Astral Projections Online December 2021
We will be returning to the Planetarium for in-person meetings starting in January 2022. Wearing masks inside will be required by the college and subject to change as COVID rules change.
Club dues and membership. We are now collecting dues/membership for 2022. If you renew after March 31 you will be renewed as a new member. Please mail it to the address on the form or bring it to club meetings. We will not collect dues during star parties.
Check our Website for updated content at www.astra-nj.com
Club Presentations Wanted:
Does anyone have any astronomy items of interest to share with the membership?
Please let us know at Club Contacts.
ASTRAL PROJECTIONS ONLINE (APO for short) is an email-linked publication for members only. If you exit APO to the club website or other resources you will need to use the emailed link again to get back to it. If you wish to retain a copy please bookmark or refer back to the email. We will make all efforts to post by the first week of the month.
Submissions Welcome: Members are invited to submit articles, photos, news, or stories for inclusion with Astral Projections Online. Please contact the ASTRA Webmaster.
Event Calendar
ASTRA’s next meeting - The December meeting will be a virtual meeting on Friday, December 10, 2021, at 7 PM EST.
Cloverdale Public Star Party - Saturday, March 5, 2022, at 6:30 PM
Jakes Branch Public Star Party - Saturday, March 12, 2022, at 6:30 PM
EVENT Cancellations: Members will receive email notification of an event cancellation, or call the ASTRA Hotline: 609-971-3331
Upcoming County Park Presentations 2022
Public Outreach, if any member wishes to support ASTRA outreach efforts with the public, please let John, Ro, or Jim know of any interest. Currently, we have two events planned with the county parks.
Note: The County Park events below will require an entry fee and registration.
January 25 - 6 to 7 PM - Cloverdale Farm County Park: Milkyway Photography and Beyond
Description: Join us as Jim Webster from the Astronomical Society of the Toms River Area discusses how to capture the beauty of the night sky and the Milkyway galaxy through photography.
March 8 - 6 to 7 PM - Prominent Women Figures in Space & Astronomy
Description: Join Rosemarie Spedaliere of the Astronomical Society of Toms River Area. You will be introduced to some of these women and how their small steps for man, have left one giant leap for all humankind.
Website Updates …
Please visit our club website. We continue to have additional updates, if there is some content that would be useful to members please let us know.
"Do not look at stars as bright spots only. Try to take in the vastness of the universe."
- Maria Mitchell, Astronomer
ASTRA Meeting - November 12
ASTRA Membership had a general open meeting to discuss current events, some show and tell and upcoming board member elections. John Endreson would like to become a regular member for 2022 and vacate the president spot. Jim Webster is willing to become club President if the membership so chooses unless someone else would run for the position. That said the Vice-President position would be up for grabs. Rosemarie Spedaliere would continue as Treasurer.
If there is any interest in any of these positions, please let the current board members know.
We discussed the success of the recent Jakes Branch Star Party and that it was estimated to have some 70 visitors view the night sky from our membership telescopes. We did have a great member turnout and plenty of telescopes were on hand.
Jim Webster reported the success of the Cattus Island presentation for Beginner Astronomy. While the numbers were only at ten, it was the allowed headcount for COVID rules. We are already setting up new dates for presentations in the Springtime at the county parks for 2022.
Jim Webster provided a brief overview of Scistarter which is a citizen science program that he has been involved with. Mostly for night sky light pollution study.
Scistarter is a great resource for someone looking to do a little bit more related to a topic of interest and a good resource for kids to get involved. Citizen science enables people from all walks of life to advance scientific research.
•Anyone can participate.
•Participants use the same protocol so data can be combined and be high quality.
•Data can help real scientists come to real conclusions.
•A wide community of scientists and volunteers work together and share data to which the public, as well as scientists, have access.
Scistarter currently has over 3,000 projects with 79 projects related to Astronomy, space, NASA and telescopes that were found from searchable tags. We touched on eight of the projects and will be adding links to Scistarter from our club website.
For more go to Scistarter.org
Other Event Reports
November 9 - Jim Webster provided a presentation on Beginners Astronomy at Cattus Island County Park. Turnout was only ten participants but this was due to COVID headcount restrictions. The included image was the completed setup prior to showtime.
