OAG means Off-Axis Guider. Antlia OAG and filter drawer assembly is an innovative accessory that integrates filter drawer and OAG. It allows you to utilize your primary imaging camera and telescope for auto-guiding, without needing a heavy additional guide scope. The OAG uses a small internal pick-off prism as a mirror to reflect part of the incoming light from the telescope to your independent guide camera. Since the off-axis guiding and imaging camera shares the same image train as the main detector, it handles very well with all bending and tilting that may be present in your setup, and you will achieve tracking accuracy greater than you would with a separate guide scope.

Antlia OAG and Filter Drawer Assembly Features

• Large pick-out prism 12*12mm, which allows the use of a larger guiding sensor and therefore a greater selection of guide stars.
• Mono-block (one-piece) design with the OAG body directly connected to the filter drawer.
• Comfortably fits APS-C sensor and Full Frame sensor.
• The total thickness plus both side adapters are 37.5mm.
• It’s right for cameras with 17.5mm back focus distance without additional adapters.
• The OAG has been CNC machined from a single aluminium block and provides a very rigid platform for guiding.
• High-quality helical focuser assembly, a 1.25-inch helical focuser with a generous 10mm of travel allows you will find the optimum focus for your guide star.
• The prism height can be adjusted to better illuminate the field of view of your auto guider. The smaller the imaging sensor in your camera the further down the prism can be set without interfering with the sensor.
• Dovetail-type threaded adapters are attached to the body with grub screws, so the adapters can be 360° rotated and locked to align with the telescope and camera.
• You can rotate the OAG 360° to find a guide star.
• A wide variety of adapters is provided to accompany multiple configurations. Antlia OAG includes 7 popular threaded sizes: M42, M48, M54, and M68 male and female for both sides. (no M42 female)
• Application is not limited to a specific brand instrument.
• Filter sliders of Dia50mm and 50X50mm, adapter rings of B-48125,B-4836,B-4831 and other adapters can be ordered separately.

The Standard Antlia OAG and Filter Drawer Attached to Imaging Setup

The OAG requires a telescope, imaging camera, autoguider, and a mount tracking equatorially with autoguiding capability. Please refer to Schematic diagram 02 to familiarize with the Antlia OAG.

You need to ensure that the distance from the prism to the main camera sensor is exactly equal to the distance from the prism to the guider sensor.