Observing with Street Lights

Observing with Street Lights
Dark sky sites not always necessary to see the Milky Way (This image was taken ouside of a B&B in Julian, CA)

Sunday, March 22, 2015

Poor weather for observing, Bob Buchheim book "The Sky is your limit", adn the big bang "lithium problem"

Greetings from Palmia Observatory,

Well, it's been a week and no photos.  The weather has not been cooperating.  It's been warm and clear during the day and then cloudy at night.  Some observatory location we have here.  Should have gone to Anza.  Yes, I could have gone out for some solar observing, but I'm still dithering about the focus problem.  I'm now of the opinion for solar images, I should set the camera to display only red pixels, not black and white.  Remember last time I could get better focus with black and white on the camera LCD.  But, it seems that since the original camera image can only have red wavelengths, I should be ahead by. Only using red pixels and not rely on whatever the camera does when it converts to black,and white.  We will see.

Meanwhile my friend Gene, is trying to analyze my previous sunspot images, taken one day apart, to see if we can calculate the rotational speed of the sun.  It should be straight forward, but having trouble getting the required contrast on some of the images.  By the way, if you are interested in doing science from your backyard check out "The sky is your Limit" by Robert Buchheim.  Bob is the secretary for our OCA and is Really an accomplished amateur astronomer.  He has a second book coming out in August.  He describes how amateurs, with just their little scopes and a camera can do some interesting and valuable science in your backyard.

The sunspots are darker than the rest of the sun because they are cooler.  Sunspots are about 2000-4000 K, while the main sun surface is 5700 K.  Yeah, just a little bit cooler.

So, I've had to get by and get my astronomy fix at CSU Long Beach Physics Colloquium.  It's nice to get back on campus and the speaker from UCSD talked about the "lithium problem".  No, not the problem that you crazies from the 60's are remembering,  but how the modern measurement of lithium in the universe is about 5 times less than the predicted level based on Big Bang nucleosynthesis calculations.  The professor hopes to resolve the problem by measuring the amount of lithium in very old brown dwarfs.  It turns out that the leading theory of the discrepancy is that lithium is destroyed in stars by their internal nuclear reactions.  But old brown dwarfs never get high enough temperature for fusion to occur and so the amount of lithium there is projected to better represent the lithium levels present just after the Big Bang.  That sounds great.  The main problem is that brown dwarfs, since they have no fusion going on, are very dim.  Brown dwarf temperatures are just in hundreds of degrees, rather than the thousands of degrees for regular stars.  The professor has got approval for 8 hours on the Hawaii Keck telescope in a couple of months to find out.  I hope he doesn't get clouded out.

In addition it sure is nice to get back on campus.  It reminded me when I was a young student.  Now, I'm just an old student, so the illusion didn't last long.  I can confirm though, and this is no illusion, that short shorts are still in fashion.

By the way, the next colloquium is this Monday, March 23, and is on the latest cosmic microwave background data taken by Planck satellite.  Several folks from my quantum and Gravity study groups will be there and we will
have lunch with the speaker.  That should be interesting and fun and also provides another opportunity for fashion review and update.

But, I digress, so with no Astro images this week how about some astrophysics charts?  I finally am getting to the end of my cosmology course and tried my own hand at calculating how spectroscopic redshift correlates with look sick time and the age of the universe.  I had heard many times that a redshift of 2 corresponds to light emitted by objects about one billion years ago.  Objects with redshift 6+ are seen at about a billion years after the Big Bang.

Assuming a flat universe and most data points to a flat universe, then with measured ordinary matter and dark matter representing about 30% of the critical density and the remaining 70% provided by dark energy. We can solve the differential equations, using Mathematica, for the expansion of the universe.  My solutions are shown below.  The scale factor in the present era is taken to be 1, so back in time when the universe was smaller, the scale factor decreases to zero, which at the Big Bang.  This is easy stuff for the professionals.  It's taken me about a year to finally get to the point of being able to do this accusation myself.  Wow, I guess I should get back on campus and do some more study.

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