You will be surprised that even small things like the position of the telescope can vastly improve your skywatching session especially if you plan to see the planets. If I plan to observe the planets, I want to see as many details as possible, and these tips will extremely improve the experience for you. Some of them require to buy or replace some accessories, but it is necessary because only then you will get the most of your telescope.
The difference between observing planets and deep sky object is that I need to use high magnification when I want to see nice details and big disk of the planet. With deep sky objects it’s not so important because no matter how big the magnification, the stars will always be only dots. They are simply too far away, and usually, I want to use a wider field to see nebulas or galaxies which means smaller magnification.
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1. Collimation: When Your Telescope Is Out Of Focus
And here comes the first problem. If you are using the full power of your telescope, it needs to be in perfect focus. In astronomy, we are talking about telescope collimation. It doesn’t matter if your telescope is new it will be out of collimation for sure. But this is applied only to Newtonian reflectors with a mirror. The refractor telescope is using lenses, and if it’s out of collimation, it means it’s faulty, and you should return it to the reseller. You can’t collimate the refractor telescope at home. However, you can easily fix that on reflector telescope. To be honest, you will be doing that very often if you are planning to travel with your telescope. Even the slight vibrations during the transport can bring your telescope out of focus.
There are many accessories which can help you to fix that. You can also make a collimation kit by yourself from a simple cardboard sheet, or you can buy expensive laser tools. I like to use a simple collimating eyepiece- Celestron Collimation Eyepiece. It’s not laser-based but highly efficient. To sum it up, before you use your telescope even for deep sky objects, make sure that it is in good collimation.
2. Star Diagonal Mirror Problem With Refractors
Now we know that you can’t fix collimation issue with achromatic refractor but you can, and you will have to fix a problem with the diagonal mirror. It’s a small piece of equipment at the end of your telescope where you are putting the eyepiece. It has 90-degree shape with the little mirror inside. It might surprise you, but it is quite a weak link in your instrument because it has a simple 45-degrees flat mirror. I thought that to create a flat mirror is easier then to grind the lens and you might think the same. But that’s wrong; it’s at least as hard. So don’t think that because it is only a flat mirror, it does not affect the quality of view through your telescope. You can check if there is an issue by simply removing the diagonal mirror piece and put the eyepiece directly into the scope. Now you have to compare the difference you see with, or without the diagonal mirror in place. There should be no difference, and if there is, you have a problem. In this case, you should consider the upgrade.
What we want from star diagonal is nothing- it to be completely neutral. This will be your case if you have an entry level telescope. You should seriously consider replacing the star diagonal mirror with something better. It can be pricey, but the results will be significantly better. It will be between $50 and $100. Of course, you can buy a more expensive one. I recommend going for the Orion 8879 1.25-Inch Enhanced Mirror Star Telescope Diagonal. It’s around $70, and it will be better than the one that came with the telescope.
3. Don’t Overpower Your Telescope
Power of the telescope is basically magnification. Maximum power is the maximum useful magnification. It means that if you go above you will overpower your scope and you will see only blurry images.
Calculating the maximum power is very easy- multiply your aperture by number two. For example, if I have a 130mm diameter, it means that my maximum power is 260x magnification. To control magnification you need to use specific focal length eyepiece. It is calculated by dividing the focal length of the instrument with the focal length of the eyepiece. In my example, if I have 650mm tube and I will use 10mm eyepiece, I will get 65x magnification. The easy trick to figure out the size of your eyepiece for the maximum power is to divide the focal length of the telescope by the maximum useful magnification which is in our case 650÷260=2.5mm. But that’s a big problem because 2.5mm eyepiece is too small, not very efficient and high-quality ones are costly. It is also worth to mention that the field of view is tiny.
So how to work around that? We can use a Barlow lens.
4. Use The Right Eyepiece To See Planets
As I mentioned above, the use of a small eyepiece is not a good idea, and we can solve this issue by using the Barlow lens. It is named after Peter Barlow, and it is a diverging lens which increases the focal length effectiveness of the optical instrument. In other words, it will multiply the focal length of the telescope by 2x or 3x. An adjustable Barlow lens is also available.
When you buy a new telescope, you usually have Barlow lens included in the accessories that came in the package. However, I can tell you for sure that it will be low-quality and with the single element lens inside. It will decrease the quality of the image, and you will certainly need to upgrade to at least 2 lenses based model. As I said in the point number 3., try to avoid small eyepieces. Barlow lens will allow you to use longer eyepiece and you will get the same magnification as with short one. Let’s say we still have 650mm long scope with 130mm aperture. If you use 3x Barlow lens, it will increase the length to 1950mm. Now calculate the optimal size of the eyepiece for this setup with Barlow lens: 1950÷260=7.5mm.
