Astrophotography: Jupiter

Most of the pictures I have taken of space objects are considered deep sky objects.  Deep sky objects are mostly galaxies and nebula.   I know when I think about space I usually think about the planets before I think about another galaxy.  Yet, planets are one of the targets I have probably spent the least amount of time trying to capture.  The main reason is that planetary imaging is much different and in some ways more difficult at least in my opinion.

For deep sky objects the very basic plan is

1.  Take a bunch of images of the object with long exposure times or at least as long as possible for your equipment and location.

2.  Stack your images into one image.

3.  Process that image to "stretch" the date.  In other words pull out as much detail as possible while also adjusting for light pollution and other noise that is introduced

Again this is very general an I will eventually have some posts explaining each step in detail.  However planetary imaging is much different.  Planets like Jupiter, Saturn or Mars require very high magnification.  Besides having a scope that can go to high magnifications, you may also need something called a Barlow or Powermate to further push the magnification of your scope.  Take right off Wikipedia:

"In its astronomical use, a Barlow lens may be placed immediately before an eyepiece to effectively decrease the eyepiece's focal length by the amount of the Barlow's divergence.^[1] Since the magnification provided by a telescope and eyepiece is equal to the telescope's focal length divided by the eyepiece's focal length, this has the effect of increasing the magnification of the image.

Astronomical Barlow lenses are rated for the amount of magnification they induce. Most commonly, Barlow lenses are 2x or 3x, but adjustable Barlows are also available. The power of an adjustable Barlow lens is changed by adding an extension tube between the Barlow and the eyepiece to increase the magnification."

The Barlow just helps get your magnification up.  They are very small targets and you need these high magnifications, but the higher the magnification the more you are subject to turbulence from Earth's atmosphere.   That turbulence causes the planet to become blurred.

Our objective is still to get many images and stack them together;  With planets we will be dealing with the turbulence from the atmsophere and so we use a different approach to get our pictures.  Instead of taking a lot of still photos we get our frames by taking a video.  We can then separate each frame from the video and only stack the good ones. The best way to take that video is hook up a USB camera to your telescope

I use a a camera made by ASI called the ASI120MM.   Instead of a DSLR camera attached to my scope I just slide this USB camera in.  So for planets you will usually have USB video camera > barlow > scope.


Then we focus on the planet and record a video.  Watching the video points out how blurry things get.

Some software is then used to break the frams out, find the good ones and stack them.  My first attempt at planetary imaging is honestly not very good at all.  But hopefully I will have some better ones in the future.