So despite the cloud cover, with it really being the only chance I would have for a few weeks to try, I loaded up the Tundra of Love and headed to the SHSU Observatory to take a run at Comet Lovejoy. It was patchy when I arrived, but promising. A large fire fueled by something unknown raged to the south. The light polluted skyglow from New Waverly/Willis/Conroe was punctuated at the treeline with an eerie orange glow and plume of black. The winds were favorable and Pleiades was near zenith, so I continued setting up my rig and performing polar and star alignment. Georgia‘s parents bought me an amazing zero-gravity field chair for Christmas, so I waited out the meridian flip and enjoyed stargazing with my hand-me-down binoculars through holes in the clouds. Since the comet was about 9 degrees or so off Messier 45, I knew that ones The Sisters had transited the zenith, I could start my data acquisition. In a serendipitous moment, the skies opened up and the blanket of stars seemed to brighten. It was a good night. Comet Lovejoy was discovered in August 2014 by an amateur astronomer in Australia named Terry Lovejoy. It’s actually the 5th comet he has discovered, so “Lovejoy” is more or less what people are calling it because it happens to be here now, but the actual designation is C/2014 Q2. I has already passed opposition (last week) and is headed toward reaching perihelion (closest approach to the Sun) on January 30. Once it begins the journey leaving our planetary region, it will have an orbital period of about 8000 years. So, if you think there is a chance you might not be here in 8000 years to check it out next time around, you may want to peek outside during this flyby.
As it turns out, this data was a lot trickier to integrate than DSOs like galaxies or nebula. We are still spinning and orbiting… none of that has changed… but the comet is moving quite rapidly through space (relative to the perspective of massive celestial bodies thousands, if not millions, of light years away). This actually requires the data to be processed in two parallel paths and then merged at the end. The comet and it’s ion tail are stacked “at their speed” and then a linear fit and starmask is used to map in the background field from the same exact frameset. I know there is a ton of room to improve, but it isn’t too shabby for my very first comet… imho.
Colors? “The green glow comes from molecules of diatomic carbon (C2) fluorescing in ultraviolet sunlight in the near-vacuum of space. (In addition cyanogen, CN, can add some violet to the green, but our eyes are fairly insensitive to violet.) By contrast, a comet’s ion tail (gas tail) — the narrow, often detail-filled part of the tail that points directly away from the Sun — is tinted blue. The ion tail’s color comes from fluorescing carbon monoxide ions (CO+). Dust in a comet’s head and tail simply reflects sunlight, so it appears Sun-colored: pale yellowish white. The greatest comets tend to get that way by being very dusty, so the most memorable naked-eye comets are usually remembered as white. Examples were the spectacular Comet Hale-Bopp of 1997 and the grand sungrazing Comet Lovejoy of 2011, C/2011 W3. But the current Comet Lovejoy is producing very little dust.”
It’s been a quick minute since I’ve seen dark skies that weren’t on the way to sleepytime. Honestly, between weather and business travel, I haven’t been out since October 26. It is only fitting that my first venture into the starlight since was last night… November 26. This past month, when I’ve had time to think about astrophotography, has been a lot of me reflecting on the simple mistake I made at my run at Barnard 33 (the Horsehead Nebula). I had adjusted the prime focus on the Crayford and didn’t tighten the tensioner well enough before slewing to Alnitak. It wasn’t until I’d captured a couple hours of data before I realized my mistake. I did get a few subs on a subsequent night to pad the error in integration, but the result was still soft. This past month, I visualized going back and doing it better… paying closer attention. In the last minutes before packing up my gear for the hour-ish drive to the dark site, I called an audible and left my APO at home. I thought (incorrectly) that if I re-tooled my setup back to the side-by-side saddle and shot through the 600mm native lens that I would be able to capture the great nebula in Orion and the Flame in the same frame. As it turns out, you need around 400mm of FoV to make that happen on my DSLR, so I had to choose. The choice was obvious and easy. I had to take another run at the Flame and try to make amends for my rookie fumble last month. I ended up without about 3.4 hours of data pre- and post- meridian transit… which cost me some edges because I didn’t compose well enough after the flip, so I trimmed the messy off before processing with a quick crop. There is some minor vignetting that I’m not 100% sure I understand given the imaging train (there should be no light loss at the edges), but I’m ok with leaving it because I didn’t want to lose any of the nebulosity exposed in the bottom center of the frame. Over all, I think this makes a good web redemption. I’m really looking forward to growing into narrowband acquisition and some improved full-spectrum sensitivity with a monochromatic CCD, but all things in time, right? I did place an order with Santa Barbara Instruments Group for an STF-8300M, but there has been no word in over a month on estimated ship date. I also have elected to start with The Sky X (w/camera plug-in) as I transition to CCD, but more on that later… after I make the switch. Happy Thanksgiving everyone.
