As promised, last weekend was the first of two excellent dark sky weekends this month. The weather turned out to be perfect for this one as well.

Jane and I went to our old favorite spot off I-10, Chuckwalla Bench, on BLM land south of Joshua Tree in the Colorado [...]]]> Chuckwalla Bench, Colorado Desert, California, 29 October 2011

As promised, last weekend was the first of two excellent dark sky weekends this month. The weather turned out to be perfect for this one as well.

Jane and I went to our old favorite spot off I-10, Chuckwalla Bench, on BLM land south of Joshua Tree in the Colorado Desert. We were joined by Dave Hasenauer and his dob.

Bad news about Red Cloud Rd., the dirt road we take to our favorite spot. The road is sadly in need of some maintenance. Portions of the road are very treacherous with deep ruts and deep sand. We didn’t encounter any problems this trip, but it will be a worry.

We had crystal clear skies all night, with temperatures around 85°F at sunset, dipping close to 50°F in the wee hours.

The evening twilight featured Venus in its new evening apparition setting in the west, Mercury just below, with Jupiter one day after opposition rising in the east.

Early in the evening while spotting satellites, we managed to catch a bright fireball meteor (7:22 p.m.) probably around magnitude -10. I saw a double terminal burst from the fireball, which traced from Cassiopeia through Triangulum. It left a persistent train that was visible for several minutes in binoculars and Dave’s telescope.

Jane even indulged in a little afocal astrophotography capturing some splendid crescent moon shots on her point-and-shoot camera.

I had a couple of “firsts” in my astrophotography accomplishments, doing my first successful drift alignment when my polar alignment was slightly off, and finally successfully capturing useful “flats” for image calibration in the morning twilight.

I also had a brainstorm about how to process the color data from bright targets without data being clipped in the bright areas. With that in mind, first let me revisit my M31-M32-M110 the Great Galaxy in Andromeda from last week, this time in full color.

M31 from 22 Oct. 2011, 4x15 minute exposures

(For all the images, click the image for the full-resolution version.)

And I promised to revisit the Pegasus 1 galaxy cluster, this time giving it an hour of exposure, which it fully deserved. Here’s the full field first.

Pegasus 1 Galaxy Cluster, click for full-resolution.

The one-hour exposure time cuts down the noise nicely, and calibrating it with a good flat field removes the vignetting. Check out this detail from the center of the cluster at full resolution:

Pegasus 1 galaxy cluster detail

Jane was observing this delightful face-on S-shaped spiral galaxy, NGC7479. It was such a small target that I didn’t think my short-focus 4-inch would do it much justice. It turned out to be a delightful crop with lots of detail.

Detail of NGC7479, click for the full field, 15-minute exposure

Another surprisingly good image came from NGC55, a fabulous extended galaxy, so far south in the sky that it’s rare to be seen by northern-hemisphere astronomers. Complicating matters is a light dome from Inland Empire cities that encroaches on our southern horizon. Nevertheless, my 15-minute exposure was worth passing on. The full-resolution shot is very nice with lots of detail.

NGC55, one 15-minute exposure, through a bit of "foreground" light pollution.

Jane also suggested one of her favorite difficult winter visual targets, NGC2359, known as “Thor’s Helmet.” I collected an hour’s worth of photons. Here’s the detail from the center of the field, click for the whole thing.

NGC2359 "Thor's Helmet," 4x15 minute exposures, detail from the center of the field.

I’ve long been fascinated with distant galaxy clusters, and they’re very difficult visual targets. Some find them to be uninteresting photography targets. I opted to try 30 minutes on Abell 426, a massive distant galaxy cluster in Perseus. Here is some detail from the center, but the full field is full of easter eggs.

Detail from the Abell 426 Galaxy Cluster in Perseus. Click for the full field.

My last target of the evening was to be an indulgent treat, the M81-M82 galaxy pair in Ursa Major. My mount battery finally quit just at the end of the second exposure, and morning twilight was about to arrive. A fabulous end to the evening.

M81 the spiral (a.k.a. "Bode's Nebula"), and M82 a peculiar active galaxy, in Ursa Major

This month is blessed with two very good dark sky observing weekends, and we opted to take the first one at a spot we’ve been thinking about for a [...]]]> Observing report, October 22, 2011

Full photo album with site pictures here.

It's very easy to miss this sign from National Trails Highway, the delightful old U.S. Highway 66.

This month is blessed with two very good dark sky observing weekends, and we opted to take the first one at a spot we’ve been thinking about for a couple of years now.

Amboy Crater National Natural Landmark is a volcano crater in California south of I-40, near the town of Amboy, CA. We first visited the site in the spring of 2010. The hike to the crater was fabulous, and the wildflowers were stunning.

Our regular site at Chuckwalla Bench is also a Bureau of Land Management (BLM) site, but unlike Chuckwalla Bench, Amboy Crater features a paved road, pit toilets, parking spots, and picnic tables. Here’s a Google Maps link to the landmark and its facilities.

The downside is that the drive is about 25 miles longer than the trip to Chuckwalla Bench. It makes for about three-and-a-half hours driving each way.

Astronomically, Amboy Crater is one of the darkest locations in the state, with frequently clear skies and sometimes overly hot conditions.

Mojo set up for astrophotography with Amboy Crater in the background.

This past Saturday evening had a nearly perfect forecast. We arrived on a hot dry afternoon, and enjoyed shirt-sleeve or light jacket conditions all evening with a crystal clear sky. We were joined by one other astrophotographer (Robin), and two seasoned visual observers (Cliff and Steve).

