How to do Infrared Astronomy from your own backyard!
In this article I will discuss how to do infrared astronomy. Infrared astronomy has several advantages, one of which, is that you can get a lot more detail without being affected by the atmosphere distortion.
It also allows you to do astronomy during the day, which
is quite advantageous so you can capture pictures of things
like the Moon, Venus and Jupiter without a lot of the problematic daytime light
from the night sky. However smaller targets are not possible due to the large
amount of infrared the sub puts out.
To do near infrared astronomy, you must have a camera, because
infrared is not visible to the human eye so you cannot see anything. If you looked
through the eyepiece it will appear black.
Preferably use a monochrome camera that is because they are
roughly three times more sensitive than colour camera, however it is still
possible to do this with a colour camera if you ensure you set the white
balance to 0.5.
You will also need an infrared filter pass filter which needs
to be attached to the front of the camera.
The infrared filter will block all the visible light, allowing
only infrared through. So, for this first example we are going to look at the
Moon.
In the episode below, I created an infrared video of the
moon using a ZWO 850 nanometre pass filter, however, it is possible to get even
more sensitive filters which only block wavelengths less than 685 nanometres. This
may be better for smaller infrared targets.
I found that focusing when using the infrared filter is a
lot easier which is probably due to a lack of atmospheric dispersion usually
found in the visible spectrum. Any telescope that uses mirrors and or lenses
can perform infrared astronomy. However, the same is not true of ultraviolet
astronomy which degrades with intervening lenses. Although when doing infrared
astronomy from ground-based telescopes water in the earth's atmosphere absorbs
a significant amount of infrared radiation as well as emitting infrared
wavelengths so this image is only in fact picking up the near infrared.
While it is technically possible to overcome this by moving
to a higher altitude most amateur cameras can only detect the infrared anyway
so it makes little difference the amateur astronomer.
This technique can also be used on other infrared targets in
our Solar System such as Venus, Jupiter, Saturn, Neptune and Uranus.
There are even some deep sky targets such as the star CW Leo which is only visible in the infrared some other good targets for infrared are
the Lagoon Nebula and the Whirlpool Galaxy both of which show more detail in
infrared.
To find the Whirlpool Galaxy check out this article. I am
planning to cover some of these infrared targets in articles.
Infrared is also used by astrophotographers as a luminance layer in a LRGB image to improve the overall sharpness of the image.
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