Jane Houston Jones » how-to stargazing

Spring stargazing: the Milky Way and beyond!

jane — Tue, 09 Apr 2013 22:56:35 +0000

Follow the dipper arc to Arcturus, then spike to Spica

Omega Centauri globular cluster 35 degrees below Spica

Springtime is my favorite observing season. In the course of an evening you can face away from our own galaxy and feast your eyes on other Milky Ways, while tracking down some of the most spectacular objects tangled among the stars and dust of our own galaxy.

Omega Centauri is one of them. It’s the largest of the 150+ globular clusters discovered in our own Milky Way Galaxy. There may be even more undiscovered globular clusters hidden behind the gas and dust of our galaxy. Omega Centauri was discovered by Edmund Halley in 1677 as a nebula, but it had been listed in Ptolemy’s catalog 2000 years ago as a star! It’s located about 15,800 light-years from Earth and contains several million Population II stars. The stars in its center are so crowded that they are estimated to average only 0.1 light years away from each other. It is about 12 billion years old, and there is some speculation that Omega Centauri may be the core of a dwarf galaxy which was disrupted, destroyed and absorbed in an encounter with the Milky Way.

This spectacular object is well known to southern hemisphere observers, but it may come as a surprise that it can be seen from many northern hemisphere locations as well. If you are south of the 25th parallel or 25° (degrees) North latitude you should be able to see it 20° above the horizon, and located 35° below Virgo’s great blue-white star, Spica. I’ve observed it from 37° North (Lake Sonoma, CA) several times (from a hill with a negative horizon) and at 33° N in this writeup, where it appeared less than 20° above the horizon definitely! It’s been seen from 42° North as well, from a very flat horizon. It’s a naked eye object, but often the horizon is hazy, so scan with binoculars if you don’t see it with your eyes.

NGC 5128, Centaurus A Galaxy, and NGC 5139 Omega Centauri, the largest Globular Cluster in our Milky Way

To find Omega Centauri, you’ll first have to find Spica, the brightest star in Virgo. It helps right now that golden Saturn is near by. To find Spica, continue the curve of the big dipper handle and “arc to Arcturus, and then spike to Spica”. Spica transits — when it reaches its highest point in the sky — at around midnight daylight saving time. Use this table of transit times for major solar system objects and bright stars and select your observing dates, object (Spica in this case) and your location and press “compute”. “Alt” next to the transit time at your location indicates Spica’s altitude above the horizon. Spica and Omega Centauri transit at the same time, so look about 35° (one clenched fist is 10°) directly below Spica to look for an oval hazy cluster the size of the full moon. Can you see individual stars? Does it look round or oval? Try with your eyes, then with binoculars.

After confirming my view of Omega Centauri and making this little sketch (sketch view as seen through my binoculars), I opened my Herald Bobroff AstroAtlas to the Centaurus constellation pages and looked at what else was in the vicinity of Omega Centauri. I remembered a favorite galaxy, NGC5128, officially named Centaurus A, but nicknamed the hamburger galaxy for obvious reasons. Now I’ve seen both of these objects from Australian skies where they are not hugging the horizon. But even through a partially cloudy horizon, I was able to see this fabulous object, with its dark dust lane bisecting the oval galaxy.

NGC5128 is one of the closest radio galaxies to Earth, so its active galactic nucleus has been extensively studied by professional astronomers, and a supernova was detected in the galaxy’s dust lane in 1986. The Spitzer Space Telescope studies have confirmed that Centaurus A is colliding with and devouring a smaller spiral galaxy! Centaurus A is located approximately 4° north of Omega Centauri, and because the galaxy has a high surface brightness and relatively large angular size (2/3 the apparent size of Omega Centauri), it’s visible to the naked eye under good conditions. My sketch was made with difficulty, by aiming my 14.5-inch reflector (with a 10mm Radian eyepiece for 200x) nearly horizontal and half-perched uncomfortably on the bottom step of my observing ladder.

M68 cluster in Hydra, NGC2903 Galaxy in Leo

Before moving on, I observed another object in the southern sky line between Spica and Omega Centauri, Globular Cluster M68, or NGC4590 in the constellation Hydra. I sketched an oval glow of stars within a diffuse squarish haze of fainter stars.

Now it was time to get vertical and observe some other objects higher in the sky. The beautiful constellation Leo was still well placed in the southwest sky after midnight. I opened my Night Sky Observer’s Guide Volume 2, the Spring and Summer volume to Leo. Gamma Leonis, or Algeiba, is a beautiful deep yellow/orange and pale yellow double star in the sickle (or backwards question mark or lion’s mane) of Leo’s head. Next, I moved to a fascinating red dwarf, Wolf 359, near the famous Leo galaxies M95, M96 and the Leo “trio” of galaxies. Wolf 359 moves 4.71″ (arcseconds) per year or 8′(arcminutes) in a century. It’s the third closest star to the sun, at 7.75 light years away. Only Alpha Centauri and Barnard’s Star are closer. At magnitude 13.6 (similar to Pluto’s magnitude) it’s faint, but the striking red color helps distinguish it from the other nearby stars.

Leo 1 near Regulas, Leo’s heart was my next target. A faint dwarf galaxy overshadowed by bright Regulus is a member of the local group of galaxies, and may be one of the most distant satellites of the Milky Way. Faint NGC2903 — a very pretty magnitude 9 barred spiral galaxy tangled in the starry lion’s mane was worth a sketch. It’s 31 million light years away, local but not attached to any local galaxy group. I had to go and have a look at the supernova in Leo’s M65 galaxy – here is Mojo’s animation of M65,combining two images of M65, one shot on 3/9/13 at Amboy Crater, and one shot on 4/6/13 at Chuckwalla Bench located at N 33° 39′ 37″, W 115° 32′ 26″

Comet C/2011 L4 (PANSTARRS) shot before dawn on 4/7/13, five-minute exposure

It dawned on me I hadn’t observed Saturn yet. Under fabulous steady skies, I was able to pump up the magnification of my 15-inch Litebox reflector to over 300x using a 6mm Televue Radian eyepiece. When I say “my” 14.5-inch Litebox, I mean Mojo’s — I have a 12.5-inch and 17.5-inch version of these fabulous time machines. This image taken by Anthony Wesley the same night shows Saturn as I viewed it. My visual view was not quite this vivid, but the contrast of the colors is very similar to what I saw, including the dark north polar region, so famous in the Cassini North Polar Hexagon images. The distinct band colors and darker north polar area I saw and sketched were varying shades of butterscotch and chocolate.

