Astro Daily

By Shelbi Etscorn

For the past nine months, I’ve had the pleasure of learning exactly what it’s like to work at an observatory that’s in the middle of taking on the huge endeavor of building an interferometer. And in my role in the Outreach Department, a lot of my job involves…well observing. But not the kind of observing you usually think of happening at a place like the MROI. My observing revolves around the people, events, and news that happen on a day-to-day basis. As such, I thought I might be uniquely qualified to give you a little inside look at how the MROI operates.

The work being done at the MROI is separated into distinct departments, although some staff fill roles in multiple areas. At its most basic these departments are Software, Instrumentation, Opto-Mechanical, Electro-Mechanical, IT, Science, Maintenance, and Outreach. Many of these are self-explanatory.

The IT department does the same work for us as other IT departments. However, not many other IT departments have networks that span about 5,000 feet in elevation, the highest reaching 10,000 feet. It isn’t easy to keep in communication with everything on the Ridge from down on campus. But our IT department somehow manages to do just that. And that’s on top of handling all the trivial issues that are the constant torment of IT men and women around the world (have you tried turning it off and on again?).

The Instrumentation, Opto-mechanical, and Electro-Mechanical departments work very closely together. They are constantly figuring out the next step in building the Interferometer from the ground up, revisiting old steps that may have failed or simply can be improved, and over all keep the project moving forward. Brick by tiny, technical, precise brick, they are the ones building the innards of the Interferometer.

While the three previous departments involve themselves in making the Interferometer work, our Science department is concerned with how it will work. Project Scientist, Michelle Creech-Eakman, is not only a Physics professor at Tech, she is also our source of knowledge for the science behind building a working interferometer. She is our face at many events and meetings in the scientific community, sharing our story that she is an acting force behind.

The maintenance department, while often helping us down on campus, is mainly found up on the Ridge. They are the ones with the ability to keep all of our heavy machinery running and most days are operating them to ensure the upkeep of the roads that lead up to the Observatory. It’s no small task, and it’s one that rests solely on their shoulders.

The Software Department, of course, concerns itself with creating and maintaining the software that is used to control the MROI. A quick story: very early on after joining the MROI, I was tasked with accompanying the Software Team up to the ridge to film the dome of the Interferometer’s telescope opening, and the telescope itself moving from side to side stopping at specific points, much as it would if it were actually observing specific points in the sky. I was doing this to show the software that had been built that could direct the telescope to focus at one predetermined direction and then another automatically, with no further direction needed after start up. This allows for multiple observations to be made, one after another, while limiting the need for constant human guidance.

The wind was brutal that day making it unbearably cold. I sat perched on the scaffolding that is used to lift and move the telescopes, trying to keep my arms wrapped around myself while also trying to prevent my tripod and camera from crashing down to the ground in the gusts, I watched as the dome opened and the telescope did what it was always intended to do. I think I yelped in joy at the start of the show.

Upon its completion, I scrambled down the scaffolding and excitedly entered the Control Room where the members of the conference team were. I was expecting whoops and hollers, but the team calmly packed up their belongings, told me they were done, and we headed back down the mountain. I guess when you do amazing things every day, even the most incredible achievement seems a little mundane.

All of the departments at the MROI actually seem to mimic an interferometer in the way they work together. Each department is like a telescope, each bringing their own expertise and bringing it together to build something amazing, in the same way the telescopes of the Interferometer will bring together the light from their section of the sky to make an image. Even more impressive, the departments create their own light. They aren’t stationary, passive structures waiting for light to fall on them, they are an active part in the forming of the light that each puts out. They are the stars and planets.

While I sit in my corner of the Outreach department, completely surrounded by all these unique, motivated, and unimaginably intelligent people – these telescopes – it’s sometimes difficult to not ask myself, what is our role here? What do they need us for? I certainly do not feel like a telescope. Writing this gave me time for some self-reflection, and I had some ideas: at first, I thought maybe Outreach was the instrumentation. Where the light brought in by the telescopes is created into something tangible that can be studied and enjoyed by everyone. But, it occurred to me, if any department deserves the spot that connects all the departments, it would have to be the previously omitted but not forgotten Administration. Our Principal Investigator, Program Director and Office Administrator work tirelessly to make sure everything gets done that needs to to make the work of all the other departments not only feasible but meaningful. They tie each of us together. No, Outreach was not found there.

