Binning and sub length Ha LRGB help please

[Danjc]

I have read loads recently but I'm still a little unsure on what to go with re the post title....I appreciate that there is no given and there are lots of variables to take into account.

Gear,

SW Evostar ED80 with SW FF/FR

Zwo ASI183mm-Pro

Baader 7Nm Ha & Baader LRGB filters

Bortle 6, Mag 19.06 going off clear outside app.

 

On Astronomy tools CCD calculator I'm confused as I seem to be able to get away with maybe binning at both 1x1 or 2x2 with OK seeing or am I not taking something into account ?

 

HA sub length I appreciate pretty much as long as I can manage but binning unsure.

LRGB just not to sure ?

 

This is an image quickly stretched of Ced214 which was just for test purposes and the first chance I had to try the LRGB filters.

The data is very thin at 9 x Lum 120s & 3 x each RGB at 120s all at unity gain (111) binned 2x2.

 Any help or advise is appreciated.

Dan.

 

 

[freiform]

Hi Dan,

unlike CCDs, binning for CMOS chips is software only. You will loose 2 bits in depth, which might not hurt itself, but the readout noise will increase due to the quantization error. There is no reason to use a CMOS camera's binning modes unless you want to quicken focusing runs or plate solving, etc. If you are heavily oversampled, downsample after acquisition.

Regarding exposure, there's some useful recommendations for the ASI183 on CN:

https://www.cloudynights.com/topic/616524-sub-exposure-tables-for-the-zwo-asi183mm-and-qhy183m-and-colour-versions/

Last night I tried high gain (200) for 120s OIII subs and on first glance the subs look good. With the low read noise at high gain of current CMOS chips and the resulting short exposure times, you can really take the pressure off a small mount .

Sven

Edited October 28, 2019 by freiform
typos

[jimjam11]

See this lengthy thread. With cmos capture unbinned and then apply binning if appropriate as part of post...

 

The exposure tables on cn are excellent guides...