November 13 - Jakes Branch Star Party was a great success. We had a good membership turnout and about seventy visitors of the public came out to observe with us. While we did not get to observe much for 2021, this was a good way to wrap up 2021.
November 20 - ASTRA Outreach
Novins Planetarium
With the James Webb telescope pending launch, the Novins Planetarium had a telescope day this past November 20, 2021. We were present for four of the five planned shows that day.
Luci Street came out to assist and the days’ events were successful. We are hoping to participate in future events at the planetarium.
Wishing everyone a Merry Christmas
The Christmas Tree Cluster ;) … image from Dean Salman via Astronomy.com
NGC 2264 is the designation number of the New General Catalogue that identifies two astronomical objects as a single object: the Cone Nebula, and the Christmas Tree Cluster. Two other objects are within this designation but not officially included the Snowflake Cluster and the Fox Fur Nebula. Wikipedia
Apparent magnitude (V): 3.9
Distance: 2350 ± 52 ly (719 ± 16 pc)
Constellation: Monoceros
Right ascension: 6h 41m
Apparent dimensions (V): 20′
Around the Web
APO EDITOR: Reposted from Facebook with permission from Loren Ball.
Loren Ball is an American amateur astronomer.
When I decided to earn my Observatory Code from the Minor Planet Center located at Harvard in the late 1990s, I
hoped to be able to measure the orbits of a few asteroids that needed additional data.
Asteroid discoveries were the farthest thing from my mind, and beyond my faintest hopes.
Over the years, I have turned in thousands of asteroid measurements, and to my utter amazement, a few asteroid discoveries fell into my lap.
I have gone through several asteroid databases at the Minor Planet Center in order to find the magnitude of my asteroid discoveries on the first night they were imaged with my 16" Schmidt Cassegrain and SBIG ST-9E cooled CCD camera at Emerald Lane Observatory 843.
I also wanted to understand the approximate physical size of each asteroid. This is something I have wanted to know for years, but I did not relish the task. Well, cloudy evenings are good for something, right? Off we go . . .
Of my 107 discoveries so far, here are the numbers :
Brightest = magnitude 18.0
Faintest = magnitude 20.4
10 asteroids were fainter than magnitude 20.0
73 asteroids were between mag 19.0 and magnitude 19.9
24 asteroids were between mag 18.0 and magnitude 18.9
The largest asteroid is 7.5 miles in diameter. It is a Trojan asteroid at the same distance as Jupiter.
The smallest asteroid is 0.4 miles in diameter. It is a main-belt asteroid.
I now have a database of each asteroid's brightness at the time of discovery, and also the physical size of each asteroid. A handful of other asteroid discoveries will be credited to me by the Minor Planet Center at some point, but this is a slow, agonizing process.
It is quite difficult for amateur astronomers to discover asteroids today because the low-hanging fruit has been picked. I was in the right place, and at the right time, about 20 years ago.
Design courtesy of my good friend David Rankin. Thanks.
To measure the orbits of asteroids, this is the information that you need:
https://www.minorplanetcenter.net/iau/info/Astrometry.html
Even though it is difficult to discover new asteroids today, it is still pretty easy to observe the brighter members. Some are even available with binoculars.
This is a very helpful web site. Be sure to add your own location data in the box at upper right.
https://www.heavens-above.com/Asteroids.aspx?lat=34.52329&lng=-86.93504&loc=Decatur%2c+AL&alt=600&tz=CST
From Wikipedia:
Loren C. Ball (born 1948) is an American amateur astronomer, who has discovered more than 100 asteroids while working at his Emerald Lane Observatory, built on the roof of his house on Emerald Lane, Decatur, Alabama. As of 2018, he has credit for 107 numbered designations with the Minor Planet Center at Harvard for the period between 2000 and 2004. None of them were co-discoveries.
He is under contract with NASA through the University of Alabama in Huntsville to do outreach to school groups and organizations.
As of 2019, he promotes asteroid education in schools and on social media.
The main-belt asteroid 16095 Lorenball, discovered by astronomers with the Catalina Sky Survey in 1999, is named after him. The official naming citation was published by the Minor Planet Center on 8 November 2019 (M.P.C. 118219).
