The big news this week is the first recordings and observations of an interstellar object. Of the 750,000 asteroids and comets that have been cataloged up to now, every one of them originate from within our solar system. This object detected by the Pan-STARRS1 telescope and named A/2017 U1 or “Oumuamua”, a Hawaiian word for scout or messenger from the distant past, came from another part of our galaxy. Based on measurements made from multiple ground-based telescopes it is believed to be rather long and of a deep red color . Below is an artist’s rendering of this extra-solar visitor. While a comet would have generated some type of coma or tail travelling near the Sun, no such activity was recorded, hence it’s believed to be an asteroid-type object.
Credit: ESO/M. Kornmesser
Measurements over multiple nights allowed to establish the trajectory, which clearly shows that it did not originate from the Oort cloud or other asteroid/comet rich fields surrounding the Sun. While the discovery was made only on an October 19 image, its closest approach to the Sun was September 9th.
Diagram showing the trajectory of A/2017 U1 (ESO/K. Meech, et al.)
Now I thing they got it all wrong. What they picked-up was the Red Dwarf mining ship swinging by our neighborhood!
ESO Press Release
Today I got an e-mail from Gary that a photo of the Big Dipper that I had submitted a few months ago got selected for this week’s column on SkyNews. Couldn’t be happier. I wish all my weeks could start this way.
Astrophotography is a combination of equipment, experience, location/timing and luck. With this photo I just happen to hit everything right and was lucky.
Using the best equipment helps, but for this photo it was the simplest of setup: my very worn Canon Rebel XTi DSLR with a zoom lens set to 17mm F4 mounted on an old steel camera tripod my father used in the 60s. So nothing special, and within everyone’s reach.
OK, for the next part I had experience on my side. It allowed me to pick the right camera settings, but was also lucky as my photo viewing was limited to that small LCD screen on the camera. I had no laptop to fully explore and review the photos and make the necessary adjustments. Even the focus was reviewed through the small camera LCD. That night I only took 4 images with 20 second exposure crossing my fingers that I would have something worthwhile once back home.
And then there is the post-processing on the computer, which is a lot of trial-error. In image processing doing steps A + B will not give you the same results as performing B + A. We all have our “recipes” for what produces good results, but every photo ends up being a unique project. With this one, I knew there was good potential.
Finally there is the location and timing. I was up in cottage country, away from city lights, and a clear sky. However there was a full moon rising, couldn’t wait too long as the sky would start to brighten. A Big Dipper low in the sky next to the trees framed everything very well.
Thanks Gary and SkyNews for selecting my photo. For all the experimentation that I do with the camera, once in a while I get everything right. I’m just happy someone noticed and said “Hey, that’s a great photo we could use.”
The Moon is white right? OK, OK… it only looks white because of the high contrast with the dark sky, it’s more grey. What? No? You mean it has color?
From samples returned by the Apollo missions we know that two of the main minerals making up the lunar regolith is titanium oxide (TiO2) and iron oxide (FeO) based basalts. While TiO2 is quite white and used in many household products from white toothpaste to white kitchen tiles, FeO is rust and closer to orange-brown (think Mars). On the Moon the result is a slightly blue-ish color in the areas with high TiO2, and more of a brown-red for the higher FeO and low TiO2 zones.
A normal image of the moon taken with DSRL, the different in hues is subtle as seen below.
Moon Natural Color (November 7, 2017) – Benoit Guertin
But it can be exaggerated by playing with the color saturation, and you get the image below, where various hues of blue-grey, orange and brown become apparent. The sharp boundaries between colors are caused by the different mineral make-up of the lava flows during the early formation of the Moon. Common interpretation of the age of the lunar surface is that the blue-grey areas are “younger” than the orange-brown.
Moon with exaggerated colors
Who says you can’t pull scientific information with simple backyard astronomy gear? The same technique, but with narrow-band filters is used by NASA and other space and research agencies to catalog the make-up of the lunar surface.
So if you are planning lunar prospecting for future mining rights, all you need is a telescope and a DSLR.