I was feeling more than a little unnecessary to the project when it hit me. In our Interferometer metaphor for MROI staff, the Outreach Department is the observer: you! It’s why I seemed to be the only one jumping for joy at an accomplishment I had no hand in while filming the work of our Software team. The Outreach Department is the one standing excitedly by, while all the fancy technology does its thing, eagerly waiting for results and observations that we can share and be amazed at with the community in the form of our newsletters, our events, and even this blog! And we can’t wait to show you what’s happening next.

Inspired by Jon Spargo’s September Skies article I shared yesterday, I did some observing last night and this morning. I had plans to meet friends at Box Canyon yesterday early evening to do some bouldering, and I realized that the western wall of the canyon would be the perfect place to catch the Moon rising over the quebradas in the distance. After a few hours of bouldering (which for me as a beginner consists of desperately clinging to rough rock and shredding the skin on my hands), we finished up on the Gimmies just in time to scoot up to the top of the west wall and set up to shoot the Moon.

There turned out to be much more haze on the horizon than I realized, delaying the appearance of the Moon by nearly ten minutes past its actual rise time. When it did finally rise above the haze, the Moon was a deep yellow/orange color, and a beautiful sight to behold.

Because the east wall of the canyon starts low on its north side and reaches a higher elevation toward its south side, we were able to witness three more “moonrises” by moving south on our side of the canyon. This was a great example of parallax, the difference in the apparent position of an object viewed along different lines of sight.

Seeing four moonrises in one night was a new record for me!

Since observing the full Moon setting in the morning is just as interesting as watching it rise, I planned to get up early this morning to do just that. I have mountains in my field of view to the west where the Moon was setting this morning, so for me moonset began about 6:25 AM MDT.

If you missed the moonrise last night, you have another chance tonight. Although the Moon has already reached its full phase (100% illuminated) and is beginning to wane (become less illuminated), it hasn’t waned by much; in our location the Moon will be 99.8% illuminated, according to LunaSolCal (print screen below). Moreover, it will still be about 99% illuminated when it sets on Thursday morning, though it won’t have that nice orange color since it sets more than an hour after the Sun rises.

Here’s hoping for clear skies and good observing!

M. Colleen Gino, MRO Assistant Director of Outreach and Communications

I am pleased to announce that Astro Daily will be sharing Jon Spargo’s informative “what’s up” article at the first of each month. Astro Daily will supplement Jon’s article with relevant illustrations, images, and sky charts. Thanks so much for letting us share, Jon!

M. Colleen Gino, MRO Assistant Director of Outreach and Communications

September Skies

Jupiter and Saturn spend most of September high in the southern sky being visible just after sunset. At the beginning of this month they will be only 8 degrees apart. You can verify this by making a fist and holding it at arm’s length. Your fist will cover an angle of about 10 degrees and the separation between the two planets should be slightly less than the width of your fist.

As the month progresses, the separation between the two will shrink slightly as the two planets begin to narrow the gap separating them as they head for a very close encounter in December. Both planets are well placed in the evening sky for hunting surface features and moons with binoculars and small telescopes. Saturn’s rings are still wide open at 23 degrees from the horizontal.

Mars becomes even more imposing rising two hours after sunset at the beginning of September and less than one hour after sunset at month’s end. While doing so, its apparent brightness improves from magnitude -1.8 to -2.5, causing it to appear slightly brighter than Jupiter. This will be the time to break out your telescopes and go hunting for surface features. The southern polar ice cap should be visible.

Venus now rises about 3.5 hours before sunrise and achieves a position of about 40 degrees above the eastern horizon. Check it out with your fist as described above. At magnitude -4.1, brilliant Venus reveals almost 72% of its cloud-covered surface.

The Moon will be full on the 2^nd, last quarter on the 10^th, new on the 17^th, and first quarter on the 24^th.  Looking east on the night of September 5^th, around 11 p.m., the Moon will pass within ½ degree of the red planet Mars. Looking east on the morning of the 14th, about an hour before sunrise, the crescent Moon will be below and to the left of brilliant Venus. On the evenings of the 24^th and 25^th, about 45 minutes after sunset, look south to see the Moon visit first Jupiter and then Saturn.