All that was left now was Comet PanSTARRS, and we had to wait until about 4:00 a.m. for Andromeda to rise in the northeastern sky. I observed it in my 7×50 Carton Adlerblick binoculars quickly and then pooped out and went to sleep until well after dawn. Mojo stayed up and took this lovely image, plus several more including a time sequence showing the comet’s motion. It’s really worth a look and a read and here’s the link. Until next dark sky observing night on May 11, I’m signing off!

Mojo’s images and report from the same night

My first view of Comet PanSTARRS 3/11/13

jane — Tue, 12 Mar 2013 09:33:58 +0000

Sunday morning (Sunday March 10) we drove home from a wonderful Amboy Crater observing night. As we drove up our street, we have a good view of Mt. Wilson and the telescopes, as you can see here. My Comet PanSTARRS sketches (and astrophotos tomorrow) from near the Mt. Wilson Observatory (but on the other side of the mountain) are below.

Mt. Wilson 100 & 60-inch telescope domes and solar telescopes from home

I drove past the telescopes on Angeles Crest Highway 2 to catch a glimpse of the comet. From home, Mt. Wilson is about 7 miles away as the crow flies. Not being a crow, I drove 13 miles to work, then 3 miles to Angeles Crest Freeway, then up 20+ miles and 5,200 feet in elevation on the mountain highway to get this view — that’s the historic 100-inch Mt Wilson Hooker telescope dome and the two solar telescopes on the ridge.

Passing Mt. Wilson telescopes from Angeles Crest Highway

We arrived at our viewing location, 23.5 miles up the hill, milepost 48.34, 34d 18′ 26″ N Latitude 118d 00’54″ W Longitude, altitude 5266 ft before sunset – the Chileo turnout just before the Caltrans yard on Angeles Crest Highway. I am indebted to my friend Steve Edberg, who has observed on these pullouts since the 1970′s. We passed many other spots which he has observed from, but which didn’t have the required “dip” in altitude, which provided a view of the western horizon depressed to a further 1 degree.

Sunset (and green flash) at my comet viewing spot on Angeles Crest Highway

We had to wait over a half hour after sunset for the twilight sky to darken. Civil twilight occurred at 7:22 p.m. PDT, when the sun dipped 6 degrees below the horizon. We scanned the sky, not only looking for the comet, but for the moon, too. But the new moon was only about 6 hours old (new at 12:52 p.m. Pacific Daylight Time March 11, and impossible to see). Thanks to Steve Edberg for explaining “horizon depression”:”Due to our elevation, looking down from 5,266 feet, the terrain horizon in the distance was lower than horizontal, so we could look “down” far enough that we gained one degree more of viewing potential. This dip of the horizon doesn’t include the terrestrial refraction at the apparent horizon, which often “raises” astronomical objects (meaning they set later than airless geometry predicts)”.

Here is what we did see, beginning at 7:34 p.m.

Here is my first sketch. Showing what Comet PanSTARRS looks like through 7 x 50 binoculars with a 7 degree field of view. We were unable to see it naked-eye. I couldn’t get both the horizon and the comet in the same binocular field of view.

Sketches show my binocular view - this is what Comet PanSTARRS looked like through binoculars

Here is the final view through bigger binoculars just before the comet was lost in the haze. Celestron 9 x 63 binos, with a 5 degree field of view. It was amazing to watch the speedy comet move!

Last views of Comet PanSTARRS (on first observation)

NASA’s Prime Time for PANSTARRS Toolkit with charts, and observations and more.

What’s Up PanSTARR Edition Podcast

Kemble’s Cascade: the joy of observing with binoculars

jane — Mon, 11 Mar 2013 07:06:40 +0000

Start your night with binoculars

Here’s Mojo’s atrophotography post from the same evening.

After some months away from dark skies, everything looks foreign, even to long time observers like me. I recognize the familiar constellations, but sometimes I forget where some of my favorite telescopic targets are located. On nights like this, I don’t just revisit the same old objects with my telescope. I sit down and scan the sky — from horizon to horizon — with my binoculars, until a stargazing project presents itself to me.

There are a lot of binoculars out there. When I was beginning my amateur astronomy hobby 25 years ago, I bought a pair of Carton Adlerblick 7 X 50 (7 times magnified) binoculars. I still use them, though I do have more powerful binos, which weigh more, which is why I rarely use them. These Adlerblicks are my go-to binoculars. They are lightweight and are great for both terrestrial and celestial viewing.

So, on some dark sky nights, I start my observing session by scanning the sky with my binoculars, and hope to find an object or theme of objects to observe. I end up with an old favorite in the binocular view pretty quickly almost every time.

Sky Map Pro sky chart crop showing Kemble's Cascade with the location of NGC 1502, 1501 and IC 342 shown

Kemble's Cascade, sketched from 7 x 50 binocular view

That happened last night (March 9, 2013), as I scanned the northern constellations from Amboy Crater, our current favorite dark sky site. All of a sudden, my entire binocular field of view was bisected by a line of bright stars, Kemble’s Cascade, an old favorite of mine! This is one of the joys of visual observing. I love to scan the sky with binoculars, then dig a little deeper to see what is in the neighborhood using my star charts. After years of observing “lists” of projects, I really enjoy just letting my binoculars be my guide to a night of stargazing.