Wikipedia information here includes named asteroids: https://en.wikipedia.org/wiki/Loren_C._Ball
NASA - Astronomy Picture of the Day
APOD: Light Pillar over Volcanic Etna (2021 Nov 15)
Image Credit & Copyright: Giancarlo Tinè
What is happening above that volcano? Something very unusual, a volcanic light pillar. More typically, light pillars are caused by sunlight and so appear as a bright column that extends upward above a rising or setting Sun. Alternatively, other light pillars, some quite colorful, have been recorded above street and house lights.
This light pillar, though, was illuminated by the red light emitted by the glowing magma of an erupting volcano. The volcano is Italy's Mount Etna, and the featured image was captured with a single shot a few hours after sunset in mid-June. Freezing temperatures above the volcano's ash cloud created ice crystals either in cirrus clouds high above the volcano or in condensed water vapor expelled by Mount Etna. These ice crystals, mostly flat toward the ground but fluttering then reflected away light from the volcano's caldera.
This Month-Member Show and Tell
Show and Tell does not have to always be telescope-related. It can be other astronomy-related items or a novelty item that would be of interest to an astronomer.
ASTRA Member John Deriso provided an overview of his homemade ball mount telescope.
A Wikipedia search for “Newtonian Telescope” will show a replica of Issac Newton’s 2nd telescope, circa 1672. The scope tube mounts on a wooden ball, which is cradled so it can move horizontally, vertically, and can also rotate so the eyepiece may be positioned comfortably for viewing. I can’t vouch for the replicas of Newton’s design now on eBay, but I’ve seen similar designs that actually used bowling balls.
The most commercially successful ball mount telescope may have been the Edmund Astroscan, a 4-1/8” f/4.2 mirror built into a one-piece red Styrene body. Designed for hand-carry with a strap, it also came with a 3-point cradle for table use. They can still be found on eBay.
Around 2000, I became interested in building telescopes (spoiler: I’ve never ground a mirror). My astronomy club had a special-interest group of members who built their own scopes. I bought in to a group purchase of 4-1/2” f/4 mirrors at $40 each. Surplus houses sold cheap eyepieces and secondary mirrors for a few bucks more. Cardboard tubes, coffee cans soldered together, PVC plumbing parts, plastic cat litter boxes for bases… all the stuff of the Amateur Telescope Maker (ATM). I happened upon a discarded 12” plastic globe that once graced a front-yard pole light. It had a hole large enough to pass a 4-1/2” mirror. I was off and running. I can hardly believe all the things I did wrong. It was a kluge, vaguely similar to the Astroscan, but it did work and gave great moon views. Halloween Trick-or-Treaters saw comet Holmes from my driveway in 2007. Alas, I loaned it to a lady who tried to interest her son in astronomy. He demonstrated gravity instead and rolled my creation off a table to the waiting cement sidewalk. “Sorry…”
Some years later, a co-worker handed me a 6” f/6 Edmund Scientific mirror (one of the best at the time) and a 1-1/4” secondary mirror: “John, I’ll never get around to making a telescope, take these!” Some months later, off for a haircut, I saw in the parking lot remnants of a large white plastic globe. It was shattered into 3 pieces, laying near a light pole, a victim of the previous night’s gale winds. Where some might see trash, I saw “TELESCOPE!” I hauled it home, bought PVC cement from Home Depot, and pondered. And glued. The hole would fit my 6” mirror.
Weeks later, I had sketches for a wood mount for the mirror and a (removable) way to hold it to the inside bottom of the ball. Three holes through the ball bottom would pass an Allen wrench for spring-loaded adjustment of the mirror tilt – collimation!
I learned to make plywood circles with my plunge router and disc/belt sander. I made the secondary mirror cage with 5 circles and 1/4” dowels in a “truss” fashion. Jigging the wood to drill-press the dowels at a weird angle was a nightmare. The “spider” – the part that holds the secondary mirror – was made from steel banding straps, rectangular aluminum tube, and model airplane hardware. The entire secondary cage was made easily removable, so the scope would fit in my car in two pieces. Grab and go! I bought a commercial focuser, and a Rigel Quickfinder red LED sight.
