Dark skies and the Milky Way

With the moon well past full combined with very clear and dark skies it was time again to do some night sky astrophotography. On an earlier outing, I had taken a few “exploratory” images of potential targets. It was now time to take some longer exposures.

My first target was Rho Ophiuchi cloud complex, a dark nebula of gas and dust that is close to the star ρ Ophiuchi of the constellation Ophiuchus (and located adjacent to the better known constellation Scorpius).

Rho Ophiuchi cloud complex. The planet Saturn is in Scorpio and is located in the upper right of the image.
Rho Ophiuchi cloud complex. The planet Saturn is in Scorpio and is located in the upper right of the image.

My tools for the night were a Nikon D700 DSLR (fairly old camera technology by today’s standards), a Nikon 85mm f/1.8 lens (a short telephoto lens that works well for astrophotography), a tripod, and an iOptron SkyTracker equatorial mount for tracking the stars on long exposures.

I took 10 exposures each of 4-minutes duration and then stacked them using the (free) Deep Sky Stacker application. The resulting image was post processed in Photoshop CS6 using Astronomy Tools v1.6.

The result isn’t bad considering I’m still pretty much an amateur at this astrophotography thing. For comparison, check out this amazing version of the Rho Ophiuchi cloud complex at the APOD site.

The next night was almost as clear so I returned again to my viewing location near Mormon Lake. This time, I used an ultra-wide angle lens (16mm). Here you can see the Milky Way rising in the east with Saturn in Scorpio and visible in the center right part of the image. The Rho Ophiuchi cloud complex is also visible to the right of the Milky Way. The glow in the lower right is from the city of Phoenix—locateded over 150 kilometers to the south.

Milky Way rising.
Milky Way rising.

While capturing these images I was treated to the yipping of coyotes, hooting of owls, and could hear a small herd of elk grazing in a nearby meadow.


  1. Dave,
    Good first attempt at Rho. I especially like your widefield of the Milky Way. It appears your camera is “unmodified”, that is, the IR cut filter is still in place. This will prevent you from imaging Hydrogen alpha at 656nm very well. I started with a DSLR too, but now have moved up to a monochrome ccd. I image sometimes with a Canon 135mm lens using a custom adapter with the ccd. Here’s my Rho from last year from my backyard in Tucson:
    I may try it again from my new very dark sky site in far SE Arizona in a few weeks once the moon goes away.

  2. Mike,

    Thanks for the compliments on the images. Your Rho image is impressive.

    You are correct that it is unmodified. The Nikon D700 is the only DSLR I own so I don’t plan to make any changes to it. I’ve seen some amazing results using monochrome CCD systems so that may be a possible route in the future. For the short term, I’m more interested in astrophotography-landscape photos using wide angle lenses and occasional attempts at DSOs.


Comments are closed.