Kemble’s Cascade is a nearly straight line of stars as long as 5 full moons lined up side by side. It completely spanned my binocular field of view. Kemble’s Cascade is one of the finest binocular objects in the winter sky, but is located in one of the most difficult constellations to actually see: Camelopardalis, the camel leopard (or the Giraffe). It’s located near Polaris, between and above Cassiopeia and Perseus. Quick hint: I aim my binoculars at the Perseus Double cluster, and scan up from there until I find it. This asterism (not a constellation, but a group of stars forming some shape) was named after Father Lucian J. Kemble, an amateur astronomer from Canada who first saw this cascade of faint stars.

I took out my sketch notebook and sketched this view from my binoculars. Now my evening stargazing project had a start. After I made this sketch, I opened my Night Sky Observer’s Guide (NSOG) to the constellation Camelopardalis to remind myself what else was in the neighborhood. This two (three, actually – the third being southern skies) book series is organized by constellation with one book for summer and spring constellations, and another volume for autumn and winter. It’s my go-to observing book. I can open it to any constellation and find a wonderful starhopping project for the night.

Camelopardalis is a northern circumpolar constellation. Find Polaris, the North Star and you are in the celestial neighborhood of the camel-leopard, or Giraffe constellation.

One of the finder charts in the chapter on Camelopardalis showed several objects near the Kemble’s Cascade line of stars – a star cluster, a planetary nebula and a galaxy. I hadn’t looked at these for a while – two are on William Herschel’s small project list, the Herschel 400, which I observed many years ago. So I settled in for a pleasant hour of starhopping. Through the telescope, only a few of the stars of Kemble’s Cascade filled each eyepiece view. So first I just rode along the cascade, star by star. The first of the deep sky objects soon was in my eyepiece.

Open Cluster NGC 1502

Planetary Nebula NGC 1501

Face-on spiral galaxy IC 342

NGC 1502 – The New General Catalogue of Nebulae and Clusters of Stars (NGC) is a well-known catalogue of deep sky objects compiled by Dreyer in 1888, as a new version of John Herschel’s Catalogue of Nebulae and Clusters of Stars. NGC 1502 is a stunning open cluster near the south end of Kemble’s Cascade, 2,680 light-years away, and estimated to be only 11.2 million years old. Once you memorize where to find the Cascade (I can see this cluster naked eye from our dark sky observing spots, and use it to find Kemble’s Cascade), you have a second easy-to-find, and crowd pleasing object to share with others. The cluster is rich with bright stars, shines at magnitude 5.7, making it naked-eye visible from a dark sky. It will remind experienced stargazers of the ET Cluster, NGC 457 in nearby Cassiopeia. (At least it reminds me of that nearby cluster)! They both have two prominent non-human “eyes” comprised of brighter stars. Take some time looking at this cluster, and find the pretty blue and gold double star embedded in it.

NGC 1501 is a bright planetary nebula with a blue color visible from a dark sky, glowing at magnitude 11.5, located 4,900 light-years distant. Though it’s not naked eye visible, it’s easy to find in a moderate-sized (6-12 inch) telescope. It will remind experienced observers of the Eskimo nebula in Gemini. If your sky conditions allow, view this nebula at high power – I used a 9mm eyepiece on my 12.5 inch f/5.75 reflector for a magnification of 202X. At this power I was able to see the faint blue color, dark and light markings, and see that it was wider in the middle. 8-10 inch telescopes will show this detail at high power from a dark sky.

IC 342 (IC stands for Index Catalogue, one of two supplements to the NGC. The first was published in 1895 and contained 1,520 objects, while the second was published in 1908 and contained 3,866 objects, for a total of 5,386 IC objects). IC 342 is a spiral galaxy seen face-on. The nucleus is bright and the spiral arms are visible in a dark sky through moderate sized telescopes such as my 12.5 inch reflector. The magnitude is an easy 9.1 — easy through a telescope, not naked-eye visible. It is 6.5 million light years away. On the SW side of the galaxy, a string of foreground Milky Way stars – 6 stars in a straight line – are easy to see. IC 342 is one of the brightest two galaxies in the IC 342/Maffei Group of galaxies, one of the galaxy groups that is closest to our Local Group. In 1935, Harlow Shapley declared that this galaxy was the third largest spiral galaxy by angular size then known, smaller only than the Andromeda Galaxy (M31) and the Triangulum Galaxy (M33), being wider that the full moon. (Modern estimates are more conservative, giving the apparent size as one-half to two-thirds the diameter of the full moon). It is almost hidden from view behind the veil of stars, gas and dust clouds in the plane of our Milky Way galaxy!

Don’t be afraid to scan the sky with binoculars, even if you don’t know where you are looking or what to do you once you see something interesting. Ask a nearby astronomer, and in many cases, she will be able to aim her telescope at your new binocular discovery. It’s a great way to start your stargazing hobby!

Missing Susan

jane — Thu, 07 Feb 2013 02:56:14 +0000

2012 Monrovia Relay for Life Luminaria in honor of Susan Niebur, @whymommy

Saturn cut from Susan's Luminaria

Luminaria for Mojo (that's a cutout galaxy which was super difficult to cut out)

I started writing this just after Susan died, but couldn’t bring myself to finish it. Today is the one year anniversary of her death on February 6, 2012. Today is the day to finish, add, publish. Today, like every day, I am missing Susan.

“All that survives after our death are publications and people. So look carefully after the words you write, the thoughts and publications you create, and how you love others. For these are the only things that will remain.” –Susan Niebur

A year ago I was reminiscing back to the day I met Susan and jotted down the next few paragraphs.

“I follow you on Twitter” she said as she looked down to my name badge at March 2010′s, 41st Lunar and Planetary Sciences Conference, near Houston TX. I looked at her name badge, and my eyes popped out a little. I was talking to @womenplanetsci! Susan Niebur!

“I’ll see you tomorrow morning at the Women in Planetary Sciences networking breakfast, won’t I”? and before I could open my mouth to form the word of my reply, she was gone. She was down the hall inviting another woman she didn’t know to the networking breakfast.