My astrophotography is extremely casual. Living in the midst of Los Angeles county, I have no desire, nor is there much reason to, have a permanent observatory of any kind. We’ve both become adept at hauling our portable observatory to locations that offer good dark skies.

Actually we have quite an advantage over astronomers in the eastern half of the U.S. The California deserts offer excellent astronomy, and are within a few hours drive of home.

My telescope is an Astro-Physics Traveler, 105mm aperture (about 4 inches) with a short f/6 focal length. The mount is an Astro-Physics Mach-One GTO “go to” mount, and my camera is an SBIG ST-4000XCM, the perfect camera for my style of casual astrophotography. It’s a “one-shot color” camera, meaning I can shoot and process color images in a relatively short time, with extra processing to extract the data from the Bayer matrix. It wouldn’t be the best sensor for doing astrometrics or narrow-band imaging with specialty filters, but it’s great for playing around and taking pretty pictures (or trying to!).

I had shot M31, the Great Galaxy in Andromeda, before, probably with my Canon 20D DSLR, but I wanted to take advantage of my wide field and gather an hour or so of data and see what I could get.

I enjoyed watching twilight fade and set up with a very good polar alignment. By now I’ve managed to learn the quirks of Software Bisque’s CCDSoft, and was able to calibrate the autoguiding with great success.

After returning home, I discovered that my first 15-minute exposure was not useable! The brighter stars in the image were fogged, probably by condensation on the CCD sensor glass. I have this mental image of bringing a telescope full of relatively moist L.A. basin air out to the desert, cooling the chip down to -5° C, and having every drop of moisture in that air condense on the chip.

After the first exposure, the combination of the imager fan and the dessicant plug mounted next to the chip managed to pull out all that moisture and leave me with a dry and clear chip. The dry desert air kept me clear for the rest of the evening.

Here is a luminance-only (monochrome) rendition of my M31 the Great Galaxy in Andromeda

The Great Galaxy in Andromeda, M31, with M32 and M110 nearby. 3x15 minute exposures, luminance only. (Click for full 2048x2048 resolution).)

Now after going to all the trouble of having a one-shot color camera, why am I presenting a monochrome rendition of M31?

I have a processing problem with the color version that I haven’t resolved yet. This galaxy has an enormous dynamic range, and this monochrome image is compressed down from a 16-bit master luminance image.

I’m only able to process the color information with 8-bit dynamic range. And my processing skill isn’t yet strong enough to preserve the color data when compressing it down to computer range. Here is the color version of this image. Note that the galaxy core is completely clipped to white in the color data, and I’m left with an ugly yellow ring around the core.

It’s an interesting problem, and I’m sure that I can find a way to do some “high dynamic range” (HDR) techniques to recover that color data near the core.

At that point, Jane called me over to see an interesting emission nebula she was observing visually in her 17.5-inch dob. The nebulosity was just detectable visually, and I really wanted an image to compare. Fun object, full of Milky Way stars, the nebula, and even some dark nebulosity in the upper right.

NGC7380 emission nebula and cluster, 3x15 minute exposures

Jane hunted down comet C/2010 G2 (Hill), a magnitude 10 interloper. It was a very difficult visual observation, but she nailed it, and I saw it as well.

10th magnitude comet C/2010 G2 (Hill)

Meanwhile Jane was also tracking down interesting galaxy groups, and had fun searching the fairly distant Pegasus 1 galaxy cluster in her 17.5-inch. I couldn’t resist imaging this as well.

My own misfires only left me with one usable 15-minute exposure of this fascinating galaxy group. Even with just one 15-minute exposure and lots of noise, it’s fun to see how many galaxies you can find in the full-resolution image. The two brightest members are magnitude 12.

Here we go from a relatively nearby solar system object, comet Hill, to a 200-million light-year distant galaxy cluster!

The Pegasus 1 galaxy cluster, one 15-minute exposure. Click for the full-resolution version, and see how many galaxies you can find in the somewhat noisy image.

Now I was just playing around. As it turns out, the Pelican Nebula was well placed, and The Sky 6 told me it would just fit in my field of view. This emission nebula is most famous for being “that thing next to the North America Nebula.”

The Pelican Nebula, one 15-minute exposure

One of my favorite visual targets is the enormous nearby open cluster M35 in Gemini in the winter Milky Way. Part of its appeal as a visual target is seeing the ten-times more distant open cluster NGC2158 which is about the same actual size as M35. The image didn’t disappoint.

Open cluster M35 in Gemini with distant sister cluster NGC2158. 2x15-minute exposures.

Finally, even though it’s almost cliché, I had to see what I could do with M42 the great Orion Nebula. It actually turned out to be a delightfully pleasing image. Sure the trapezium area is blown out to white, and maybe I can work out a way to recover that, but it sure is a fun picture. B^)

M42 the great Orion Nebula, 2x15-minute exposures

The snow-capped peaks were beautiful from the Foothill Freeway

It had been several months since our schedule, the weather, and the moon phase all cooperated to give us a chance to get out to our favorite astronomy spot. Jane and I, joined by Dave Hasenauer, ventured [...]]]> Click here for the full photo album with lots more pictures.

The snow-capped peaks were beautiful from the Foothill Freeway

It had been several months since our schedule, the weather, and the moon phase all cooperated to give us a chance to get out to our favorite astronomy spot. Jane and I, joined by Dave Hasenauer, ventured out to the Colorado Desert with promises of a chilly evening but mostly clear skies. The snow-capped peaks of San Jacinto and Gorgonio mountains were calling to us from almost our first moment on the road.

