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In Search Of the Vulcans
jonerik writes: "No, not those Vulcans. The BBC has this article on the Southwest Research Institute's (SwRI) search for the Vulcanoids, a belt of perhaps a few hundred small asteroids (perhaps between one and 25 kilometers in diameter) theorized to exist inside of Mercury's orbit around the sun. Because of their closeness to the sun and small size, the asteroids - if they exist - would be hard to observe from the ground. To that end, a NASA F/A-18 is being used to conduct a search 'of the twilight sky near the Sun that is far darker and clearer than can be obtained from the ground,' says Dr. Dan Durda of SwRI. According to the article, 'The camera used in the latest search...is trained on the region of space close to the Sun after the star has dipped below the Earth's horizon. The camera grabs twilight images at a rate of 60 frames a second.' The researchers hope to have a better idea of whether or not the Vulcanoids exist in another month or two."
sounds like a good excuse to re-test what they can do. or use it as a test bed for some anti-missle stuff.
"no really, we are taking pictures of rocks in space..."
Photos are taken during totality. One camera is stationed near the beginning of the totality path. A few more are placed in various places along the path. A final camera is placed near the end of the totality path. Typically there is about 2 to 3 hours time between the 1st and last camera images.
The images are searched for faint moving objects that are in orbit around and near the sun.
Thus far, a few comets have been detected but no Vulcan asteroids have been found.
chongo (was here)
According to the SWUIS page the 60 fps rate of the camera is used for jitter compensation, so presumably the fast frame rate is quicker than the characteristic timescale of the aircraft motions.
An aside: for the larger aircraft-borne telescopes like the Stratospheric Observatory for Infrared Astronomy (SOFIA) the telescope is "as stable as a mountaintop telescope sitting on a 10 meter cement foundation" according to the FAQs. From that page:
This post is strictly my own opinion and not necessarily that of my employer.
-dexter "still looking for planet x" riley
As for the concern about stable cameras, NASA has been flying mounted scopes for some time. The guidance and anti-vibration systems are good enough to conduct real astronomy. In fact, craft such as SOFIA are pushing the technology even further. Yes, scopes on aircraft is outstanding practice.
One might, however, ask if the glare of the twilight combined with observing low to the horizon will impact their ability to find Vulcans. Compared to the Eclipse method, the f-18 observing conditions are poor (low in the horizon, reduced image brightness, glare from the Sun that just set, dust, etc.). On the other hand the number of minutes to observe during totality (see my other posting on this topic) are limited. A single f-18 run can rack up more minutes than ground based eclipse imagery can in a decade.
Better would be to fly cameras on an f-18 or Concord or SR71 in the Moon's shadow during a total eclipse. You can get the best of both worlds.
Better still would be to observe from space with a special telescope that can take images near the sun.
Each method as its +/-'s as well as cost tradeoff. I wish this new Vulcan program all the best in the hopes that they can do what others have failed to do so far.
chongo (was here)
Why do this now ?
Because they are there.
* Maybe they'll be stable enough to mount a nice in close power station without having to worry about Mercury's gravity well
* Maybe observing their orbits could point to some more information on the GU theory
* Maybe they could lead to some more theory on planetary formation with formation of planets close to stellar bodies
* Maybe the knowledge gained from this can lead to new designs on high-altitude fast turnaround observation of objects coming at us from the sun (Like, the last two near-miss asteroids)
* Maybe they are completly unremarkable chunks of stone, worth two or three papers and then forgotten about.
It's a ground based observation at objects too close to the sun for most observations, done on the cheap with minimal new hardware designs. I'd be very suprised if the total budget for this was much over 3 or 4 million total
The things you want NASA to do ? Guess what - they are already doing them. It's just they like doing a wide variety of different things, because you never know when you'll find something interesting in an unexplored area of science.
Not really. Radiation pressure from the Sun only affects dust-sized particles.
Unless you're thinking of the Yarkosky effect, in which the asteroid's spin and re-radiation can cause a drag? It's not clear that the Yarkosky effect is significant, actually. It's a subject of considerable investiagation right right now.
Even if it is, the effect is has will drop like the radius of the body to the minus one power (you radiate proportional to your area, but mass - and thus acceleration - goes like radius cubed). It's usually thought of as potentially important for meteroids, but asteroids probably don't notice much.
Going to the Moon would cost billions of dollars. This project probably costs in the thousands. Arguing that we shouldn't be spending this money because we should be going to the Moon makes little sense, when you look at the numbers.
So why aren't they using it on one of our fine fleet of space shuttles?
Maybe because the space shuttles are grounded.
"I have never let my schooling interfere with my education." - Mark Twain