On the day after that memorable and inspiring 2010 breakfast, I was in the conference hotel elevator with Susan and her husband Curt, who I knew from my work on the Cassini Mission to Saturn at JPL. Susan was rushing home, due to illness, I overheard in hushed elevator-abbreviated spouse-speak. I didn’t know anything about her cancer. All I knew about Susan was her science and her amazing personal presence. If you are lucky enough to meet someone in your lifetime with this electric aura, you’ll know it in an instant. I knew it. I knew she was a super-star the moment we met.

When I got home from that conference, I followed @whymommy in addition to @womenplanetsci on Twitter, found Susan’s Toddler Planet blog, and her Mothers with Cancer website. I read through several years of posts non-stop. I was sucker-punched with the news of her cancer, her cancer and science outreach, advocacy, and her fierce love for her family. My own sister Wendy had just completed breast cancer surgery and was about to start radiation at exactly the same time I met Susan. And at the same time my darling beloved husband Mojo was recovering from prostate cancer surgery, and had yet to receive his first post-op PSA. (Both are now three years cancer free.)

I was so very sad (heartbroken actually) to have missed the 2012 LPSC conference, held shortly after Susan died. Mostly, I wanted to feel Susan’s spirit there at the Women in Planetary Science luncheon, and share remembrances, laughs and tears with colleagues.

Oh, I miss her so.

I added this today: Four months after Susan died, it was time for our local Monrovia CA Relay for Life event. The cancer survivors take the first lap around the park, walking through and past hundreds of luminaria – hand decorated white paper lunch bags illuminated with a glow stick (no candles allowed, fire marshall regulations) inside – each remembering a loved one or thanking a caregiver.

Each year, the walkers stop and look at the moon or planets through our Sidewalk Astronomy club telescopes. This year, in addition to sharing the night sky with the crowds at my telescope, I made three luminaria. One was for my sister Wendy who is breast cancer free since 2010. One was for my hubby Mojo – who is prostate cancer free since 2010. The luminaria I made for Susan had a cutout of the planet Saturn for the light to shine through. I observed Saturn through my telescope, and thought of Susan, then colored the bits of luminaria cutouts to match the planet’s golden yellow hue, and made this special view of Saturn. I dedicated it to this amazing woman whose light and inspiration continues to shine on so many of us every single day.

Here are a few links I haven’t seen mentioned in other blogs:

But first, I really missed Susan’s DC Mom friends blog & Twitter posts. Getting a little caught up today.

Division for Planetary Sciences (DPS) of the American Astronomical Society (AAS) announcement

Dr Jim Green presents Susan with the NASA Planetary Science Public Service Award (video)

Susan speaking about Women in Planetary Science and leading NASA Missions (video)

NASA Solar System Exploration Susan Niebur’s NASA Solar System Exploration “people” page with great links!

Susan’s blog Turning awareness to action: donate, educate, advocate, volunteer

My cancer blogs with tips from Susan to Donate, Educate, Advocate, Volunteer

Here’s Emily Lakdawalla’s February 2012 Planetary Society blog about Susan.

What’s Up in 2013 at a glance

jane — Mon, 07 Jan 2013 18:29:31 +0000

All year long, astronomers have been writing about Comet ISON: will it sizzle or will it fizzle? Both! Here’s my What’s Up video, with December status (written in mid November, but luckily, the comet didn’t completely fizzle)

ISON in December 2013

Comet ISON first spotted by amateur astronomer Bruce Gary and has been imaged by many eagle-eyed observers with good astrophotography equipment since mid August. A selection of images and data are shown here. I’ll update this frequently as more is understood about Comet ISON. Meanwhile, here is a wesbite with current Comet ISON magnitude and location which is constantly updated!

Comet ISON survived its close pass of the sun on November 28. Scientists are unsure what is actually left of the comet. A fragmented nucleus? Nothing but orbiting dust? Stay tuned!

Here’s an excellent Star Chart showing Comet ISON’s path in November, courtesy of Skyhound’s Skytools3 software. (These are the charts I use for my own deep sky observing.) The chart has not been updated for December as of November 30th.

Latest visible comet news here.

December 2013

You may have noticed a very bright ‘star’ in the western sky. That’s Venus! Venus shines at its very brightest, magnitude -4.9 this month. It sets about three hours after sunset at the beginning of the month and one and a half hours after sunset at the end of the month. This is a great month to view the dramatic changes in the apparent diameter and phases of Venus as it races towards its conjunction with the sun. The first observations of the phases of Venus were made by Galileo in 1610!

Mars continues to grow brighter and rises near midnight, and Jupiter rises earlier in the evening, heralding the best viewing season for Jupiter watchers.

The beautiful Geminid meteor shower will only slightly be marred by moonlight on the night of December 13 and 14. The radiant lies near Gemini with brilliant Jupiter above and the constellation Orion below. From a dark sky, but even from the city, the mighty hunter Orion is easily visible in the southeast sky. Take a look at Orion’s shoulder star, red Betelgeuse and its knee star, blue Rigel and the Orion Nebula.southwestern horizon.

The Milky Way and all the visible planets and comets should encourage stargazers to escape the city lights this month. Join me in the California Desert November 30, at MOjave National Preserve. We have no chance to See ISON for another week, but there are other nice comets, planets, stars, and dark sky objects too enjoy from dusk to dawn.

The times to look will be just after dusk, low to the horizon at sunset, and higher at dawn for northern latitudes the first half of the month. On December 1, look for a pretty diagonal lineup of the comet, Mercury and the crescent moon just before sunrise in the southeast. Then for the second half of the month, the comet becomes circumpolar. It will appear near the constellation Draco on December 26th, when it is half an a.u. (0.42 a.u.to be exact) from Earth. Will the comets’ tail span a quarter of the sky? I’ll update this as more info is available.