On the 22^nd we can be thankful that summer is over as the autumnal equinox brings us the first day of fall for the northern hemisphere at 7:31 a.m. MDT.

Stay safe and Clear Skies!

Jon Spargo

Twilight is more than a seriously successful but silly series of movies about vampires, and Twilight Time is more than a song by The Platters. Twilight refers to a very specific time of day; the time of day when the Sun is below the horizon but our atmosphere is still illuminated to some degree by sunlight. This happens twice a day at the transition from day to night (dusk), then again in the transition from night to day (dawn). These twilight periods at dusk and dawn are further separated into three time periods: civil twilight, nautical twilight, and astronomical twilight.

Civil twilight begins in the morning when the center of the Sun is 6° below the horizon, and ends when the Sun rises. In the evening, civil twilight begins when the Sun sets and ends when the center of the Sun is 6° below the horizon. This form of twilight has the brightest sky, and barring other conditions such as clouds or fog, there’s enough sunlight to continue outdoor activities without artificial light. At this time the brightest stars and planets can be seen as well.

During nautical twilight, the sky is getting noticeably darker, but the horizon is still visible. While not fully dark, you’ll likely need a form of artificial light to conduct outdoor activities, and the sky is dark enough for sailors to make nautical readings based on the stars, thus the term “nautical twilight”.  After sunset, nautical twilight begins when the center of the Sun drops 6° below the horizon and ends when it is 12° degrees below the horizon. Similarly, it begins in the morning when the center of the Sun is 12° below the horizon and ends when it is 6° below the horizon.

Finally, astronomical twilight is dark enough to be indiscernible from total darkness for the average observer, particularly in a light polluted sky. The horizon is no longer visible, and many faint stars and celestial objects can be seen. However, the sky is not fully dark in the evening until the center of the Sun is 18° below the horizon; you have to wait until this point to see the faintest celestial objects. The sky remains fully dark until the Sun is less than 18° below the horizon in the morning. The chart above illustrates the different types of twilight and their corresponding solar angles (not to scale).

Now that we have the different types of twilight covered, I’d like to once again share one of my favorite tools to get the times for these events, LunaSolCal. In a previous blog post I talked about how useful I find this app to be for telling sunrise and sunset times, moonrise, moonset, and lunar phase information, and much more. LunaSolCal is available for both iOS and Android devices. As you can see in the print screen below, when you choose the “Sun” tab, the app displays not only the time of sunrise and sunset for your chosen date and location, but the times for the three types of twilight as well. This app is one of the best free tools I’ve come across, and I heartily recommend it!

M. Colleen Gino, MRO Assistant Director of Outreach and Communications

New Mexico Tech’s Magdalena Ridge Observatory, Etscorn Campus Observatory, and the National Radio Astronomy Observatory’s Very Large Array aren’t the only facilities conducting astronomical observations and research in our dark sky area around Socorro. From Magdalena to Pie Town, the number of amateur astronomers building observatories for both private and business use is steadily growing. One such example is a recently constructed private observatory near Pie Town that is outfitted with a 40-inch reflecting telescope, one of the largest aperture private telescopes in the country. Another facility of note is the nearby SkyPi Online Observatory, where users can operate robotic telescopes to image celestial objects remotely. The Magdalena Astronomical Society, well known for holding the popular Enchanted Skies Star Party, operates a 16-inch computer-controlled telescope at John Briggs’ Astronomical Lyceum in the dark sky village of Magdalena. And that’s just scratching the surface of the astronomical activities occurring from Socorro all the way to the Arizona border along Route 60.

You can read all about this and more in the MRO Department of Outreach and Communications’ monthly newsletter. The September issue of the MRO Inquirer, which features the article described above by guest author John Briggs, will be sent out to members of the Friends of MRO next week; early and direct delivery of MRO’s monthly newsletter is one of the perks of membership. If you’re not a member of our Friends group yet, don’t despair – our newsletters are released to the public in the middle of each month.

