Constellations II: Leo the Lion

Click to enlarge and discover many stars!

Five weeks.  That is how long I had to wait from my first session photographing Leo the Lion to my second.  That is how long I had to wait for a mostly clear night, but even then, in the early evening of May 29th, I just finished my shots in time before large clouds rumbled in.

Five weeks prior, on April 22nd, the skies were much clearer and Leo was still directly overhead.  But as that was more of a test-shoot, compiling light, dark, and bias frames with my Canon EOS DSLR camera, I wanted to get a second set to see if there was any noticeable difference in the final imagining.  In particular, I wanted to shorten the focal length from f/22 to f/14, about mid-range.

I don’t think the focal setting change made much of a difference, but at least I did learn a few more things about the stacking software, DeepSkyStacker.  For example, the stacking “Intersection Mode” works wonders if you have to move the camera a bit and to ignore the stray wisps of clouds.  I know now for future reference that the sky does not have to be perfectly clear, just clear enough.  I can also take as many light/picture frames as I want, so long as I keep the object approximately centered.  DSS figures out the rest!

The one aspect of this technique I wish I could improve is to highlight better the apparent magnitudes.  Regulus is the brightest stars in my picture, but you cannot tell.  I don’t want to faux edit the image just to make the brighter magnitude stars bigger, but I do want to research possible PSP techniques to highlight the bigger stars.

I am also amazed at how accurate the picture is.  Compare the above image with this star chart and you can mentally plot the smaller stars.  Pretty cool!

Constellations I: Testing Ursa Minor, Snagging Draco

Do you see Polaris, Ursa Minor, and Draco?
Click to enlarge to full size.

On Monday, the same night I photographed Jupiter and Io, I also set up my tripod and new digital camera.  I want to start taking wide-field pictures of the night sky.

As a test subject, I pointed at the Little Dipper.  On the digital camera, everything has to be set to manual.  The longest setup time was in getting the focus just right.  For this, I used the brightest “star” available, Jupiter.

I took 17 images at ISO 3200, 18mm, and 10 second exposures.  I then took eleven dark frames – same camera settings but with the lens cap on.  This is to ascertain camera noise.  Finally I took 14 bias frames.  These are dark as well – lens cap on – but very fast shots.  In reading up on this, it’s possible I did not need bias frames, but I used them anyway.

I put all these images into DeepSkyStacker, and the above is what I got.  This is not a very interesting part of the sky, and my light pollution does not help.  In Ursa Minor I can see Polaris and the two bright end stars, but the middle ones are more difficult.  Something like Draco I cannot see at all.  So it is remarkable what the camera can pull out!

I am pleased with the amount of stars I captured.  Can you see Polaris and Ursa Minor?  I also got all of Draco in this picture, which surprised me.  Do you see it?

If you are having trouble (like so many of my co-workers did), please see this cheat image I created.  I purposefully am not showing the image directly in the blog post, to give you time to first study the raw picture before looking at the “answers.”