Jupiter reaches opposition January 4th, 2014, and rises earlier in the evening. Venus bright as it ever gets – a whopping magnitude -4.9. It will be a fabulous view – a particularly good astrophoto and sketching target as it grows in diameter, but shrinks in phase. Mars increases in brightness and rises earlier (after midnight). Mars will be a great target for 2014.

That’s all for this year, I’m Jane Houston Jones

Counting meteors from Amboy Crater – Lyrids 2012

jane — Thu, 03 May 2012 20:33:50 +0000

Amboy Crater at dawn

2012 Lyrid Meteor Shower Meteor Profile showing peak near 04h-06h UTC

My visual meteor observing report with 30 minute (or less) intervals, and magnitude distribution

Saturday night, April 21, Mojo and I headed to our new favorite dark sky spot, Amboy Crater, one of the darkest observing locations in the US. This spot has great horizons and its remoteness keeps all but the serious observers away, though we’ve met delightful observing buddies at this spot. Our one way drive from Monrovia, CA is 170 miles, fyi.

After a night of observing, you can’t beat the morning hike to Amboy Crater, a 6,000 year old volcanic cinder cone, either. Even in the summer it’s cool at dawn. Look carefully at the oxidized lava beds as you follow the hiking trail to the crater and you might find some Chuckwalla lizards! Chuckwallas can reach 16 inches in length, weigh up to 2 pounds and are specially adapted for desert living. Chuckwallas are my very favorite herps, well, next to the desert tortoise, that is.

The peak of the Lyrids occured at 1:30 a.m. Eastern (10:30 Pacific). The constellation Lyra was barely above my horizon at that hour. This meant the highest rates were probably recorded several time zones east of my California location. I set up my observing area, shut my eyes until about 11:00 p.m., and then I managed to observe straight through the night — from 11:40 p.m. until just before dawn at 5:16 (6:40h – 12:16h UT).

Here are a few tips I use to prepare myself for a night of meteor counting. First, I read Bob Lunsford’s weekly meteor shower recap on the Yahoo meteorobs group email list which discusses amateur meteor astronomy. It’s a good place to “lurk” and learn.

Bob wrote “The Lyrid (LYR) shower is expected to reach maximum activity on the night of April 21/22 with rates up to 15 shower members per hour. The radiant is located at 18:08 (272) +33. This area of the sky is actually located in extreme eastern Hercules, eight degrees southwest of the brilliant blue-white star Vega (Alpha Lyrae). The radiant is best placed just before the break of dawn when the radiant lies highest in the sky. While Lyrid meteors can be seen in both hemispheres, the north is favored as the radiant lies much higher in the sky. Rates will fall rapidly after maximum and little activity will be seen the remainder of the week. At 48km/sec. the Lyrids would produce meteors of medium-swift velocity. It should be noted that the Lyrids can occasionally produce bright meteors of fireball class magnitude.”

Next I familiarized myself with the spring sky and printed out some all-sky charts, marking the radiant between Lyra’s bright star Vega, and the Keystone section of Hercules. I then decided where to look — 50-70 degrees above the horizon, 20-40 degrees away from the radiant. I selected the area around the bright star Arcturus in the constellation Bootes. When counting meteors you don’t want to look directly at the radiant as the meteors will look like short streaks, or points of light.

For this shower the rates were not expected to be too high, so I decided to record (for my first time) the magnitude of each meteor. I made a note of the magnitude of Saturn, Mars and Venus and re-familiarized myself with the magnitudes of many bright stars nearby during my prep time. Then, I selected two small constellations (Corona Borealis, and the head of Draco) which contain magnitude 2-5 stars and memorized their magnitude.

Armed with all these stellar magnitudes, I settled down and waited for it to get dark. Once it did, I began the first important observation — estimating the limiting magnitude. The limiting magnitude is the magnitude of the faintest star near the zenith that the observer can detect using the slightly averted naked eye. It defines both the condition of the sky’s clarity and the quality of the observer’s eyes. I keep a set of these charts on a clipboard and take them with me on all observing trips, even if I am not observing meteors. Every 30-45 minutes, between my half-hour counting sessions, I re-counted the stars in the selected areas, to note any changes in the sky clarity or the condition of my own eyes.

In a nutshell my skies were Magnitude 6.5, which is very dark. Weather conditions: clear, 98 degrees at sunset, 62 degrees at dawn. It was a shirtsleeve weather night almost all night long, tho’ I put on a fleece jacket at about 4 a.m.

Between 11:40 p.m.and 5:16 a.m. (06:40h – 12:16h UT) I counted 36 Lyrids, 6 Sporadics and 2 Anthelion meteors. A quarter of the Lyrids I saw were very bright -1 or brighter meteors. I took short breaks between counting sessions to re-estimate the limiting magnitude, have a snack, check on what Mojo was imaging through his telescope, stargaze through my own scope, etc.

06:40h-07:10h UT – 7 Lyrids
07:30h-08:00h UT – 3 Lyrids
08:15h-08:45h UT – 5 Lyrids, 1 sporadic
08:50h-09:20h UT – 5 Lyrids, 1 sporadic
09:30h-10:00h UT – 6 Lyrids, 2 sporadics
10:05h-10:25h UT – 1 Lyrids, 1 sporadics, 1 Anthelion
Break to look at Saturn, have a snack, scan Milky Way
10:59h-11:29h UT – 2 Lyrids, 1 Anthelion
11:30h-12:00h UT – 7 Lyrids (2 fireballs!)
12:01h-12:16h UT – 1 sporadic

You can see that I saw the most meteors just as I was getting started (which was near the peak) and again near dawn (when Lyra was at its highest in the sky). Just before 5 a.m. 12h UT both Mojo and I saw a very bright bollide, greenish in color in the western sky. I estimated its magnitude at -5, brighter than Venus. It probably was much brighter. Coincidentally, 3 hours later an even more impressive bollide streaked across the California Sierra foothills, and broke up in the atmosphere, sprinkling meteorites over a wide populated area. Both of these bollides were Lyrid fireballs!