We kindly ask that you consider becoming a Friend of MRO and support the work the MRO Outreach team is doing. Along with publishing a monthly newsletter, the Outreach Department produces the Astro Daily articles and is active on all social media platforms, sharing our love of astronomy with the local community and beyond. While our monthly public star parties and seasonal observatory public tours are on hold due to COVID-19 restrictions, we expect to be able to offer virtual streaming star parties and observatory tours soon. Your membership contribution would help support these endeavors, and make you a vital part of our mission to develop education and outreach programs, and to expand the frontiers of astrophysical research.

If you are interested in learning more about Friends of MRO, please follow this link.

If you’re awake in the hours before sunrise you’re in for a treat. Sirius, the brightest star in the night sky, is currently making its appearance in the early AM, rising a few hours before the Sun. Sirius first became visible in the east less than an hour before dawn a few weeks ago, its helical rising. Since stars rise about 4 minutes later every day, it will be visible longer and longer before sunrise. By the end of November, it will rise about 9 PM in the evening.

The Dog Star, as it is called, is in the constellation Canis Majoris, the big dog. The term “dog days of summer” comes from the fact that for those of us in the northern hemisphere Sirius in in the same portion of the sky as the Sun in July and August. The ancient Romans thought that since the Dog Star is so bright it must be hot, and that its heat added to that of the Sun’s made the 20 days before and 20 days after its alignment with the Sun all the hotter.

Sirius is a binary star; Sirius A, the brightest of the pair, is a hot main sequence star, undergoing thermonuclear fusion in its core. Sirius B is a white dwarf, a stellar corpse. Known as the Pup, Sirius B was also a bright bluish star once more massive than Sirius, but it exhausted its resources and ceased fusing hydrogen to helium some 120 million years ago.

Sirius is about 25 times more luminous than our Sun and nearly twice as massive. If our Sun was replaced by the Dog Star, we wouldn’t be having this conversation. The dog days of summer would be a freezing respite compared to the temps the Earth would be exposed to. Luckily, Sirius is just a fairly close neighbor at 8.6 light years away.

The star chart above shows where you can see Sirius in the wee hours of the morning. If you’re not an early bird don’t despair; just wait a few months and you will be able to observe this glimmering orb in the evening.

M. Colleen Gino, MRO Assistant Director of Outreach and Communications

By Shelbi Etscorn

In my last article, I talked about the green flash that can be seen at the moment when the sun is below the horizon. To recap, this green flash happens because of the way light is refracted in the atmosphere. When the sun is just below the horizon all colors that have longer wavelengths (like the reds and oranges) are out of our line of sight below the horizon. All colors with shorter wavelengths (like the blues and violets) are dispersed into the atmosphere above the horizon where we aren’t able to see them. But the green is just right for us to be able to see a momentary flash.

In this last week (and just about every summer in New Mexico), you may have noticed a different phenomenon that can be explained with the same science behind the green flash. With smoke in our skies from wildfires in surrounding states, sunrises and sunsets have suddenly become even more beautiful than usual in our New Mexico skies. But why does smoke, which we usually think of as an ugly, hazy blob, help create such beautiful skies every dawn and twilight?

I’ve already given you a hint. As you may recall, the white light from our sun is actually made up of all the colors of the rainbow. A rainbow is simply the light from our sun being “bent” or refracted by water droplets in the air, causing the different wavelengths of light to separate to the point that each individual color is distinguishable.

Going through the colors of the rainbow in order (remember ROY G. BIV?), the colors found at the beginning have the longest wavelengths, while the ones at the end have the shortest. The colors with the shortest wavelengths can more easily interact with particles in our atmosphere and are scattered by them, while the longer wavelengths aren’t very much affected. This is why sunrises and sunsets already appear to be red, orange, and yellow. These are the colors that have the easiest time making it through our atmosphere to arrive at our eyes, although some of the shorter wavelength colors still make it through as well.

When wildfires fill our atmosphere with an abundance of minuscule particles, the effect our atmosphere already has on sunlight becomes amplified. Even more of the blues and violets are scattered out of the light that we eventually see, making the reds and oranges of that light appear even more vibrant and intense and causing beautiful, deep colors to appear in the sky.

