser on my Newtonian. Need new holes? What dimensions or space between those holes? Which base plate? Please help....
Please do not use the mewlon without a filter foil in front of the tube, otherwise the energy of the sun would destroy the internal mirror elements, including the built-in corrector. In this case, i recommend our AstroSolar filter foil ASTF280, productno.: 2459318, which can be clamped to the tube.
Answer by: Baader Web Team (Admin) on May 13, 2024 8:05:00 AM
I have the Astro-Physics version of the VarioFinder, but I'd like to mount it on a dovetail for tangent arm use using either the EQ dovetail or a tube ring(s). Can the dovetail be purchased separately? I did not see it in the Baader catalog. What is the OD of the tube to spec for tube rings?
You have a lot of documentation on how using this with an eyepiece but none that I can found if I want to directly connect my camera to the eyepiece holder without going through the eyepiece itself.
* In this case is there a minimal extension distance to respect between the camera and the (empty) eyepiece holder? (with eyepiece for full frame hybrid you say 95mm)
* What is the impact of the extension distance on the magnification? (with eyepiece equivalent focal length is Feq=Ftel*(d/Feye-1)
Adaptation to the eyepiece is pretty straight-forward: To use the maximum aperture, remove the T-thread from the T-ring and insert 2" / S52 Nosepiece # 2958551. Then you can insert it into your eyepiece holder, just like an eyepiece.
You can also use the T-thread of the adapter and use Baader 2" / T-2 (M48) nosepiece with Safety Kerfs # 2458130 or Baader 1¼" T-2 nosepiece with Safety Kerfs # 2458106, if your telescope hasn't got a T-thread (M42x0.75) on its own (some telescope have got one integrated). This is fine for cameras up to APS-C (or MFT, if you want to use the 1¼" nose piece).
For a full frame camera, T-2 can cause vignetting, and you should use the S52 / M48 adapter #2958552 plus Baader M48 extension tube 40 mm / 2" nosepiece with Safety Kerfs #2958640 as adapter to the 2" eyepiece clamp. This way, you can use the full aperture.
The distance between camera and sensor doesn't change the focal length, as you are using the native focal length of your telescope. So, on a telescope with a focal length of 1000mm, the camera sensor has to be placed 1000 mm behind the objective. Only then you'll see a sharp image.
Caution: If you are using a star diagonal, you should remove it for photography. A 2" star diagonal is approximately 10-11 cm long, so you may need a mechanical extension to reach focus without it, if the focuser doesn't extend enough. We have extension tubes for T-2 (e.g. Baader T-2 / 40 mm Extension Tube # 1508153); for M48, you can stack e.g. some M48 extension tube 40 mm / 2" nosepieces #2958640.
The backfocus of your telescope or the camera adaptation in general should be mentioned in the manual of our telescope. If you can insert an eyepiece without a star diagonal into your focuser and see a sharp image, you probably don't need an additional extension.
Answer by: Baader Web Team (Admin) on May 6, 2024 9:55:00 AM