Orion wide field reprocessed

[rcheshire]

I need to get a life.

This is a reprocessed orion wide field. This time with what I believe is proper bias, dark and flat frame calibration - except that the flat is at iso 800.

Canon 1000D, 247 frames, average 15 seconds, 200mm, f/2.8 - 3.2, approx 62 minutes - unguided.

It seems to me, that without overdoing the processing, this is about what to expect from an image of this size. Maybe someone else could extract more data - histogram attached.

[Octane]

Rowland,

Hope you don't mind, I had a two minute play in Photoshop with the attached JPG.

Note, the halo around M42 is not something that I've introduced -- it's in your data. Not sure where that's come from other than some kind of processing done in Pixinsight?

There's some data in there. :)

H

[rcheshire]

Thanks H. No problem, it's good to get a second opinion.

I have a feeling that it's a combination of the dithering issue, calibration, possibly the flat and the method of integration/pixel clipping, and the camera/sensor - or so I'm told.

I'll start again.

[irwjager]

Seems to me you got a great life, practicing astronomy! :thumbsup:

I think I got a wee bit more out of the JPG, but like you, I wouldn't want to overdo it with the processing.

Nice going!

[rcheshire]

That tool set is amazing Ivo. But I need to get some of the PI processes under control, particularly pixel clipping.

I found the problem. Basic really. The final combination of the exposure subsets required a different clipping algorithm. Having done that the quality of the image and any underlying problems is immediately evident in the L* channel. Unless I push it really hard, the streakyness and milky appearance is all but gone. Differential flexure is a large part of the problem, but I've managed to minimize that by integrating the images in the way that I have.

The lesson is dithering - reframing the subject periodically throughout an imaging run. This is true for unguided work, particularly with accurate polar alignment - a fluke.