castor and pollux exposed
by Ted Frimet
No, we haven’t changed the sex of our favored Gemini twins. This title has been haunting my mind, for a few days now.
The Father of Advertising, David Mackenzie Ogilvy bombards my mind with memories of past reads. Among more discrete topics, Ogilvy wrote that sex sells. Well, only that is, if the subject is relevant to that which you are selling.
I could have tried to sell you snake oil, however Draco isn’t in my eyepiece at the moment. And snake oil, I presume isn’t too tasty. Nasty stuff. Very few repeat customers. Hence the title. No snakes, just bare naked ladies.
Oh how, just how do we save the title and write a smidgen of Astronomical significance?
Ah-Ha! Join me on a short journey, where we shove off to a near death experience. Or rather, a Near Earth Object (NEO) that was categorized as potentially hazardous. That’s WordSpeak for ye old end of days. A story, charred down to the boney essentials and filled with magnitude and parallax. Starring of course, a bare naked comet, better known now-a-days as Asteroid 3200 Phaethon.
Phew. The essay that follows is shorter than that intro. Thank the heavens!
I was sitting on the couch a few weeks back, lamenting the clouds that precluded us from enjoying the marvels of the yearly Geminid meteor shower. Yes, a few days had passed. But I hang onto my lamentations. They become the core excuse for not hauling out my 12 inch dob, into the backyard on the least stable viewing nights. Then some smart bloke wrote about the Ursids. Some consolation, I thought! As a newcomer to amateur astronomy, I was pretty certain that Ursid would not be the bees knees, and leave me sulking for another 12 months while waiting for next years Geminids.
Let’s take this back to the couch, again. Perfecting the art of couch potato, remote in hand, my hind brain motions to battle with my forebrain. And won. Out popped a reminder that this evening 3200 Phaethon, a NEO, was an able and willing target. A quick check on regional weather ( that’s fancy astro-speak for looking out the window ) showed the promise of a clear night. Of course, a promise of a clear, stable atmosphere to an amateur astronomer almost always leads to broken promises, and cloudy nights. A sheen of clouds rolled in with hardly any notice. Leaving me to whimper. sigh. Cloudy sky. What to do?
Some of you are aware that I have been cultivating data on the variable star Algol, from minimum to minimum. This continues to be an ongoing project, with 39 out of 69 data points still required to be filled. I’ve been requesting telescope time on those evenings, where and when I can fill the gaps in my data. The two scopes that have been successfully tasked are the fourteen and seventeen inch telescopes at the Dark Sky Observatory (DSO), located in North Carolina. A quick check of my spreadsheet, shows that I have imaged Algol, during 10 (minimum to minimum) sessions, since November 16th, on both DSO-14, and DSO-17. Being fond of the more diffuse star light results of DSO-14, I decided to capture Phaethon, status quo.
Based upon previous observational success with a smaller 28 meter asteroid, J2012 TC4, I cast my line out to 3200 Asteroid Phaethon. I bait my hook with a 10 minute interval, 4 seconds exposure, for 60 images. The proverbial float on the water bobbed up and down. Asteroid on the hook – I cautiously check the first 8 images. Viewing them in quick succession I quickly established that the asteroid was moving out of frame. This was moving much too quickly to produce a viable video. I cancelled the remainder of my Skynet observation. I resubmitted anew at 30 second intervals. Voilà.
Asteroid Phaethon is the remnant of a comet that produced the Geminid’s. Kevin D. Conod, writing for The Star-Ledger composes his article, “N.J. Night Sky: Shooting stars from an asteroid” (updated Dec 9; Posted Dec 9) and can be read here: https://goo.gl/7b5YtK Conod writes briefly to remind us that the Geminid’s parent is Phaethon.
And this now lays a foundation of future thought, for this amateur, that I should pay more attention to asteroids that pass thru other cometary debris fields. And pay homage to the bare naked ladies – those asteroids stripped of their cometary nebulosity and consider them as the source of my yearly visual delights – our dazzling meteorite showers.
Here is the final video of Asteroid 3200 Phaethon:
Some final thoughts and thank you’s. There was a technical error in my first video, where I confused apparent magnitude with absolute magnitude. The error occurred to me after reading a critique by Joe Stieber, a fellow member of UACNJ. I am equally gracious for our AAAP Club President, Rex Parker, taking the time out to vet the video, and make recommendations that were equally helpful. And a shout out to our Observatory Chair, for an early distribution of the asteroid video. And for discovering at a late hour, a broken link on YouTube. Fortunately, the only sacrifice was the 230 or so, original views on the first two published movies. The current count is now 30, views and that can grow, going forward.
Below you will find some of my commentary, on some of the quirks of remotely imaging NEOs as I reached out to Joe, by way of UACNJ posts:
The creator may be in the structure, but the devil is still in the details!
Thank you, for refocusing me – on Asteroid Phaethon.
I rechecked the ephemeris data with the NASA Horizons web interface. I plugged in the longitude and latitude of the DSO-14 telescope location. And the AP Magnitude comes back at 11.8, across the board.
My photometric tool must be measuring “absolute magnitude” and not apparent magnitude.
Stellarium displays an absolute magnitude of 14.60 for this asteroid.
So, the data I measured, as an overall average of 13.94, isn’t too far off the mark for an amateur.
I must make an effort to be clear on “absolute” measurements, versus “apparent”.
After this email, I will make the necessary correction to the video’s text.
I set the telescope exposure time for 4 seconds, at 30 second intervals. So the 60 frames should represent about a half an hour.
However, DSO-14 is a shared resource, and I have lower priority. The reality in time management pushed this to an hour observation, over-all.
As for the “jumps” in magnitude – they are as recorded, and I rechecked four frames. A closer examination might show that lower numbers corresponds to stars being in the field of view. Or not. This will have to wait until I have much more time for evaluation, and a second pot of coffee! (side note to self – use the small mug!)
On the face of it, however – the data is real, and my opinion based upon the data is that the asteroid is not a uniform object for reflectivity.
As for the “orientation” part of the video – showing the asteroid in the vicinity of Pegasus, I rechecked with Stellarium and I am still in the ballpark, so to speak.
When I plugged in the long/lat for the telescope, incorporated my start time, and date and looked for Pegasus – I found the asteroid where I expected it to be.
If there is a discrepancy, it probably comes down to parallax. When observing near earth objects, recording the origin of the telescope is paramount, to getting correct on screen observations.
DSO-14 is located at:
-81.415 Longitude ( or 81.415 W )
The time of the first image taken was on:
December 17, 2017 02;08:12 UTC, which is December 16th, 2017 21:08:12 EST.
I was going to scribe out the date-time groups, however, for brevity sake, I’ll list the first and last data points.
The date-times are UTC.
Happy New Year, and Clear Skies for All !