Photometric Transformations

On the evening of 01 March 2019 (UTC), I collected a new set of photometric data using my 'G' and 'R' filters.  The target was, once again, Messier 46.  I like this particular object because it's a rich open cluster with nice selection of stars and it has a bonus object NGC 2438.

I took 200, 4 second images with 2x2 binning with each filter.  Running it through my stacking program, about 180 individual images were actually used for each stack.

Here is the Green stacked image:

and the Red stacked image:

After running the stacked image through Astrometry.net to get the WCS transformation (which is used to convert x,y pixel locations to RA, DEC coordinates), I use the IRAF task 'starfind' to locate the stars in the field of view.

The next step is to perform aperture photometry on each of the detected stars.  The result of this will a measured flux for each star.  The flux can then be converted to astronomical magnitudes following the transformation algorithm described Chapter 6 of the CCD Photometry Guide published by the AAVSO.  To calculate the transformation coefficients, I used the Sloan g' and Sloan r' photometric standards from the The AAVSO Photometric All-Sky Survey Data Release 10.

Here is my plot for T_gr = 1.570281 (slope = 0.636828)

and for T_g_gr = 0.291380:

and finally T_r_gr = 0.022768:

So then I can compute the magnitude of each star relative to a bright standard star I've chosen within the field of view.  After computing these magnitudes, I can compare my measurements to the Sloan g' and Sloan r' magnitudes.  The results are shown in the following two plots:

Along the x-axis is the Sloan g' or r' magnitude of the star, and along the y-axis is the percent difference between my measured magnitudes and the catalog magnitudes. As you can see, the accuracy is less than 1.5% even for stars as faint as magnitude 14.5.  The accuracy drops to less than 0.5% for stars brighter than about 12th magnitude.

So overall I'm fairly pleased with these results.  I'm going to take one more set of data using my 'B' filter, which I can then compare to the Johnson B and Johnson V magnitudes to see if I get similar results.

Not that it will be scientifically viable, but at that point I'll have 'R', 'G', and 'B' images of this region, so I'll probably combine them to produce a color image as well.  It might be pretty to look at.

Some New Binaural Beats

Binaural beats are created by playing a single frequency in one ear and a slightly different single frequency in the other ear. The difference between the frequencies create a noticeable beat pattern to the listener. Binaural beats are said to have therapeutic value.

Currently available binaural beats combine a single beat frequency with an ambient sound/song mixed in. This is fine, but I find that using this technique may not offer the desired full therapeutic effect. I see this as similar to taking a pharmaceutical drug, which is typically 1% active ingredients (a single kind of molecule) and 99% filler material.

My binaural beats does two things differently. First, there is no filler material. What you get is 100% pure binaural beats. Second, the beat frequency varies throughout the entire session. People are all different and therefore they respond to different beat frequencies. It’s arrogant for us to assume that specific frequencies effect everyone exactly the same way. Single frequencies create an audio experience that is fairly static. Using my binaural beats, the listener receives a variety of beats, similar to the “ensemble effect” in natural medicines where a plurality of molecules are synergistically mixed.

The varying beat frequencies are produced in a very unique way as well. I’ve taken the motions of astronomical objects (e.g., the four Galilean moons of Jupiter) and converted these into the individual frequencies for each ear. This provides a beat frequency that is slowly changing, and directly connects the listener to events happening in the universe. This also entrains the brain in different ways throughout the session, offering a richer and dynamic therapeutic experience.

The binaural beats that I offer can vary in base frequency, range of beat frequencies, and length of session. In this sense, the sessions are made to order. How the beating changes, though, is completely dependent on the motions (in this case) of the astronomical objects.

ADL Continues! Live every day at 2h UTC!

A kind message from my wife:

Astronomy Daily *Live* Every Day at 02:00 UTC

I'm jumping into a new realm of insanity.  Hope you'll join me on the ride!

Astronomy Daily *Live*

ADL is a casual, open-minded, skeptical, educational, and fun conversation about astronomy and related fields.  Whether you're a newbie, amateur, advanced amateur, or professional, please join me every day at 02:00 UTC starting on 14 January 2018.  Most conversations will be directed by the participants, but I'll usually have some topics in my back pocket to keep the conversation flowing.  Open topics can include Q&A, observing, gear, telescopes, cameras and other instrumentation, data analysis and research, journal paper reviews, personalities, astro-art, projects and institutions, and pretty much anything else the participants suggest.

Consider this as a daily gathering of friends to hang out and discuss topics of mutual interest.  Get away from the TV and the news for a while, and come talk live with people from all around the world who share a similar passion for astronomy!

Email cosmiclettuce AT gmail DOT com and I'll send you a link to become a panelist when the show goes live!

My youtube channel URL is: https://www.youtube.com/user/cosmiclettuce

Please subscribe, set a reminder, and join the conversation!

Continuing to Contemplate Galilean Moon Motion

I decided to see if there are any explanations for what the higher-order derivatives (3rd, 4th, 5th) of position actually feels like, and I didn't get much of an answer.  However, they all have names.  The best source of info on this subject that I was able to find is this article:

What is Derivatives Of Displacement?

So yes, the 3rd derivative is called 'Jerk', which I call 'Bump' -- it's a change in acceleration.  The 4th derivative is 'Jounce' (the change in the 'Jerk') and 5th derivative is called 'Crackle' (the change in the 'Jounce'), which to me don't relay any kind of physical sensation.

In the case of the motions of Jupiter's Galilean moons, I can now look at the past seven days of motion:

Galilean Moon Motion 08 June 2017

Looking at the motions of the four Galilean moons of Jupiter.  The following plots are for 08 June 2017.

In all of these plots, I'm showing the 0th (position), 1st (velocity), 2nd (acceleration), 3rd, 4th, and 5th derivatives of position as a function of time.  So the 0th derivative is in km, 1st is km/minute, 2nd is km/min^2, 3rd is km/min^3, 4th is km/min^4, and 5th is km/min^5.  What do the higher-order derivatives feel like?  Not sure, but the 3rd order probably feels like a bump (a change in acceleration).


Io motion around Jupiter:

Europa motion around Jupiter:

Ganymede motion around Jupiter:

Callisto motion around Jupiter:

Io motion relative to Europa:

Io motion relative to Ganymede:

Here's how the 4th derivative sounds:


Io motion relative to Callisto:

Europa motion relative to Ganymede:

Europa motion relative to Callisto:

Ganymede motion relative to Callisto:

All of this will be converted to audio so I can experience how it sounds.

Chaos Plots

These images are based on the equation:

N+1 = (lam) * N * (1-N)

where 'N' is the current population level (scaled between zero and one) and 'N+1' is the next population level.  'lam' goes from zero to about five until things get a bit crazy.

This little work is based on the video:

https://www.youtube.com/watch?v=ETrYE4MdoLQ

In the plots below, the x-axis is the 'lam' value, and the y-axis is the 'N' value.