While we can be thankful for the beautiful display, smoke in the air from wildfires does cause issues with astronomical observatories, and, much more importantly, is a sign that somewhere homes and lives could be at risk. While they’re here, I get up early in the morning to enjoy the stunning colors that paint the sky, but I look forward to the day our sunsets go back to their previous brilliance, which has always been rich and vivid enough for me.

Have you ever found yourself looking at a night sky full of so many stars that you’re unsure of which constellation is which? This may not be a problem for those of you in highly populated areas with light polluted skies who are lucky to see a handful of the brightest stars at night, but for those of us in rural dark-sky locations, the struggle is real. Especially when you’re trying to identify some of the constellations with dimmer stars and less recognizable patterns, such as Camelopardalis, Microscopium, or Serpens Caput, to name just a few. I tell you what: my ability to pick out those tricky constellations on my own is kaput, so it’s a good thing there’s an app for that!

There’s actually a heap of sky map apps to choose from for both Android and iOS that help you identify what’s in the sky and much more, so you can take your pick. One of the most basic apps I use is Sky Map, free for Android devices. You simply point your smartphone or other handheld device at the sky and Sky Map shows you what what’s up in that exact location in the sky, day or night.

Sky Eye is similar to Sky Map, in that you point it toward the sky and it shows you what’s at that point in the sky in real time, but it has other useful features as well. In addition to the real-time mode that uses your device’s GPS to determine your accurate location and shows you what up currently, you can set it for a particular date, time and location. Not only does it display constellation lines and labels, major star names, and Messier objects, but it includes the altitude – azimuth, equatorial coordinates, and hour angle of the objects in your field of view. It even has a night vision mode to preserve your dark adaptation. This useful app is free and available for both iOS and Android devices.

So the next time you see so many (or so few!) stars that you’re not quite sure what you’re looking at, consider using one of these handy handheld planetarium apps to find your way in the sky.

M. Colleen Gino, MRO Assistant Director of Outreach and Communications

Yesterday in “Stack It!” I talked about a test I was running to see how the result of stacking hundreds of extremely short exposures compared to the results you get with a single long exposure image; you might want to read that first for the background information on the results I’m sharing today.

To pick up where I left off yesterday, it took a LONG LONG LONG time to process the stack of 422 images – over 16 hours! The processing was taking up most of my computer’s brain, so I couldn’t really do anything else while it was thinking so hard. It’s not wise to deny me the use of my computer for 16 hours. By the time I saw the product of the stack, at 11pm last night, I was too tired to do anything but take a cursory glance at it. I was not impressed with what I saw.

After a good night’s sleep, an excellent cup of coffee, and a fortuitous catch of a smoky sunrise, (image below) I felt excited to get my hands on that ugly, unprocessed stacked image and see how much I could pretty it up.

I opened it up and, yup – it was just as ugly as I remembered it to be. But that’s not unusual, most images need a bit of processing to bring out their potential. Next, I tracked down an image to compare the stack to, which was a single long exposure image of Orion, taken a couple of years ago by fellow MROI astrophotographer, Dylan Etscorn. Let the comparisons begin!

Right out of the gate, the single exposure definitely looked better than the stacked image. And keep in mind, the stacked image consists of 14 minutes worth of exposure time, while the single image was just three minutes long.

Next, I did some basic processing to both images, mainly just trying to get the red out of the background and stars of the stacked image while trying to leave the red in the nebulae, and adjusting the contrast and color a bit in the single exposure.

After getting this far, I could clearly see the winner so decided not to spend any more time on image processing. The images below are identical to those directly above, just cropped so you can more easily see the detail, or lack thereof, in the nebulae.

The images below are cropped once more, to focus on the Orion, Running Man, Flame, and Horsehead Nebulae.

For this particular test anyway, I’m changing the chant from “Stack It! Stack it Good!” to “Stack It? Stack it, Baaad.”. Now, that doesn’t mean that you shouldn’t try stacking short exposures, especially if that’s your only option. In fact, I’m sure I’ll try this again myself. I could even reprocess this set of images with different parameters and likely come up with a better result, although I’m loathe to give up the use of my computer for 16+ hours again anytime soon. But in spite of the 4 AM wakeup call to shoot Orion, over 800 shutter actuations on my beloved D850, the 16+ hours of computing time, and a less than dazzling final result that I’m likely just going to toss, I’m glad I went through the exercise. In the end, I’m of the opinion that it is better to have stacked and tossed, than never to have stacked at all.

