Often many young astronomers have asked me if they can see through clouds with a telescope. So, I decided to explain it in this blog post, so that you can have a clear idea too. In this post, I am going to answer can telescope see through clouds are not.
No. Telescope can’t see through clouds. Telescopes work just like our eyes do. Whenever light hits our eyes, we can see. Similarly, telescopes will only be able to see if the light rays hit the objective mirror.
On a cloudy night, lights from the stars get blocked by the clouds. So, we can’t see through our telescope.
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So, What Can We Do?
There is nothing we can do when mother nature is against us. However, we can be prepared for it in advance.
If we somehow know that there will be clouds in the sky at 10 pm tomorrow night, we can set out for stargazing much earlier, when there will be fewer clouds.
The way we can predict this is by using a weather forecast site or app. Today, there are thousands of weather forecast apps or sites. However, not all of them are geared towards astronomy or stargazing.
The one I like for stargazing is Clear Dark Sky.
What Is Clear Dark Sky?
Clear Dark Sky is a cloud forecast website made for astronomers and fellow stargazers. This site works based on observing sites. For a specific observing site, say Blackfoot, the site will predict if there will be a dark and clear sky in the next 48 hours.
Clear Dark Sky is made specifically for amateur astronomers who just have dipped their leg into astronomy.
The forecast data comes from a model developed by Allan Rahill, working at Canadian Meteorological Center.
How To Use Clear Dark Sky?
Clear Dark Sky covers the USA, Canada, and some parts of Mexico.
Once you input the latitude and longitude of your observing site (you can also input data by keyword), the site will offer you a coverage map for that particular location.
Here are the step-by-step processes to get cloud coverage forecast from the clear dark sky:
[NB: ALL THE IMAGES ARE COLLECTED FROM ClearDarkSky.Com]
1. Selecting a Location:
First, you need to select the location of the observing site near you. Go to cleardarksky.com. You can choose a location by either inputting the latitude and longitude of that location or selecting a major city from the right sidebar. I have selected Arizona. Here’s how it looks:
2. Selecting The Observatory
On the next page, you’ll find a chart of observatories. From there, choose the one closest to you. I am choosing the 61” Kuiper Telescope.
3. Observing the Chart
On the next page, you’ll be presented with a sky chart from that observatory, in my case, the 61” Kuiper Telescope. The chart will show the exact forecast of the sky (cloud cover, transparency, seeing, darkness) and ground conditions (Wind, Humidity, Temperature) in the next 48 hours.
Here is the chart I got:
How To Read The Chart?
We need to read the chart from left to right. Each column in the chart points to a different hour. The time is in 24-hour format.
A digit 1 on the top of the column means it’s 1 am. 1 on top of 4 means it is 2 pm.
For forecasting the cloud coverage, we need to look at the rows labeled as ‘Sky,’ i.e., the first 4 rows.
To know the cloud coverage, we’ll have to look at the first row termed as ‘Cloud Coverage.’ You’ll see each block is designated with a color ranging from white to blue.
Pure white means overcast, and pure blue means clear sky. Also, by clicking on each of the blocks, you’ll get more information on it for that particular hour.
That’s how you can get a cloud forecast for your area in the next 48 hours.
For more clear information, click here.
Similarly, you can get information like the transparency of the sky, visibility, degree of darkness, temperature, humidity, wind, etc., of that particular observing site in the next 48 hours.
Needless to say, the forecast you’ll get will not be 100% accurate, and it can fail sometimes. Generally, the forecast is 80% to 90% accurate most of the time.
As now you know how to predict the cloud coverage of a particular area, you can prepare in advance if the sky is predicted to be cloudy in the next 48 hours.