New Main: Finders & Guide Scopes
An astronomy finder is a small, low-magnification telescope or sight that is attached to a larger telescope to help locate and centre celestial objects. There are several types of finders available, each with its own unique features and benefits.
We carry different types of finders and guiders:
Straight-Through Finders: Straight-through finders are more traditional finders that provide a magnified view of the sky. They consist of a small telescope or optical sight that is mounted to the telescope and aligned with the telescope's line of sight. These finders are typically easier to use for beginners because they provide a direct view of the sky, but they can be more difficult to align with the telescope.
An astronomy right-angle finder is a type of finder that provides a comfortable viewing angle by allowing the viewer to look into the finder at a 90-degree angle to the telescope. This makes it easier to aim the telescope at objects near the horizon without having to contort your neck or body into awkward positions.
Right-angle finders typically consist of a small, low-power telescope that is mounted at a right angle to the telescope's optical path. The telescope may be fixed or may rotate around the finder's axis to provide additional viewing flexibility.
An astronomy off-axis guider (OAG) is a device used in astrophotography that allows for accurate guiding of a telescope without the need for a separate guide scope. Instead of using a separate telescope to guide the imaging telescope, the off-axis guider uses a small prism or mirror to divert a small portion of the light coming into the telescope to a guide camera.
The off-axis guider is typically mounted directly to the imaging telescope, so it shares the same optical path as the imaging camera. A small prism or mirror is positioned in the light path, diverting a portion of the light to the guide camera while allowing the rest of the light to pass through to the imaging camera.
The guide camera attached to the off-axis guider is used to monitor the position of a guide star, and sends correction signals to the telescope's tracking motors as needed to keep the star centered. Because the guide camera is located within the same optical path as the imaging camera, the guiding signals sent to the telescope will result in accurate tracking of the object being imaged.
An autoguider is a device used in astrophotography that helps to improve the accuracy and precision of telescope tracking. It works by using a small camera to continuously monitor the position of a guide star and send correction signals to the telescope's tracking motors as needed.
Autoguiding is particularly useful when photographing faint or distant objects, as even slight inaccuracies in tracking can cause the image to blur or become distorted over time. By continuously monitoring and correcting for these inaccuracies, an autoguider can help to ensure that the telescope remains precisely pointed at the desired object throughout the entire exposure.
Most autoguiders consist of a small camera that is mounted to the telescope and connected to a computer or control module. The camera is typically sensitive enough to detect stars that are too faint to be seen by the naked eye, and can provide a high-resolution image of the guide star for analysis. The autoguider software uses this image to monitor the position of the guide star and determine whether any corrections are needed. If the star drifts off center, the software sends signals to the telescope's tracking motors to move the telescope back into alignment. This process is repeated continuously throughout the exposure, resulting in a perfectly tracked image.