Twilight on Chuckwalla Bench

During our twilight setup, some fellows from Arcadia stopped to check out the equipment. Dave was all set up and ready to show Jupiter if we could find it. While hunting in the twilight glow, we all exclaimed as a flock of probably 100 geese were approaching from the west. The geese turned out to be our guide to Jupiter! They flew right in front of the planet, and gave our eyes a convenient focus target. We all enjoyed the view through Dave’s big dobsonian.

Jane had plans to attack the faint periodic comet 103P/Hartley, famous for its huge outburst of a year ago. Jane and Dave both claim to have found the glow of the incredibly diffuse comet. I tried for an image of it myself, but was convinced I didn’t have anything. This is my shot, with the comet buried deep in the winter Milky Way in Monoceros.

Can you find the comet?

Can you find the comet? Here’s a full-resolution crop of the center of that field. Look right in the middle, and try to ignore that my focus wasn’t especially good for this picture!

Look for the faint cotton ball in the center.

I was delighted that most of my hard-won imaging skills hadn’t been completely lost during the time away from it. I didn’t get a perfect focus for my first couple of shots of the evening, the comet Hartley photo above being one.

Even with a less-than-perfect focus, this one of the Rosette Nebula in Monoceros turned out pretty well. This is only 30 minutes of exposure, and it’s pretty clear this object would benefit from a couple hours of exposure time.

The Rosette Nebula, click for the full frame

The Cone nebula is another one that could benefit from a lot more exposure time, but at least by now I’d corrected the focus. I love this beautiful field, with a vast mix of Milky Way stars, emission, reflection, and dark nebulae. The “cone” that gives the nebula its name is near the center of the image. This is also two 15-minute exposures stacked.

The Cone nebula in Monoceros, click for the full resolution image.

A bright supernova was discovered just a couple weeks ago in small distant galaxy NGC 2655 in Camelopardalis, very high in the northern sky. Jane and Dave both enjoyed hunting it down, and the nova is bright and easy, itself as bright or brighter than the rest of the galaxy. Of course I had to get an image, here’s my crop of the field with the supernova marked.

Supernova in NGC 2655, click to see the whole wide field image.

Finally Jane suggested this great pairing, “The Owl and the Cigar,” she called it, M97 the Owl Nebula paired with galaxy M108 in Ursa Major. I only got one 15-minute exposure of this field, as the clouds were starting to move in, but I loved the colors in the Owl nebula, and the detail in M108. It’s fun to contemplate the difference in their distances, with the Owl being the gasping exhalation of a single star in our galaxy, and M108 being billions of stars in a very distant galaxy.

The Owl and the Cigar, M97 (top) and M108, click for full resolution

The first half of the night was interrupted several times by loud flights of two or three helicopters passing nearby. We speculate that they may have been in service to the border patrol, using infrared or intensified imaging. Our little site must have been interesting to see from their vantage point.

Pre-dawn Chuckwalla Mountain with the moon and Venus

By the time the sky show was interrupted by clouds, we all were tired and cold and felt like we’d had a full evening. Amazingly it was only 11:00 p.m.! We all tucked ourselves into warm sleeping bags to catch a few hours of sleep. Meanwhile the sky cleared again for spectacular pre-dawn show of the moon and Venus. We all got up to enjoy the old crescent moon, Saturn, and watch for Mercury to rise over Chuckwalla mountain.

With the local star finally clearing the horizon, we packed and headed off to breakfast at Chiriaco Summit. By the time Jane and I arrived back home in Monrovia, it was raining!

P.S.: In the photo album linked here, I included some detail photos of my astrophotography equipment, with captions, for the benefit of some friends who’ve wondered how these things happen.

We hadn’t expected to be able to observe during this part of the summer from Chuckwalla Bench in the High Colorado desert south of Joshua Tree, but this August night’s forecast at Desert Center [...]]]>

These cumulus clouds were nearly stationary all evening, making quite the light show with an electrical storm

Observing report, August 7, 2010

Chuckwalla, CA

We hadn’t expected to be able to observe during this part of the summer from Chuckwalla Bench in the High Colorado desert south of Joshua Tree, but this August night’s forecast at Desert Center looked very inviting. The forecast high there was 101°F with a low of 74°F. I believe our actual location is at a higher altitude; it always seems at least a couple of degrees cooler.

It was forecast to be breezy though, and that can make it uncomfortable to observe as well as blow telescopes and tripods around. We did have some periods when the wind was a nuisance, but for the most part it was pleasant t-shirt and shorts weather all night long.

I caught this great lightning bolt from the distant electrical storm, with the camera on a small tripod and the bulb left open for a while.

We had crystal clear transparent skies overhead all night, with a great sugary Cygnus Milky Way transiting high overhead mid-evening, but there was an interesting weather phenomenon happening some number of miles north-northeast of us.

As the sun was setting, we had this great view of some towering cumulus clouds catching the sunset glow to the northeast. Over dinner I thought I saw a lightning flash in the clouds. As it turned out, throughout the evening all the way to 2:00 a.m. we were entertained by a sometimes massive electrical storm that seemed to be nearly stationary. I caught this one good lightning strike off in the distance. The full-res version is a crop from the center of a very large picture.

It was also to be a fun evening to see a planet grouping in the west, following the sun to the horizon. I caught this great shot of bright Venus, with Saturn to the upper right, and Mars to the left. To the far left is the bright star Spica. Click to see the great full-resolution picture. In binoculars, Mercury was also visible, but deep in the red sunset glow well out of the field of this picture. In a few days the crescent moon will join the trio for another good picture.

Bright Venus grouped with Mars (left above) and Saturn. Click for the full 4MB experience.

