Jump to content

Banner.jpg.b83b14cd4142fe10848741bb2a14c66b.jpg

number of stacking pictures.

twelly27

By twelly27
in Getting Started With Imaging

Recommended Posts

twelly27

twelly27

Posted
Posted

Hi All

Im wondering if there is a general average number of pictures to take of the moon to stack and get a noticeable result from, as im new i thought i might start with about 15?

if anyone has a common number they use please let me know.

Regards

Chris

Link to comment
Share on other sites
ollypenrice

ollypenrice

Posted
Posted

One bit of Registax not to overlook is the resample-drizzle option on the second page. This is remarkable because it allows the software to derive sub pixel information from the stack and resize the picture upwards to exploit it. A free lunch!

Olly

Link to comment
Share on other sites
ollypenrice

ollypenrice

Posted
Posted

Drizzle; imagine a circle photographed in a digital camera of any kind. Zoom in and it will look like a staircase of little pixels rather than a pure curve. Now move the camera by half a pixel left and half a pixel up and image it again. Lie the first picture on top of the second, make it semi transparent, and now your staircase steps will be half the size they were before. You have improved the resoution. Result!! :grin:

But... how can you show this extra resolution? :huh:Your screen still has the same number of pixels so it can only show the extra resolution if you make the image bigger, which you do, by resizing it. :grin: :grin: Now you can show your tiny-stepped staircase to the awaiting world.

This can ONLY be done if each picture in the stack contributes some new information about where the real pure circle lies. This means the target must not lie on the same exact pixels in each sub exposure. In fast frame imaging the seeing and the lack of guiding will make sure that this happens naturally. In deep sky autoguided imaging you need to use dither guiding - moving the mount a tiny amount between subs.

I hope this is a semi decent explanation? Feedback welcome since I teach this stuff to our beginner guests and perfer not to confuse them too much!

Olly

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted

Have you read the article by Craig Stark linked above, Olly? I think it's a fairly good explanation. It also makes the point that the image must be undersampled in the first place which may be why I've had little success with it for planetary imaging as I aim to oversample where possible.

James

Link to comment
Share on other sites
ollypenrice

ollypenrice

Posted
Posted

Have you read the article by Craig Stark linked above, Olly? I think it's a fairly good explanation. It also makes the point that the image must be undersampled in the first place which may be why I've had little success with it for planetary imaging as I aim to oversample where possible.

James

Yes, it's very good.

Olly

Link to comment
Share on other sites
Neeken

Neeken

Posted
Posted

Just read the article Neeken. Very interesting. Thanks for posting the link.

James

No problem.

About to head out for the evening, sky is clear. Quite the moon though, but maybe I'll try and get some better moon shots. Still can't get them totally crisp, maybe today is the day ;)

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.