My other Meteor blogs and adventures

Flying through the Leonid Storm of 1999 – aboard USAF’s ARIA from Edwards AFB

Leonids 2002 – aboard NASA’s DC-8 from Dryden Flight Research Center

Observing meteors from the city – yes you can!

My meteor observing gear

January Quadrantids and a demoted constellation

August Perseids and meteor recording tips

Lyrid 4/22/12 fireball movie with radiant map

Mojo’s astrophotography from Lyrid shower night

Viewing meteor showers from light polluted LA – not impossible!

jane — Mon, 09 Jan 2012 05:17:29 +0000

The white area is greater Los Angeles. I observed from my driveway in Monrovia, indicated at the "red/white" border zone marked with cross-hairs

My meteor watching setup - comfortable chair, blanket, clipboard, red flashlights, clock, binoculars, snacks

The graph shows the ZHR (Zenithal Hourly Rate), which is the number of meteors an observer would see under a very dark sky with the radiant of the shower overhead. (this chart is being updated as more reports are submitted)

I prefer to drive far from LA to view meteor showers from a dark sky, but those darn showers don’t always happen on weekends or days I can take off work. So this week, I observed the Quadrantid Meteor Shower from my bright moonlit Los Angeles County driveway until after midnight, snoozed until moonset at 3:00 a.m., then had a fairly decent sky from 3:00 a.m. to 5:15 a.m. when the sky started to brighten from the dawn light. Although I didn’t see many meteors, and only one before the moon set at 3:00 a.m. PST January 4th, I was thrilled with my observations.

Take a look at this colorful map. See that white blob? That’s Los Angeles on a light pollution map. That white ribbon? That’s the California coastline. White on these maps designates the most light polluted areas in the world. There is no worse place for light pollution. LA is the model of a major metropolitan meteor-observing maelstrom of star-obscuring light pollution. This white color on the map is described in bleak terms on the Clear Sky Chart website’s light pollution map page: “The entire sky is grayish or brighter. Familiar constellations are missing stars. Fainter constellations are absent. Less than 20 stars visible over 30 degrees elevation in brighter areas. Limiting magnitude ranges from 3 to 4. Most people don’t look up.” Monrovia is on the north edge of the white blob that is Los Angeles, indicated by the cross-hair. (all those little crosses on the map are other astronomy locations). Red is the next to worst light pollution zone, and the ribbon of red color next to Los Angeles is the San Gabriel Mountain foothills. Monrovia is nestled between the Los Angeles basin and the mountains. It’s fine for moon and planets at our monthly Old Town Sidewalk Astronomy nights, not so good for meteors and anything else astronomical.

The three oval white blobs on the left lower quadrant are Santa Catalina, San Clemente and San Nicholas Islands! The yellow, green and blue zones are in the ocean. It’s even light polluted well off the coast of Southern California!

I usually drive 150-300 miles to one of the black teardrop shaped pin spots on this light pollution map of California. Those are the best and darkest locations for the stargazing and astrophotography we enjoy. Mojo and I prefer Amboy Crater, Hole-In-the-Wall Campground in Mojave National Preserve, and a spot near Desert Center 60 miles past Indio on I-10. We also love the dark skies at Glacier Point at Yosemite.

But this week was the peak of the Quadrantids, and I didn’t want to drive a 6-hour round trip for 3 hours of meteor watching, especially on a work night. So I found a good spot in my driveway and it blocked a lot of the local light sources. I nestled my comfy observing chair up next to a cinder block wall. This wall, plus strategically placed tall trees blocked the moonlight and oncoming car lights from my view. To my south was not the Milky Way, but the milky gray — the color of skies over Los Angeles. I could see the big dipper stars, and part of the little dipper. Below these two constellations was the radiant of the Quadrantids. This area wouldn’t even rise until after midnight, but I wanted to say I observed the Quadrantids during the actual peak, and check for earthgrazing meteors on the horizon.

I estimated my limiting magnitude at a dismal 3.9 using star counting charts. I settled into my meteor-watching chair, sipped some hot green tea and waited. And waited. And waited some more. From 11:00 p.m. until 12:30 p.m (PST) I saw exactly one meteor, and it wasn’t even a Quadrantid. The moon was high overhead now, and so I snoozed until moonset at 3:00 a.m. Wednesday morning.

When my alarm went off, I headed back out to the driveway. I adjusted my chair, adjusted the dark blankets I placed over the fence between my driveway and the neighbor’s all-night security lights. By careful placement of my head, and with blankets on the fences and shrubs I had no lights shining directly at me.

It was a little after 3 a.m. and I started observing an area above the radiant, centered on the bowl of the big dipper. My back was facing the well-lit LA basin, my view to the north was overlooking the San Gabriel mountains and Mt. Wilson Observatory. By 3:18 I had seen my first Quadrantid. At 3:30 I counted stars again. Without the moonlight, my limiting magnitude rose to a respectable 5.1 using this star counting chart. I repeated this exercise several times, until I could barely see stars after 5:00 a.m. My last limiting magnitude calculation before I packed it in was 2.9.

This chart shows the data from 48 observers in twenty countries. Data (still coming in, I’ll update the chart a couple of times) is averaged based on the observers seeing conditions, visual acuity, cloud cover percentage, etc. You can see that the highest rates — at the peak of the Quadrantids were in excess of 80 per hour. This is the number of meteors which would be seen overhead at the zenith (in a dark sky) if the highest rate was kept steady for one hour. In reality, the highest rates last usually for only a few minutes for showers like the Quadrantids with a very narrow peak. How many did I see from my Monrovia driveway? I saw three from 3:00-3:30 a.m. and another three from 3:30-4:00 a.m. I saw five from 4:00 to 4:30 a.m. and between 4:30 and 5:00 a.m. I saw three, plus heard nearby roosters crowing! I finished the observing with 2 more Quadrantids between 5:00 and 5:15 a.m. and was heralded by a veritable rooster symphony as the sky brightened. My total count over a little more than 2 hours was 16 lovely Quadrantids, two sporadics, and one Anthelion! Here’s my report which I submitted to the International Meteor Organization. Amazingly, this number is almost exactly the prediction from NASA’s Meteor Fluxtimator when I entered Quadrantids from downtown Los Angeles on the 3rd and 4th of January 2012. How about that! You can observe a meteor shower from Los Angeles!