I did take a couple of interesting piggyback Milky Way pictures. My focus wasn’t perfect, and the white balance doesn’t seem quite right. They are mostly untouched except for some slight darkening of the blacks. They are both five-minute exposures on my stock Canon 20D. I think if this camera were modified to remove the deep red filter, the red hydrogen-alpha glow of the North America nebula would show more.

Cygnus Milky Way, north with bright Deneb to the lower left from center.

And here is a late-night shot of Cassiopeia.

Cassiopeia reclines in the summer Milky Way. The "double cluster" is visible near bottom center.

And of course I did some exposures through the Astro-Physics Traveler as well. Here is the Swan Nebula, M17, four ten-minute exposures, ST-4000XCM one-shot color camera. Click on each for the full-resolution image.

M17 also known as the Swan Nebula or Omega Nebula.

I knew that the Ring Nebula, M57, would be an almost silly target for a telescope with this wide field of view. It would appear as a tiny donut swimming in a field of Milky Way stars, just as it often does visually in a telescope. Of course that made it irresistable. Here is the full field:

There's the Ring Nebula, M57, just right of center.

And now as you can see in a crop at full resolution, it’s not a bad image at all. This is three ten-minute sub-exposures (30 minutes total).

Full-resolution crop from the wide field above, M57 the Ring Nebula.

Finally I wanted to get one of Jane’s (and my) favorite Cassiopeia star clusters, one discovered by Caroline Herschel, and known as the Magnificent Cluster, NGC7789. This scaled down version is not terribly impressive, but the full-res image is a treat to swim around in.

The Magnificent Cluster, NGC7789, in Cassiopeia

On a techy note, for the first time I started to have some issues with haze forming on the chip. Given the presence of those nearby cumulus, I guess I can’t always count on the desert air to be completely water-free.

Besides the great deep sky and planets, of course we also had lots of meteors from the forward edge of the Perseid meteor shower. Jane did some great counts, and I enjoyed some bright meteors while the shutters were open.

‘Til next time …

Happy Independence Day!

This weekend wasn’t our usual dark sky new moon weekend; there would be a third-quarter moon rising just at midnight. With summer sunset at 8:00, and no real dark sky until about 9:00, we were looking at [...]]]>

Jane snapped this shot of me shortly after sunset, squinting into the bit of wind we had.

Happy Independence Day!

This weekend wasn’t our usual dark sky new moon weekend; there would be a third-quarter moon rising just at midnight. With summer sunset at 8:00, and no real dark sky until about 9:00, we were looking at a really short (for us) desert observing session of about three hours. Next week is when all the big June star parties are being held.

The weather was fair, not too awfully hot, or too awfully windy, just a little of both. The sky was brilliantly clear, and seeing was not particularly good. Sometimes we just say WTF.

This was one occasion when I was glad to be living “in the future.” I somehow managed to completely wedge the ASCOM driver that lets my laptop communicate with the telescope mount. That’s the kind of thing that really eats up the clock when the moon is about to chase away your dark sky!

Right there in the middle of the desert, I was connected to the net by USB tether to my Motorola Droid. (Thank you PDANet!) I posted a plea for help on the Astro-Physics User Group mailing list. The author of the driver responded to my post and helped me set it right within an hour.

I had time for maybe two short exposures of a couple of objects, and Jane badly wanted a piggyback shot of Scorpius. That would be my first priority, and I had fun shooting it. I used a fixed-focus 35mm f/2.0 lens on my Canon 20D, and the big constellation just barely fit in the frame. We have a fairly strong light dome to the south from the Inland Empire. I cropped the shot just below the constellation where the light is strongest.

The fishhook of Scorpius fills the frame, with lots of Milky Way and dark nebulae throughout. Some light glow to the south.

Jane had the “Bug Nebula” NGC6302 on her observing list, and I tried a shot of it myself. It’s a tiny thing relatively speaking, so there’s not much to see in the full field. There’s one interesting object in the lower left corner which could be another planetary, or possibly an artifact of my own creation. It only shows up well in one of my two sub-exposures.

That little red blob in the middle is the "Bug Nebula." There might be another planetary in the lower left corner, that or an imaging artifact.

Here’s a cropped version at full resolution of the bug itself. Jane’s view in her big dob was actually very nice.

Not very impressive, but it somewhat resembles the visual view we had through Jane's big dob, minus the red color

With only a little time left before moonrise, I wanted to see what I could get of the nebula around Rho Ophiuchus. It’s only one ten-minute exposure, and you’ll find lots of impressive images of this region out there on the net. I’m still tickled with what I was able to capture.

One ten-minute exposure of the Rho Ophiuchus region

Finally the moon put an end to the dark sky observing, but moonrise itself was quite an event. The moon was joined quickly by Jupiter to the south. Jane has a great afocal shot taken through the eyepiece of her Televue Ranger. You’ll have to see that one on her observing report!

Moonrise with Jupiter over Chuckwalla Mountain. There's a light from the microwave station on Chuckwalla Mountain just below Jupiter to the right of the moon.

Update: Jane wound up using most of my astrophotos below in her July NASA What’s Up podcast. Check it out!

The forecast was for a very temperate desert evening, so six of the Old Town Sidewalk Astronomers headed off to the Colorado Desert to play outside all night. Seeing was [...]]]>

Mojo, Caroline, Jane, Catherine, Gary, and Todd

Update: Jane wound up using most of my astrophotos below in her July NASA What’s Up podcast. Check it out!

The forecast was for a very temperate desert evening, so six of the Old Town Sidewalk Astronomers headed off to the Colorado Desert to play outside all night. Seeing was forecast poor, but actual conditions seemed much better.

