There’s been lots of attention over Mars this past week. I can’t really blame all the media coverage, the Mars 2020 Perseverance EDL to the Martian surface was really cool and a great feat for NASA. I enjoyed watching it live on the NASA YouTube feed. But this weekend let’s turn our attention to the Snow Moon; the only full moon in February.
The full moon will occur at 3:17am Saturday, so tomorrow evening will be the best time to catch it. There’s nothing particularly special about this full moon, not a Blue Moon (second Full Moon in the month) or “Super Moon”. The name Snow Moon comes from the Farmer’s Almanac as February is normally the month that receives the most snow in North America.
The great thing about full moons is that you don’t need to stay up all night and wait outside in the frigid cold to see it. At this time of year, in the Northern hemisphere, the Moon is visible for more that 12 hours a day.
If you’re tempted to photograph the Snow Moon, leave the mobile phone behind, it’ll just give poor results and you’ll end up frustrated with frozen fingers. Instead just enjoy the view, paying close attention to the various dark “seas” spanning the lunar surface.
If you do try taking a picture, grab a DSLR or compact camera with manual mode. Set the ISO around 200 and the focus to manual. Your shutter speed should be high, around 1/800s; a full moon is surprisingly bright. You’re get better results by slightly under-exposing your shot. If you have a tripod, use it, else try to steady yourself on something (railing, chair, car roof, etc..) Subtle movement can easily ruin the details in you photos.
Looking back, the “Great comet of 2020″ C/2020 F3 NEOWISE was a fantastic sight and well worth the 3am alarm to snap some photos back in July. But comet images are notoriously difficult to work with. Should I also add that in older times, comets were often seen as a bad omen, the bearer of bad news? Cough, cough COVID-19 cough…
Anyways, back to astronomy… There are essentially two types of photo registration (alignment) software out there: 1) Deep Sky which uses pin-point stars to perform alignment; 2) Lunar/Planetary uses the large “disk” of a planet or Moon to align based on surface details.
I turned to standard photo-editing software for a manual alignment and stacking. This is essentially opening one “base” image and then adding a 2nd image as a new layer. I change that 2nd layer to be overlaid as a “Difference” and manually align this 2nd layer to match the base layer. Once that is done I change the layer mode to Addition, and then hide this 2nd layer. Repeat the steps for a 3rd, 4th, 5th, etc. layers until you’ve added all your images. Always aligning with the “base” image to ensure no drift.
If you simply add all those layers up, you will get one very bright image because you are adding pixel intensities. You can do that and then work with the Levels and Curves to bring it back down, or if like me, working with GIMP, then use the Py-Astro plug-ins to do the merging and intensity scaling in a single step with a Merge all layers. Py-Astro can be downloaded here. I haven’t explored all that the plugins have to offer, that will hopefully be in another blog.
Stacking 11 individual frames results in an improvement over a single RAW image (image below). With the stacked image, I’m able to work with the intensities to darken the sky while keeping the comet tail bright.
However the sky gradient is pretty bad, due to the camera lens and because at 4am the sun is starting to shine on the horizon. So off to IRIS to correct the background gradient. From GIMP I save the files as a 16BIT FIT that I can use in IRIS. For steps on how to do this, see my blog about how to remove the sky gradient.
After a quick spin in IRIS, I’m back in GIMP for final color and intensity adjustments, I boosted the BLUE layer and adjusted the dark levels for a darker sky.
The folks at JPL created a short film showcasing Perseverance’s critical descent phase for the Mars landing. If everything goes according to plan, we shall have a new rover on Mars at 3:40pm EST on February 18, 2021.
Perseverance is currently “cruising” at 84,600km/h through space with Mars as a target. To give you an idea of what kind of speed that is, here are a few benchmarks:
- The fastest commercial jet: the Concord flying at Mach 2.04 is just under 2,200km/h
- Space Shuttle re-entry speed: 28,100km/h
- Voyager 1, leaving our solar system : 61,500 km/h
- Parker Solar Probe (fastest man-made object) : +250,000km/h
Perseverance was launched on July 30th, 2020 from Cape Canaveral Air Force Station, Florida, on top of a Atlas V-541 rocket.
