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Explains how to achieve proper focus with the star diagonal installed on the telescope.
Details the process for safely cleaning the mirror surfaces of the star diagonal.
Explains how to achieve proper focus with the star diagonal installed on the telescope.
Details the process for safely cleaning the mirror surfaces of the star diagonal.
The Orion High-Reflectivity Mirror Star Diagonals are precision optical accessories designed to provide a comfortable viewing angle for astronomical observation with refractors, Schmidt-Cassegrains, and Maksutov-Cassegrains. They are not suitable for Newtonian reflector telescopes. These diagonals are essential for achieving focus in many short-focal length refractors.
A star diagonal redirects the light path from the telescope's focuser by 90 degrees, allowing observers to view celestial objects from a more comfortable position, especially when the telescope is pointed high in the sky. The high-reflectivity coatings on the precision flat mirror maximize light transmission, ensuring bright and clear images. The diagonal reverses the image from left-to-right, a characteristic that is generally not noticeable during astronomical viewing but may be relevant if using star maps that need to be flipped to match the eyepiece's reversed view.
The diagonals are available in two main versions:
All models feature top-quality machined housings and a brass compression ring inside the opening of the diagonal. This compression ring prevents the thumbscrew from directly marring the barrel of the eyepiece, ensuring a secure and scratch-free hold.
To use the star diagonal, first remove the cover caps. Insert the barrel of the diagonal directly into the telescope's focuser and secure it in place with the focuser's thumbscrew(s). Next, insert your chosen eyepiece into the diagonal and secure it with the diagonal's thumbscrew. If using a 2" star diagonal with 1.25" eyepieces, ensure the 1.25" adapter is in place. For 2" eyepieces, remove the adapter.
The diagonal's position can be adjusted to suit observers of different heights. To do this, loosen the thumbscrew(s) on the telescope's focuser, rotate the diagonal to the desired angle, and then re-secure it. It is crucial to ensure the diagonal's thumbscrew is tightened before rotating to prevent the eyepiece from falling out.
Focusing is achieved using the telescope's focusing knob. The 1.25" diagonal typically requires approximately 9cm of inward focus travel relative to the eyepiece's focus position without the diagonal. The 2" model requires slightly more inward focus travel, around 11cm, relative to the eyepiece's focus position without the diagonal.
For filter use, the 1.25" diagonals are threaded on their barrel to accept Orion 1.25" filters. This allows for convenient filter changes without needing to remove and reinstall them when switching eyepieces. The 2" diagonal can accept Orion 2" filters on its barrel or on the bottom of the 1.25" eyepiece adapter when used with a 1.25" eyepiece.
The star diagonal is designed to be durable, but it should be protected from prolonged, unnecessary exposure to the elements. When not in use, it is recommended to keep the diagonal capped on both ends, preferably stored in a foam-lined eyepiece case. After use, it's advisable to leave the diagonal uncapped overnight in a dry place to allow it to completely dry out. Storage in a cool, dry environment is crucial, as humid conditions can degrade the optical coatings on the mirror, which is not covered by the warranty.
Cleaning the diagonal's mirror requires careful handling due to the high-reflectivity coatings. Avoid touching the mirror surfaces with fingers or coarse materials. Clean the mirrors only when noticeably dirty, using only lens cleaning tissue and fluid specifically designed for telescope optical coatings. Do not use regular tissue or fluids meant for eyeglasses or household use.
To properly clean the mirror, it must first be removed from its housing. For all models, remove the four Phillips head screws from the bottom of the diagonal. For 2" models, also remove the two button head cap screws from the side of the diagonal (requiring a 2mm or 5/64" hex key). The mirror is gently supported by foam padding and can then be carefully slid out of the diagonal housing.
Once the mirror is removed, use compressed air to remove dust and debris. Then, gently wipe away smudges with telescope optical cleaning fluid and tissue. Apply fluid to a tissue and gently wipe the mirror surface. Use a clean, dry piece of tissue to gently wipe up any remaining fluid. Repeat if necessary, but use caution, as excessive pressure can cause scratches.
General| Brand | Orion |
|---|---|
| Model | 8727 |
| Category | Accessories |
| Language | English |