Jane packed her 17.5-inch dob, and I loaded the Astro-Physics Traveler 102mm f/6 refractor to do some astrophotography. The highlight of the evening promised to be comet McNaught 2009R1, but it wouldn’t be available until the pre-dawn hours. That left me with late spring galaxies and summer Milky Way targets. (Jane also had a great target which she’ll be writing about!)

I tried the M84-M86 region of Virgo last month with the AP180, but the field of view was too narrow. I knew it’d be a good warm-up for tonight. The grey scale version looks better to me than the color rendition.

M84-M86 region in Virgo, "the Nine Gals"

Jane and I both love piggyback pictures, taken at “naked eye” scale. This is one of “the teapot” and the Sagittarius Milky Way. The full-size image isn’t bad, but it looks better scaled back a bit. Click for the really big version. It’s fun looking through all the dark nebulae and bright clusters.

Looking towards the center of our galaxy.

Deep in the Milky Way just above the spout of the teapot is Barnard’s famous “Ink Spot” dark nebula, B86.

Barnard 86 "The Ink Spot"

I started out trying to fit M8 “The Lagoon Nebula” in the same field as the nearby Trifid Nebula, but they wouldn’t quite fit. So I did 15 minutes just on M8, and love the result.

M8 The Lagoon Nebula and cluster

I love hunting for the Pipe Nebula, a huge dark nebula best seen in binoculars. Seeing the Pipe is a portent of great transparency and dark skies. The detail photo here is centered on the Pipe, taken piggyback with the 20D. Click for the full field, see if you can find the Pipe there.

Do you see the pipe outlined here? Click for the full field.

Ever since I started doing astrophotography, I’ve been waiting for the opportunity to shoot M16 The Eagle Nebula. This nebula is famous for its Hubble Space Telescope image showing the embedded dark nebulae as stellar nurseries, the “Pillars of Creation.”

I only did one fifteen minute exposure. By then it was getting quite late, and I need to catch a couple hours of sleep before getting up to catch comet McNaught. Naturally that means I had an airplane fly through the image! Should I wipe it out with Photoshop? Naaaah.

M16 The Eagle Nebula and cluster. Plus United flight 2037. (Just kidding!)

Jane and I napped for a couple of hours, with alarms set to catch comet McNaught in the early hours

This image of McNaught is made from ten one-minute exposures. They’re stacked with the comet centered, so the background stars are streaked. It looks out of focus, but it’s actually just the motion of the comet you see.

Comet 2009R1 McNaught, ten one-minute exposures stacked and centered on the comet.

I also took my ten comet pictures and made a little animation that shows the motion of the comet against the background stars over the course of 15 minutes or so.

Comet McNaught moves against background stars over fifteen minutes. The sky is also brightening with dawn towards the end.

I was also taking piggyback images of the sky where McNaught was lurking. Can you find the little green dot near the center?

This is the "naked eye" view of the sky where Comet McNaught can be found. The horizon is tilted as an artifact of the way the mount holds the telescope and camera mounted piggyback. Click for the full scale version.

Here’s a little close up of the beautiful binocular cluster Collinder 39 in Perseus with the green dot of McNaught just to the right. The color was evident in binoculars even.

This is somewhat the view in a pair of binoculars of large open cluster Collinder 39. See the green dot of comet McNaught slightly up and right of center.

What a fabulous night of astronomy! Shirt sleeves or light jacket all evening.

Mojo setting up his "desert office" for some astrophotography

Equipment notes: The telescope shots were taken with an SBIG ST-4000XCM one-shot color CCD camera, at prime focus of an Astro-Physics Traveler 105mm f/6 refractor. The mount is an AP Mach 1 GTO on a wooden tripod. The piggyback photos were taken with an unmodified Canon 20D digital SLR camera.

Update: Be sure to see Jane’s A Ten Planet Night report from the same evening!

Jane and I were by ourselves for the dark sky weekend of November 14, 2009. We set up at our usual spot at Chuckwalla Bench. Unlike the past two months, this night featured a cold air mass that [...]]]>

Photo from Feb. 2009 of the Astro-Physics Traveler getting ready for a night of imaging at Chuckwalla Bench

Jane and I were by ourselves for the dark sky weekend of November 14, 2009. We set up at our usual spot at Chuckwalla Bench. Unlike the past two months, this night featured a cold air mass that required bundling up well. It also implied that the seeing from our desert location might not be perfect.

Jane brought her 12.5-inch Litebox dobsonian, and I opted for the 4-inch Traveler refractor (seen in my heading photo).

The night turned out to be beautiful. The seeing was good, and we were able to enjoy a few early Leonid and Taurid meteors as well. My goal was to try getting more exposure minutes on some classic targets, and try to get some piggyback constellation photos as well.

M33 and Triangulum region

Triangulum, Aries, and Andromeda, piggyback naked-eye resolution

The famous Pinwheel Galaxy, M33, was a difficult object for me when I started out in astronomy with a classic 8-inch Celestron SCT. The face-on spiral is enormous in the sky, covering almost as much area as the nearby Great Andromeda Galaxy. But its surface brightness is low, so with a little magnification it’s possible to look right through the galaxy without seeing it. I later learned that it sometimes shows up better in binoculars than a telescope.

If you click on the naked-eye resolution photo nearby, you can find M33 as a faint smudge just to the left of center. M31 the Andromeda Galaxy bright core is in the upper left.

The three bright stars of Triangulum are in the lower third, just left of center. The bright stars of Aries are also in the lower third, to the right of center. (Might be fun to use Flickr’s photo tagging feature to highlight the features.

