Wednesday, September 28, 2005

Dumbbell Nebula Messier 27 from last night

I took a quick set of shots of Messier 27, a planetary nebula, last night from Ryerson, after fixing a piece of equipment on the telescope. This is 128 images of 15 seconds added together to make a 32 minute equivalent exposure.

Wednesday, September 21, 2005

Cajon Pass

Have you ever driven from Las Vegas to Los Angeles? Two thirds of the way there, you are driving along I-15 in the high, dry Mojave Desert at 3,000 to 4,000 ft, and suddenly you begin a steep curving descent, reaching very high speeds, hoping to retain control of your car. The topography is tortured with impossibly steep mountains and hills running across your path, but... you look far below and see a large wash cutting a path through the mess, and that is what the freeway follows. You see that the freight trains too run through this steep canyon. If you knew a little more, you'd also know that all the infrastructure for gas and oil to Las Vegas runs through here too. A few minutes of this wild driving and then you are dumped out into a low plain; it's cooler, more humid; the coastal air is tinged with both Pacific moisture and the exhaust of 15 million cars.

The drop, the canyon you pass through, is Cajon Pass. It is a critical transportation, infrastructure, and drainage corridor. It is also entirely a creation of the San Andreas Fault.

On your left side as you head towards L.A. are the San Bernardino Mountains. On your right, and more impressive in appearance, are the San Gabriels. They, and some other ranges to the west, constitute the Transverse Ranges, a east-west set of ranges. They are really one mountain range, formed from the compression along a kink in the San Andreas slip-strike fault. The motion of the Pacific plate, normally slipping smoothly, rides hard against the North American Plate at this location, compressing the land up into an unstable, steep, untenable range.

Why there is a usuable (although steep) pass right in the middle of the mountains can't be ascribed to luck--the San Andreas Fault runs NW-SE right through the pass. You can see a diagram of this from here: (The link was down today but it's been up before).
Also, I've annotated a TERRA image of Southern California:

The full image showing the whole region is here:

This is a nice block diagram showing the region from the USGS.

Imagine sliding the left side of the satellite image down and to the right, and now the San Gabriels and San Bernandinos line up.

Not only does the fault create the range, it also slices the range up.

University of Chicago and Hyde Park types will be amused by the roads in the small settlement near the base of the canyon. Google Hybrid link.

Another point of interest is the strongest plume of sediment you can see in the ocean. The Cajon Pass drains through a convoluted path of washes, creeks, and dams to the sea right there. Is some of that silt from the rapidly eroding rocks of the Pass? Absolutely.

I originally started writing this entry in August, trying to start out with a broad comment about how geology completely controls topography. I am amazed at how every geographic and topographic structure can be explained geologically. That approach to the entry didn't work, so instead I wrote about a specific instance. And what's amazing is I am finding these explanations everywhere.

Thursday, September 15, 2005

Ortiz response

This was posted on the Minor Planet Mailing List by Ladislav Nemec.

Michael Brown wrote up his page about the issue here.

Reiner Stoss forwarded Brian Marsden's CCNet post about the issue to the MPML as well; it is available here for the moment.

Hello MPML,

Jose Luis Ortiz of Sierra Nevada Observatory asked me
to forward his letter.


Hello MPML, I provide you this information which will
go to my webpage in the next days. The detailed timeline
of our find was given to Daniel Green, director of CBAT long
before any controversy. Anyone can ask him and check against
any other timings of events provided by M. Brown. I suppose
that this has been done by the pertinent authorities and
that is why no official request on anything has been sent to
us by the International Astronomical Union (IAU).

Here I will repeat the timeline of events and even expand
some details:

The analysis of most of our 2003 survey images had been
postponed several times because they had a different optical
configuration to the current one and many images had problems,
so only this year did we begin processing them.

On Monday July 25th the object is found in some of our
March 2003 triplet images. We do all possible checks to discard
image artefacts being the cause and to make sure it is not a
false positive. We had had false positives in the past so we
were very careful. We realized that the object was very bright
and could be the same one mentioned in a DPS abstract web page.
A regular google internet search on K40506A leads to a public
internet web page with what appears to be coordinates of many
things. This is no hacking or access to private information nor
spying of any sort. Some of the coordinates shown in those pages
are not very far from ours despite the several years difference
so the object could be the same one but we cannot really tell as
we are not dynamicists and we decided to submit the astrometry
to the Minor Planet Center (MPC) because the MPC is to make such

On Wednesday 27th a report with our 3-day 2003 astrometry is
sent to the MPC with the subject "possible new object" as we
were not sure if it could be new or not. MPC reports have a very
short and specific format and are not regular scientific publications.
Astrometry of known or unknown objects is regularly submitted by
many of us to MPC and as I said they are not peer-reviewed
publications and have no references or bibliography sections,
but even if we had that option there was no possible reference to
give as K40506A was nothing standard and it was not even sure that
it was K40506A.