Hibernation. The project lay abandoned in the basement for a year and a half because I couldn’t think of an original way to mount the ball. It was top-heavy from the secondary cage weight, and if I let go the whole affair rolled over. Bah. I finally settled on a larger version of the Astroscan 3-point mount, a “Y” – shaped wood structure with gimballed low-friction contacts at the ball and… and caster wheels, for “sidewalk astronomy!”. Chunks of lead made from the plumber’s solder were glued inside the ball until it balanced without being constantly held. And still room inside for a bag of eyepieces and a sandwich! Years later, I mounted a hacked green laser pointer to swiftly sweep around the sky. The scope swings in altitude, azimuth, and the eyepiece rotates so the little kids can reach it.
Don’t ask for plans, there aren’t any! I unwittingly made this the hardest of my designs, and I guarantee I’ll never do it this crazy way again! Now, on to the 12” Truss-Tube Dob!
Outreach material below is distributed free for public outreach.
Let’s Explore Space - What’s in the Sky December 2021?
Messier 33 - Triangulum Galaxy
Distance to Earth: 2.723 million light-years
Radius: 30,000 light-years
Magnitude: 5.72
Apparent mass: ~50 billion M☉
Stars: 40 billion
Coordinates: RA 1h 33m 50s | Dec +30° 39′ 37″
Constellation: Triangulum
Credits: APOD Nov 12, 2021 Bernard Miller
The small, northern constellation Triangulum harbors this magnificent face-on spiral galaxy, M33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy. M33 is over 50,000 light-years in diameter, the third-largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way. About 3 million light-years from the Milky Way, M33 is itself thought to be a satellite of the Andromeda Galaxy, and astronomers in these two galaxies would likely have spectacular views of each other's grand spiral star systems. As for the view from planet Earth, this sharp image shows off M33's blue star clusters and pinkish star forming regions along the galaxy's loosely wound spiral arms. In fact, the cavernous NGC 604 is the brightest star-forming region, seen here at about the 4 o'clock position from the galaxy center. Like M31, M33's population of well-measured variable stars have helped make this nearby spiral a cosmic yardstick for establishing the distance scale of the Universe.
The Triangulum galaxy, also known as Messier 33, is sometimes said to be the farthest object visible with the unaided eye. But you’ll need perfect dark sky conditions – and good eyesight – to see it. Even with binoculars and a telescope, this pinwheel-shaped spiral galaxy is not easy to spot. That’s because it’s turned face on to us. So it has a low surface brightness in our sky. The Triangulum galaxy, named for its location in the constellation Triangulum, is the 2nd-nearest spiral galaxy to our Milky Way, after the Andromeda galaxy (M31). It’s about 2.7 million light-years away.
earthsky.org
For more on M33 Triangulum Galaxy or Pinwheel Galaxy visit EarthSky.Org and Freestarcharts.com.
On the lighter side of astronomy …
To all our ASTRA members, families, and friends …
Happy Holidays, and Merry Christmas.
Apollo 8 Christmas Eve message December 24, 1968 … YouTube.
ASTRA Member Astrophotos
M33 - Triangulum Galaxy
By Ron Bernknoph - Nov 2
M33 is located in the triangle-shaped constellation Triangulum, earning it the nickname the Triangulum galaxy. About half the size of our Milky Way galaxy, M33 is the third-largest member of our Local Group of galaxies following the Andromeda galaxy (M31) and the Milky Way.
Orion Constellation
By Rosemarie Spedaliere - Nov 5
Good Morning Orion! Cell Phone image.
Orion is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the most conspicuous and recognizable constellations in the night sky. It is named after Orion, a hunter in Greek mythology. Its brightest stars are blue-white Rigel and red Betelgeuse.
Skull Nebula - NGC 246
By Ron Bernknoph - Nov 5
It is a few days past Halloween but this is NGC 246, otherwise known as "The Skull Nebula" in the constellation of Cetus. It is a planetary nebula of a star that is now the center white dwarf. This is about 1600 light-years away from us.
This was a stacked image of 49x 3-minute exposures.
