M42 by Canon 10D in Tai Po on 25-10-2003 16.59UT

[HK.Raymond.Tse]

Dear all,

This is (my 1st) M42 photo taken jointly with Bug whose manual
guiding technique using very economical method (Celestron off-axis guide and ToUCam on notebook monitor) is excellant and I believe he can accurately guide for a long time (longer than 5 min is not a problem).

Single JPEG image on 25-10-2003 16.53 UT by C8 with F6.3 focal reducer at prime focus of Canon 10D, on EM-200 mount. 322 seconds manual guide at ISO 800.

My simple process in PhotoElements using levels, brightness/contrast. Image slightly cropped and re-sized for posting.

Any suggestions as to how to reduce over-exposure of the central bright stars ?

How do we stack one long exposure image with one short exposure image ?

[oldsaltfish]

if you want to stack 2 photo, just use photoshop or something else to cut the centre bright stars, then paste the centre of the short exposure image and make them matched well.

[oldsaltfish]

例如這個:

[Wah!]

You may select the center part of short exposure image with feather edge and then copy + paste it onto the long exposure frame. May need some more adjustment such as color, contrast, curve....