Sunday night, December 16th, was the evening of the closest approach of Comet 46P/Wirtanen. The comet was close enough and bright enough with an apparent magnitude between 4.0 and 4.5 that you could see it with the naked eye if you had good, dark skies. Thankfully, that’s just what I have living out in rural Missouri, and we also had crystal clear skies. The comet can be seen between the Pleiades Cluster and Taurus through Wednesday, but as the Moon’s phase transitions from 1st Quarter to Waxing Gibbous, dim objects in the sky will be harder and harder to see. Throughout this coming week, the best time to view the comet will actually be in the very early morning after moonset. You can check out more about where to find and when to view the comet at Sky and Telescope, https://www.skyandtelescope.com/astronomy-news/observing-news/comet-46p-wirtanen-and-moon/.
The image below of Comet 46P/Wirtanen is the result of stacking 63 exposures each with a shutter speed of 20-seconds, ISO 6400, aperture f/8, and a focal length of 200 mm on a Nikon D500 through a Tamron 70-200mm f2.8 riding atop a Celestron 8″ SCT. The telescope was there just to provide the clock drive so that the camera moved with the stars’ diurnal motion. Each raw image file was corrected for dark current, bias current, and the response across the frame was normalized using a flat field image. I’ll write up a tutorial on how to collect these images and why they’re necessary later. The images were then aligned and stacked on the comet, which is why the stars appear as streaks. Since the comet is moving quite rapidly past us, its motion relative to the distant background stars is very noticeable, even in the short timespan of this image set.
You may have noticed the very green color to many of the images of Comet 46P/Wirtanen, including this one. The green color is not a image processing artifact, but is indicative of the comet’s composition. Most comets contain a enough cyanogen (CN) and diatomic carbon (C2). As a comet approaches the Sun and its surface warms, volatile materials such as cyanogen, water, and others begin to vaporize forming the comet’s coma and tail. When cyanogen and diatomic carbon interact with the Sun’s ultraviolet light and fluoresce to create the characteristic greenish glow of many comets.
I’m WAY behind on this. Right after the Rally in the 100 Acre Wood, my schedule exploded! (vomited more like) I’ve not had much free time since. 🙁 I’m going to try to get caught back up now that the semester is just about at a close and the first two are Week 6 and Week 7’s topics Water and Love.
I had better hopes for this one than how it turned out. Honestly, I was hoping to catch a water crossing on stage at the rally and use that, but that never happened so I’m stuck with this shot of the creek right beside the Steelville, MO city park where Friday’s Parc Expose was. I should have had a polarizer on the lens. That would have helped cut some of the glare and enhance some of the contrast. I wanted some of the lens flare from the Sun, but I think I got too much.
Who says roses are out of style? I got this along with 11 others for Tabatha. This is images in front of my upright grand with a off-camera strobe.
This week’s Straight Out Of Camera theme was “Green”. My first thought was, “Have you been outside? Ain’t NUTTIN’ green out there!” So ok, time to think a bit more. I have some green coasters made from old printed circuit boards, which are pretty cool, but no good ideas on how to use them were coming to mind. Finally, I realized that a way that I could incorporate the term “green” in multiple ways setting up a winning roll on our craps table. So I set up the table with typical types of bets, most pass line, a couple of come, a few place bets, and that one jerk that always plays the don’t pass. I set the point to eight, and set the dice to an easy eight. Sucks for the player with the hard eight bet and the jerk playing the don’t pass, but everyone else is a winner and gets some nice cash salad for their efforts!
For the lighting, I used a remote speedlight with a bounce card high and behind the scene and the pop-up flash with one of those little hot-shoe mounted pop-up diffusers.
Here is the exposure data.
Camera Nikon D7000
Exposure 0.003 sec (1/320)
Focal Length 28 mm
ISO Speed 100
This didn’t come out exactly like I wanted, but it was close. I’d give it another go later in the week, but I’m not confident that I’ll get another clear night. If the weather cooperates, I may post an update later, but for now, here’s my shot and my thoughts on its creation.
I’ve taken star trail images in the past, but I’ve never tried to put myself in them. What I wanted was an image of me presenting the Universe. Unfortunately, I failed to take into account how bright the northern sky would be. As a result, instead of me in front of the swirling starry night, it turned out to be ghost me.
Device: Nikon D7000
Lens: 18-70mm f/3.5-4.5G
Focal Length: 18mm
Focus Mode: Manual
AF-Area Mode: Single
Shutter Speed: 1927.4s
Exposure Mode: Manual
ISO Sensitivity: ISO 400
This week’s Straight-out-of-Camera project theme was Porcelain/Ceramic. At first, I thought about doing something with an old set of ceramic brake pads, but then I saw the Bailey’s mug. I figured this would be a good opportunity for me to work on my product photography. The set-up was fast and rough, and there’s a few other things that I think I’d do differently if I’d taken the time to get all of the lighting gear out. Such is the problem of not having a dedicated studio space here at the house. I need to fix that.
Camera Nikon D90
Exposure 0.017 sec (1/60)
Focal Length 50 mm
ISO Speed 200
Exposure Bias 0 EV
Flash On, Return not detected
Lens 50.0 mm f/1.8