M33 the Pinwheel Galaxy

Again “click to embiggen” as Phil Plait would say. This image is a stack of four 15-minute exposures with the AP Traveler and the SBIG ST-4000XCM one-shot color CCD camera. I love seeing the famous red star-birth regions sprinkled through the arms of this nearby galaxy.

In terms of technique, I used a Bahtinov focusing mask for the first time. It saved a lot of time in finding and maintaining focus. Autoguiding worked perfectly. It felt really good to have confidence to take long sub-exposures and stack them in Photoshop. This was my first true one-hour image, and the first I’m proud to have seen at full resolution.

Auriga and IC 405

Piggyback view of Auriga, naked-eye resolution

Auriga was one of the first constellations I identified and recognized on my own as a new astronomer, so I’m always delighted to see it again.

In the piggyback shot, the bright Auriga stars form a squashed pentagon slightly left of center. The right-most star doubles as part of Taurus. North is to the left, and the brightest star there is Capella. In the full-resolution image you can see the Milky Way open clusters M36, M37, M38, and I think that’s M35 in Gemini in the lower right.

Jane was enjoying touring through targets in this part of the sky, and spent some time attempting to see visually the difficult target IC 405, the Flaming Star Nebula. (Her companion post on the subject is coming soon.) I was intrigued as well, and took 30-minutes of exposure time on IC 405. It’s not visible in the piggyback view, but is found in Auriga near the upper center of the picture.

IC 405 the Flaming Star Nebula

I wasn’t familiar with this target, and the 30-minutes of data here shows only the brightest areas of this faint nebula. Longer exposures and a Hydrogen-alpha filter will show the nebulosity extending out to the left and curling up like a huge comma. This was a really fun target, and I’m looking forward to Jane’s discussion of it.

Orion, the Flame and the Horseshoe

Orion, piggyback naked-eye resolution

Finally I wanted to see if my little 4-inch refractor could possibly do justice to one of the most popular astrophotography targets. Here in my naked-eye resolution piggyback photo is the Orion constellation, with its famous bright star-birth nebula near the dead center of the photo.

The target I had in mind wasn’t the Orion nebula itself, but two very different nebulae near the left-most belt star Alnitak (Zeta Orionis). Just to the left of Alnitak is a bright yellowish nebula called the Flame. In a telescope it shows a lot of detail, looking almost like tire tracks. The full-resolution picture of the constellation has just a hint of the flame. If you already know it’s there, you might be able to see it.

For my piggyback photos I used my Canon 20D digital SLR camera, mounted on top of the AP Traveler. I shot 5-minute exposures, and tried to subtract a 5-minute dark frame, which doesn’t seem to make much difference.  The camera does leave behind a reddish glow which I’ve removed in Photoshop.

Just below Alnitak is the Horsehead nebula, also known as Barnard 33. Seeing the Horsehead visually is a fun and difficult project, requiring really good transparency and a fairly large telescope. Jane observed it visually in her 12.5-inch.

The Flame and the Horsehead in Orion

I never dreamed the image would turn out this nicely. The big white bright blob just above center is Alnitak. In the lower right is Sigma Orionis, one of my favorite multiple star systems. Of course the bright Flame is just left of Alnitak, and dark nebula B33 is just below center.

Just as with M33, this image is made up of four 15-minute exposures. The telescope is a 105mm f/6 Astro-Physics Traveler, with an SBIG ST-4000XCM one-shot color CCD camera. The mount is the AP Mach-1 GTO on wooden tripod, and I did autoguiding and image capture with Software Bisque’s CCDSoft. I used SBIG’s CCDOps software to process the Bayer-matrix one-shot color pixels out to luminence and RGB components, combined the L and RGB components in Photoshop, then stacked the four color images for the final photo.

It was another perfect new moon Saturday for a trip to our favorite spot in the Colorado Desert out I-10.

Yes this is a very full Grand Caravan!

Jane and I happily took out all [...]]]> Full photo album of setting up and astrophotos here at the Whiteoaks Photo Album.

Update: Here’s Jane’s version of the same evening.

It was another perfect new moon Saturday for a trip to our favorite spot in the Colorado Desert out I-10.

Yes this is a very full Grand Caravan!

Jane and I happily took out all the seats of the old Grand Caravan and filled it with telescopes and gear. We brought her 17.5-inch Litebox dob, and our AP180EDT f/9 refractor.

Jane has been indulging my dabbling in astrophotography lately. I’ve been delighted that Jane is using some of my astrophotos for the What’s Up podcast, lucky that she wants imperfect images that are closer to what one might actually see in an amateur telescope.

This 180mm f/9 refractor should be an outstanding astrograph; it’s certainly an amazing visual astronomy instrument. I dabbled with it a little last year in Anza Borrego, knowing I needed to learn a lot of operating technique to get some good results. I solved a few mechanical problems then, and ran into autoguiding calibration later. Those lessons served me well, even though it’s almost a year later.

Early in the evening was Jupiter time, and we all spent some time soaking up the gorgeous views through a binoviewer in steady seeing. 300x on Jupiter showed lots of detail in the bands, including a nice red barge in the North Equatorial Belt, and nice little disks and color on the moons.

I’m going to take a few paragraphs to talk shop, gadgets, problems, and solutions.

Setting up the AP180, all ready to take flats, except there's no known focus position!

My camera is an SBIG ST-4000XCM single-shot color CCD camera which perfectly suits my recreational needs. The big AP180 is mounted on an older 900QMD mount, a simple but stable platform without GOTO electronics or servos.

The 900QMD mount comes with digital encoders on the R.A. and Dec axes, but having spent several years using this telescope for primarily lunar and planetary observing, those encoders went unused for the life of the mount.

