Often new astronomers ask me if they can use a telescope in the city as their house is in an urban area and there is no way to drive off to a rural area for stargazing. So, I thought of answering the question in details in this article. Will a telescope work in the city? Let’s find out!
Yes, you can. Though light pollution will make it harder to stargaze in the city, but with some precautions, you can actually use a telescope in the city. Also, many people use filter to reduce light pollution when stargazing. This can also be used while you are using telescope in a city.
There are basically 2 ways to successfully use a telescope in the city: one is to reduce or fight the light pollution and the other is to use filters. We’ll talk about both of them. A combination of both approaches will help you to accurately stargaze in a city.
1. Fighting Light Pollution In A City
Use Shadow To Your Advantage
As by now you know, light is the greatest enemy when it comes to using a telescope in a city. The light source can be as simple as a neighbor’s light bulb or a street lamp.
So, when choosing your location, you need to find a place that is shadowed and not disturbed by any nearby light sources. This is extremely important for your eyes to be adapted to the dark.
If you can’t find any such places, the next best thing to do will be covering your head with a black cloth so the eyes can get adjusted to the darkness.
I always try to set up my telescope under the shadow of a tree or wall. They offer a reasonable protection against light.
Protecting The Lens From Light
Only protecting your eyes from stray light won’t do, you’ll also have to take care of the optics of your telescope. I’ve found dew shields to be most effective in such cases. Dew shields are useful for various reasons, they cut out light and at the same time, increase the amount of time you can use a telescope in the outside.
Here is one of my favorite dew shields for everyday use. You can check the latest price at Amazon from here.
Prepare For ‘Best’ Conditions
Do you know what makes light pollution worse? Dust, pollution and water vapor. High humidity as well as dusty air both can make light pollution far much worse. So, you need to be prepared in advance for the ‘best’ viewing conditions in your area.
There are many websites, apps which will give you an accurate prediction of weather in your geographical region. Use these websites in your advantage to know when will be the next best viewing condition.
Now that you know when there will be minimum light pollution in the sky, you can easily make preparations in advance for using the telescope during that period.
Wait For The Right Moment
If you know the right moment, even in light pollution you can successfully observe an star. The best moment to see any object in the sky is when the object is at its highest position. When the object is at the highest position, you can observe the object through minimum layer of atmosphere. As a result, the impact due to light pollution will be minimal.
Also keep in mind some basic things, like observing a star in full moonlight won’t work at all.
Also, light pollution considerably gets reduced after midnights, when people go to sleep. In some areas, street light is also turned off after a specific hour. Use that to your advantage!
Start With Larger And Brighter Objects
The larger and brighter an object is, the less it will be affected by the light pollution. So, when starting out, choose comparatively larger and brighter objects. Light pollution has little to no effect on moon or solar observation.
Be Nice To Your Neighbors
Lights from the neighbor’s house can really make everything screwed up. A nice way to deal with this situation is to actually be ‘nice’ to your neighbors and ask them kindly if they can turn off the light while you are stargazing.
A Nice Escape To The Rural Side
Though this article is all about how to use a telescope in the city, sometimes the best thing to do is to escape to the rural area and stargaze until you are completely satisfied!
2. Using Filters- The Second Approach
Using filters is a great way to reduce the effect of light pollution when using a telescope. There are various types of filter for reducing light pollution, such as:
- Anti-Light Pollution Filter
- City Light Suppression Filter
- Ultra-High Contrast Filter etc.
The main principle by which these filters work are more or less the same. They can mute out a specific range of wavelengths of light e.g. the range of street light. This can significantly improve your stargazing experience.
Here are some pointers on using filters for stargazing:
- As I have told before, filters mute out specific wavelengths of light such as the street light, but allows other wavelengths of light, such as light coming from a distant nebula. As a result, when viewing through the telescope, the light from streetlamps won’t disturb you. With a filter, the sky will appear much darker and the nebula (or any other distant object) will seem much brighter. As a result, it will be easier to spot and observe any extraterrestrial object.
- The effectiveness of the filter will vary from object to object. For example, if you are observing an object that emits light across a wide range of spectrum (e.g. a galaxy or reflection nebula), then the filter won’t be able to produce a much different result. On the other hand, you can observe objects that produce light across the narrowband spectrum much more effectively with a filter (e.g. emission nebula or H-Alpha).
- Filters are only a helping tool. They are not an alternative to complete dark sky.
So, I hope you got the answer if a telescope will work in the city or not. The thing is, in the city, things will not always flow in your way. And when things start to flow in the opposite direction, you’ll have to improvise and make the ‘Best’ out of your situation!