I have a silly newbie question here.
Taking astrophotos from Bortle 9 skies here in Singapore, what exposures do you set in order to get dim objects such as Flame and Horsehead nebulae?
I usually get images that are washed out and processing them after stacking just creates noise and artifacts.
I currently do not have any narrow band filters nor is my DSLR Astro modified.
Any advice from the experts here would be greatly appreciated!
Thank you!
Exposure times
Exposure times
I can only identify Orion! 
Re: Exposure times
Just for reference, my equipment is as follows :
Laptop with PHD2
SV205 guide camera
Angeleyes 50mm guidescope (190mm focal length)
Orion ST120mm (600mm F5) Achromatic refractor
Canon EF 70-200mm f2.8L lens
Sigma 120-300mm f2.8 lens
Maxvision 150/750 F5 Newtonian reflector
iOptron CEM-25P mount
Canon EOS 6D DSLR
Laptop with PHD2
SV205 guide camera
Angeleyes 50mm guidescope (190mm focal length)
Orion ST120mm (600mm F5) Achromatic refractor
Canon EF 70-200mm f2.8L lens
Sigma 120-300mm f2.8 lens
Maxvision 150/750 F5 Newtonian reflector
iOptron CEM-25P mount
Canon EOS 6D DSLR
I can only identify Orion!
Re: Exposure times
Hi Vince,
There are detailed qualitative treatments to evaluate optimal exposure times for your given imaging location, factoring your system setup, etc.
However the short answer to this could also be just experimenting with various exposures and ensure fundamentals like the resulting stretched histogram does not have the dominant hump too far to the right (best to have it just 1/3 from the left). The essence behind this thought is to ensure nothing gets too overexposed (eg: sky background brightness vs object brightness). Without narrowband filtration and LPS filters, it could be anywhere from few seconds (30 seconds) to 1-5 minutes. Try at various exposure times of the same object at the same setup and locale conditions, and put the lights data into appropriate exposure folders and check the histogram from appropriate softwares. At my end, i have found 5minutes to be optimal, but it is based on RGB monochrome DSO imaging (for a 3.5" refractor).
The above also assumes you have overcome and ensure that your mount is tracking well enough (and autoguiding well), to have good decent HFD star profiles.
Good luck!
There are detailed qualitative treatments to evaluate optimal exposure times for your given imaging location, factoring your system setup, etc.
However the short answer to this could also be just experimenting with various exposures and ensure fundamentals like the resulting stretched histogram does not have the dominant hump too far to the right (best to have it just 1/3 from the left). The essence behind this thought is to ensure nothing gets too overexposed (eg: sky background brightness vs object brightness). Without narrowband filtration and LPS filters, it could be anywhere from few seconds (30 seconds) to 1-5 minutes. Try at various exposure times of the same object at the same setup and locale conditions, and put the lights data into appropriate exposure folders and check the histogram from appropriate softwares. At my end, i have found 5minutes to be optimal, but it is based on RGB monochrome DSO imaging (for a 3.5" refractor).
The above also assumes you have overcome and ensure that your mount is tracking well enough (and autoguiding well), to have good decent HFD star profiles.
Good luck!
Re: Exposure times
Hi rcj,
Thank you for the very informative advice!! Appreciate it!
Yes, my tracking mount is decent enough to track long exposures up to a minute plus.
I'm still trying to find out the optimal exposure times + ISO to get the cleanest reference frame.
In the meantime, my ZWO ASIAir has arrived and I've been playing with it (when weather permits) along with my ZWO ASI120MM guide camera.
Thank you for the very informative advice!! Appreciate it!
Yes, my tracking mount is decent enough to track long exposures up to a minute plus.
I'm still trying to find out the optimal exposure times + ISO to get the cleanest reference frame.
In the meantime, my ZWO ASIAir has arrived and I've been playing with it (when weather permits) along with my ZWO ASI120MM guide camera.
I can only identify Orion!