I cannot resize your too large photo for you, other than "stealing it" to resize it on my computer and then store it in one of the accounts of the picture hosts that I use. Seems like you'll have to resize it yourself.
The noise derives from the high ISO you chose (ISO 1600), even though at a wide open lens (f4) at the lowest possible ISO (100) a 20-second-exposure would not have given you a photo this bright, of course. If you wanted to produce a photo that suggests almost daylight but stars in the sky then choosing the high ISO was the way to go (or a bulb exposure of I-don't-know-how-long ... but loooooooooooooooooong!) - only do you then have to live with the noise. Or put the photo through NeatImage (for example) ... but you will then lose even more sharpness, I'm afraid. For something did move the tripod, some wind, something...