I shot a few subs of the deceptively small Crab Nebula (Messier 1) last night before realizing that the seeing just wasn’t where it needed to be for me to get that target under my belt. It will have to wait for another time. So, after calling that audible and knowing that I had let my focuser gravity drift the night before on my Flame attempt, I decided to grab a few more subs and see what happened when I integrated both nights (which I had never tried previously). The result was about 2.7 hours worth of data that looked like a train wreck when I stacked it, but after cropping off the tattered edges, there was some good in the middle… even if still out of focus. Live and learn. I will definitely put more time into this DSO in the future!
The Flame Nebula (NGC 2024) is an emission nebula in the constellation Orion. It is about 900 to 1,500 light-years away. The bright star Alnitak, the easternmost star in the Belt of Orion, shines energetic ultraviolet light into the Flame and this knocks electrons away from the great clouds of hydrogen gas that reside there. Much of the glow results when the electrons and ionized hydrogen recombine. Additional dark gas and dust lies in front of the bright part of the nebula and this is what causes the dark network that appears in the center of the glowing gas. The Flame Nebula is part of the Orion Molecular Cloud Complex, a star-forming region that includes the famous Horsehead Nebula (Barnard 33). It is one of the most identifiable nebulae because of the shape of its swirling cloud of dark dust and gases, which bears some resemblance to a horse’s head when viewed from Earth. This stellar nursery, as it is known, can contain over 100 known organic and inorganic gases as well as dust consisting of large and complex organic molecules. The red or pinkish glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis. Magnetic fields channel the gases leaving the nebula into streams, shown as streaks in the background glow. A glowing strip of hydrogen gas marks the edge of the massive cloud and the densities of stars are noticeably different on either side. The heavy concentrations of dust in the Horsehead Nebula region and neighboring Orion Nebula are localized, resulting in alternating sections of nearly complete opacity and transparency. The darkness of the Horsehead is caused mostly by thick dust blocking the light of stars behind it. The lower part of the Horsehead’s neck casts a shadow to the left. The visible dark nebula emerging from the gaseous complex is an active site of the formation of “low-mass” stars. Bright spots in the Horsehead Nebula’s base are young stars just in the process of forming.
This is a very short 5x180s integration with no noise reduction applied. I want to come back to this target when I have some time to spend with it. It is much brighter than I expected!
Messier 16, the Eagle Nebula (NGC 6611), is a young open cluster of stars in the constellation Serpens. The Eagle Nebula is part of a diffuse emission nebula. It contains several active star-forming gas and dust regions, including the famous “Pillars of Creation” region. This region of active current star formation is about 7000 light-years from us and the tower of gas that can be seen coming off the nebula is approximately 9.5 light-years or about 90 trillion kilometers long.
Back to back nights with new moon darkness have been a real treat. I learned a lot… like not to try and clean my sensor when there is a caliche road anywhere within 500 miles and that you can never check your focus too often. This image of the Eastern Veil nebula suffers from some focus drift because I didn’t have everything nice and snug on my Crayford. Some of the images from this weekend are plagued by the mound of dust I introduced into my sensor. I started dithering for the first time. I am getting better at using FWHM (full width half maximum) focus… especially after losing hours of data to my inattention to this gremlin. Overall, it was just great to be out under the stars and feeling like I’m making progress. I’m grateful.
The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus. It constitutes the visible portions of the Cygnus Loop, a large but relatively faint supernova remnant. The source supernova exploded some 5,000 to 8,000 years ago, and the remnants have since expanded to cover an area roughly 3 degrees in diameter (about 6 times the diameter, or 36 times the area, of the full moon). The distance to the nebula is not precisely known, but Far Ultraviolet Spectroscopic Explorer (FUSE) data supports a distance of about 1,470 light-years. The analysis of the emissions from the nebula indicate the presence of oxygen, sulfur, and hydrogen. This is also one of the largest, brightest features in the x-ray sky. This particular image is of the Eastern Veil (also known as Caldwell 33), whose brightest area is NGC 6992, trailing off farther south into NGC 6995 and IC 1340.
