> STACKED IMAGE VS. LONG EXPOSURE
Witch is better. Stack or long exposure? It depends…
Long exposure will reveal more details but stack will improve the contrast and faint details by decreasing the background noise. It also decrees the atmosphere turbulence winch as the noise has a random distribution (of course this is more obvious for short exposures)
Long exposure is also hard to shoot as you need guider setup. Also at my place there is a lot of wind, so this is a hard thing to do. Best is to estimate the limited exposure of the sky background and do a stack with that exposure. To estimate it look at the histogram the peak should be 1/3 away from the left.
Below is a comparison of Galaxy M33 between long shot – 80 seconds at ISO 51200 and stack of 20 frames by 30 sec. at ISO 12800.
The single frame is easier to process but stacked frame give us more signal to noise ratio. We can always add more and more signal by taking extra frames. You can use higher ISO and reduce the noise that way.
SKY is the limit :)
One shot:
Stack:
If you have used DeepSky stacker to stack RAW files, maybe you have notice that the resulting image is poor of color saturation. This is because it has a higher number of bits then the display could show.
Last test from passed night put an end of the questions witch is better CCD or CMOS. My old CCD K-m fall back compared to CMOS K-5.
HDR stands from High Dynamic Range. In short it is the number of tones that compose the image. The larger it is, the best capability we have to see details in the bright and dark regions of a scene.
Witch is better. Stack or long exposure? It depends…
NGC 7000, South America nebula in Cygnus, taken by me from NAO Rozhen. 2 shots composed by 45 frames @ 30s, ISO 51200 with SW 200pds and Pentax k-5. Same processing with DeepSky Stacker and LightRoom.