Enlarging Image?

[Paulus]

If you have an image with a resolution of 240 pixels / inch and wanted to crop and enlarge an area in the image.

Would increasing the number of pixels / inch in Photoshop to say 960/inch prior to cropping give a better enlarged image?

(I am referring to this http://stargazerslounge.com/imaging-image-processing-help-techniques/118023-1st-attempt-m57.html)

At the moment when I zoom in the ring is lost as there are too few pixels.

Its probably a silly question, when I think about it my first instincts are you can't get something from what is not there.

Assuming that is the case what is the best way to get the ring larger on the image, Barlow lens?

Any help much appreciated

Paul

[Tim]

The best way to increase the size is to use a drizzle method. You can do this in DSS.

x2 drizzle is 4x the picture size, x3 drizzle is 9x the size.

You can use the greater pixel/inch method sometimes to smooth things out a bit, but do try the drizzle method, it works a treat.

There is also a saying in PS that you should only increase an image size by 10% at a time for best results.

HTH

TJ

[Paulus]

Thank you TJ,

I'll give it a go when I get some more data to work with as there is woefully little there at the moment. Lets hope for a few clear nights soon!

Cheers,

Paul

[Tim]

PS, if you use a barlow, you also increase the f ratio, meaning you will need longer exposures to get the same detail.