The Great Lick Refractor - Dark Sky Photography

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April 28th, 2017

In 2017, we're capturing the cosmos using a Canon 6D DSLR camera attached to the 129 year old Great Lick Refractor -- a 36 inch refracting telescope at the Lick Observatory atop 4,265 ft. Mount Hamilton near San Jose, California.  This project was funded by Kickstarter (The Great Lick Refractor) on March 20th, 2017, and will consist of 3 or 4 trips to the telescope throughout the year to use the power of its massive lens.  The experience and findings will be shown below.


Night 1 - March 31st, 2017

Finally we caught a break during a week of on and off rain.  Sunny, clear skies prevailed on this day, however, the wind was still strong, and would prove to be a challenge throughout the night.

This being the second time we've imaged through this giant telescope (we first tested our methods for 3 hours in November 2016), we were hoping to gain more knowledge of its astrophotography capabilities through the only way possible -- trial and error. As many of you may know, aside from some preliminary calculations one can make - some definite, some approximate - trial and error is a key component to mastering any astrophotography setup, and so it's what we've set out to do with the Great Refractor.  We know its 129 year old lens isn't perfect, as it suffers from some amount of chromatic aberration, which means it focuses the red and blue spectrums of light slightly apart from each other, creating a "fringe" around the edges of objects.  We also know that using its effective focal length of ~17,000 mm will produce images that are much more "zoomed in" than our much smaller 8 inch, 1000 mm reflecting telescope, and this can make judging our image quality more difficult as it's much different than we're use to.  But we do know that at 36 inches, this thing has light gathering power like we've never seen, and the fact that we can put a modern day DSLR camera on the end of a 57 foot long, 129 year old telescope is just awesome!


Now back to the weather... at dusk the skies were clear, but the wind was gusting to 20 - 30 mph, which shook the entire dome from time to time. These are the obstacles you have to battle doing astrophotography. Nothing new, except for the much more limited time we had on this gigantic beast, as opposed to the endless nights we've had to trial and error our personal setup.


As the first quarter moon began to set below the view of the telescope, we pointed at Messier 1 -- a supernova remnant which was before just a tiny spec when we used our 8 inch telescope, but the Great Refractor would have it filling up almost the whole frame. 

  • Raw image file of M1

    Raw image file of M1

    ISO 20000, 45s

  • Same single image with a touch of editing to show contrast

    Same single image with a touch of editing to show contrast

    ISO 20000, 45s

The Canon 6D does really well at high ISO, and we didn't have much time with this object as it was quickly setting below our field of view, so a whopping ISO 20000 was used with 45 second exposures. The Great Refractor has a tracking motor, but no autoguider, so we were happy to get such long exposures without having the stars trail. One thing that is hard to get used to, though, is that the stars do not become pin-pointed -- no matter how much the focus is adjusted.  It's just the nature of this telescope. As already mentioned, the specs of the this telescope are just way beyond anything we're ever seen, and we just have to get used to it.

As the night went on, we targeted the Eskimo Nebula (NGC 2392), some other objects which didn't work out quite as well, and ended the night on Jupiter. With the wind still blowing mightily, we took video of Jupiter. Here is some footage of the giant planet:

We'll continue to process the content we captured this night, and will report the results when ready right here on this page.  Our next night at the 'scope is coming next week, and as it stands now the weather is looking to be great.

Stay tuned!

Night 2 - May 2nd, 2017

On this night we welcomed some of our backers from the Kickstarter project.  The sky was completely clear and the temperature atop Mount Hamilton was mild after a very warm day.

We began the night by looking at the first quarter moon, and before we settled in with the eyepiece, we dropped the camera in for some quick shots.  The Great Refractor's 17,000+ mm focal length provided an up close viewing experience of its surface.

Terminator line on the first quarter moon

Terminator line on the first quarter moon

This sample image shows the chromatic aberrations from the 129 year old lens -- seen in the purpleish fringing near the edges of the craters, but overall we are very happy with the results.  What an awesome close-up of our moon!

Next, we'd put the eyepiece in and point the Great Refractor at a double star, and a faint spiral galaxy for everyone present to observe.  The double star was bright and straight forward, but the faint spiral galaxy required use of averted vision - that is - when you look slightly off to the side of an object and then view it "out of the corner of your eye."  This method makes it easier for your eye to recognize the contrast of the faint smudge on the night sky, which is useful for viewing many galaxies and nebulae.

After that, it was time to point the 'scope at Jupiter.  The conditions were much better this night than our previous trial on March 31st (described above).  The wind was calm and the overall "seeing" of Jupiter was very good.  "Seeing" is a term that refers to the amount of twinkling and blurring in bright nighttime objects due to Earth's everchanging atmospheric conditions.

We captured several videos of the giant planet -- here are a few of the frames.  You can see one of Jupiter's moons, Io, transiting across the planet as a small black dot.

  • Jupiter through the Great Lick Refractor

    Jupiter through the Great Lick Refractor

  • Jupiter Up Close with Io transit

    Jupiter Up Close with Io transit

Below is video of Jupiter. For those of you who like to edit astrophotography, click here to download the raw video file (~25 MB) so you can edit it yourself!

Jupiter with Io Transit

The spectacle of Jupiter was awesome. This telescope shines when it comes to viewing objects in our solar system as it really "takes you there."

We finished the night by viewing M3 - a globular cluster - which is a cluster of mostly older stars found in the halo of our galaxy. The different colors of the stars correspond to their ranging temperatures and sizes. For now, we'll leave you with a quick and dirty edit of M3 captured through the Great Lick Refractor.  Our next night at the 'scope is in late August.  Until then...


M3 Star Cluster

M3 Star Cluster

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