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Telescope Focus Problems & How To Get Better Views Of The Planets

Can you see planets through a telescope good enough? If you’re feeling frustrated with the views you’re getting of planetary details, the following may help. It involves a test, with 12 questions to help solve telescope focus problems and other viewing frustrations.

Here’s my troubleshooting guide to help you solve your telescope viewing problems when it comes to seeing details of planets.

12 reasons you’re not getting the best possible views of planets with your telescope

A test on why your views of planets through a telescope aren’t satisfactory…

Here are 12 questions to ask yourself if you think you’re not getting the best view of the planets through your telescope…

  1. Are you looking at a planet that has little to no detail?
  2. Are you using the appropriate magnification?
  3. What are the atmospheric conditions (bad turbulence?)
  4. Position of planet: Is the planet just too low on the horizon?
  5. Do the optics need collimation?
  6. Are heat sources interfering, e.g. rooftops or air conditioning vents?
  7. Are you indoors looking through a window?
  8. Has the telescope adjusted to the surrounding air temperature?
  9. What’s the quality of your optics?
  10. If using a diagonal, is it in place properly?
  11. Is it the Barlow lens or the eyepiece causing the blurriness?
  12. Do you need a filter to improve contrast?

Read on for how you might resolve your telescope focus problems or other issues interfering with your views.

Planetary detail

Some planets have little to no detail when looking at them through a telescope. Venus is an example, because Venus has a thick atmosphere. As I wrote in what you can see of Venus through a telescope, that’s all you’ll get to see (unless you’re experienced enough with the right gear to see contrasts in the cloud blanket).

The following, which I wrote, will help you with the details you’ll likely see with certain planets:

Magnification

Magnification to see good details of planets can range from 30x to 300px, depending on the target planet and the viewing conditions. I cover magnification for each planet in my write up on telescopes best suited to planetary views.

You should know that telescopes have a maximum useable magnification (though viewing conditions can limit what can be achieved).

If magnification is the problem, you might need a better quality telescope or an extra eyepiece, depending on your set up.

Atmospheric conditions

Although, planets are bright enough to view with the typical suburban light pollution, a location that’s dark, dry, and elevated will give you the best experience.

See my article on some of the best places to stargaze, which has a link to a tool showing designation dark sky sites.

Apart from pollution, air turbulence, cloud cover, and mist are things that can interfere with views.

What can help? Cloud Forecast – From Clear Outside, will give you the outlook for your local atmospheric conditions, so you can know when conditions are favorable.

Timing & position of planet

Timing: No matter what telescope you use, you will get the best views of planets when the planets are closest to Earth. Sky map apps will keep you up to date with notifications of these events.

For example, Mars, especially its white poles, can appear clearer when it is closest to Earth.

Position: When a planet rises at sunset, wait until it is higher in the sky for the best views (i.e. a few hours later, after sunset).

Collimation & telescope blurry blues

If you are using high magnification for planet viewing, optics being out of alignment will affect the telescope’s performance. 

Are all optical elements aligned on the same axis? 

If not, you might need to collimate your scope. This is especially important for Newtonian reflectors and more so with short focal ratios (< f/6).

This applies less to refracting telescopes – see my article on refractors vs reflectors to find out more.

This is about aligning the optics. In some, it is simply a three-step process. 

  1. Align the main mirror roughly 
  2. Position the secondary mirror 
  3. Fine-tune the alignment of the main mirror 

Still, check the specifics for your individual telescope which are often on the website.

Refracting telescopes and Maksutov Cassegrains rarely need collimation.

Schmidt Cassegrains sometimes need it but the long focal ratios of these scopes mean that small collimation errors are less noticeable. Though, I have a step by step article on collimating an SCT and another on collimating Dobsonians.

Eyepieces

The best outdoor gift to yourself is to get some extra eyepieces. Which are the best eyepieces for viewing planets? I cover the features and metrics to consider in my article of what to look for in telescope eyepieces.

But for the ones that you have, do they need cleaning? Check them for smudges or gunk. I have an article covering how to clean eyepieces that includes the dos and don’ts, that will help here.

Barlow lens & star diagonals

If you suspect the problem is your Barlow lens, my article on how to use a Barlow lens might help. In this I also cover where to place the Barlow lens if using a star diagonal if you’re worried that it’s misaligned.

Using filters

Filters can improve what you can see. Red/orange filters should help you view the polar caps and major landmarks like Syrtis Major and Hellas on Mars. This will depend on what side of Mars is facing the Earth.

Getting hold of a good selection of color filters and having an understanding of the landmarks will also help just as much as having the best eyepieces to see details and contrasts on the planet’s surface.