Back at Home

The central portion (~4 arcmin.) of one of the images of the
72-inch. The asteroid is moving along the red line and is
identified by the green circle.  Three of the comparison
stars used are identified in the image.

I have arrived back at home with a hard drive full of pictures and data.  Although we processed our data every day to see what we had and to evaluate if we needed to change observing strategies, the final processing is yet to come.  We plan to do a process of converting the instrumental magnitudes we obtained of the asteroids to the standard system of magnitudes determined back in the 1960's.  There are now multiple magnitude systems, but we will stay with the Johnsons-Cousins system since we used those photometric filters on the 72-inch.  In the future, everyone will be using the Sloan filter set made famous by the more recent Sloan Telescope.  However, for the next couple of years, we do not have sufficient comparison stars in all fields to do this.  We can always go back and reanalyze our data later if we see the need.

I use Brian Warner's program Canopus to analyze the asteroid data.  This is quickly becoming the industry standard.  Brian Skiff at Lowell uses it for all his work.  We got 3 or 4 nights on the two asteroids, which is not enough to accurately determine the rotational period.  However, the Near Earth Asteroid is easily bright enough to obtain more data from GMARS, and my new 16-inch is just barely large enough to follow the Trojan.  From a 72" to a 16".  I guess beggars can't be choosers.

A Trip to Happy Jack

Dome of the Discovery Channel Telescope

Today was a busy day.  After stumbling out of bed, we met some of Lowell's staff for lunch.  I worked on our data from the night before while Linda prepared for her colloquia (talk given by a visiting astronomer).  She gave a talk on the English astronomers John Goodricke and Edward Pigott who discovered the periods of the first variable stars.  John Goodricke was deaf and died at age 21.


In the audience was one of Linda's former students from MIT.  He was working for the USNO, and was just hired by Lowell to be the chief scientist to interface with the engineers building the new 4.3-meter Discovery Channel Telescope in Happy Jack, about 40 miles south of Flagstaff.  Steven offered to take us down there on a personal tour, which we gladly accepted.



Steven told us that although slightly behind schedules, he expects the DCT to get first light sometime this year.  We got to see the aluminized mirror still in the container, the actuators which will keep the 4 inch thick mirror in perfect shape, and the mount as it is being assembled within the dome. We toured the control room and got to walk out on the catwalk to see the magnificant view.



Best Night of the Week

The 72-inch Perkins Dome in the moonlight

Finally, a good day in northern Arizona, not that we were conscious much to enjoy it.  The next time they want to make a zombie movie, they just need to film on location at an observatory.  The observations to date on the Near Earth Asteroid and the Trojan were both interesting, but not definitive at this time.  More observations are required, and we will get some this night.

We were warned that the guider was swapped out on the 72 inch during the day.  That resulted in some electrical issues and a runaway dome.  When we arrived in the early evening, we could not get the dome to find its home position.  The technician drove from town, and got it synced, but could not explain what happened.  He also focused the guider, which was then off.

Jupiter, Venus, Mercury (faint), and Mars (fainter) at Dawn

Technical issues aside, we were back in business as the last of the afternoon clouds burned off.  Brian Skiff was taking spectra on the 42 inch telescope and dropped by to talk photometry.  I later went over to the 42 inch dome to see his spectra program.  It is a continuation of a program started at Mt. Wilson many years ago.   He is getting several spectra of 114 solar type stars each year.  The idea is to see how they compare to our own sun.  Our sun has an 11 year solar cycle and created the Maunder Minimum from 1645 to 1715.  Do other solar-like stars do the same?  They figure they will need 50 years of data to get good enough statistics.

Clear night at last

Linda shows the Navajo students how the telescope works.

So far, our expectations for the quality of the skies is batting zero.  Whenever we think it will be a good night, it is not and vise versa.  Tonight we thought we would be completely past the bad weather caused by the low pressure system passing through Northern Arizona, yet some of the clouds and humidity lingered into the night.  We also thought bringing 50 Navajo middle school students plus their teachers into the dome would be a mess.  That worked out better than I thought.