Eastern Veil Nebula - NGC 6992
By Ron Bernknoph - Nov 5
The wispy filaments of the Eastern Veil Nebula are a part of a larger overall network of nebulae in the area of the sky, called the Cygnus Loop.
49x 180-second exposures. I enjoy shooting this one as it is so colorful and really interesting looking.
Dumbell Nebula - M27
By Ron Bernknoph - Nov 8
M27 resides more than 1,200 light-years away in the constellation Vulpecula.
These types of nebulae are formed when evolved giant stars eject their outer envelopes, exposing the hot core of the star, ionizing the surrounding cloud of expelled material with ultraviolet light. The clouds keep expanding until they dissipate into the surrounding space. 47x 180 seconds
Horsehead Nebula - Barnard 33
By Matthew Michota - Nov 8
The Horsehead Nebula is a small dark nebula in the constellation Orion. The nebula is located just to the south of Alnitak, the easternmost star of Orion's Belt, and is part of the much larger Orion Molecular Cloud Complex.
Comet 67P
By Matthew Michota - Nov 8
67P/Churyumov–Gerasimenko is a Jupiter-family comet, originally from the Kuiper belt, with a current orbital period of 6.45 years.
Ring Nebula - M57
By Ron Bernknoph - Nov 12
The Ring Nebula (M57) is a planetary nebula in the constellation of Lyra. 34x 3 minutes.
Horsehead Nebula - Barnard 33
By Matthew Michota - Nov 8
Reprocessed by Ally Nudo - Nov 15
APO Editor: I would like to welcome Ally to the league of Astro imagers. Great image processing.
Cygnus Wall - NGC 7000 - Nov 15
By Matthew Michota & Ally Nudo
The Cygnus Wall, a portion of the North American Nebula (NGC 7000) in the constellation Cygnus. Astrotech 102edl APO w/ .8 reducer
ZWO asi2600mc pro / Ioptron GEM 45
Optolong L Enhance
Bortle 5, Gillie park in Lacey, First Quarter Moon.
Astronomy & Space Theme Music
For our December issue of APO, we’ll feature the full concert of The Planets at the Proms 2016, as performed by Edward Gardner and the National Youth Orchestra.
Gustav Holst
Gustav Theodore Holst, born September 21, 1874, in Cheltenham in the UK was an English composer, arranger, and teacher. Best known for his orchestral suite The Planets, he composed many other works across a range of genres, although none achieved comparable success. Holst died in London on May 25, 1934. For more Wikipedia & Britannica.
Edward Gardner leads the National Youth Orchestra of Great Britain and the CBSO Youth Chorus in a performance of Gustav Holst's The Planets with Colin Matthews' supplementary piece "Pluto, The Renewer." Recorded live at the Royal Albert Hall on August 6th, 2016 as part of Prom 29.
Over the years “The Planets” has influenced music for TV and Movies either directly or indirectly. We’ll sample “Mars - The Bringer of War”.
While not strictly astronomy-related, the Quatermass BBC TV serial series created by Nigel Kneale from the 1950s featured “Mars - The Bringer of Mar” as its intro for its first two serial series with each of its episodes. The third serial series departed from this and used a different intro. Surprisingly the third serial revolves around a deceased Martian insect race on Earth. If there is interest all three original serials are linked below including the movie version.
The Quatermass serial three main sci-fi plots are still in use today with different adaptations over the years, bbc.co.uk.
"We go to them" was the 1953 Quatermass Experiment, where an Astronaut returns from space and turns into an alien. - YouTube
"They go to us" was 1955's Quatermass II, in which zombie aliens invade. - YouTube
"They've always been here" was 1957's immortal Quatermass & The Pit. - archive.org
Quatermass and the Pit or Five Million Years to Earth Movie 1967 - archive.org
Inside Film blog has more on the influence of Gustav Holst's “The Planets” on modern film, including Star Wars.
- Inside Film
Members Submitted Articles & Items
Whatever it is, the way you tell your story online can make all the difference.
Comet Leonard C/2021 A1
By Jim Webster
While all the focus comet wise has been with 67P these last few weeks, the next one will be taking over the interest of many of us very soon for a short time.
It is anticipated that Comet C/2021 A1 will be brightening enough to be viewable to the naked eye, worst case by binoculars.