M. Colleen Gino, MRO Assistant Director of Outreach and Communications

While perusing the web yesterday, I came across an interesting astrophotography video tutorial about stacking hundreds of very short exposures to produce an image that is comparable to a single image with a much longer exposure time. The point was that while many people have a camera on which they can control the exposure length, and a tripod on which to mount the camera and keep it stable (perfect for relatively short exposures), not nearly as many people have some kind of tracking mount necessary for taking long exposure astrophotos. Personally, I’ve not had much success with this short exposure stacking method in the past; the resulting stacked image had nowhere near the detail of a single long exposure. But, it’s been a while since I tried it, so I figured it was time to give it another go!

First, a little background information for those not familiar with astrophotography. One of the primary challenges we face in photographing the night sky is getting an image without noticeable star trails. Unless our intention is to shoot star trails, as in the image above, we want to see nice, round, pinpoint stars in our image. This is not as easy as it sounds, because the Earth is rotating on its axis so the stars appear to move through the sky. This motion of the stars is not really noticeable when you’re just watching the sky, but it becomes very noticeable in a photograph taken with a camera on a fixed tripod. The longer the exposure time of the photograph, the more star trailing you get.

The way we account for this is by attaching the camera to a tracking mount, a device that rotates at the same rate as the Earth but in the opposite direction, resulting in stars that appear (mostly) motionless (and therefore points of light rather than streaks) in our camera’s field of view. If you don’t have such a device, the only way to achieve round stars is to limit your exposure time such that you don’t capture the apparent motion of the stars in your photograph.

Enter the astrophotography 500 rule, a simple formula for calculating the maximum exposure time for the focal length of the lens you’re using to get round stars. For full-frame cameras, you simply divide 500 by the focal length of your lens, and the resulting number is the approximate number of seconds you can expose without seeing elongated stars. (If you have a crop sensor in your camera, the formula is 500/lens focal length/1.5.) Note the word “approximate”; to get accurate results you must take much more into account, such as the pixel size of your sensor, the f-stop of your lens, the declination of the object you are photographing, and atmospheric conditions. A full explanation of getting an accurate result is beyond the scope of this article (though I’ll likely discuss it in the future), so we’ll stick with the approximate result for now.

As an example, this morning I went out in the early AM to photograph the constellation Orion for this exercise in stacking short exposures. I was using a Nikon D850 which is a full-frame camera, and a 50mm lens so I could get the whole constellation in my field of view. According to the 500 rule, my calculation would be 500/50=10, so I should see little to no star trailing in a 10 second exposure. Turns out I had extremely noticeable star trailing in that 10 second exposure, so I kept reducing the exposure time until I was happy with the results. Turns out I had to reduce the exposure time quite a bit, this being primarily due to Orion’s location — it was rising in the east, so its apparent motion over the same period of time was greater than if I were shooting, say, close to the north pole, as illustrated in the image below (another topic for a future article!). However, the 500 rule gave me a pretty good starting point.

Now to get back to the exercise of stacking images. I took 422 two-second exposures, so the sensor was exposed to light for a total of 844 seconds. All things being equal, this stack of images with a total integration time of 844 seconds should yield similar results as a single 844 second (14-minute) exposure. All things aren’t equal in this scenario, so the result won’t be exactly the same, but how close will it be? This is what I’m trying to determine: how does a stacked set of images “stack up to” a single image of equal integration time?

Well, I hate to disappoint you, but I can’t answer that question today. Turns out, it takes a very, very, long, long, LONG, long time to calibrate, align, and stack 422 images (as well as 153 dark frames, 104 bias frames, and 102 flat frames, more on that later). My computer has been diligently working on it for about six hours so far, and has about another five or so hours to go. So please tune back in tomorrow, when I share my results!

M. Colleen Gino, MRO Assistant Director of Outreach and Communications