think that yours is a bit too grainy, due to high ISO ... a touch of star trails as well ... 25 secs is a bit on the long side ... esp when you are zooming in. It makes the star trail more prominent ...
But if I don't see high ISO and long shutter, I could hardly see the "star" on the pic. What is the best to capture the point star?
on the other hand, can digital SLR (mine is D70) take star trail? I know it can set to "bulb" i.e. long exposure, control by the shutter release, but din't try that while I was in NZ... now Singapore don't have this kind of night sky....
i don't know if D70 is capable of taking point-stars. becos D70 has a median filter built into the firmware to smooth out noisy pictures.. so your low magnitude stars might be mistaken for noise and get smoothened out. The median fitler is also applied to RAW files according to some astro-photog camera review page. So it's not really "true" raw in that sense.
Nikon has already made known that the D70 was not designed for astro-photography. :cry: your picture may have contained more weaker magnitude stars but might have already been removed.
Try not to zoom in ... my feel is that you were using a zoom lens (southern cross does not look that big on my screen for my pic) that cause the trail to come out at 25 sec ... try using <50mm lens for same time. You should get better results ... and dun use AF but use MF ... needs a few tries to get it right ... that's why I am not posting my pics ;p
While you're at it (with the 50mm lens) use the largest aperture possible to increase the amount of light you'll get for the selected exposure time, if you want distinct points of starlights then with a F/1.4 or /1.8 lens you'll get a few more stops of light compared to the F/4.5 setting you used.