PI Help needed - Problem stacking Oiii

[jjosefsen]

Hi,

I need some help..

Im trying to stack my 33 Oiii frames from two weeks ago.

The result looks "washed out" when viewed with a "normal STF", but looks normal when "24 bit lookup table STF" is applied.

Examples (might need to zoom in to really see):

Problem - Normal STF

No Problem - 24bit STF

 

I have tried many, many different settings! Different rejection algorithms, no rejection, no normalization, different rejection setings, average combination, median combination, you name it!!

The individual subs don't show the same problems when viewed with a normal STF, and the Ha frames i just stacked with the same settings look fine.

 

33 frames in total

Altair Hypercam 183m V2  (12bit)

All frames calibrated with darks and flats and cosmetically corrected.

 

Please help, and let me know if you need any more data.

 

//Johannes

[AstroCava]

Don't worry... 24bit STF is a more accurate representation of data, but the data itself are the same. This difference between visualizations are mainly related with images with High Dynamic Range or high bit depth. You will need to work with 24bit STF until perhaps the final stretch.

Have fun!

Sergio

[jjosefsen]

9 minutes ago, AstroCava said:

Don't worry... 24bit STF is a more accurate representation of data, but the data itself are the same. This difference between visualizations are mainly related with images with High Dynamic Range or high bit depth. You will need to work with 24bit STF until perhaps the final stretch.

Have fun!

Sergio

Thats good to know, thank you.

I still wonder why it is like this though.. I don't think this image is either high bit or HDR.

[harry page]

8 minutes ago, AstroCava said:

Don't worry... 24bit STF is a more accurate representation of data, but the data itself are the same. This difference between visualizations are mainly related with images with High Dynamic Range or high bit depth. You will need to work with 24bit STF until perhaps the final stretch.

Have fun!

Sergio

Or the Opposite with very little Dynamic range as here   its called Posterization

 

Harry

[jjosefsen]

Aha.. this makes more sense to me. Since the Oiii channel is quite weak compared to the Ha.

Thanks guys. Will keep trucking with it. ?