The Most Important technique for Deep Sky AP

Time is the most expensive commodity there is and is not refundable. Use it wisely!

After years, and many tools, accessories, and various expenses, once you properly understand the basics, the most important skill is one and only one: time and therefore the quantity and quality (because selection must be RUTHLESS) shots aka data, the rest is futile.

True but, as always, there is more to it.  Less than ideal equipment or less than ideal setup of either equipment or software can waste the one component that everyone agrees there is too little of and that is time. Poor focusers, poor mounts, messy cabling, and much more,  the list of potential causes of (unnecessarily) bad data is long. Dealing with weather and seeing and the moon are bad enough w/o screwing things up ourselves by failing to do things right or cheaping out on equipment.

Arun H:

time and therefore the quantity and quality (because selection must be RUTHLESS) shots aka data, the rest is futile.

More accurately, photons. To an extent, aperture can compensate for time.

But that makes you just want to go deeper! The funny thing is, with our highly automated rigs getting long integration times has never been easier. It's also not as impressive when you know that at lot of the time was spent sleeping, watching Netflix or going out to dinner. Not only is it important, it's never been easier.

Tony Gondola:
The funny thing is, with our highly automated rigs getting long integration times has never been easier. It's also not as impressive when you know that at lot of the time was spent sleeping, watching Netflix or going out to dinner. Not only is it important, it's never been easier.

Being old I really appreciate that I can sleep. I started this just before the first ST4 auto guider and I know I would no longer be doing this if I had to stay up all night hand guiding or even manually starting exposures!

I used to manually guide back in the film days and I kinda liked it. I doubt I can do it now but I still manually slew and start exposures for at least one rig. Manually focus all them (3, sometimes 4). And I like being out under the stars and I wouldn't be doing AP if weren't for this. I just wish for a better weather than the current one. Somewhere tropical-ish and pitch-black dark.

I'd add neuropathy in my case so obi one automation kenobi is my last hope. I'd exchange all this AI crao to be able to get under a dark sky…
That said I think a lot of people, including me,  change or add gears when they should focus on the real stuff, which is the total integration time for a choosen target. Diminishing return is not a good excuse 😀 

Do not forget also that a new scope is the shamanic rituals to invoke wheater.

I totally agree. A few months ago I made a commitment to gathering at least 40 hours of data on each target. I have not been disappointed.

Franco Geraci (aka Voloire):

BryanHudson:
As being 100% mobile, setting up and tearing down for each session, capturing 20-40 hours is not realistic for me. I don’t prefer to capture data for the same target night after night. My aim is to get the most out of 1.5 to 3 hours of imaging. I’m very content to enjoy the superior work of those who grind to capture hours and hours of data. 
I enjoy getting the most out of the time I have. This image is 1.5 hours of integration. All the images my AstroBin gallery are 1-3 hours. I come from the world of traditional photography where the “joy of photography” is my aim. I suppose my thinking comes under the heading, “too each his own.”

 amazing take my good friend! Nice job on that bubble :-)

Thank you!

Brian Boyle:
Being old, I am painfully aware of how precious remaining time is.

Those who say time is free must be young.

On balance more time on a target is generally better, but dont forget the systematics which can really impact the idealised SNR calculations.  I am in awe of those who manage to get close to the idealised SNR limit in 20+ hr integrations, but it is not for me. My one 40hour imtegration was on the Helix, and I was happy with it, but the opportunity cost on other targets was significant. 

I am equally in awe of some of the post-processing techniques that have been  introduced in recent years.  

So for me, it remains a balance.

I hear you Brian!

For my interests recently, I often want minimum limiting magnitude.  In that case I have found that with my short f.l. refractor, I can match what I see in some of the DSS2 images, if and only if, I am shooting in Bortle 1 with just a few hours.  Certainly, my noise floors cannot compare to a 40 hour exposure under that condition, but for me NXT seems to resolve that issue mostly.  If I had more access to B1 skies, I certainly would dig deeper with time.  When I shoot from my B4 home site, I get all the time on a subject I can, but would likely blow a whole season on three targets!  So like most others who responded here, I do with low integration totals.

Oh, and I am old and like my sleep!  But when in B1 skies, I love being outside with the gear, comfortable recliner and binoculars.

Franco Geraci (aka Voloire):
20+ hours minimum per object, better 40.

possibly true in many locations.

But I image from Bortle 1 and 20 hours is not required. 

with my wide field refractors F5 between 5 and 10 hours is enough. adding more does not seem to improve the results. 

some of my best images happened with about 3 hours of data, on nights of great seeing.

Seeing quality and Focus are more important than time on target IMHO. 20 hours of crappy data wont lead to a great image.

Just my opinion.

andrea tasselli:
Time is the most expensive commodity there is and is not refundable. Use it wisely!

Truer words were never written. 

I'm also old, and I also image mostly from a Bortle 1. Even so, my goal is 40 to 80 hours on a target depending on various other factors--weather, seeing, transparency, the moon, rig operations, target availability, and my larger agenda.

Quality of data matters a lot--it's essential. But my experience is that 40 hours of quality data will produce a far better image than three hours. It's not even close. But it depends on what you want. If you want to get the Ha bridge between M86 and the Eyes, you might need 200 hours--even in a Bortle 1. If you want a good take on the IFN around Polaris, 20 hours is probably a good start. If you want the dusty regions around M72, I can tell you from experience that 7 hours at F8 isn't enough. 

But Andrea is right. Time is supremely expensive. I've mitigated that cost by placing three scopes in the New Mexico desert with a fourth coming in June. Once I got all three rigs operational, I found that anything less than 40 hours per target produced more data than I could ever process. So my 40 hour minimum goal not only helps me produce better images, it also helps me preserve my sanity and my marriage.