Ha acquisition

[Brian28]

Hi all , when taking a sequence of frames for Ha , do you still need to take dark , bias and flats  ? 

 

Cheers Brian 

[red dwalf]

a lot depends on the camera your using

 

 

[Hallingskies]

Flats most definitely.  I must admit I don’t mess around with darks and bias, I just take out the noise with a preprocessing hot pixel filter in Astroart.  Depends how picky you want to be I suppose, but it works for me.  My camera is an ATIK 460 but other cameras may not be as forgiving.

[Wiu-Wiu]

Flats for each filter, darks and bias could be made once and used as master frames for a while. 

[Spaceade]

7 minutes ago, red dwalf said:

a lot depends on the camera your using

 

Specifically Bias's, effectiveness depends on the level of noise banding.

[david_taurus83]

Hi Brian, flats are always recommended for each filter. If your Ha subs were the same length and same temperature (cooled camera) of your RGB subs, then you can use the same darks as the RGB subs. However, since Ha is fainter than broadband RGB, sub lengths tend to be longer so you would need new darks if this is the case. Bias frames depend on the camera. If a DSLR, then I've always shot bias. I now have an ASI1600 and I've read bias is not necessary.

 

To sum up, dark frames need to be the same length and temperature of the light frames. So if your RGB frames were 180s then you'd need 180s darks. If your Ha frames were 600s then you'd need 600s darks.

[Brian28]

Thanks Guys ..