The kids had spent part of the day touring Lowell Observatory on Mars Hill before coming down to Anderson Mesa Station.  As it turned out, one of the telescope operators arrived late, so Linda and I were pressed into service to operate the 72-inch and teach the kids about what we do.  The kids arrived on a school bus and were broken up into six groups, which were rotated between six stations.  We let them move the telescope and send commands over the computer.  Most were excited about slewing a telescope as large as their school bus.  As often happens, the teachers had more questions than the kids.



Students crowded into the Warm Room.



After the kids left, we got started on our Near Earth Asteroid while waiting for our Trojan asteroid to rise high enough to observe.  The NEA (one of the larger ones) was last observed 25 years ago from Sweden.  That lightcurve got a very high rating and has nothing in common with the one we got Monday night.  We shall see if this data sheds any 'light' on the situation.  The humidity started out at about 50% but by 3 AM, had risen up into the 80's.  We toughed it out with our target disappearing over the horizon as Nautical Twilight flooded the sky with light.  We left the dome in our review mirror while watching the planetary conjunction to the east.

Nearly Skunked

Brian Skiff examines a Palomar Sky Survey plate from 1955.

In the morning, we went up to Mars Hill to use Lowell's library to find a paper from 1993 on the Near Earth Asteroid we were observing before midnight.  For some reason, that article has not been scanned so is not available online.  It took less than a minute to locate the journal on the many shelves and find the paper.  After analyzing our data from the night before, Brian Skiff and Larry Wasserman wandered by.  Brian had found some old Palomar Survey plates in the Lowell archives.  On the light table, we looked at a plate taken by George Abell in January 1955 which had his hand notes about globular clusters in the Fornax Galaxy Cluster directly on the plate.

 

After dinner, we headed down to Anderson Mesa Station.  We knew that our night would be delayed in getting started because the Lowell docents were bringing a group of 14 Navajo middle school students went through the 42-inch and 72-inch telescopes.  Linda and I ended up passing out hot chocolate and answering questions. 

 

The 72-inch Telescope at Anderson Mesa Station.

When we did get going, we were nearly skunked. When we started the telescope at about 8:30 PM, the humidity was 78 percent and climbing. The operating rules says the dome must be closed when the humidity gets as high as 90 percent. The humidity steadily rose over the next hour. I wanted to get a few observations of the Near Earth Asteroid in case it turns out to have a long period, which we did. However, after only three images, we had to close the dome.   At about1 AM, the humidity was at 93 percent and still climbing. We with clouds headed our way, we called it a night and  got nothing on our primary Trojan target.

 

Tonight, the docents are bringing 50 students. That will likely be a mess, but they promise to be gone by 9:30 PM.

First Full Night at the Telescope






After getting in at a reasonable time the night before because of the weather, I stayed up to try to acclimatize to the observing schedule.  Today, after sleeping in I was hunkered down in the motel room watching rain, hail, and then snow out the window while I worked on an abstract and paper for the upcoming DPS meeting, which is due at the end of the month.



In the 72-inch Control Room

Things were not looking great for the night when Linda and I went out to dinner with a couple of the Lowell astronomers.  We arrived at the 72-inch at dusk to see skies clearing.  We got through the telescope and camera start up routines without much trouble, and were pleased to find our evening target, a Near Earth Asteroid which a suspected binary.  In 1993 it was reported to have a 2.4 hour rotational period, and we observed it about that long.



After midnight, we switched over to our primary target, a Trojan asteroid on the leading edge of the Trojan swarm.  It is on the edge of the Milky Way in a crowded field - a real test for StarBeGone, a routine in our analysis software that can remove background stars that are polluting the light from the asteroid.  Figuring it was time to refocus the telescope - disaster struck!  Disaster always strikes after your support team has gone to bed.  In this case, the camera control software did its nightly crash. The computer crashed when we tried to activate the focus program while the telescope was still guiding.  It took a while with diminished brain capacity to realize what we had done, but once we did, it only took a few minutes to reboot everything.  On we went.  As I write this, we are well into imaging the asteroid with about two hours of darkness left in the night.  Not bad for a night we considered a wash!

Out on Anderson Mesa

Tonight was our first night on the 72-inch telescope, and we spent the morning at the Lowell library settling on our targets.  Unfortunately, we were the only ones there on a Sunday morning, and nobody left the Wifi password.  After retreating back to our motels, that evening, we went 12 miles south to Lowell's Anderson Mesa Station. 

