Friday, September 24, 2010

A Batty Sunset

Melinda had a night off tonight, and one of the things we always wanted to do one summer evening is to head down to Campbell Avenue where it crosses the Rillito River (more properly a wash this time of year). We don't get the local paper, but we found from the Internet that the annual Bat Fest was held September 11th this year, so we missed that. The colony of Mexican Free-tailed Bats migrate south of the border for the Winter, so we needed to go soon. This evening was perfectly clear and mild, so it was time to pull the trigger!

We chose to take one of the access ramps down to the river bed and as soon as we were under the bridge, we saw the signs - bat poop! You can see the accumulation in less than a week, since the rain we got last weekend had the Rillito flowing. Looking up you couldn't see them in the dark crevasses of the bridge structure, but you could hear them (Melinda thought it was a hummingbird twittering sound), and the camera flash illuminated them as they prepared for a night's feeding. I recall reading that this colony has a few tens of thousands of inhabitants, and since we live less than 2 miles away, the bats that frequent our neighborhood likely call this bridge home. They are certainly welcome visitors - the 1.5 million bat colony in Austin Texas is estimated to consume 5 to 15 tons of insects every evening! They certainly contribute to the lack of summer pests in the Tucson area.

Finally the sun set, twilight fell, and Jupiter, a couple days past opposition (the point opposite the sun as seen from Earth), popped into visibility low over the Rincon Mountains. Melinda and I picked our positions, not knowing quite what to expect, since this was our first time attending what is, of course, a daily event.

And then suddenly the unheard signal was sent and the hordes were released, filling the air with swift-moving fluttering shapes. It was dark enough that it was difficult to freeze their motion without using the flash, but clouds of them were seen in silhouette against the twilight glow in the west. The display seemingly went on for many minutes, and I had time to experiment with different methods of capturing them on camera, most not very successfully. We'll definitely be back to experience it and try again to capture better images. And as I pointed out to Melinda - it was about the cheapest "date" you can have in Tucson!

The story even has an astronomical ending! After getting back to the car, we thought for a couple minutes about dinner. We headed the couple miles over to Red Lobster. Parking, we had a perfect view of the rising moon split by Thimble Peak. Of course, the camera was stowed, but in 30 seconds I'd reassembled with telephoto lens, guessed the right exposure and still caught it with a bit of the thimble in silhouette. Picking a different parking spot, we would have missed it all together. A perfect ending for a happenstance evening!

Thursday, September 23, 2010

Bloomin' Season Winds Down

We've got two fishhook barrel cacti in the front yard, and other than size (one is about 10" high, the other 24") they look identical. However, the smaller one (rescued from the bottom of a Mexican wash) blooms in the Spring, the larger (rescued from a bulldozed desert road) is a Fall bloomer. This larger one has been blooming for a couple weeks now, but with the shorter days, I hardly get home from work in time to see them open, and just about the last buds are showing themselves. The yellow fruit are from a year ago, the green ones are from this year's flowers just closed. The smaller, springtime bloomer is visible at upper left. It will be sad to see the end of the desert flower season, but the cooler temperatures the shorter days bring are welcome to just about everyone. It is nice to see the week's extended forecast and see double digits! We've not been over 100F in a couple days now!

Tuesday, September 14, 2010

It's a Bird, It's a Plane...

Occasionally I keep a watch on for good passes of the International Space Station (ISS) or for Iridium Flares. Seen from a dark sky, they can be quite spectacular, but even from town they are fun to hunt out.

I noticed a few days ago that the ISS would make a good pass over Southern Arizona tonight. Starting at 7:36pm in the NW, it would spend 4 minutes crossing the sky until entering the earth's shadow in the SE. I've tried to image it, but it always seems disappointing. Tonight I had planned to do it from Kitt Peak while visiting a friend observing on the 90" telescope, but between my cold and Melinda's call to come in to work tonight, I thought I'd try it from town again.

The 8mm fisheye lens that the club has on long-term loan has an ultra-wide field of view, so used it on my Canon XSi. In test exposures shortly before the ISS appearance, skyglow in town dictated that I drop the ISO to 200, and f-stop to F/4 to keep from saturating the detector in a 4 minute exposure. The 5-day-old moon got hidden behind my neighbor's palm tree. Right on schedule, it appeared below the Big Dipper and swiftly crossed the sky, much brighter than Jupiter low in the SE. I always think there should be a sound associated with it, like that of an airplane, but no, dead silence... It made it to 75 degrees high, nearly overhead. In the photo the summer triangle is visible overhead, a distorted view of the Big Dipper at lower right, Cassiopeia upper right. I got lazy on processing, and used Photoshop's "auto color correction", thus losing the peach-colored glow of local light pollution. There are a few ghost images of bright lights on my neighbors' houses.