The R.A. axis encoder is removable so you can use a polar alignment scope, and the encoder shaft has a slip fit into a metal sleeve when it’s in place. Last year I discovered that this mechanical connection slips very easily, rendering the encoder useless.

The trick I settled on, which worked again tonight, was to cut a little piece of rubber band and push it into the fitting to serve as a tightener.

Jane aligns the Telrad on her 17.5-inch Litebox

To use the digital encoders for pointing, I acquired a BBox from JMI, connected that to a USB-Serial adapter, and used Software Bisque’s TheSky 6 to serve as my controller. I’ve learned by experience (at Fremont Peak observatory) that the alignment doesn’t need to be 100% perfect. I’ve learned the trick of syncing the software and encoders to a bright star near my target, then doing an accurate short slew to my actual target.

(One problem I haven’t quite solved yet is play in the polar scope. I haven’t figured out how to tighten the polar scope in position, in the correct orientation, so it doesn’t wiggle.)

So with a not-quite-perfect polar alignment, autoguiding becomes my essential partner. CCDSoft can be tricky software to work with when calibrating the autoguiding. The error messages and manual don’t really help solve problems like “Illegal motion in X-axis, error 352.” I thought I might even be dealing with a problem in the mount mechanics. In retrospect, I think I also hadn’t learned the correct switch settings on the QMD controller. (“Guide” and “.5″ works much better than the 16x slew mode for visual!)

On perusing the Software Bisque support forum last week, I was able to learn that their autoguiding calibration depends entirely on there being only one bright star in a large region of the guide imager. While I could see the guide motions working perfectly and orthogonal, the software doesn’t do matching of the star field, only looking for the one significant guide star.

Having discovered that, I was finally able to successfully calibrate the autoguider. And with one successful calibration (remembering to set the current declination), I could autoguide on different targets successfully for a long time.

(The Software Bisque manuals hint that there’s a way to link to TheSky so CCDSoft knows the declination of its target, but I haven’t figured that out yet.)

M74 two 15-minute exposures, SBIG ST-4000XCM, 180mm f/9, October 17, 2009

Pisces was high overhead, and I love M74, so I decided as a first target to revisit that favorite. I settled on 15-minute exposures. The first one came out “double vision” when the autoguider momentarily lost track during the exposure, but that was the only time that happened during the evening.

NGC7541 in Pisces, 15 minutes

A visit to the Night Sky Observers Guide suggested NGC7541 as a Pisces “showpiece,” and I love galaxy groups. This one was gorgeous in Jane’s 17.5-inch, too.

NGC7640, 15-minute exposure

Jane showed me NGC7640 in her 17-inch, a really lovely look, and I thought it would be a great target. We’re starting to enjoy comparing visual and imaging views.

NGC253, 2x15minute exposures

I admit I get impatient when I’m imaging, and want to collect more targets rather than more exposures on the same target. As a result, I have a little more noise in my images, but I’m having fun anyway. That said, I couldn’t resist spending some time on NGC253, the Silver Coin galaxy. I had a tantalizing glimpse of this target last year at Anza Borrego when I hadn’t yet learned how to make the autoguiding work. This time I got two lovely 15-minute exposures. Well worth it.

Pre-dawn crepuscular rays at Chuckwalla Bench

After a few hours sleep, we were greeted with lovely pre-dawn crepuscular rays, Venus, and Saturn making its return after solar conjunction. Not to worry, the telescope was capped, and about to come down into its box, anyway. (You can see the box ready to be loaded with telescope.) Jane paused to take this lovely picture.

On nice modern monitors, you can really enjoy the full resolution of your pictures. Jane and I just replaced our old Viewsonic CRT monitors with some [...]]]> The world is full of wallpaper managers for every operating system out there. I enjoy wallpapers taken from some of my digital photography, such as this trip to Yosemite last year.

On nice modern monitors, you can really enjoy the full resolution of your pictures. Jane and I just replaced our old Viewsonic CRT monitors with some nice Dell 23-inch LCD models.

Immediately I saw that I needed to regenerate our collection of wallpaper photos to match the aspect ratio and higher resolution of our new monitors. I admit to being a stickler for my wallpaper photo albums. I have these requirements:

• I want to scale and crop the photos to fill the screen exactly, no tiling or stretching.
• I want no black bars, letterboxing, or distorted aspect ratios
• I want to dim the maximum brightness of the photos so my desktop icons are still discernable

My Canon 20D full-resolution pictures have more than enough pixels to fill the biggest screen, so I cobbled together a shell script some time ago using the PBM (Portable Bitmap) tools that have been around since probably the 80′s for manipulating images. I don’t think many of the Linux distros install the toolset by default, but they’re easily available. On Ubuntu or Debian you can install them with “apt-get install netpbm”.

I start by making a work directory (“wallpaper” in this instance) and a subdirectory to hold the full-resolution original images, named “full”. I collect copies of my full-resolution pictures there in ~/wallpaper/full.

Next I need to work out the transform. My original resolution images are 3504 pixels wide by 2336 pixels vertically. My monitor is 2048 pixels by 1152 pixels.

Rather than work out the math, I just scaled an original picture to the monitor width to see how tall it would be. This command pipeline would scale a picture to 2048 pixels wide:

jpegtopnm full/IMG_1234.jpg | pnmscale -width 2048 | pnmtojpeg >IMG_1234.jpg

Opening that scaled image in Gimp told me that it was 2048 x 1365. That tells me that I need to crop some lines from the top and bottom of the image to fit them exactly to my monitor field. 1365 – 1152 leaves 213 lines to cut from the image. With the pbmtool “pamcut” I plan to cut 107 lines from the top of the image and give it a total height of 1152.

