My Astro Photo Of The Day

[Autumnlicious]

First off, the asteroids orbit intersects with just inside Earths and Mars orbits. To get to it before it gets a gravitational assist (valid term of art), one must merely launch into a highly elliptical orbit, obviously increasing eccentricity over time, until one attains a velocity that would coincide with making landing on the asteroid.

When you are ready to land on the asteroid, you are matching the asteroid's orbit, which is an martian transfer orbit. So you've already burned all they fuel you would need to put yourself directly into your own mars transfer orbit even without an asteroid. Tada....

Nice to have a giant rock that provides living space and a cache for supplies, no?

When the asteroid does a flyby Mars, and thus a gravitational assist (calculated so as to allow the next half orbit), spacecraft merely need to disengage and aerobrake.

The majority of energy in this system to adjust the orbit comes from the planets, like two people playing catch. Another piece of the proposed enforced resonant bi-elliptic orbit is that it moves at twice the normal keplerian speed of an object.

A modified heliocentric elliptical orbit where at aphelion and perihelion the object passes out of solar sphere of influence into a local hyperbolic orbit under the sphere of influence of one of the planets is possible. But to keep this up like a tennis volley requires course planning so precise that extensive fuel burn would be required during each pass to ensure to the object pass through the correct window.

Precision is definitely a problem. The fuel burn, I am not too worried about. Then again, it would be nice then to inspect this idea in full, no?

As to twice keplarian velocity, keplarian with respect to what? If to the planet it implies no gain. You need to exceed the Keplerian orbital velocity by at least a factor of 1.4 anyway just to leave planetary sphere of influence to go into a transfer orbit to where ever you are going.

with respect to the planet.

If you manage to make your ship match the orbit of the asteroid so as to be prepared to land on it, then you would have placed your ship under exact same gravitational influence that the asteroid would be under, and your ship would thus follow exactly the same path your asteroid would have followed, even if there was no asteroid.

Yes.

So your ship would coast to mars in exactly the same way your asteroid would have. Once you are there, your ship would sling shot around mars just like your asteroid.

One needs to merely change their velocity vector just enough to graze the atmosphere of Mars such that one continues in a degenerating orbit. Aerobraking.

http://en.wikipedia.org/wiki/Aerobraking

If you plan to depart from the theoretical orbit of your asteroid so as to land, well you have to burn the same fuel to so this either way. Orbital mechanics ring a bell? Along the way if your asteroid didn't need any fuel, neither would your ship if you place it into the same orbit as you would have placed your asteroid. If your ship needed some fuel to do course corrections, your asteroid would need a whole lot more.

True. I am assuming that some significant section of the asteroid would be dedicated purely to power generation and engines to allow for course adjustments.

However, you once again neglect the primary goal of using a giant rock - radiation shielding. Yes, changing orbital parameters to ensure the appropriate windows would be met is difficult.

As to the weight of the ship's shielding, let's compare that to the fuel weight. Your ship only needs to carry fuel to make one set of orbital correction for a small ship to get into the Mars transfer orbit, and one set of correction to come out of Mars transfer orbit into either a martian orbit or a Mars aerobrake orbit.

May I point out that radiation shielding for cosmic rays is rather large and heavy for the amount of volume it would protect? May I also point out that the asteroid is a giant radiation shield. No doubt there are sections inside that are less irradiated compared to the outside, required no doubt less of that heavy ass shielding.

One of the primary issues with getting to Mars lies in defeating the radiation bath in space. So far, the prevailing idea I've heard requires the assembly of a Mars bound ship inside low earth orbit, as there would be no way to launch a complete, shielded vehicle up.

Your asteroid with its bonus shield would need to carry all the fuel for for orbital correction during each leg of its back and forth between mars and earth. One missed orbital window at either end of its elliptical orbit, and the thing slings off into the wild black yonder, needing another few dozen years to put back into correct orbit.

I keep hearing about "all this fuel", and the only thing I am thinking about is: you mean fuel for ion thrusters? Oh dear, RTG's will /never/ provide the required power.

I do concede that a fuck up in utterly missing an orbital correction window would result in a whirlwind tour of the outer solar system. Indeed, that would be "bad".