Here’s the meteor shower calendar for 2012

Interested in counting meteors? Here’s the IMO Visual meteor observing form plus instructions and FAQs

More about the Quadrantids and their namesake constellation, Quadrans Muralis

Post-Perseid depression (or how to observe meteor showers)

Perseids from Amboy Crater (a dark sky site)

Watching asteroids fly by

jane — Fri, 11 Nov 2011 00:40:28 +0000

It was 23°F inside the observatory while we were observing the asteroid

Asteroid 2005 YU55 sketched November 8, 2011

Asteroid 2005 YU55 wasn’t my first visual observation of an asteroid passing near Earth, but preparing to view it brought back some great memories of our first one, asteroid 2002 NY40, nearly ten years ago.

Here’s a little writeup about both observations. First up, Tuesday night’s observing of Asteroid 2005 YU55. It’s 400 meters (1,300 feet) in diameter. On November 8, 2011 it passed 0.85 lunar distances (324,600 kilometers or 201,700 miles) from the Earth. It has been studied by radar using NASA’s Deep Space Network’s Mars Antenna in California’s Mojave Desert. The Herschel Space Observatory took some measurements in the far-infrared. The Swift Telescope observed it, too. Oh, also legions of amateur astronomers imaged, sketched and observed this “once in-a lifetime” event, including me!

Tuesday afternoon, I drove 100 miles to a friend’s private observatory near Mt. Pinos. I knew as soon as I looked at the sky that I’d never find the asteroid in my telescope. The near full moon wiped out all the fainter stars I’d need for star-hopping to the asteroid. It was 30°F upon arrival, snow on the ground, and it got colder as soon as the sun set – to a low of 23°F.

After an hour, Steve, the owner of the observatory found asteroid 2005 YU55. He was stunned at the movement as it zipped across the eyepiece view. Three of us took turns stepping up a ladder to reach the wide field eyepiece atop his 14-inch reflector. The 1 degree field of view in the eyepiece we used is equal the apparent diameter of two side-by-side full moons. We took turns watching the faint asteroid move for about a minute or two, then letting the next person have a look. It took the asteroid about 9 minutes to traverse the eyepiece field. My sketch shows the asteroid’s motion in about 2 minutes, and this star chart gives you an idea what the we saw in the sky and in the eyepiece.

You can see the constellation Pegasus high overhead on the star chart. That’s where we were aiming. As we tried to follow the faint asteroid in the eyepiece, we each made a triangle out of slightly (magnitude 9 and 10) brighter stars which the 11th magnitude asteroid would pass by. That way we had fixed objects to anchor our view of the motion.

This was no glittering diamonds on black velvet view. The nearly full moon was right next to where we were looking, and it brightened the sky and the ground. Only the brightest stars were visible. “It was a fast-moving ghost against other fixed ghosts in the moonlit background sky”, described Steve. I saw a grey poppy seed moving against a grey felt sky. It made us gasp in amazement that we were looking at it with our own eyes, especially since it was so small and so faint! After an hour or so of viewing, we packed up and headed back home, 100 miles away.

Now, here’s a little trip down memory lane for me – my first asteroid flyby on August 17, 2002.

On August 17 and 18, 2002, Asteroid 2002 NY40 zipped past Earth 1.3 lunar distances – 530,000 kilometers or 330,000 miles away. From 9:30 to 10:30 p.m. on August 17th our deck in suburban San Rafael, CA was filled with telescopes. We invited astro friends over for a spur-of-the-moment asteroid party, gambling that our inland location would be fog-free, unlike many of the usual astro spots.

After a quick dinner, a dozen of us stepped out on the deck. Mojo was the first to spot the swift 9th magnitude asteroid 2002 NY40 in his 14.5-inch f/4.8 LITEBOX reflector. Our friend Jim also found it in his 8-inch LX-10. Our friend Stacy was happy to spot the moon in her new 10-inch dob without a finder. For a good hour we kept the asteroid in Mojo’s scope. All our pals got to see the asteroid whiz through the field of view several times through two telescopes.

Both observations were amazing. You can always go back and look at videos and images, but you only get one chance to see celestial events like these with your own eyes. And I plan to try and observe every once-in-a-lifetime event that I can.

Nasa JPL Press Release about the November 8th close flyby of 2005 YU55

Nasa Science News about the close flyby of 2002 NY40

A Month of Moon Views

jane — Mon, 12 Sep 2011 23:22:07 +0000

Lunar Landing Site Chart - click for larger versions. Courtesy Lunar and Planetary Institute

My photo of a three day moon. East is at the bottom. Mare Crisium is the egg-shaped feature on east limb.

Here's my photo of a five-six day moon, near first quarter. East is at bottom here too. The middle sea visible above/West of Mare Crisium is the Sea of Tranquility, site of the Apollo 11 landing.

Here's my photo of a fourteen day or full moon. East is at the top. Notice the features are less distinct, but look for the long rays spreading out from the two large craters Copernicus (lower middle left) and Tycho (lower right).

Finally, my photo of a 21 day or third quarter moon. West is at the bottom left

Fasten your seat belts. I’m going to take you on a guided month-long tour of the moon and highlight some of my favorite lunar features. You can use this travelog all year to observe or sketch the moon any time the moon is visible. You’ll be surprised how some of the familiar geology you’ll see on our rocky neighbor changes as sunrise or sunset illuminates different sides of crater walls. If you don’t have a moon map, click on the one to the left, or the other one at the bottom.

The visible features I describe will be illuminated by sunlight from the right to the left as shown on this moon chart. It takes 14 days from new to full moon. At full moon the entire disk will be illuminated, then sunset darkens the features night by night, from right to left. Try viewing the same features before, during and after the full moon.