At Anderson Mesa is the 31-inch, the 42-inch Hall Telescope, and the 72-inch Perkins telescope whose dome is shown to the right.  We were concerned for this night's observing run because we had been seeing weather reports all day predicting clouds and perhaps rain for the evening.  We still had plenty to do.  The Prism camera had just been remounted on the telescope and would need to be focused before we could take some dome or sky flats.  Also, we had to get familiar with the telescope.  Linda used it back in January and thankfully had a notebook full of instructions.  All of the software was custom written and much of it command line driven.

Larry Wasserman came by early in the evening to check us out on the telescope.  After about 45 minutes of - first flip this switch and then push that button, and then fill the CCD camera with liquid nitrogen chilling it down to -113 C.  Larry then quickly ran us through starting up the various pieces of software while warning us that the camera control computer often crashes every night requiring a 5 minute restart.

All this time the wind was howling outside, gusting to 40 mph.  We pointed out that the manual said we could not open the dome slit with gusts that high.  Larry responded 'really?' and called Brian Skiff to find out if the manual was outdated.  It turns out that it was - the only consequence of the high winds would be that we might not be able to guide and have poor images.

After making our way through several forgotten steps, we slewed to our first target and watched a star bounce around on the guiding screen.  However, we locked on, and the telescope managed to get a passable image measuring 3 arcseconds.  Linda thought that was terrible, but I reminded her that was a good night at GMARS.  All this time, Larry had me watching the Doppler Radar which revealed that a rain shower was headed our way, so we beat a hasty retreat.  With all of the forecasts predicting clouds for the rest of the night, we decided to call it a day and will try again tomorrow.  The forecasts were right.  It rained off and on in Flagstaff for most of the night and we continued to get snow flurries into the next day.

The Lights of Flagstaff

It is Sunday morning, and our first night on the 72-inch is tonight.  The 72-inch Perkins Telescope is located at Lowell's Anderson Mesa Observing Station, about 12 miles south of Flagstaff.  It was established in 1959 as the observatory's dark sky site away from the lights of town.

Even though Flagstaff has 58,000 people, it is as dark as they come for a town of that size.  This is because over the years, it has established aggressive light pollution ordinances.  In 1958, Flagstaff passed what is believed to be the first light-pollution legislation in America. This ordinance prohibited "the use of certain commercial searchlights within the city limits" with a misdemeanor fine of $300 or "imprisonment in the City Jail not to exceed 90 days."

A lighting code was adopted in 1989 establishing dark zones. It was updated in 1992 and 1999. A sign code adopted in 1997 now manages commercial sign design and that mandates light lettering on dark backgrounds instead of the typical dark lettering on bright panels. 

Ralph Megna and I visited Flagstaff last year and were struck by how dark it seemed in the main street in town.  Of course, our eyes were not dark adapted.  Still, it was quite an achievement.  Last night I walked to the Barnes and Noble and took a brightness reading with my Sky Quality meter from a dark corner of their parking lot.  I got a reading of 19.05 magnitudes per square arcsecond with a 4 day old moon in the sky.  As a comparison, my backyard in Rancho Cucamonga normally measures around 18.0 to 18.3 magnitudes.  GMARS will typically be around 21.3 on a moonless night.  I will get a reading from Anderson Mesa later this week.

Flagstaff in a picture taken from Mars Hill in June 2003.  Route 66 crosses town just to the left of center.

(Get Your Kicks On) Route 66

I headed out this morning for the six hour drive down the Main Street of America - Route 66.  Route 66 passes through Rancho Cucamonga where I live.  It then goes through Fontana, Rialto and up through the Cajon Pass.  From there it parallels the 15 and 40 Freeway into Arizona.  To the right is an old gas station which can be found in Ludlow off the 40 Freeway.

Route 66 was first established in November 1926 and was originally 2,248 miles from Chicago to Los Angeles.  It was realigned many times in its existence changing its length. Route 66 was removed from the highway system in June 1985 after much of it was bypassed with modern freeways.  Portions of the road still exist and is now designated "Historic Route 66" with historic districts and business associations being created to promote the small towns along the route.  You can see several of these districts along the way to Flagstaff.

I picked Linda French up at the Amtrak Station Flagstaff.  Later tonight we are having dinner at Larry Wasserman's house.  Weather forecasts are calling for rain or snow on Monday.  Yuck!