The only way the rover will be able to decelerate from its current cruising speed is by plunging into the Martian atmosphere at the right angle and using the atmospheric friction to slow it down. That “7 minutes of terror” is the time the rover will spend on re-entry, from approaching Mars at the right angle, to landing in the desired spot on the Martian surface.
Lots of steps need to go right, timed correctly to have a successful landing. Only 22 of the 45 landers sent to Mars have survived a landing. The US is by far the country with the most success (sorry Russia, you’re space program is awesome, but you suck at landing on Mars)
Glancing up at the night sky that February 18, 2021 evening will be very easy to spot Mars, but also the Pleiades star cluster (Messier 45). Mars will be about 5 degrees north of a almost half-illuminated moon. And if you keep looking higher up by 10 degrees you’ll see the famous open star cluster nicknamed the Seven Sisters, also used as the Subaru emblem.
I live in a heavily light polluted city, therefore unless it’s bright, I won’t see it. But boy was I ever happy with the outcome of this comet! In my books C/2020 F3 (NEOWISE) falls in the “Great Comet” category, and it’s by far the most photographed comet in history because it was visible for so long to folks on both sides of the globe.
My last encounter with a bright comet was in 2007 with periodic 17P/Holmes when it brightened by a factor half a million in 42 hours with this spectacular outburst to become visible to the naked eye. It was the largest outburst ever observed with the corona becoming temporarily the biggest visible object in the solar system. Even bigger than the Sun!.
So when the community was feverishly sharing pictures of the “NEOWISE” I had to try my luck; I wasn’t about to miss out on this chance of a lifetime.
I have to say that my first attempt was a complete failure. Reading up when it was the best time to try to photograph this comet most indicated one hour before sunrise was the right time. So I checked on Google Maps where I could setup for an un-obstructed view of the eastern horizon (my house was no good) and in the early morning with my gear ready at 4am I set off. To my disappointment and the “get-back-to-bed-you-idiot” voice in me, it didn’t work out. By the time I got to the spot and had the camera ready, the sky was already too bright. No comet in sight, and try as I might with the DSRL, nothing.
Two evenings later and another cloudless overnight sky I decided to try again, but this time I would make it happen by setting the alarm one hour earlier: 3am. That is all that it took! I was able to set-up before the sky could brighten, and then CLICK! I had this great comet recorded on my Canon SD memory card.
I didn’t need any specialized gear. All it took was a DSLR, a lens set to manual focus, a tripod and 5 seconds of exposure and there was the comet. I snapped a bunch of frames at different settings and then headed back home to catch the last hour of sleep before starting another day of work. Lying in bed I felt like I had accomplished something important.
As the comet swung around our Sun and flipped from a dawn to a dusk object I decided I should try to photograph it once again, but this time with the Skywatcher 80ED telescope. At that point, the comet was dimming so every day that passed would be more difficult. It was only visible in the North-West horizon at sunset, which meant setting up in the front the the house, fully exposed to street lights. Not ideal, but I had nothing to loose trying.
I used our tree in the front yard to act as a screen and was able to locate and photograph this great comet. Polar alignment wasn’t easy, and when I had the comet finally centered and focused with the camera, overhead power lines were in the field of view. I decided to wait out 30 minutes and let the sky rotate to the lines out of the view. Besides, it will get darker anyways which should help which the photo. But I also realized that my “window” of opportunity was small before houses would start obscuring the view as the comet would dip to a lower angle with the horizon.
I’m sure in the years to come people will debate if this was a “Great Comet”, but it my books it’s definitely one to remember. It cemented with me the concept that comets are chucks of “dirty ice” that swing around the sun. Flipping from a dawn to dusk observable object after a pass around the Sun is a great demonstration of the elliptical nature of objects moving in our solar system.
Now waiting for the next one…
Back in March, the astronomy crowd was buzzing about a possible”naked-eye” comet expected in late May 2020. Comet C/2019 Y4 (ATLAS) was first detected at the tail end of December as a very dim magnitude 19.6 object and by mid-March it had brighten to an easy telescope target magnitude of 8. Those not familiar with the magnitude scale, going from 19.6 to 8 is not a doubling in brightness, but around a 4000 times increase!
