The Attempt to Escape Chicagoland Perma-glow.
Ah, Door County, Wisconsin! I’ve heard rumblings about this little peninsula jutting off of the state of Wisconsin. In fact, it is this peninsula that prompts some residents of Wisconsin to call their state the “mitten” state. I could see that, maybe, if I was really drunk. We all know that mitten description belongs to the state that actually resembles a mitten – Michigan. But, I digress.
Door county is a very scenic location. The cliffs along the shoreline of Lake Michigan are stunning. The teal hue of the crystal clear water is breathtaking. I first experienced this area back in June for the Great Milky Way Chase, a social media challenge run by the folks over at Milky Way Chasers. I’ll write a separate post about the craziness of that challenge another time.
That trip, however, made me a fan of this Midwestern spot. For one, Door County is in a Bortle Class 3 index in terms of light pollution. Granted, this is not the best, but for east of the Mississippi, a class 3 is phenomenal, and will produce nice images. The Bortle scale is a 0-9 numeric scale that measures the night sky’s brightness of a particular location. It quantifies the astronomical observability of celestial objects and the interference caused by light pollution. For reference, Chicago is located in an 8/9. Until getting into astrophotography, I had no idea just how far reaching light pollution was.
To put this in perspective, Door County is ~300/350 miles from Chicago, and its still in a Bortle 3. Granted Milwaukee, Sheboygan, and Green Bay to the west all emanate light, as well. It is crazy how far these lights travel. In the image above, you can see the “light blooms” from the various cities on the horizon. What’s the point to all this about light pollution? Well, in order to see the some of these fainter celestial objects, you need as little extra light as possible.
Tracking the “Christmas Comet” – 46P
December treated us to a visible comet in the night sky around the constellation Orion and the Pleiades. Known as Comet 46P/ Wirtanen , or “the Christmas Comet”, this small green/teal object was visible for most of the month, but made is closest approach on Dec. 16th. It also so happened that the Geminid meteor shower peaked on the 13th. Unfortunately, for us mid-westerners, were clouded out for the peak of the showers. I decided to head to Wisconsin on the 14th, as soon as the clouds cleared, in hopes to catch some stray meteors. I didn’t see anything really spectacular.
What Could Go Wrong?
The whole point of this trip was to try out very basic “deep sky” photography. I’ve used a star tracker on wide-angle and normal focal lengths, but never with a telephoto lens. It intimidated me. Since I had all night to fumble around in the cold, now was as good of a time as ever to go for it. The issue with longer focal lengths is that your tracker’s polar alignment needs to be spot on. I’m horrible at this alignment, honestly, and figured this whole thing would be a disaster.
I also wanted to use the astro-modded Nikon D7000 for the first time. After shooting with full frame stuff for a while, I forgot that the crop sensor stuff lacks a number of the extra functionality that the pro-level cameras offer. The biggest of these missing features is the ability to take longer than 30-second exposures. I did have a wired remote with me, but the D7000 uses a different connector. Well, crap… I guess it’ll have to be saved for another trip. I was back to using the D850.
The image at the top of the article is a typical wide-angle shot that dominates most of my nightscapes. This was tracked, as well. There’s some very faint nebulousity around Orion that I attempted to capture. The extra long exposure time helped in that regard. I still didn’t quite get it in these shots. An astro-modded camera helps capture the faint reds in this h-alpha channel…. which, well, see above. LOL.
After getting a few images in wide angle, I switched over to the telephoto. You know what’s fun while shooting with a telephoto at night? Finding your target subject. With the much narrower field of view, and looking into darkness, this proved quite the task. The extra weight of rig itself is not to be underestimated. DO NOT skimp on a sturdy tripod or tripod head/ballhead. You will regret it and it will drive you absolutely nuts as nothing will stay put. This stability is critical with long exposures! I finally invested in a quality ballhead and tripod that can handle the weight and it is 100% worth the money. 100%. 100,000%.
The next step is locating Polaris. For those of us from the land of light polluted skies, this simple process can quickly become disorienting when a billion more stars are visible! I remember a trip to New Mexico, seeing truly dark skies for the first time since I was a kid; and no longer able to find the big dipper. The constellation was “hidden” within the millions of stars a low light polluted area unveils. Sounds silly, but it is true. Of course, once you get your “bearings” , you’ll start to see those iconic constellations again with ease. There’s a few apps out there for the phone to assist you, too. My favorites are Sky Walk 2 and Stellarium.
How did this all turn out? Well, here’s a few shots!
All three of these were taken with the Nikkor 70-200mm lens at 200mm. I did not have the polar alignment perfect, *surprise surprise*, so kept the exposures limited to 13-20 seconds before they started to trail. A bump in ISO coupled with a wide aperture gathered enough data to bring out detail. In an ideal world, I would have taken something like 40 exposures for the subject, another 10-20 “dark” frames, and then light frames. This way the stacking software could subtract out the digital noise, and get more of the high dynamic range needed to bring out the beautiful details in these heavenly subjects. These images were made from 5-6 exposures and then stacked to bring out more detail and noise reduction. Honestly, I wasn’t expecting to pull this much detail from such little data. I guess that is a testament to the latest camera sensor sensitivity!