The art of using a telescopeApexeloptic
What do you expect from a telescope once you have one? More or less, it’s a bit of a surprise.
One of the greatest pleasures of amateur astronomers is to show others the magnificence of the starry sky. When people first see the moon and Saturn through a telescope, the exclamation is the greatest reward for those telescope owners.
That’s not the charm of astronomy, it goes deeper than that. Visual observation means looking for objects that are extremely faint, small, hard to find, or all three. But the harder the task, the greater the reward for success. The excitement and joy always lie in finding and seeing celestial bodies that are so far away from us. I have enjoyed the charm of telescopes for many years, tested and compared dozens of such mirrors in the night sky, and hammered my judgment during these times. The following is the experience of such a telescope enthusiast for many years.
1. What is a telescope?
A telescope is an optical instrument that uses a lens or mirror and other optical devices to observe distant objects. Refraction of light through a lens or reflection of light through a concave mirror causes it to enter a small hole and converge into an image, which is then seen through a magnifying eyepiece. Also known as the “Thousand Mile Mirror”.
2. What is the function of a telescope?
The first function of a telescope is to magnify the angles of distant objects so that the human eye can see at even smaller angles. The second function of the telescope is to direct the beam of light collected by the objective lens into the eye, which is much larger than the diameter of the pupil (up to 8 mm), allowing the observer to see faint objects that would otherwise be invisible.
3. How do telescopes work?
A telescope is a kind of visual optical instrument used for observing distant objects. It can enlarge the small angle of distant objects by a certain magnification so that it has a large angle in the image space so that the objects that can not be seen or distinguished by the naked eye become clearly discernible. Therefore, the telescope is an indispensable tool in astronomy and ground observation. It is a kind of optical system through the objective lens and eyepiece so that the incident parallel light beam still remains parallel to exit.
4. The art of using a telescope
Many people buy telescopes as if they were a color TV, hoping that they will produce images of their own. But telescopes are much more.
Like a piano, its return is always proportional to the time you spend on it. However, learning to operate a telescope well is much easier than learning to play a musical instrument. If you stick to it and practice some of the techniques mentioned below, you’ll get good at it in no time.
(1) Know your device
Naturally, everyone would use his new telescope for the first time during the day. This is your chance to get familiar with the telescope,
Its operation, pointing, focusing, different eyepieces, and magnification, and then you can do anything at night.
Almost every telescope has a star finder on its side to help you aim. You need a star finder
Mirror. Because the field of view of the main telescope is so small, only a small patch of sky can be seen. You can’t tell exactly where he’s pointing.
The higher the magnification, the smaller the field of view. At 50 times magnification, you can see only as much sky as your fingernail can cover at arm’s length. An eight-fold star finder, on the other hand, would give you as much sky as a golf ball would cover an arm’s length.
This is large enough to aim at some objects and make them appear in the star finders’ field of view. Once they are in the field of view, center them on the crosshairs. If this were done with a primary mirror, it would be incredibly difficult.
The most important thing to do first: You’ll need to adjust the screws on the star finder holder to make it parallel to the main telescope. During the day, use the low-power eyepiece and aim the primary mirror at an object at least a few hundred meters away (but not at the sun! Don’t point your telescope at the sun, or you’ll blind yourself. The distant treetops are ideal. Never mind that it’s upside down.
Now look through the star finder and see the top of the tree? Is it in the middle of the cross wire? Adjust the screws on the finder holder until the crossing point of the cross wires coincides with the target. Now check the primary mirror to make sure it’s not moving. Then switch to a higher power eyepiece and repeat the steps until the finder’s point is precisely adjusted and locked.
You ask, why is the top of the tree upside down or pointing in other strange directions? Because it’s a telescope, and there’s no up or down in the universe. Therefore, the directionality of the field of view is irrelevant. Bringing the image back to the correct point requires extra optics, which adds to the cost and complexity of the equipment and may reduce the quality of the image slightly. Thus, “exactly” lens structures are used in ground-based telescopes, and they are only used to look at things on the ground.
Then there’s the stent. There are two basic types of telescope mounts: equatorial and horizontal.
The equatorial bracket only allows the telescope to travel north-south and east-west across the sky. The flat type moves up and down, left and right. The flat bracket has the advantage of simplicity. The equatorial style is very useful, but you need to get used to it.
Equatorial bracket. If this is the one you bought, find its polar axis. Outside, set up your telescope with the polar axis pointing toward the North Star. The telescope will now be able to track the movement of objects on the celestial sphere around this axis.