New Moon Phase Day 1 – 6 The moon rises at dawn, and sets at dusk. The new moon phase starts at solar conjunction. This is the starting point of the lunation or period of the Moon’s cycle around the sky. Day 1 is very difficult to observe. On day 2, the “sea” of Crises, Mare Crisium becomes visible. To the south is Petavius, a large crater with a central peak of over 8000 feet. Day 3 brings Mare Fecunditatis, south of Mare Crisium, into view. On day 4, Mare Crisium and Mare Fecunditatis are fully visible, and the walled plain Janssen is visible. On day 5, Theophilus, Cyrillus and Catharina make a nice group of craters. The crater Maurolycus, with a central peak like Theophilus, appears on day 6. The moon is now approaching first quarter. The terminator (boundary between the sunlit and dark parts of the moon) is now at the center of the moon’s disk.

First Quarter Phase Day 7 – 13 The moon rises at noon, and sets at midnight. The crater Hipparchus is at its visible best near the terminator on day 7. Look for two craters within Hipparchus. Day 8 brings into view the rugged Appenine mountains, and to the north the oval walled plain Plato. With binoculars or telescopes, find the “Straight Wall”, a lunar fault line. Tycho and Copernicus are on the terminator on day 9, and so is Clavius, the large walled plain south of Tycho. On day 10 look for the Jura Mountains and Sinus Iridum (the bay of rainbows) with its hook-like curved mountainous point on the edge of Mare Imbrium. This is one of my favorite objects on the moon to observe and sketch. On day 11, look back on the whole moon and observe the dark lunar lava plains divided by mountains. On day 12, look at Gassendi, a large crater with a smaller crater next to it. Together they look like a diamond ring. As full moon approaches, look back over the objects you observed each night and see how different they look.

Full Moon Phase Day 14 – 21 The moon rises rises at dusk, and sets at dawn. Look at the bright ray systems. The direct sunlight on the moon at this phase washes out features, and you see no shadows, just like when the sun is directly overhead on earth. The long rays of Tycho are most dramatic at full moon! Day 15 brings sunset to Crisium, 2 weeks after we first viewed its sunrise. Watch the shadows cast on the walls of the plains including the darkened Mare Crisium, and craters on day 16 through 18. Day 19 is a good one to view the “Sea” of Tranquility, famous as the landing site of Apollo 11. There is a link to lunar landing sites at the bottom of the page, by the way. Day 20 brings the terminator to another of my favorite observing and sketching sites, the three craters Theophilus, Catharina and Cyrillus. Mountains are the highlight of day 21. The Apennines, and the large craters Kepler, Copernicus and Tycho are beautiful at lunar sunset. The last quarter moon has arrived.

Last Quarter Moon day 22 -27 The moon rises at midnight, and sets at noon. You really have to be dedicated to view this phase, or maybe just sleep deprived. Mare Imbrium and Copernicus are darkening on day 23. On day 24 through 27, most observers are sleeping when the moon is visible. Use binoculars to observe earthshine over the surface of the moon. These are the days (or rather nights) to turn your eyes, binoculars or telescopes to other wonders of the night sky: planets, comets, meteor showers and galaxies. Say good-night to our close neighbor. If you didn’t catch all these features, there’s always next month!

A moon map with almost all the features labelled

Check out all 6 Apollo landing sites, plus moon phase/landing site maps on this flyer I made for the GRAIL mission launch week in September 2011. (PDF)

USNO’s great Phases of the Moon and Percent of the Moon Illuminated pages

Here’s the original 1990 article I wrote for John Dobson’s Sidewalk Astronomy newsletter. My mom contributed the adorable lunar drawings.

My Sketches at the Eyepiece website

The Crescent Moon

jane — Sat, 19 Feb 2011 21:47:05 +0000

The moon's summer and winter path, courtesy NASA's Starchild website

The winter's moon - a smiling crescent just after sunset Feb 5, 2011 (click to see moon upper center)

Closeup of winter crescent moon

The summer's "backwards C" crescent moon at sunset, late June 2007 (click to see moon in lower right)

Closeup of summer crescent moon

Have you ever wondered why the crescent moon looks like a smile in the winter and spring and like a backwards “C” in the summer and fall? It looked like a smile right now – below, next to and above Jupiter for several days after the February new moon. You can see the same waxing (getting bigger) crescent in early March 2011. Just look in the western sky after sunset beginning the day after new moon, on about March 5 or 6th. You’ll also see Jupiter and Mercury just above the horizon an hour after sunset.

Early birds can see a repeat of the waning (getting smaller) crescent moon phase a few days before the new moon, too. Look in east the last days of February up until new moon on March 4th. That bright object sharing the dawn skies with the crescent moon is the planet Venus! You can read more about moon phases here on the EarthSky website.

The best way to understand the reason why, is to look where the sun is, and how and where it shines on the moon. Draw an imaginary line connecting the setting sun, the moon, and any other planets that appear in the sky. That imaginary line is the ecliptic – the path the sun takes through the stars. It’s also the Earth and planets’ orbital plane. You can think of it as a projection of Earth’s plane on a sky sphere. The planets orbit the Sun, and the moon orbits the Earth and so you will always find the planetary lineup along the ecliptic.

In the winter and spring, the ecliptic appears almost vertical and arcs higher in the sky. The moons’ lit side faces the sun. That makes the waxing crescent moon look like a smile, or a boat, or the old moon in the new moons’ arms once light reflected off the Earth – called earthshine – reveals the unlit disk of the moon lit by reflected from Earth.

In the summer/fall, the ecliptic has a lower or shallower angle in the sky, and the lit crescent, as always, faces the sun, showing us a lit crescent facing the sun, which appears like a backwards “C”. I could write more, but instead, I’ll let you enjoy the images from our own observing sessions in the winter and the summer, and then get out and see the crescent moon for yourself soon.