Planetary Astrophotography

Inevitably, when a human being has a telescope, binoculars or any other aid to watch the night sky, the temptation to create a permanent memory of what they see, is always there. “What if I can capture this moment in a photograph?”.  Whenever I attend our Saturday night public events at Fox Observatory in Sunrise,FL (www.sfaaa.com ) , there are always people who use even their cell phones to capture what they see through the eyepiece. And those moments are memorable.

Some 10 or 15 years ago, the mere thought of capturing high quality photos of the night sky was reserved for the pros, the very wealthy or NASA. Today, although high end deep sky cameras are still expensive, they are far from the unreachable prices they had before. Technology has brought this “science/art” to the backyard of hundreds of thousands of amateur astronomers worldwide.

Zero Investment

And getting started with astrophotography does not mean necessarily that you break the bank. The simplest forms of astrophotography consist of simply pointing up any camera to the sky or taking a photo through the eyepiece of a telescope (afocal photography). Getting it right requires some practice of course, but in both cases, it requires only a camera that you probably already have. So let’s call this the Zero Investment level. Amazing images can be obtained like this and the variants to shoot them are numerous.

One Small Step…the $100 Investment

But OK you got the telescope bug and bought or already have one. Let’s say that for deep sky not all telescopes are suitable and the gear and software plus the shooting are more complex, but for planetary imaging it is different.  Not to say that “any” telescope will work but most of them can be used to obtain good quality photos. And when we refer to planetary imaging we are talking not only to be able to get photos of Mars, Venus, Saturn and Jupiter but also to shoot amazing images of Moon craters and other geological formations.

For planetary imaging all you need is a webcam…..yes the same ones you used to buy for your computer when they didn’t come with a camera. But this camera has to be modified so if you are like me (lazy) and rather buy the camera ready for use without having to do any modifications to it, good news. They are sold ready to be used. The most popular and famous is the Phillips ToUcam. Other cameras are sold ready such as the Phillips SPN900NC, the Meade LPI, several models from Imaging Source and the Celestron Neximage which is basically the same as the ToUcam with a different housing and ready to use in your telescope.

So why do we call this the $100 investment? Well because if you already have the telescope and assuming you already own a computer, technically you only need to buy the camera. What you need for planetary imaging is:

1-      Telescope

2-      Camera

3-      Processing Software

4-      Computer

Software for capturing and processing is mostly free and you download from the internet. Some examples of capturing (more on the technique and software in future blogs) software are AmCap and wXAstro Capture. On the side of the processing software, the most popular one to use is Registax (http://www.astronomie.be/registax/ ). All of them free.

Comments

Ok so at this moment we will not enter in the details of how to shoot, use the capture software, processing etc. We will use a simple example of a recent capture and describe the gear used, conditions, place etc and a couple of tips to obtain better results.

Usually we are told that planetary imaging does not require much tracking and that only keeping the target in the center of the screen is enough. True…..BUT. I am an old fashioned guy and good imaging (Planetary and Deep Sky) is based on the details. So I try to align my telescope as best as I can. I rather “focus on the focus” and settings of the capture software than trying to keep my target on the screen. This is especially critical if you shoot the moon since during capture you are better off with good tracking and a stable image.

The Example of what you can do!

So here is the image of our example:

 

 The data for this image is the following:

Location: ROSA Observatory (that is the fancy name I give to my backyard!!) Weston, FL (26 06’ 53” N; 80 24’ 48” W)

Better than average seeing conditions, stable atmosphere clear sky, cool dry weather.

Telescope: Celestron Nexstar 6” (Orange OTA) with Starbright XLT coating, 1500mm focal length, mounted on a Celestron CG5 (GOTO) equatorial mount, no focal reducers.

Mount alignment with Polar scope and two star alignment routine on tracking mode.

Imager: Celestron Neximage with Cut Off Filter (this is a good accessory to have) and Celestron Ultima 2X Barlow

Resolution: 640x480

Capture software: AmCAP ,  at 25 frames per second.

 Processing Software: Registax 5, stack of the 44 best frames of a total of 1614, processing with wavelets

Post processing: A bit of Photoshop Elements 8