These days, amateurs are not content just to watch the passes, but image the ISS through telescopes equipped with webcams or video cameras. Surprisingly good results can be obtained, though I've not tried it (yet!). There are also programs to allow you to catch it crossing the face of the sun or moon! Fun stuff!

Arizona After Dark (Part 2)

After Friday night's adventure on Kitt Peak, Saturday we were to head down to the Tucson Amateur Astronomy Association's new dark-sky site, the Chiricahua Astronomy Complex (CAC). Developments have moved very rapidly the last 18 months as the land was bought, donated to the club, and an initial development that includes bathrooms, showers, and parking for about 30.

It was our first trip to the location since development had begun, though it had been open to several star parties through the spring. On Saturday, we were a bit hesitant since there were abundant high clouds, but thought we'd enjoy the road trip and check it out.

We arrived just after sundown and had to jockey for a parking spot - about 20 cars and over 30 people, I'd estimate. We jumped to setting up the 14" Celestron, and our astro-buddy Christian rolled up and set up next to us. John Kalas offered a tour of his personal observing site, about 200 yards away. It was quite impressive - framing started yesterday on his roll-off observatory with 4 piers and living quarters.

We did a little visual observing and also took some fisheye pictures of the sky. Of course, the thin high clouds made the light domes from nearby cities look much worse than on a clear night. But we were able to do some observing through the clear zones. The first picture taken to the south with the 8mm fisheye (and using Christian and his 16" to block the neighbor's light) shows Douglas due south, the setting 4 day old moon to the west, and Jupiter brilliant in the east. The Milky Way blazes through the cloud cover. All exposures are 60 seconds with the 8mm fisheye @ F/2.8, ISO 1600.

Similarly, I also took a shot to the north. Again, scattered clouds block some parts of the sky, but the Big Dipper, hugging the horizon and Polaris are in the clear. There are some small light domes I've not identified. Willcox is off the Dipper's handle. Just east of north must be the Fort Bowie National Historic Site. The glow between them is as yet unidentified...

It is going to be a great site - even now with the goodie tray that John Kalas set up in the water heater room was a great place to congregate while on bathroom breaks or to wait out the clouds. It is a longish drive, but once we've got sleeping quarters and some big scopes there, it will be a Mecca for astronomers!

Arizona After Dark!

We're just past the last dark-of-the-moon, the best time for amateur astronomers to get out under dark skies and not have to worry about light pollution caused by the moon. We've only got to deal with man-made light pollution! This last Friday, Melinda and I went up to Kitt Peak to try to image an Iridium Flare that would appear over the 4-meter telescope.

While we had the best of intentions to arrive early and set up, rush hour traffic conspired against us and I opened the shutter seconds after the peak brightness. Clicking on the image and looking above the 4-meter dome, you can see the fading streak of the satellite, not nearly the -7 magnitude predicted.

While we were up at the mountaintop, we took a few snapshots of the domes there. Since I work for Steward Observatory, I stayed close to their section of the mountain, since I'd not gotten permission from Kitt Peak to roam over their area. In the deepening twilight, brilliant rising Jupiter dominated the eastern sky with the lights of Tucson and rising fall constellations. Included here is the straight shot, then an annotated image is enclosed to point out some things to look for. Tucson has grown mightily the 5 decades since the observatory was founded, but Phoenix to the north has a bigger sky glow than closer Tucson.

Just up the hill a bit from where we parked to the south is the historic 36" Spacewatch Telescope. This telescope was originally housed on the University of Arizona Campus in the '20s, and was relocated to the darker skies of Kitt Peak in 1962. Since the 80s, it has been utilized by the Spacewatch Project to look for near-earth asteroids and comets. The program, now expanded to a nearby 72", has been very successful. We took the opportunity to shoot our Milky Way galaxy behind it in this 40 second exposure.

Also visible a few yards away was the setting crescent moon, with a planetary alignment to the west. Besides the moon, with it's dark side visible from earthshine, was brilliant Venus to the left, orange-tinted Mars at center top, and bright star Spica at center. All were setting in the west over the village of Sells, the capital of the Tohono O'Odham nation, within which the Observatory is located.

Another few yards from where we parked was still another view of the 4-meter telescope. A 90 second exposure showed the dome lit up by the Milky Way, and the glow of Tucson from the right. Visible to the left of the dome is the North Star Polaris, and to the right is Cassiopeia. Just after I opened the shutter, I spotted a flare from a satellite catching sunlight as it tumbled. Besides the bright flare, it came back into view a few seconds later and is visible in the image. An annotated image is again provided to point these out.