Sweep your telescope across the sky from the eastern horizon and point it toward the western horizon, and imagine that this is the trajectory of the stars at night. At first, the movement of the equatorial bracket seemed awkward and unpredictable. But remember, no matter where the telescope is pointed, it is always moving toward or away from Polaris (north and south in the sky) and perpendicular to that direction (east and west in the sky). This requires you to practice and adapt during the day.
(2) Observation skills
The challenge of astronomy is that we have to look at objects that are very far away from us. On Earth when you want to see something, your instinct is to get close and see it. But for distant stars and galaxies, we stay where we are. Thus, from the dawn of telescope astronomy to the present, the art of observation has always been the art of maximizing your eye.
Observation hints. When you look through a telescope, focus carefully. A good observer is always willing to take the time to focus and make the stars as sharp as possible. Many people find it better to keep both eyes open because closing one eye tires the working eye of the other. You can cover one of your eyes with your hand.
Don’t expect to see celestial details all at once; one glance is always less than the next. That’s true whether you’re looking at a galaxy that can only be distinguished from the sky background, or details on the moon, or a bright planet.
One reason it takes time to see the details is the earth’s unstable atmosphere. At high magnification, stars always appear to shimmer and boil due to the faint but ever-present thermals above us. The intensity of the flicker, called atmospheric vision, varies from night to night and even minute to minute.
When you look at a “quivering” object, unexpected details flash in a moment of atmospheric stability, when the star image becomes sharp but disappears before you know it. Experienced observers will remember these wonderful moments and forget the rest. Atmospheric visibility is especially important for observing bright objects with high magnification, but it can also affect faint objects.
However, the main reason it takes time to see details is not the effect of the atmosphere but the eye and consciousness. Spotting faint objects in the field of view means learning new visual skills that require concentrated effort.
You will find that the eye’s imaging of some extremely difficult objects is very slow. When a detail is seen and fixed, you will think that nothing will be seen. But a few minutes later, another detail appeared, followed by another.
To assure you of this, look at a patch of sky with the naked eye and try to spot faint stars. Some stars
It will be seen immediately, others will take several minutes. When no stars appear, most people decide to give up but hang on a little longer. Stars may appear in areas previously thought to be empty. After a while, you’ll be able to see at least half a star.
A great way to train your visual skills is to sketch. You don’t have to make it into art. Our main goal is to
Write details in your notebook in a more direct way than words. No artistic talent is required to sketch a starfield, but by sketching a sky field containing a faint asteroid or exoplanet, you can identify changes in the positions of these objects by examining sketches made days or weeks ago.
For sketching the planet, try drawing the moon with the naked eye. If you have sharp vision, the moon shows much more detail to the naked eye than the planets do to a telescope! Draw a semicircle a few inches in diameter, draw some circular targets, and then draw the line where the light and dark parts of the moon meet. Carefully pencil in the main dark areas and look for small spots. Now you see more detail on the surface of the moon than you could have imagined.
You should not waste any opportunity to train your eyes with a telescope. You can see different effects of the same object at different magnification rates. Try to observe faint stars and draw planets in detail. In the beginning, it all seemed futile.
Observation notebooks will be filled with useless sketches and failure notes. But seemingly useless work is necessary because, over the course of a few weeks, the effects of training begin to show. Objects thought to be extremely difficult or impossible to observe are identified on the first observation, and faint images appear in the field of view. Indeed, the details will become so sharp that observers will attribute the essential improvement to better observing conditions. But it’s mostly due to your eyes.
(3) Make yourself more comfortable
Naturally, this is destroyed by the discomfort or inconvenience of the telescope. You’ll need a table for star maps, red flashlights, eyepieces, notebooks, pencils, and other equipment. For me, the perfect solution is a card table with four collapsible metal legs. It’s big, light and easy to store.
The convenience of having a rotating eyepiece disk is so great that it has become almost a necessary accessory for telescopes. If you can find or make an adjustable viewing chair, your telescope will show you a whole new world.
The erratic operation of an equatorometer or moving too fast can lead to bad results, especially if you don’t have a clock. Make sure the telescope is in balance. It shouldn’t be easier to move in one direction and harder to move in the other. Don’t be afraid to disassemble the equatorial device, and if it really displeases you, return it to the manufacturer.
In winter, follow the standard advice of astronomers and wear clothes in the low 20s to 30s, or you’ll suffer. How successful summer observations were made before the invention of mosquito repellents remains a mystery.
In short, any effort to make your observations easier, safer, and more comfortable is worth it, no matter how much trouble it may cause up until then.