In the last post, I wrote about what is collimation and what sort of an effect a non-collimated telescope has on imaging. Taking it from there, let's see what are the equipment we can use in collimating a telescope.
No-Tools:
Firstly let's ask the question whether we can collimate a telescope without almost any tool. It is possible for someone with real good patience and a reasonable eye-sight could collimate a telescope that is not seriously misaligned just by star-light (point at a star, keep adjusting up until the slightly out of focus image stops being an ellipse and becomes a disc). However using a collimation cap makes the job much more easier.
It is not necessary to collimate the telescope during the night when using this method. It is possible to perform daytime collimation by center-spotting your primary mirror. What is center-spotting? It simply means marking the exact center of the primary mirror. Some of the telescopes come with the center marked from the factory. If you have one of these, then you are in luck. If not, you need to mark the exact center of the primary mirror and that can be a bit tiresome, I used threads and a protractor to find the exact center of my primary mirror.
In the center-spotting method, you make sure that the reflection of the pupil of your eye and the center spot and the center point of the focuser tube are perfectly aligned.
Collimation Cap:
This is one of the most low tech devices that can be used in collimation. The sole usage of the collimation cap is to make sure that your viewpoint is at the center of the focuser tube. As with the No-Tools method, you can opt to use the Collimation Cap and a bright star or during day light with a center-spot.
Collimation Eye-piece:
One of the cheaper collimation aids is the Collimation Eye-piece or a Cheshire Collimator. Even when using a Cheshire/Collimation Eye-piece, you would still have to mark the center spot of your primary mirror.
What then, is the use of a Collimation Eye-piece over a simple Collimation Cap? The Collimation Eye-piece comes with cross-hairs which can be used to accurately align your center-spot as opposed to trying to align it with the reflection of the pupil. However the downside of the Collimation Eye-piece is that since it has a much smaller field of view, it can be used only to align the primary mirror.
Laser Collimator:
Laser Collimator is one of the most high-tech gadgets that are used in collimating telescopes. While being high-tech, there are both good and bad reviews for laser collimators. One of the most common complaints against the laser collimators is that they themselves need calibration first. However there is an interesting video (link shown below) which shows collimating a telescope under a few minutes using a laser collimator which sort of proves that once you get the hang of it, it is very efficient.
External Links:
I came across following links when I was collimating my own Newtonian. I found them to be quite informative and useful and thought that someone else may also find those to be useful:
AstroBaby's Guide to Collimation: A tutorial on how to collimate your telescope using a collimation cap or a collimation eye-piece.
Orion's Collimating Eye-piece: An article on how a collimation eye-piece works and what it does.
Collimation Tools: What you need and what you don't : An article similar to this one explaining the various types of collimation tools and their usage.
Collimating a Newtonian Telescope: A youtube video that shows how to collimate a Newtonian with a laser collimator.
No-Tools:
Firstly let's ask the question whether we can collimate a telescope without almost any tool. It is possible for someone with real good patience and a reasonable eye-sight could collimate a telescope that is not seriously misaligned just by star-light (point at a star, keep adjusting up until the slightly out of focus image stops being an ellipse and becomes a disc). However using a collimation cap makes the job much more easier.
It is not necessary to collimate the telescope during the night when using this method. It is possible to perform daytime collimation by center-spotting your primary mirror. What is center-spotting? It simply means marking the exact center of the primary mirror. Some of the telescopes come with the center marked from the factory. If you have one of these, then you are in luck. If not, you need to mark the exact center of the primary mirror and that can be a bit tiresome, I used threads and a protractor to find the exact center of my primary mirror.
In the center-spotting method, you make sure that the reflection of the pupil of your eye and the center spot and the center point of the focuser tube are perfectly aligned.
Collimation Cap:
This is one of the most low tech devices that can be used in collimation. The sole usage of the collimation cap is to make sure that your viewpoint is at the center of the focuser tube. As with the No-Tools method, you can opt to use the Collimation Cap and a bright star or during day light with a center-spot.
Collimation Eye-piece:
One of the cheaper collimation aids is the Collimation Eye-piece or a Cheshire Collimator. Even when using a Cheshire/Collimation Eye-piece, you would still have to mark the center spot of your primary mirror.
What then, is the use of a Collimation Eye-piece over a simple Collimation Cap? The Collimation Eye-piece comes with cross-hairs which can be used to accurately align your center-spot as opposed to trying to align it with the reflection of the pupil. However the downside of the Collimation Eye-piece is that since it has a much smaller field of view, it can be used only to align the primary mirror.
Laser Collimator:
Laser Collimator is one of the most high-tech gadgets that are used in collimating telescopes. While being high-tech, there are both good and bad reviews for laser collimators. One of the most common complaints against the laser collimators is that they themselves need calibration first. However there is an interesting video (link shown below) which shows collimating a telescope under a few minutes using a laser collimator which sort of proves that once you get the hang of it, it is very efficient.
External Links:
I came across following links when I was collimating my own Newtonian. I found them to be quite informative and useful and thought that someone else may also find those to be useful:
AstroBaby's Guide to Collimation: A tutorial on how to collimate your telescope using a collimation cap or a collimation eye-piece.
Orion's Collimating Eye-piece: An article on how a collimation eye-piece works and what it does.
Collimation Tools: What you need and what you don't : An article similar to this one explaining the various types of collimation tools and their usage.
Collimating a Newtonian Telescope: A youtube video that shows how to collimate a Newtonian with a laser collimator.
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