So I made this shell script to process all of the photos. The plan is to read all of the files from the “full” directory, and write perfectly scaled images to a subdirectory named “2048″. I’m also going to use the “ppmdim” utility to reduce the overall brightness of the images just a little. Here is the final script, called “mkwall2048″:

for i in `ls -1 full`
do
echo $i
jpegtopnm full/$i \
 | pnmscale -width 2048 \
 | pamcut -top=107 -height=1152 \
 | ppmdim 0.8 \
 | pnmtojpeg >2048/$i
done

This loops through every file in the “full” directory, putting the filename in variable $i. The rest of the script is a pipeline that feeds the image through five different tools from the Portable Bitmap collection, as follows:

1. jpegtopnm converts the input file to a portable “any” map, then feeds it to stdout
2. pnmscale scales the image to a width of 2048 pixels, preserving the aspect ratio
3. pamcut slices off the top 107 lines, and preserves the next 1152 lines of the image
4. ppmdim reduces the brightness of the image by 20% (80% of the existing brightness)
5. pnmtojpeg converts the portable bitmap image back to a JPEG file

I’ve adjusted this script using the same process to make perfect wallpapers for my laptop monitors and desktops at work. It’s a real treat having a slideshow of my favorite photography available behind my work.

I love to make panoramas almost anywhere I take the camera. There are some examples on last week’s Mojave National Preserve trip, a weekend at Moonstone Beach, and the Fremont Peak Star-B-Q.

Making them smoothly takes a little practice, so I thought I’d pass on my pointers. I use a Canon 20D [...]]]>

Moonstone Beach in Cambria, CA

I love to make panoramas almost anywhere I take the camera. There are some examples on last week’s Mojave National Preserve trip, a weekend at Moonstone Beach, and the Fremont Peak Star-B-Q.

Making them smoothly takes a little practice, so I thought I’d pass on my pointers. I use a Canon 20D and Panorama Factory.

Panorama Factory is so good at stitching together the pictures, you really don’t need to make any special effort at leveling the camera. No tripod is required, just turn and shoot. But a little preparation pays off later.

Once I’ve found a spot to take a panorama, I mark the beginning by taking a black frame: Turn off auto-focus, put the camera in manual exposure mode, then cup my hand over the lens to make a black frame.

The pano pictures will blend best if they all have the same exposure. I’ll use the built-in light meter while panning around the scene, and try to pick a median setting that doesn’t go more than one stop or so toward over or under exposing. In a lot of scenes with a brightly lit portion, this might be a challenge.

I try to avoid using the widest-angle setting of my lens to avoid any vignetting, and like to choose a “50mm equivalent” focal length, which is 35mm on my Canon 20D. You might also turn off auto-focus to keep the camera from suddenly focusing close if you sweep across a foreground object.

You don’t always have a horizon line, but it’s a handy reference if you do. My Canon 20D has auto focus targets in the viewfinder that serve as a nice leveling tool. Work from left to right and give each shot a little overlap. That’s about all the care you need to take.

I’ll end the series with another black frame. Don’t forget to put your camera back into auto-focus and your preferred exposure mode. A low ASA setting will help keep the noise low.

I shoot all my pictures in RAW mode, so they have to be processed into JPEGs. I use Adobe Lightroom for that. Generally if the exposure and white balance look good, the pictures shouldn’t need any adjustment. If some adjustment is needed, the panorama will come out best if you can apply the same adjustment to all of the photos. Lightroom’s copy and paste settings feature is useful for this.

Once you have your collection of individual shots, you can start through Panorama Factory’s wizard to begin stitching them. Since you shot from left to right, the filename order will be correct when you import them to Panorama Factory.

(I’m still using V4 of Panorama Factory, so some of these settings might have changed, but I’m sure the basics are still valid.)

Remember you can import all of the pictures with one step, by doing a multiple-select in the file browser. (I always make an individual work directory for the pano pictures.)

After the import, select “Fully automatic” photo stitching, set the camera type, and yes to “Automatically detect focal length.” DO select “Correct barrel distortion,” and DO NOT select “Correct brightness falloff.”

Yes, do select “Automatically fine tune.” But do NOT take the recommendation to allow Panorama Factory to do exposure matching or exposure correction. You took care of exposure matching at the time you took the shots by selecting one manual exposure for all of the pictures. And, at least in V4 of Panorama Factory, I’ve found that it tends to posterize the image when it does any exposure adjustment.

Say “yes” to sharpen the final image. I use a setting of 50%, but feel free to experiment.

For an output format, I select “Image file only,” and set either “Partial” or “360 degree” panorama as appropriate for the series.

Here’s one note, if you select 360 degree panorama, and you have a full overlapping frame on each end, Panorama Factory sometimes does not find the 360 degree point and duplicates part of the image. Deleting one shot from the pano on either end will solve the problem.

I typically use the “Spherical projection.” Not sure why.

I have other tools for printing, so all I want out of Panorama Factory is the image. I’ll select “Prepare image for internet display” and “Maximum size.”

Now when you click “Next,” Panorama Factory will work its magic for a few minutes. Save the image at the end. When it’s all done, I’ll use Photoshop or VuePrint to make thumbnail versions for my photo album, usually 800 pixels wide.

Admittedly I need to try this with V5 of Panorama Factory, but I bet the process will be close.

Once you develop a rhythm for making panos, you’ll enjoy making more of them.  I always take the laptop along on a road trip, and frequently I’ll make the panoramas right there in the car while Jane drives.

I’ll try to make another post on how I mix them into a JAlbum photo album.