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Oh, and to follow up on the big emphasis on shielding, something that seems to be missed as a point - I must point out that one cannot get away without cosmic ray shielding. In fact, metals cause secondary radiation scatter of cosmic rays to be worse than had they (the cosmic ray) merely passed through your body. This is due to the nature of metal and light, high and low energy. So far liquid hydrogen, hydrogen rich plastics or massive magnetic fields are thought to be the solution to such a problem.

I ask, why not use a pre-existing volume and mass for intercepting that nasty shit, burrow into it, and therefore devote your resources to something else. Like changing orbital parameters and accumulate shit on the asteroid like a giant fucking space loading dock.

[Houston I Am]

Glad to see you still alive and well... Insight is shutting down to everybody who doesn't have an insight account so you will see a few of us here.

[orogenicman]

Glad to see you still alive and well... Insight is shutting down to everybody who doesn't have an insight account so you will see a few of us here.

That's just as well. It was already dead as far as I'm concerned. Glad to hear from you, HIA. Welcome to your new home.

[Abraham3]

I see you're still shooting. Looks good. What's a SkyStacker?

I don't know if you've heard yet, but Insight is closing its doors to non-Insight customers at midnight tonight. So you finally got me over here. But I need someone to debate. Can I bring Mishka over?

Just kidding. Pics look good. My wife and I were both SLR users for many years until walking around Disneyworld just made it too bulky and we picked up a little Olympus point-and-shoot (this is in the film days). When digitals came out we couldn't afford DSLRs and we've been slowly moving up through the nicer pseudo-SLRs (currently a Fuji S-5200). But we swore to ourselves that our next camera would be a DSLR. I looked around and decided the Canon T2i was the one we needed but it's a little pricey for us and the bundled lens (18-55mm) is crap. We're considering now just getting the Canon for ourselves without any other presents between us. Still a bit high. Maybe. If you were starting over would you consider the T2i?

[orogenicman]

I see you're still shooting. Looks good. What's a SkyStacker?

I don't know if you've heard yet, but Insight is closing its doors to non-Insight customers at midnight tonight. So you finally got me over here. But I need someone to debate. Can I bring Mishka over?

Just kidding. Pics look good. My wife and I were both SLR users for many years until walking around Disneyworld just made it too bulky and we picked up a little Olympus point-and-shoot (this is in the film days). When digitals came out we couldn't afford DSLRs and we've been slowly moving up through the nicer pseudo-SLRs (currently a Fuji S-5200). But we swore to ourselves that our next camera would be a DSLR. I looked around and decided the Canon T2i was the one we needed but it's a little pricey for us and the bundled lens (18-55mm) is crap. We're considering now just getting the Canon for ourselves without any other presents between us. Still a bit high. Maybe. If you were starting over would you consider the T2i?

Hi Abe. Please, whatever you do, don't let the assholes over there know about this place. I have the T1i (it is modified for astronomy work), and I have been very happy with it. I have also heard good things about the T2i. I agree that although the lens that comes with it is very functional, the optics sucks. I've proven that to myself when attempting some widefield astrophotos. Very poor optics, IMHO. But for general photography, it is fair, but not great. Good lenses are at a premium right now. Exceptional lenses are hard to come by.

As for debaters, I think you will find plenty to debate over here. Houston told me what Insight was doing. I'm not surprised. I left for different reasons, since I am actually an Insight customer. I think you know why. Anyway, great to hear from you. I hope you hang around a while.

Folks, Abe is a great guy. You're gonna really like him.

[orogenicman]

I forgot to respond to your question about DeepSkyStacker. It is a program that calibrates and stacks astrophotographs.

[orogenicman]

I finally made it out to the observatory last night, and boy am I tired! Here is the first result:

NGC 2237 (The Rosette Nebula), in Monoceros

From SEDS:

The Rosetta Nebula is a vast cloud of dust and gas, extending over an area of more than 1 degree across, or about 5 times the area covered by the full moon. Its parts have been assigned different NGC numbers: 2237, 2238, 2239, and 2246. Within the nebula, open star cluster NGC 2244 is situated, consisted of the young stars which recently formed from the nebula's material, and the brightest of which make the nebula shine by exciting its atoms to emit radiation. Star formation is still in progress in this vast cloud of interstellar matter; a recent finding of a very young star with a Herbig-Haro type jet by astronomers at the NOAO has been announced in Press Release NOAO 04-03 on January 22, 2004.