As a result, we can use longer eyepieces and enjoy higher magnification with a wider field of view. The general rule is to use longer focal length eyepiece with good quality Barlow lens rather than a short one. Planets will be sharper with more details and easy to look at.
5. Try To Use Orthoscopic Eyepiece For Planets
Orthoscopic eyepieces are specifically designed to give you the best possible view of planets. Their focus is very high but only in the center of the eyepiece. I don’t recommend to use them when you want to see a larger object where your eyepiece is full of details like the moon, but they are great for viewing planets. More from the center the viewing object is the more blurry image you see. However, the center is very bright with high focus, so small planets are with a lot of details in high definition.
This is just a suggestion, and it is not mandatory equipment to view planets. You can do that with a regular eyepiece, but if you want to squeeze the maximum from your telescope and you focus only on observing planets, it is a good idea to try them. Keep in mind that orthoscopic eyepiece is not very comfortable to use especially with the glasses and you need to train your eyes to get used to them.
There are many brands you can choose from, and I went for Baader Planetarium Classic Ortho 10mm Eyepiece. I’m very happy with it. It is a decent orthoscopic eyepiece on the budget.
6. Is It Worth To Buy Filter For Planetary View?
So now you have your telescope in good collimation, you upgraded some accessories and still want to improve the planetary view. Filters can help with that.
It’s not going to be a huge improvement, but you can really notice it when you have good atmospheric conditions and bigger aperture which is collecting more light. In this case, you can work with more light, and filters help improve contrast and details of the planets filtering some type of the light. Which type of light is filtered depends on the color of the filter. Every color is for the different object, and some are just for improving observation in high-density light areas like cities or locations near the towns, this is called pollution filter.
But we are talking about planets, and there is one filter color that you can use for everything. It’s a blue filter, and this filter is well known as an all-in-one filter for telescopes. You can use a blue filter for any type of objects, not only planets. But as I said it depends on many factors so don’t worry if you don’t have one. It’s not going to decrease the experience. But I will definitely say that you should buy one especially if you plan to do astrophotography, they are not an expensive upgrade for your telescope.
7. Position Of The Planet On The Sky
This may seem obvious, but many people don’t know about that. If the target is very close to the horizon, it will produce a bad image experience. The problem is that the atmosphere is very dense near the horizon and there is also a lot of smog. The higher the planet is on the sky, the better image will be seen in the telescope. So don’t hurry, just wait until you have a great position of the planet at least 30 degrees above the horizon. You will see many more details, and the image will be sharper.
8. How To Place Telescope Properly
Sometimes, if you are at home on your balcony or in the small backyard in the city, your options to position the telescope are limited.
The first advice is if you have a chance to go on a trip with your scope or going somewhere outside, try to place it on the firm surface. It will prevent movements when you are walking around it.
Another important thing is to observe the objects on the sky above nature environment. If you have only buildings around you, then you have no option. But buildings and concrete tend to soak up the sunlight during the day and then releasing the heat up in the sky during the night. It is creating turbulence in the air like you see on a hot day close to the road surface. This will decrease the quality of the observing planet.
9. Prepare The Telescope Before The Sky Watching
If you have your telescope at home and you are going out on your backyard to spend some time watching planets, you need to know a small tip before you start the session. Especially in winter when the outside temperature is lower, and you bring your warm telescope from the inside of your house- wait at least 30 min before you start making observations. It is because the telescope and mirrors or lenses depends on what you have, needs to cool down to surrounding temperature. If not it will be releasing hot air from the tube and create turbulence in the air which causes a fuzzy image.
Do the same thing with eyepieces. 30 minutes should be enough time, but all this depends on the size of your scope and the temperature difference. If you have a big aperture and it is very cold outside, then you have to wait longer. Meanwhile, you can prepare everything else like accessories you need or snacks 😉 Also your computer if you plan to do some video astronomy.
10. Choose The Right Time To Watch The Planets
This tip can really help you to see some amazing details on the planets.
As we know all planets including Earth are on the orbits around the Sun. That means the position of all the planets in our solar system is always changing. If you have seen any documents or movies where people are planning a trip to Mars, you must have noticed they try to schedule the flight when Mars is physically closer to Earth. You can apply the same thing when you are going to watch a particular planet. Use any astronomical software or app to see where the planets currently are and when are they physically close to the Earth.
Here is a good website called TheSkyLive where you can check the current solar system configuration in real time. If you follow this, you will see the much bigger disk and many more details like Saturn rings, Jupiter’s Great Red Spot, moons of the planet and many more.
I hope that these tips will help you to experience the full beauty of the planets through your telescope.
Of course that there are many more things you can do to get a better planetary view, like better telescope or to go and observe the sky in rural area far away from any cities and light sources where the night sky is so dark that you don’t even need your telescope to enjoy the beauty of the universe. Although with the right telescope, it will be another level.