Star Adventurer: Many short or few long exposures ?

[Astrofriend]

I continue with my Star Adventurer experiments how to get the most out of it.

I can notice when I taking 120 seconds exposures with my Star Adventurer mount and the 150 mm camera lens I sometimes get elonged stars. And with that long exposures also the brighter stars oversaturate.

How will my equipment perform if I take more and shorter exposurers, can my Canon 6D handle that? It has relative low readout noise at higher ISO settings but limited dynamic range then.

Here I have done two tests to compare:
http://www.astrofriend.eu/astronomy/tutorials/tutorial-dynamics/tutorial-dynamics.html

At least in this case I feel the camera can handle the shorter exposure and still have good dynamics.

I live close to a big city, but I have found two places out in the east close to the coast where I have a relative dark sky. With my small Star Adventurer I can easily go out there and doing astrophotographing.

Almost all my earlier AP have been done with a very lightpolluted sky.

/Lars

[Demonperformer]

I use the results of this article to decide on my optimal sub-length (although others dispute the algorithm). It is where I got the formulae in my signature, and a short discussion on some of it can be found here. Once you know your optimal sub-length and the total time you want to capture, it is a simple division of one by the other to determine the number of subs.

[Astrofriend]

Hi,

Thanks for the equation, I will investigated deeper later.

/Lars

[Astrofriend]

I took a new set of photos, both exposure time and ISO setting was different.

 

http://www.astrofriend.eu/astronomy/tutorials/tutorial-dynamics/tutorial-05-dynamics.html

 

For me it's hard to see any difference, or what do you say?

 

It's only the green channel.

 

/Lars

[sloz1664]

If your imaging project is M45 The Pleiades, then you want sort exposures of say 120s so as not to over expose the star cores. This will help keeping the stars tight and greatly reduce the star trailing. 

Steve

[Astrofriend]

Hi Steve,

I only use M45 as a testobject. My exposures were 30 second and 120 second. But total only 8 minutes for each set. I try to optimize it for comet photos later this week, fast moving comet. But heavy clouds every night. From the test I have done so far there isn't very much difference if I use only 30 seconds exposures relative 120 exposures.

/Lars