November 2019

To see how these differences can show up in the creation of an image, let’s look at Hubble’s most famous image, the Pillars of Creation (first image)

When I first saw this image, I wondered where in the sky this image came from, and I assumed I couldn’t produce an image that was in any way recognizable as these amazing pillars of gas. To answer the first question – where in the sky did this image come from – now look at the first 3 images attached. These are all images I have taken with different size camera lenses or telescopes.

The first is a wide-field view of the summer night sky looking south. If you were in a very dark place in New Mexico – where this picture was taken — you would see something like this (but without the color and without the lines). The color is visible in this long time exposure, but your eyes can’t see color in light as faint as the natural Milky Way. This is the brightest part of the Milky Way, where we are looking right into the center of our galaxy. At the bottom, near the horizon, to the right you would see the stars making up the tail of the constellation Scorpius, the scorpion. The green lines are to help you see the curve of its tail, ending in two stars close together. Near the middle is the constellation Sagittarius, the archer. Many people see the stars as forming a teapot (instead of an archer), with the handle to the left, the spout to the right, and a lid on the top. The green lines are to help you see the stars making this shape. Above it are several pinkish nebulae and clusters of stars in the Milky Way. Notice the blue rectangle that includes two of these pinkish nebulae.

The second picture is a greatly enlarged area of this rectangle, where you can begin to see some detail in these two nebulae consisting mostly of hydrogen gas, where new stars are forming, surrounding a cluster of existing stars. In this picture the blue rectangle surrounds the object known as the Eagle Nebula, and it outlines the next image. The third picture shows the Eagle Nebula in more detail, with the center part, which includes dark obscuring dust, surrounded by a blue square. This is where in the sky the Hubble image comes from.

The fourth image takes the picture within that square, greatly enlarges it, and turns the square so it is straight up and down rather than tilted. Note that this very great enlargement of my image makes the brightest stars look like large bubbles rather than small dots. This is because the atmospheric turbulence smears the light from the stars in my telescope. Also, the whole image looks fuzzy because the image has been enlarged beyond the practical capability of my telescope to create a sharp image. The Hubble telescope does not suffer from these problems. But there is another difference. My image is taken in visible light, and the color (mostly red) is what you would see if you could transport yourself to see this nebula up close and bright. The Hubble image, on the other hand, uses special filters and then combines different wavelengths of light using specially assigned (artificial) colors – called the Hubble Palette — to bring out the greatest detail in the nebula. It is not how it would look to the human eye if you were close to the nebula.

The remaining 5 images (5 through 9) take you on a gradual magical transformation of my image into the amazing detail of the Pillars of Creation produced by the Hubble. So my images are only poor, blurry representations of what the Hubble can produce, but I think they can still be pretty pictures in their own right, and they are created at only 1/250,000th of the cost! I will keep sending you more of my pictures for free, but of course you can get Hubble pictures on the internet for free also. Well, not quite for free. Your taxes help to pay for them. But well worth it, I think!

Keep looking up (and paying your taxes),

Carter, (sometimes) Resident Astronomer,

Lookout Observatory