That dramatic increase in brightness help fuel the hype for the Great Comet of 2020, and there were two other factors that got people excited:
- It would be visible at dusk from the Norther Hemisphere, hence within easy viewing to much of the world population.
- It was following a similar orbital path as the “Great Comet of 1843“, suggesting that it was from the same original body and could potentially provide the same viewing spectacle. That 1843 comet was visible in daytime!
Well all that went south when the comet’s breakup was observed in late March after peaking momentarily at magnitude 7. It began to dim, along with any hopes of a Great Comet repeat. Below is a graph showing the the original (grey line) and revised (red) comet brightness forecast (dots being observed measurements) on this chart created by Seiichi Yoshida (email@example.com)
Comet C/2019 Y4 is expected to make its closest approach to the sun on May 31st, however most experts believe it will disappear (disintegrate) before that date. Seeing that I had a small window of opportunity to capture the comet I decided to try my luck last Saturday evening.
Below is an extremely processed (and ugly) image that I got by combining 25 photos (15 seconds each at ISO 3200) using my Skywatcher 80ED scope. The photo just about makes out the distinctive blue-green hue and elongated shape of a comet. It is around magnitude 10, very diffuse and about 147 million km away from us the day this photo was taken.
I pushed the image processing so hard that I was able to pick up faint magnitude 13 galaxies!
On to the next comet!
Telescope: Skywatcher 80ED
Camera: Canon 80D
Image: 25 x 15sec at ISO3200 (6 minutes)
The last time Jupiter was in a favorable position for good photos was 2010, so while I have photographed the planet a few times since, the results weren’t really satisfactory. So on July 7th, finally took the equipment out and set my mind to image some planets (Venus was also in a good position).
As luck would have it, the Great Red Spot was pointing our way, and landed my best shot of it yet. We may be past the May 2018 sweet spot for opposition, but that doesn’t mean you should not attempt to observer or photograph the Jupiter. Still plenty of good days ahead.
I took about 11 video sequences of the planet, and sure enough the last one yielded the best result. I guess as the evening progressed, the air cooled and provided for better viewing.
Televue 3X barlow
Vesta Webcam with IR/UV filter
Processing with Registax and GIMP.
Last Saturday evening, if you happened to look outside and had a clear view there is no way you could miss the Venus-Moon close encounter in the dark blue sky. But just in case it was cloudy, or you weren’t paying attention here it is.
For those curious on the camera setting, the above is cropped from a single frame at 33mm f/4.5 1/30sec and ISO800 with Canon 80D.
Moving up to 85mm gives you the image below, also at 1/30sec and ISO800. Both images were hand-held from a bedroom window. Could a tripod have helped? Sure, but I figured I could do just fine , especially with image stabilization enabled on the lens.
To put a bit of perspective on the distance of these two heavenly bodies and their apparent size in the sky I’ve added a bit of information on the above image. While Venus may be nearly 4 times larger in diameter, it looks quite small next to the Moon in the sky.
After yesterday’s photo with the smart phone, I decided to go for a more professional shot and grabbed the Canon 80D and capture once again the Moon and Jupiter through the clouds. However this time around took two exposures, and stitched the together.
The wide-angle was 24mm F4.0 1/10s ISO-1600. This was to pick up the clouds against a night sky as well as Jupiter. Then a close-up of the Moon, with a shorter exposure and lowered ISO to pick up details of the lunar surface (85mm F5.6 1/250s ISO-200).
Opened them both in GIMP and played with layers, masks and curves to get the desired image. The close-up Moon photo was scaled down to match the 24mm wide-angle photo to avoid having gigantic moon.
Sometimes all it takes is a little cloud layer to hide the background stars to really reveal how bright Jupiter is right now. The photo below was taken with my smartphone on May 26th, with Jupiter clearly visible next to the Moon.
Jupiter and Earth were at their closest (opposition) on May 8th, but the entire month of May is a good time to spot Jupiter as it’s up high in the sky most of the night. Once Venus sets in the early evening, Jupiter is the brightest “star” in the sky, a good 20 times brighter than the next brightest stars.
Up until May 28th, Jupiter and the Moon will be near each other in the night sky, making for good photo opportunity.