NOTE: This is my first attempt at a long exposure of this object. It was late, and I rushed it a bit, resulting in the stars being slightly out of focus (a recurring theme lately), and an off-center target. Considering the fact that the object is so huge that it doesn't fit in my field of view, I'll settle for what I got, though I'm definitely going to have to redo this one.

Image:

11x5 minutes for a total of 55 minutes at ISO 1600
Stacked in DeepSkyStacker, Dark Subtracted
Processed in Adobe Photoshop CS3 Extended
Taken on December 8, 2010 at the Louisville Astronomical Society Observatory, in Curby, Indiana

Equipment:

200 mm f5 Konus Newtonian with Baader coma corrector and UV/IR cut filter
Losmandy G11 Gemini GOTO mount on Heavy Duty Tripod
Orion Shorty Autoguide Scope with Starshooter autoguider

More to come (and I might rework this one)

[orogenicman]

Messier 78 Nebula complex, a part of the much larger Orion Nebula complex

From SEDS:

Messier 78 (M78, NGC 2068) is the brightest diffuse reflection nebula in the sky, situated in the rich constellation Orion.

This object was discovered by Pierre Méchain in early 1780. Charles Messier added it to his catalog on December 17, 1780.

M78 belongs to the Orion complex, a large cloud of gas and dust centered on the Orion Nebula M42/M43, and is about 1,600 light years distant. It is the brightest portion of a vast dust cloud which includes NGC 2071, NGC 2067, and very faint NGC 2064. Together with some other nebulae, all these nebulae are associated with the molecular cloud LDN 1630 (from Lynds' Catalogue of Dark Nebula), a part of the Orion complex.

As a reflection nebula, M78 is a cloud of interstellar dust which shines in the reflected and scattered light of bright blue (early B-type) stars, among them the brightest, HD 38563A, and second-brightest HDE 38563B, both of about 10th visual apparent magnitude. The nature of M78 as a reflection nebula was discovered by Vesto M. Slipher of Lowell Observatory in 1919 (Slipher 1919), by the investigation of its spectrum: M78 exhibits a continuous spectrum, which resembles that of the bright stars enlightening it. At its distance, M78 measures almost 4 light years in extension.

NOTE: I continue to have focusing problems that I think is due to my camera not seating properly in the focuser. Will have to investigate this.

Image:

10x5 minutes for a total of 50 minutes at ISO 1600
Stacked in DeepSkyStacker, Dark Subtracted
Processed in Adobe Photoshop CS3 Extended
Taken on December 8, 2010 at the Louisville Astronomical Society Observatory, in Curby, Indiana

Equipment:

200 mm f5 Konus Newtonian with Baader coma corrector and UV/IR cut filter
Losmandy G11 Gemini GOTO mount on Heavy Duty Tripod
Orion Shorty Autoguide Scope with Starshooter autoguider

[leo-rcc]

Dude, the wormhole is opening.

[orogenicman]

NGC2264, in Monoceros

Clouds of glowing hydrogen gas fill this colorful skyscape in the faint but fanciful constellation Monoceros, the Unicorn. A star forming region cataloged as NGC 2264, the complex jumble of cosmic gas and dust is about 2,700 light-years distant and mixes reddish emission nebulae excited by energetic light from newborn stars with dark interstellar dust clouds. Where the otherwise obscuring dust clouds lie close to the hot, young stars they also reflect starlight, forming blue reflection nebulae. The field of view spans about 0.8 degrees or nearly 2 full moons, covering 43 light-years at the distance of NGC 2264. Its cast of cosmic characters includes the the Fox Fur Nebula, whose convoluted pelt lies at the upper left, bright variable star S Mon immersed in the blue-tinted haze just below the Fox Fur, and the Cone Nebula at the far right. Of course, the stars of NGC 2264 are also known as the Christmas Tree star cluster. The triangular tree shape traced by the stars appears sideways here, with its apex at the Cone Nebula and its broader base centered near S Mon.

Image:

10x5 minutes for a total of 50 minutes at ISO 1600
Stacked in DeepSkyStacker, Dark Subtracted
Processed in Adobe Photoshop CS3 Extended
Taken on December 8, 2010 at the Louisville Astronomical Society Observatory, in Curby, Indiana

Equipment:

200 mm f5 Konus Newtonian with Baader coma corrector and UV/IR cut filter
Losmandy G11 Gemini GOTO mount on Heavy Duty Tripod
80 mm f5 Orion Shorty Autoguide Scope with Starshooter autoguider