Apparently this report went unnoticed to the MPC and since we did
not get a response, the next day we seek help of OAM people for
precovery (that is, to try to find the object in publicly available
image archives on the internet) as we had no experience on this.
This requires orbital computations for which we do not have expertise.
R. Stoss was particularly helpful as a reputed person in precoveries.
The description of the process is very technical but I reproduce
it here anyway, quoting parts of his own words to the minor planet
mailing list.

The initial orbit based on the three positions from 2003 was a
crap, even retrograde if I remember well, but it was good enough
to find it on NEAT data from few days later. This way the orbit
was improved iteratively, the prediction improved, new frames
found etc. until the NEAT archive was plundered. The next step
then is to go to DSS, until back to POSS I. From all the 1-opp
TNO precoveries I had done so far, this one was a no-brainer.
The object was very bright and the "stepstones" were perfect,
i.e. the frames and plates were perfectly "timed". Thus DSS2
and 1 were plundered and some POSS I non-DSS plates as well and
both NEAT and DSS data submitted.

Additionally, as it was getting dark in Spain and weather was
clear in Mallorca, I opened over internet the 30-cm scope and
started to prepare it for the night, looking We had to start
before the end of nautical twilight because the object would set
behind the shelter soon. We did 30 images of 30s each and stacked
with Astrometrica in sets of 10 images to get three measurements.
Motion could not be seen visually but the numbers showed it moving
and in the right direction. So I decided we should report these
three data points instead of stacking all 30 images to get one
data point. One data point would have been better (better SNR etc.)
but I know the MPC folks and their pretentions

As a result of all of this the provisional designation of the
object was assigned to our 2003 images, but Brown's group received
credit through several means. It is evident that they spotted it
first, but did not report it to the MPC so the provisional
designation came to our images.

We have been studying physical properties of large Trans Neptunian
Objects for several years and have published more than 10 scientific
peer-reviewed papers on them, so we are driven by purely scientific
goals here. We conduct also our own survey since late 2002 in order
to find a few very large TNOs and report them to the astronomical
community as soon as we find and confirm them because we believe that
international scientists working together, collaborating and sharing
resources can boost science progress and do the best possible job.
In other words, our survey is not only to feed our work, but also to
provide the scientific community with objects that can soon be
studied by the international community with all its man and
technology power.

Jose L. Ortiz

Friday, September 09, 2005

potassium part 2

Sure enough, as I suspected in my previous post, taking the potassium chloride out of the container brought the count rate up 50% to 120 microrads/hr. I celebrated by tasting it, confident in my body's metabolic control over potassium. It was salty.

Thursday, September 08, 2005


Brown, Trujillo and Rabinowitz have submitted a paper to ApJ Letters for it:

2003 EL61: bulgy or salt and pepper?

The TNO object first reported by the Ortiz et al now has a light curve that either has it spinning every fast and non-spherical or covered in spots a la Pluto.

New Scientist has the press release.

Wednesday, September 07, 2005

Division for Planetary Sciences meeting

The DPS of the American Astronomical Society is meeting with the Royal Astronomical Society (alas, not that RAS) in Cambridge this week. This is the meeting where Michael Brown, Trujillo, et al at Keck are announcing their big TNOs. Will we find out the proposed name for 2003 UB313 and 2003 EL61 and it's satellite?

Tuesday, September 06, 2005

Radioactive potassium

A store-bought container of potassium chloride, aka Salt Substitute, contains enough of the naturally occurring potassium-40 isotope ( 0.0117% abundance per the CRC, page 4-24) to produce 5.5x the amount of background radiation when placed on a geiger counter, with the container intact. The rate would have been higher if I had taken the salt out of the container, as the metal base shields some percentage of the 1.31MeV(max) beta electrons.

Paul Frame at Oak Ridge has a great site about radioactive consumer products at
and see the potassium info page at