Widefield shots - LMC, Carina, Orion

iceman (Mike) · #1 09-03-2005, 09:44 AM

Hi guys.

As I said, there's a couple more that I processed last night and here they are.

They are all taken with Sony DSCP100 on a fixed tripod, 2 or 3 shots @ 15s (ISO400) stacked in registax, processed in photoshop. I can't do any longer than 15s, or any more than 3 stacked shots, otherwise I get star trails.

Click on the image to go to the full version, with mouse-over labels. If the labels are already there, mouse-off to see what I mean Full-size versions are around 200k, and with mouse-over images, another 200k. Dialuppers take note.

Orion

LMC area

Carina area

Thanks

rumples riot · #2 09-03-2005, 01:35 PM

Nice wide fields Mike, Especially like the Carina Shot.

MiG · #3 09-03-2005, 05:27 PM

Pretty cool. I should try image stacking. I've only tried single exposures at ISO 50 and 100 so far.

Have you tried stopping the lens down? It makes the stars look way nicer (sharper and without chromatic abberation). I saw a big difference between F2 and F5, although that's quite a big light reduction too.

[1ponders] (Paul) · #4 09-03-2005, 11:08 PM

What f ratio were you using Mike. Actually Mike imaging orion that close to the celestial equator your lucky to get 15 sec.

iceman (Mike) · #5 10-03-2005, 06:20 AM

These were taken at f2.8. My digital camera only gives me 2 manual settings for f/ratio. I can set the exposure time no probs, but i'm either f2.8 or f5.6, that's my only options.

f5.6 might be better, but it cuts in half the amount of light coming in so I just wouldn't get as much detail. I can't increase the exposure time to compensate without a tracking mount or a barn-door tracker.

Thanks for the replies.

MiG · #6 10-03-2005, 08:47 PM

Quote:

Originally posted by iceman
...f5.6 might be better, but it cuts in half the amount of light coming in so I just wouldn't get as much detail. ..

Even worse, a factor of 4 because the aperture size is reduced by 2 hence the area by 4.

Can you stack more images to increase the brigtness? The quality increase should be worth it.

iceman (Mike) · #7 10-03-2005, 08:50 PM

No, because the stars will trail if I stack more than 2 or 3. If I had a tracking mount, I certainly could.

[1ponders] (Paul) · #8 10-03-2005, 09:03 PM

Mike, Robby told me of a technique in PS to align your images and I modified it to take into account rotation when I was doing my asteroid shots. If you've not bumped or moved the camera its not toooo bad. Just takes a bit of fiddling. If your interested in using a slower f ratio let me know and I'll write it down and post it. Otherwise you could try the rotate option in Registax. I've had limited success with it but it does work on the right images.