One astrophotograph is better than ten
Category: Astrophotography method
Posted by: Tom How
A really deep, high contrast and low noise astrophotograph takes a large amount of exposure, even on a fast telescope. All beginners make the mistake of not concentrating full on a single target
When you start out in astrophotography, you will be very happy just to see your target on the laptop screen, and grab a couple of frames. The pleasure comes from actually getting the equipment to work and seeing astronomical targets on the laptop screen in far greater detail than you'd even seen before in the eyepiece.
As you progress in astrophotography, you'll start to concentrate more on the finished images than the actual process involved. The process is a means to an end, and the end is a nice picture!
One thing that I am constantly telling new astrophotographers is to take MORE FRAMES. It is tempted to collect 10x60s on ten different targets in the course of an evening. However, 100x60s exposures of a single target will result in a finished image which is of more value and gives more pleasure than the ten lesser photographers.
This is, of course, very very difficult. It is somewhat boring to simply sit and wait for the photons to be collected. Learn to do this. Buy a dobsonian so that you've something else to do whilst the imaging rig is doing its job.
On my reasonably fast F5 telescope I rarely take less than 2 hours of total integration on a single target. Four hours is quite normal. Six hours is not unheard of. Especially when you get into narrowband imaging, vast integrations are vital to get a smooth quality data set which you can aggressively process.
Of course, there is a danger here, especially in narrowband imaging. The more exposure you take, the more details come out in your image. The more exposure you pump into an astrophotograph, the more the low contrast astronomical features become visible in your astrophotograph. So there is a temptation to "carry on". You think "perhaps I should add another couple of hours". So you do. And then some more low contrast features creep into the dim areas of your astrophotograph, and so the wheels turn.
At some point you need to stop - but to take really good astrophotographs takes a minimum of a couple of hours of data. 10x60s might look recognizable, but two hours of data will give you a transformation.
When you start out in astrophotography, you will be very happy just to see your target on the laptop screen, and grab a couple of frames. The pleasure comes from actually getting the equipment to work and seeing astronomical targets on the laptop screen in far greater detail than you'd even seen before in the eyepiece.
As you progress in astrophotography, you'll start to concentrate more on the finished images than the actual process involved. The process is a means to an end, and the end is a nice picture!
One thing that I am constantly telling new astrophotographers is to take MORE FRAMES. It is tempted to collect 10x60s on ten different targets in the course of an evening. However, 100x60s exposures of a single target will result in a finished image which is of more value and gives more pleasure than the ten lesser photographers.
This is, of course, very very difficult. It is somewhat boring to simply sit and wait for the photons to be collected. Learn to do this. Buy a dobsonian so that you've something else to do whilst the imaging rig is doing its job.
On my reasonably fast F5 telescope I rarely take less than 2 hours of total integration on a single target. Four hours is quite normal. Six hours is not unheard of. Especially when you get into narrowband imaging, vast integrations are vital to get a smooth quality data set which you can aggressively process.
Of course, there is a danger here, especially in narrowband imaging. The more exposure you take, the more details come out in your image. The more exposure you pump into an astrophotograph, the more the low contrast astronomical features become visible in your astrophotograph. So there is a temptation to "carry on". You think "perhaps I should add another couple of hours". So you do. And then some more low contrast features creep into the dim areas of your astrophotograph, and so the wheels turn.
At some point you need to stop - but to take really good astrophotographs takes a minimum of a couple of hours of data. 10x60s might look recognizable, but two hours of data will give you a transformation.