We finally finished off the photo-ops provided from the Steward 90" parking lot, so we headed down to a clearing partway down the mountain where we had planned to shoot the comet 103P/Hartley. We set up my 11" in the dark, and I quickly acquired it in the eastern sky (it is actually in Pegasus, in the Tucson lights shot above, but too faint to be seen). I had some issues with the telescope mount, and didn't get the exposure series I had hoped for, but one decent exposure showed it pretty well in a 3.5 minute exposure. It is quite extended and difficult to spot, but is supposed to get much brighter the next 2 months, approaching naked eye visibility!

I almost forgot to mention our rarest of sightings! When relocating a couple miles down the mountain, as we passed milepost 11, we spotted an animal heading into the grass. Melinda pointed and said "Coyote", but it had a long feline tail. I saw the rear haunches and tail of a mountain lion! I don't recall ever seeing one on the mountain in my hundreds, if not thousands of trips up to the Observatory, so it may have been my first. I've seen bobcats, ringtail cats, fox, deer, coyote and rattlesnakes, but no lions. They are not endangered, but they are so solitary they are seen rarely. Melinda was a bit spooked to be out alone afterwards, but I knew it was long gone and wouldn't bother us. But I was stoked to see one!

Sunday, September 12, 2010

Catching Up...

We've been a little remiss in updating the blog lately. It was a slow week, both of us at work, and then the weekend started and we've been running ever since! We've lots to post, but scant time and energy at the moment, so look for more tomorrow.

In the meantime, our summer rainy season seems to have ended. We've had lots of clear nights the last couple weeks. Clouds have returned and partially spoiled the weekend observing, but they are not part of a typical monsoonal flow. It makes for some pretty sunsets, though, and I captured a few shots tonight. With drier desert to the west, clouds only typically advance a little past Tucson, letting the sun set in clear skies, resulting in the traditional spectacular Arizona sunsets.

Sunday, September 5, 2010

Picnic + Observing = Star-B-Que!

Last night was the Fall version of the TAAA's twice-a-year cookout and star party up at the Kitt Peak picnic area. We started doing this way back when I was club president in the mid-90s and we are currently allowed upwards of 60 people, but almost never fill up. It is always a great time to meet at such a great location - you couldn't ask for better skies, full use of a pavilion, gas grill, flush bathrooms, and great friends with which to hang out. I'm guessing we had about 35 members on this excursion.

Bittersweet emotions this trip as we found out that our friends Thom and Twila Peck lost his father earlier in the day (back in our "other home town" of St Charles, IL), and it was the last hurrah of another friend, long-time newsletter editor and star party volunteer George Barber. George finally found a job after a 4 month search, but unfortunately, is leaving us for northern Utah.

When I first heard of holding the event so early in the fall, I thought for sure we would be doomed by monsoon rains, which usually extend to mid-September. After anxiously watching the weather all week, the resurgence of moisture got pushed back further and further and it turned into a spectacular evening with moderate temps. We started out with a surge of mosquitoes right about sunset, but the evening bats moved in and the insects fled for cover - no longer an issue.

I decided to break out my 11.25" Newtonian telescope, all home-made except the mount. It has been years since using it - I've been spoiled by the Celestron 14" plus Hyperstar for wide-field imaging and short exposures. The 11" has a little longer focal length (about 1 meter compared to 650mm), so gives a little closer view of night time objects, but at F/4 isn't a lot slower, so exposures still stay short. Melinda chose to use an 8" Celestron on an alt-az mount that simplifies moderate magnification viewing, but without a go-to, she had to work harder with a star chart to find her way around the sky! I had planned to spend time collimating the optics, but after the rough alignment at home, it didn't need any, so the first object was the 36" Spacewatch telescope atop the mountain in the fading dusk. Just under a mile away, note the star rising behind it it slightly out of focus with the long focal length!

While the star party atmosphere can be fun, being in close quarters in such a dark sky has it's issues. I'm sorry, but your loud classical music "bugs" me - I'd rather hear the rhythmic chirping of the crickets than "The Planets" or the loud grinding of go-to scopes (do they make mufflers for those things?). Bringing your dog to a star party? Come on - I know they are family members, but given the relatively good chance of encountering a snake, skunk, scorpion or other denizen on THEIR turf, the idea of bringing them is questionable. And lights - it is a star party after all, yet the bright lights (just because they are red tinted does NOT make them ok if they are blinding!), and back up lights without warnings is just rude! The exodus at 9:00 seemed a little early to me, 45 minutes after it got dark... Oh well, rant mode is now OFF...