A Target Poor Environment

Observing runs are often planned around factors that extend beyond when targets are best observed.  In this case, work and teaching schedules were determined when we could use the 72-inch.  However, early May 2011 is not the optimum time for observing Jupiter Trojan asteroids.

As I mentioned in a previous post, Trojans are divided into to two camps that share an orbit with Jupiter.  The Greek camp proceeds Jupiter in its orbit by 60 degrees and is now on the western horizon at sunset.  The Trojan camp follows Jupiter in its orbit and rises after midnight.  These camps refer to how the asteroids are named; from either Greek or Trojan characters from Homer's the Iliad.  There is a Greek and Trojan 'spy' in the opposing camps.

In planning our observing list, we considered if we could observe any of the early evening Trojans.  However, complicating the mere two hour observing window was the issue of the Moon passing through the area early in the week.  No matter what we did, we could not obtain multiple nights on any of the asteroids from the Greek Camp.  Then the coup de grace; we got an email from one of the telescope operators saying that the asterisk beside our time on the telescope schedule meant that the early evening was blocked for some college students and that we would have access to the telescope at 9:30 PM. That settled that, a late dinner it is.

So we are now searching for targets to observe before the Trojan camp is high enough to observe - just after 1:00 AM.   I suggested a Hilda asteroid.  This dynamic family is in a 2:3 orbital residence with Jupiter.  Linda suggested a couple of Near Earth Objects, one of which is a known binary asteroid.  I suppose we will do paper-scissors-rock when we get there.

The 1.8-meter (72 inch) Perkins Telescope

For our observing run, we will be using Lowell Observatory's 1.8-meter Perkins Telescope. It is located at Lowell's Anderson Mesa Station south of Flagstaff. The 1.8-meter telescope has a long history. The mount and original mirror were first constructed in 1931 in Delaware, Ohio, and at the time it was the 3rd largest telescope in existence. For over six decades it was operated by Ohio Wesleyan University. In 1964 it was moved to Lowell Observatory and three years later the original mirror was replaced with a 72 inch mirror. In 1998, the telescope was sold by Ohio Wesleyan to Lowell Observatory and is now operated in partnership with Boston University.

The 72 inch telescope has a 2048 X 2048 CCD camera which provides a 13.65 X 13.65 arcminute field of view with a scale of .39 arcseconds per pixel. The optical system has a focal reducer providing an F ration of 4.34.

I toured Anderson Mesa in 2003 and got to see the telescopes which also include a 42 inch, 31 inch, and 21 inch telescopes. These telescopes are still work horses of Lowell's asteroid program, but all are showing their age. One astronomer told me that the 72-inch 'breaks nightly', but it is usually software related and fixed.

A New Observing Run

Some of you followed a blog I created telling of my trip to Cerro Tololo Inter-American Observatory (CTIO) last August. Its purpose was to study Jupiter Trojan Asteroids using the 0.9-meter telescope. Linda French and I were successful in obtaining lightcurves and rotational periods for several Trojans.

We published our work with a poster paper at the Division of Planetary Sciences meeting in Pasadena last October and with a paper in the Minor Planet Bulletin this January.

Now, in anticipation of future funding for studying these objects, we are concentrating on observing the smaller Trojan asteroids which will require using larger telescopes. While at CTIO, we talked to Larry Wasserman, an astronomer at Lowell Observatory who offered to help on the project. Larry tried getting some lightcurves in the Fall, and Linda had an observing run in January which was mostly clouded out. Linda then applied for and received some time on the Lowell 1.8-meter Perkins telescope located at their Anderson Mesa observing site. This run is six nights starting May 8.

Jupiter Trojan asteroids are a group of asteroids that share the orbit of Jupiter. They inhabit the L4 and L5 Lagrangian points, 60 degrees ahead and behind Jupiter in its orbit. Trojans are thought to have been trapped in this orbit early in the formation of the solar system and represent primordial material.

Almost all Trojans larger than 100 km in size have had their rotational periods determined. However, only half of the Trojans with sizes ranging between 50 km and 100 km have any data on their properties. Those that do suggest an excess of Trojans spinning extremely fast or slow. Over the next few years, we plan to focus on these smaller Trojans along with a sampling under 50 km in size in order to provide the statistical base to determine the mechanism causing this unequal distribution.