Checking for the best possible days for viewing it appears December 6 to December 8 will be most favorable. Look eastward towards the constellation Bootes starting from 3 AM to roughly 5:30 AM EST. May be good enough on one of these days for the membership to meet at Seaside and observe this event together.
For more on Comet C/2021 A1 check out the following links: theskylive.com
For Sale By Member
Unistellar EVScope for Sale.
It arrived in September and has been used just a few times. It includes the optional $400.00 backpack. I am going to sell it online in a few days for $2900.00 for both scope & backpack in the original shipping box. A very nice Christmas present for someone! Will offer several hundred dollars off to group members (300.00 perhaps a little bit more but it already is a $3400.00 package) First come first serve. For more info: Unistellar
If interested please contact the owner directly. Richard Zoll Richard.Zoll@comcast.net
What’s Up: December 2021
Sky Watching Tips from NASA
Provided by NASA Jet Propulsion Laboratory.
For more go to NASA Jet Propulsion Laboratory webpage: What’s Up: Skywatching Tips From NASA
This article and images are distributed by NASA Night Sky Network
The Night Sky Network program supports astronomy clubs across the USA dedicated to astronomy outreach.
Visit nightsky.jpl.nasa.gov to find local clubs, events, and more!
The James Webb Space Telescope:
Ready For Launch!
By David Prosper
Webb will observe a wide band of the infrared spectrum, including parts observed by the Hubble - which also observes in a bit of ultraviolet light as well as visible - and the recently retired Spitzer Space Telescope. Webb will even observe parts of the infrared spectrum not seen by either of these missions!
Credits: NASA and J. Olmstead (STScI)
NASA’s James Webb Space Telescope is ready for lift-off! As of this writing (November 15), the much-anticipated next-generation space telescope is being carefully prepared for launch on December 18, 2021, and will begin its mission to investigate some of the deepest mysteries of our universe.
The development of the Webb began earlier than you might expect – the concept that would develop into Webb was proposed even before the launch of the Hubble in the late 1980s! Since then, its design underwent many refinements, and the telescope experienced a series of delays during construction and testing. While frustrating, the team needs to ensure that this extremely complex and advanced scientific instrument is successfully launched and deployed. The Webb team can’t take any chances; unlike the Hubble, orbiting at an astronaut-serviceable 340 miles (347 km) above Earth, the Webb will orbit about one million miles away (or 1.6 million km), at Lagrange Point 2. Lagrange Points are special positions where the gravitational influence between two different bodies, like the Sun and Earth, “balance out,” allowing objects like space telescopes to be placed into stable long-term orbits, requiring only minor adjustments - saving Webb a good deal of fuel!
Since this position is also several times further than the Moon, Webb’s sunshield will safely cover the Moon, Earth, and Sun and block any potential interference from their own infrared radiation. Even the seemingly small amount of heat from the surfaces of the Earth and Moon would interfere with Webb’s extraordinarily sensitive infrared observations of our universe if left unblocked. More detailed information about Webb’s orbit can be found at bit.ly/webborbitinfo, and a video showing its movement at bit.ly/webborbitvideo.
Webb will follow up on many of Hubble’s observations and continue its mission to study the most distant galaxies and stars it can - and as you can see in this comparison, its mirror and orbit are both huge in comparison, in order to continue these studies in an even deeper fashion! Credits: NASA, J. Olmsted (STScI)
Once in its final position, its sunshield and mirror fully deployed and instruments checked out, Webb will begin observing! Webb’s 21-foot segmented mirror will be trained on targets as fine and varied as planets, moons, and distant objects in our outer Solar System, active centers of galaxies, and some of the most distant stars and galaxies in our universe: objects that may be some of the first luminous objects formed after the Big Bang! Webb will join with other observatories to study black holes - including the one lurking in the center of our galaxy, and will study solar systems around other stars, including planetary atmospheres, to investigate their potential for hosting life.
Wondering how Webb’s infrared observations can reveal what visible light cannot? The “Universe in a Different Light” Night Sky Network activity can help - find it at bit.ly/different-light-nsn . Stay alert to the latest news from NASA and Webb team as it begins its mission by following #UnfoldTheUniverse on social media, and on the web at nasa.gov/webb.