I had not intended to do any serious imaging, just getting into the familiar swing of things after not using the ole' Newt for so long. And with the occasional wandering TAAA member, it was nice to show what the DSLR (even a 5-year old Canon 20Da) can do. So I shot a couple sequences of familiar deep-sky objects, mostly 2 or 3 minutes exposures, and a couple exposures to stack and beat down the noise at the ISO of 1600. First up are M8 and M20, the Lagoon and Triffid Nebulae. These are very slight crops from the full frame, and show the predominant red glow of hydrogen clouds along the Milky Way. The Triffid contrasts the red glow with a nice blue reflection nebula in the northern section. The Lagoon is 8 minutes of total exposure, the Triffid is 10 (one extra 2 minute exposure).

Another popular objects in telescopes last night was the Veil nebula - a supernova remnant where a star running out of fuel blows off part of it's mass into a shell of gas. It is an impressive, though faint object in large, low power fields, and for all the world looks like a ghostly Cheshire Cat smile against a rich star field in the constellation Cygnus. A reasonably sized image like this or larger resolves the nebula into twisted filaments of red (again, from hydrogen) and blue (a mix of hydrogen, oxygen and other elements). This is an uncropped image, since this eastern arc of the Veil barely fits...

And someone requested a galaxy image, though they never returned to see the results - a shot of NGC 7331 with nearby companions, and a half degree to the upper right, is a galaxy cluster known as Stephan's Quintet. Both of these objects have north to the left, as opposed to north up in the above images. The Veil is 14 minutes total exposure, the galaxies have 24 minutes.

And last, but not least, while working nearly alone (only the Kalas', Paul Lorenz, our friend Donna and we remained) I searched for the "bright" comet P/10 Tempel, shining at just over 9th magnitude in Cetus, low in the southeast at 1am. It is nearly opposite the sun from us, so you can imagine looking down the tail from the stellar-looking nucleus. I couldn't find a suitable guide star in a minute or two of looking, so just let the scope track for 6 - 90 second exposures, for a total of 9 minutes. When stacking on the comet nucleus, you can see it's northward motion trailed the stars into little streaks. Unfortunately, this comet is not getting any brighter and will fade as it recedes from both the sun and from us.

An appropriate conclusion to a great night's observing, we got home by 2:20 and after downloading pictures, hit the pillow about 3am. A fun time!

Wednesday, September 1, 2010

Road Trip!

For years we had talked about going to Bisbee. After a while, it got to be an inside joke - whenever anyone mentioned it, Melinda lamented "Dean won't take me there", which was untrue, just hadn't gotten to it! So Saturday, with an open day we finally made it!

Bisbee was incorporated as a mining town 130 years ago, located on veins of copper, silver and gold atop the Mule Mountains. Supposedly at one time in it's heyday, it was the largest city between St Louis and San Francisco. But the boom times passed and in the '70s it was discovered by hippies and artists, and that funky community spirit remains more than a generation later. To borrow a phrase, the town seems an embodiment of Keillor's "The town that time forgot and the decades cannot improve." There is a lot of history here, with 100+ year old Victorian architecture, displays of mining equipment and museums, and in fact, tours of underground mines are all popular. The "Lavender Pit", named after a mining engineer, not the color of the rocks, is just east of town, and is one of the first strip mines.

The population currently stands at just over 6,000, and it is the county seat of Cochise County. Built into the hills and canyons, it stands over a mile high and offers a welcome respite from the desert heat of Arizona. The curved streets are full of antique stores, art galleries, restaurants and realty offices. There is an abundance of empty storefronts too as the recent economic downturn had people coming to town less and hanging on to their money. On a walk up "Brewery Gulch" in search of a place to eat, we spotted a painted bench that matched my tie dye shirt, parked under an "art installation".

After an early dinner, we took off for the 100 mile return drive to Tucson. We had to be back to feed the livestock, since we had only planned on a day trip. Melinda found a few items of interest in browsing the antique stores - a fabric swatch book and a straw hat were her prizes. Interestingly, a couple weeks ago she had been looking for a marble top end table for our Illinois bedroom, and had difficulty finding what she wanted. In Bisbee she saw over 6 of them! My gem of the day was an optical gizmo listed as a "Russian Scope", and it was obvious the owner didn't know what he had. It was a little inspection microscope, with 2 objectives providing 25X and 50X, with a nice calibrated scale and well corrected eyepiece - complete with Russian manual for $35! We've spent lots more for plastic versions at work that don't work nearly as well, so I was very happy. We'd be happy to return for a visit, perhaps planning to stay overnight next time to give time for more exploring!