The Helix Nebula (NGC 7293) is a large planetary nebula located in the constellation Aquarius about 700 light-years away and spans about 2.5 light-years. Gases from the star in the surrounding space appear, from our vantage point, as if we are looking down a helix structure. The remnant central stellar core, known as a planetary nebula nucleus or PNN, is destined to become a white dwarf star. The observed glow of the central star is so energetic that it causes the previously expelled gases to brightly fluoresce.
Sweet, dark skies. Last night was my very first imaging session during a new moon and the skies were glorious… well, relative to normal for this neck of the woods.
I’ve been wanting to shoot the Bubble Nebula for some time now. I know I’ll come back to this target after I get some better Ha response in my imaging rig, but here is a short integration first attempt with poor tracking. I opted to not crop out Messier 52 because it gives a neat perspective.
The Bubble Nebula (NGC 7635) is a Hydrogen emission nebula in the constellation Cassiopeia. The “bubble” is created by the stellar wind from a massive hot central star about 10 to 40 times larger than our own. The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow. It was discovered in 1787 by William Herschel. You can also see Cassiopeia’s open cluster, Messier 52 (NGC 7654), in the upper right of the photo.
I made the 115 mile round trip to my closest dark site last night. I didn’t realize until after I was done polar aligning and taking flats that the local university had a lab scheduled for the facility. Over the hours of dusk and the beginning of nightfall, dozens of students were driving in with every form of light known to man blasting from their vehicles. I shot dark subs while this was going on and enjoyed some java and a gorgeous sky whilst kicking myself for leaving my binoculars at home. Once things settled down and the gaggle of them were doing their thing around the grounds, I started imaging. The low-pass filter in my unmodded DSLR makes red band targets challenging unless you are going to sink a lot of integration into them, so I decided to try something… well, not red. This is my first attempt at the Iris, but definitely not my last since this is such a cool DSO. I did the integration early this morning in a hurry, so I’ll likely go back and redo all the post processing to try and take care of some more of the noise issues when I have time to focus on it. At any rate, it was a wonderful night out despite the lingering headlights and faint murmur of “like, ermagerd, <insert pop-culture drama>, like, I know, right, like” on the wind.
The Iris Nebula (NGC 7023) is a bright nebula in the constellation Cepheus. NGC 7023 is actually the cluster within the nebula, but everyone kinda lumps it all together in colloquialism. It livies about 1,300 light-years away and is six light-years across. There are four main flavors of nebulae: reflection, dark, planetary, and emission. The etymological root of “nebula” means “cloud”. This one happens to be a reflection nebula… which means the energy from the nearby stars is insufficient to ionize the gas of the nebula to create an emission nebula, but is enough to give sufficient scattering to make the dust visible. The main star lighting this puppy up is SAO 19158.
The CSC looked awesome last night despite the moon phase, so I went out for another run at some targets… and practice. I arrived early enough to take flats while I unloaded the rest of my gear and then shot bias frames while I was balancing and doing my polar alignment. The sky was very clear and the visibility was far above average for where I image. The only issue was the moonlight from being about 70% full phase (waxing gibbous).
I was having some trouble finding targets bright enough to image. I blame my ignorance of the night sky for most of that, but the ambient light definitely was part of it. I even had a difficult time with star alignment due to the diminished relative brightness of the alignment stars. Eventually, I shot a few lights and darks of M92 – because it is very bright – just to have something to process, but over the course of a few hours, I tried several targets with no result. I even realigned my mount thinking I surely must be slewing off target. Nope and nope. The night grew colder and even though I was running my dew heaters, I didn’t have them set high enough to prevent moisture from forming on the front element. I will pack a hair dryer for times like this moving forward so I can do a quick recovery.
As the moon moved toward setting, the promise of amazing imaging was near, but I was cold, hungry, frustrated, and out of coffee… all with another hour and a half until moonset. I decided to just pack it in. It was a good learning experience and another night of practicing set up, balance, alignment, acquisition, and tear down of my gear. Practice is good.