If you are interested in astronomy, a great way to learn more about the night sky is to learn how to use a telescope. Doing a few simple tricks and aligning the finder with the telescope will allow you to find any planet visible in the night sky. Get a glimpse of the stars and planets with this quick guide on how to focus on a planet with a telescope.
Part 1 of 2: Align the Finder
Step 1. Locate the finder on the telescope
The finder is usually a small tube that sits on the side of the telescope. It has a wide viewing range, so it can be used to search for small objects in the sky; however, keep in mind that it only works if it is correctly aligned with the telescope.
When you look through the finder, you should see the crosshairs. After you have correctly aligned the finder, you will be able to center an object in the crosshairs, and see how it gets bigger in the telescope
Step 2. Set the telescope eyepiece to the lowest magnification
The lowest magnification of the telescope has the widest range of view when looking through the eyepiece. On a smaller telescope, the eyepiece will have a number written in millimeters, such as 20mm or 25mm. Higher numbers have a lower magnification. Look at the eyepieces of your telescope and make sure the lowest magnification is in place so you can see.
Step 3. Focus the telescope on an object at a close distance
This process is easiest to do during the day, when many different objects can be seen more easily in the distance, but it doesn't necessarily have to be during that time. Pick a distant object like your neighbor's chimney or cell phone tower and locate it through your telescope.
If the telescope can be fixed in place, activate this feature to prevent it from straying away from the object you are locating
Step 4. Adjust the finder to focus on the large object in the reticle
Now that the telescope is focused on something, you will need to move the finder until you see exactly the same object centered on the crosshairs. Most finders will have screws on the side that allow you to adjust their position. Once you've adjusted the finder, look through it again and make sure you still see the object centered in the crosshairs. Then look through the telescope and make sure it is still pointing at the object.
- If both views are of the object, you have managed to align the finder.
- The finder moves out of place easily, so you may have to repeat this process if the telescope is moved or bumped.
Part 2 of 2: Focus on a Planet
Step 1. Find the star maps and planet guides for the month
The different planets are more or less visible depending on the time of year and where in the world you are. There are many websites and guides that will tell you what is viewable based on the month and location you are in. Use this as a guide in choosing what you want to search for.,
These guides will give you an idea of where to look in the sky to find a planet with the naked eye
Step 2. Adjust the telescope to its minimum magnification
Just like you did to align the finder, make sure the eyepiece with the lowest magnification is in place. The magnification in telescopes is measured in millimeters and the lowest will probably be about 20 to 25 mm.
You should adjust the magnification before locating the planet in your finder because you could move the telescope out of position when making the change
Step 3. Locate the planet in the telescope finder
Once you have found the planet you are interested in with the naked eye, position the telescope so that it is pointing in that direction. Look through the finder until you find the planet and focus it on the crosshairs.
Avoid moving the finder from its place while trying to locate the target. Move the telescope to adjust the position of the finder, otherwise it will no longer match the position of the telescope
Step 4. Locate the planet through the telescope eyepiece
If the finder has been correctly aligned with the telescope, you will be able to see the planet through the eyepiece. You may need to move the telescope a bit to see the planet, but it should be fairly close to where you focused with the finder.
If you zoom out too far and still can't see it with the telescope, make sure the planet is still visible in the finder. If it is and you can't find it with the telescope, try realigning your finder
Step 5. Focus on the planet using the focus buttons
With the side buttons you can shorten or lengthen the distance between the eyepiece and the telescope lens. Changing this distance allows you to focus on the object in question. Adjust the buttons until you see the image in sharp focus.
Try changing the eyepiece to increase the magnification and refocus. You may find that the larger the image, the more difficult it is to focus properly. For smaller home telescopes, the higher the magnification, the lower the image resolution. Smaller telescopes are not effective enough to focus on a planet at high magnification
- To calculate the magnification of the telescope, divide the focal length of the telescope by the focal length of its eyepiece.
- Powers greater than 300x are rarely achieved.