Registax for Saturn - Just "smudging" the image?

[maxwolfie (Greg)]

I'm trying to stack 99 light frames (RAW files from a DSLR) of a very, very tiny Saturn. When I stack them, they all just "smudge" the Saturns across the screen.

Examples below:
One raw frame:
http://img805.imageshack.us/img805/7062/saturnone.png

After stacking:
http://img696.imageshack.us/img696/8104/saturnz.png

How can I get Registax to actually "align" the images so that I only have one Saturn?

EDIT: Also, is there a way to zoom in to say, 200% or 300% in Registax? It would make processing a bit easier when my target is so small.

FWIW I've tried using Ninox however I'm finding it very difficult to use.

[Shiraz (Ray)]

Never seen that effect Greg - should work with default settings if you put a single smallish track point on the planet (say 30-40 pixels). Select drizzle when you stack to get a bigger result and possibly improve the resolution.

which version are you using? Is the single image of the same size as those you are stacking, or has it been cut down in size? Does the planet move a lot between frames?

[maxwolfie (Greg)]

Registax 6. I've just cropped it for the sake of not having a massive file on the forum. Saturn itself is tiny compared to the entire frame. The planet moves a LOT between frames, as I was shooting on a standard fixed tripod.

Any ideas?

[sheeny (Al)]

G'Day Greg,

So you are taking these shots on a fixed tripod, not tracking, correct?

I think you will find this results in too much drift between frames for registax to correctly register Saturn. I think it might be registering (aligning) the background noise.

You could try manually aligning saturn i.e. select manual aligmnment, single alignment point and go through each frame and select Saturn in each frame. There is an option on the alignment page to select the amount of zoom.

Good luck... you are really pushing the limits!

Al.

[maxwolfie (Greg)]

Originally Posted by sheeny

G'Day Greg,

So you are taking these shots on a fixed tripod, not tracking, correct?

I think you will find this results in too much drift between frames for registax to correctly register Saturn. I think it might be registering (aligning) the background noise.

You could try manually aligning saturn i.e. select manual aligmnment, single alignment point and go through each frame and select Saturn in each frame. There is an option on the alignment page to select the amount of zoom.

Good luck... you are really pushing the limits!

Al.

Yep, just a fixed/static tripod. There is a fair bit of difference between where Saturn is on each image.

I've tried manually specifying the alignment points for each image but I had no luck (same result). Any ideas as to how else I might be able to align and stack these images?

[sheeny (Al)]

Well you could go right back to basics.

Load them all into Photoshop as a stack. You could try to see if Photoshop can align them , but I doubt it will - the bit you want to align is so small compared to the background.

Zoom in to about 400%, and turn all the images off except the bottom one of the stack. Turn the second bottom one on and make it 50% opaque, then drag it till it lines up on the bottom image. Repeat this with each successive image in the stack.

When you have them aligned, adjust the opacity of each image from the bottom to 1/n opacity e.g. 100%, 50%, 33%, 25%, 20%, 17%, etc. this will ensure each image contributes the same amount to the final stacked image.

Have fun!

Al.

[ZeroID (Brent)]

I've had similar problems when there are insufficent alignment points or too much movement between frames. Old Registax 2 seems to actually do better than 5 or 6 for some reason but I think Al is right, it looks like a manual job.
Is there enough detail to be worth the exercise ?

[Screwdriverone (Chris)]

I used PCFE for splitting the "sliding" images of planets from a non tracking DOB into 400x400 pixel centred BMP's which were then loaded into Registax.

PCFE standard settings allow for it to determine the centre of each FOV (ie the planet) and therefore provide you with ALIGNED versions of the planet, Registax can then process these easier.

Try PCFE, there is a link on Mike Salway's Planetary Processing guide article here.

Take a read of the article, its here http://www.iceinspace.com.au/63-306-0-0-1-0.html

Cheers

Chris