Planetary imaging, video vs images?

[mbaddah]

I'm seeking the expert advice of all you planetary imagers out there :)

Something that's always confused me is, when imaging planets, is there an advantage of recording a video then splitting them in individual image files rather than simply taking images from the beginning? What are the advantage/disadvantage of each method?

Many thanks in advance.

[duncan]

Hi mbaddah,

Probably the biggest reason for capturing video is seeing conditions.
Look down a bitumen road on a very hot day and the end of the road looks like it is shimmering all over the place. By using video at say 10FPS(frames/second) you can capture the odd good frame. When run through programmes like Registax the bad frames are discarded, good frames are kept and aligned and then stacked together to bring out more detail.

Thats my very basic understanding of it.Hope it helps.
Cheers,
Duncan:thumbsup:

[mswhin63]

Occasionally when seeing is really bad, I like to view each image and manually remove the really bad ones, as these can have a tendancy to spoil the final result if the setting are not quite right in Registax.

This is especially good for smaller planet in my scope at least. EQ mounted scope may not be so bad.

[iceman]

I'm not 100% sure on what you mean. Do you mean finding the high quality frames out of the whole video sequence and using only those?

Or do you mean processing the files in registax as individual files, or as an AVI?

[kinetic]

One of the usual ways to capture is to save as an AVI.
An AVI is a movie file which is just BMPs as individual frames
of a movie.
As has been said, the AVI movie capture gets LOTS of frames
saved very quickly and captures the odd really good, crisp frames.

If you just went 'click' take a frame, 'click' take another, you might
only get 1 good frame out of 1000!

Taking an AVI at 15 frames per second or faster gets you lots more
data to work with.

Then the next step is a bit of a choice.
My method is to open the AVI with a program called AVI2BMP
which does just that, it re-saves the AVI as separate BMPs.
I then feed that set of BMPs into Registax which has a quality
estimate function that can be set up to compare your best frame
in the set to every other frame.
On a good night of seeing, some AVIs of 1000 frames might get
you 300-500 good frames that are useable.
On an exceptional night, you might get 750 good ones, maybe better.

Then you register and stack them in Registax or DSS and go from there
with post processing such as deconvolution or Unsharp masking etc.
Novices like me can get something from nothing with a bit of hard work.
Masters like Mike, Paul, Bird and Trev make my stuff look like a waste
of time :)

Steve

[mbaddah]

Ok so if I've understood correctly, the reason it's better to record a video is it's a much faster method of obtaining a series of images rather than just rapid screenshots? Makes sense to me :) Thanks for the responses.

[bmitchell82]

Not just a much faster way of capturing,

That is just a by product of the capture method, when the atmosphere stills it could be for .5 of a second if your taking 15 photos a second then you just caught 7 crystal clear images.

If you get say 5 still moments per minute you just captured 35 crystal clear frames and in DSO if we captured 35 crystal clear frames we would be doing backflips.! :)