You can find a printer-ready version of this article on our Night Sky Notes resource page every month, free to share with your club newsletter, website, or even local paper!
More from Night Sky Network
The Night Sky Network program supports astronomy clubs across the USA dedicated to astronomy outreach.
Visit nightsky.jpl.nasa.gov to find local clubs, events, and more!
Check Your Sky Quality with Orion!
The following article is a part of an original article that was distributed by NASA Night Sky Network and last updated on December 2020.
The Dark Sky Wheel, showing the constellation Orion at six different limiting magnitudes (right), and a photo of Orion (left). What is the limiting magnitude of the photo? For most observing locations, the Orion side works best on evenings from January-March, and the Scorpius side from June-August.
Have you ever wondered how many stars you can see at night? From a perfect dark sky location, free from any light pollution, a person with excellent vision may observe a few thousand stars in the sky at one time! Sadly, most people don’t enjoy pristine dark skies – and knowing your sky’s brightness will help you navigate the night sky.
The brightness of planets and stars is measured in terms of apparent magnitude, or how bright they appear from Earth. Most visible stars range in brightness from 1st to 6th magnitude, with the lower number being brighter. A star at magnitude 1 appears 100 times brighter than a star at magnitude 6. A few stars and planets shine even brighter than first magnitude, like brilliant Sirius at -1.46 magnitude, or Venus, which can shine brighter than -4 magnitude! Very bright planets and stars can still be seen from bright cities with lots of light pollution. Given perfect skies, an observer may be able to see stars as dim as 6.5 magnitude, but such fantastic conditions are very rare; in much of the world, human-made light pollution drastically limits what people can see at night.
Your sky’s limiting magnitude is, simply enough, the measure of the dimmest stars you can see when looking straight up. So, if the dimmest star you can see from your backyard is magnitude 5, then your limiting magnitude is 5. Easy, right? But why would you want to know your limiting magnitude? It can help you plan your observing! For example, if you have a bright sky and your limiting magnitude is at 3, watching a meteor shower or looking for dimmer stars and objects may be a wasted effort. But if your sky is dark and the limit is 5, you should be able to see meteors and the Milky Way. Knowing this figure can help you measure light pollution in your area and determine if it’s getting better or worse over time. And regardless of location, be it backyard, balcony, or dark sky park, light pollution is a concern to all stargazers!
How do you figure out the limiting magnitude in your area? While you can use smartphone apps or dedicated devices like a Sky Quality Meter, you can also use your own eyes and charts of bright constellations! The Night Sky Network offers a free printable Dark Sky Wheel, featuring the stars of Orion on one side and Scorpius on the other, here: bit.ly/darkskywheel. Each wheel contains six “wedges” showing the stars of the constellation, limited from 1-6 magnitude. Find the wedge containing the faintest stars you can see from your area; you now know your limiting magnitude! For maximum accuracy, use the wheel when the constellation is high in the sky well after sunset. Compare the difference when the Moon is at full phase, versus new. Before you start, let your eyes adjust for twenty minutes to ensure your night vision is at its best. A red light can help preserve your night vision while comparing stars in the printout.
Did you have fun? Contribute to science with monthly observing programs from Globe at Night’s website (globeatnight.org), and check out the latest NASA’s science on the stars you can - and can’t - see, at nasa.gov.
Tonight’s Sky: December
Step outside on a cold December night when the stars shine bright to find the Big Dipper, Cassiopeia, and Cepheus. They will help you locate a binary star system, a fan-shaped open star cluster, and a variable star. Stay tuned for space-based views of a ragged spiral galaxy, an open star cluster, and an edge-on galaxy.
Other Calendar Items of Interest
APO Editor’s Note:
Removed previous months “What’s Up” and “Tonight’s Sky” since APO links to prior months postings of APO.
Added Skymaps.com “The Evening Sky Map” and will be posted with each new issue of APO.
Skymaps.com - The Evening Sky Map - Select the current month and download the Northern Edition.
Submissions Welcome
Members are invited to submit articles, photos, news, or stories for inclusion with Astral Projections Online. Please contact the ASTRA Webmaster.