Help! Moon, webcam, mosaic, where to start?

[themowgli]

Hi all,

Help needed. (I have googled this but can only come up with peoples finished articles rather than the process). First up I'm a noob with imaging/webcam, and I'm a bit stuck with the process of making a mosaic of the moon and need some guidance.

I've taken 5 different avi's using sharpcap, which I hope/think covers the whole moon. Then I figured I should next stack them in registax. I'm a new user, so maybe I'm not using it correctly, but the final image comes out a bit squiffy. So couple of questions.

1) Is using registax the first thing to do after capturing the avi?

2) If so, how can I stack the frames so that it only captures one part of the moon at a time. ie. i believe its trying to stack a picture of one sweep of the moon i.e. from one side to the other. Is this the wrong way to do. Soory for posting what is probably a really dumb question, but I just can't make head nor tail of it.

Appreciate your help.

Thanks

Am using a 8" dob btw, so moon is drifting across FOV.

[smerral]

I'm not sure I fully understand you, but you need to stack each avi individually in registax. When doing the first one, save the wavelets setting so that each section is processed in the same way. Then you need to use another software to stitch them together.

[Cornelius Varley]

Hi all,

Help needed. (I have googled this but can only come up with peoples finished articles rather than the process). First up I'm a noob with imaging/webcam, and I'm a bit stuck with the process of making a mosaic of the moon and need some guidance.

I've taken 5 different avi's using sharpcap, which I hope/think covers the whole moon. Then I figured I should next stack them in registax. I'm a new user, so maybe I'm not using it correctly, but the final image comes out a bit squiffy. So couple of questions.

1) Is using registax the first thing to do after capturing the avi?

2) If so, how can I stack the frames so that it only captures one part of the moon at a time. ie. i believe its trying to stack a picture of one sweep of the moon i.e. from one side to the other. Is this the wrong way to do. Soory for posting what is probably a really dumb question, but I just can't make head nor tail of it.

Appreciate your help.

Thanks

Am using a 8" dob btw, so moon is drifting across FOV.

I think your main problem is that you are using a dobsonian mounted telescope for the imaging. Ideally you need to image one discrete area of the moon at a time then moving on to the next overlapping area. By using your method, Registax will have problems trying to stack frames using a constantly moving target, hence your problems will the final images.

Peter

[dmahon]

Each AVI should concentrate on a certain part of the moon, tracking it as it moves. If the AVI sweeps across the moon from, one side to the other, Registax should disregard the bits of the image on either side and only keep the small part in the middle which appears on all the frames.

When you have taken your AVIs, each concentrating on a part of the moon (though you want a small amount of overlap to help you later on), stack each AVI seperately, so that you end up with 5 images, and process each one similarly. Then stitch them together, a bit like a jigsaw puzzle, with another program (eg Photoshop).

Eg:

[themowgli]

Each AVI should concentrate on a certain part of the moon, tracking it as it moves. If the AVI sweeps across the moon from, one side to the other, Registax should disregard the bits of the image on either side and only keep the small part in the middle which appears on all the frames.

When you have taken your AVIs, each concentrating on a part of the moon (though you want a small amount of overlap to help you later on), stack each AVI seperately, so that you end up with 5 images, and process each one similarly. Then stitch them together, a bit like a jigsaw puzzle, with another program (eg Photoshop).

Eg:

Thanks for the replies folks. I thought this was the case too, so thought it maybe something I was doing wrong in registax. Looked through all the FAQ / help etc, couldn't find exactly what my problem was. However, with what Peter has said, maybe there's too much data there and the program can't cope. I would have thought it would be able to keep the bits that appear on all frames too but maybe I'm expecting too much here. Is there anyway to split the avi up into different parts perhaps or telling registax I only want to stack frame between say 1-100 i.e. 10 seconds worth of video if at 10fps. And then repeat the process on frames 101-200 etc etc. Is this possible, and if so how?

Thanks again folks.

Simon

[Cornelius Varley]

VirtualDub is the tool you need.

Peter

[themowgli]

Thanks, Is that to split the file up into however many parts? If so, before feeding back into registax, what's the limit with the area of the moon I should use each time. i.e. a tenth? twentieth?

Thanks again

[Dave Smith]

If you use the scan frames button in Registax it will draw a rectangle around the area that is present in all frames. You can then see if it is big enough to proceed. Then set your alignment points within that rectangle.

Dave

[themowgli]

Hi Dave,

Thanks for the reply. It seems my initial problem is that I was doing a sweep from one side of the moon to the other in one single avi file. I did 5 in all, just pushing the scope down a little each time, so that I would cover the entire thing. So I think that was where registax was falling down in that it couldn't stack all the frames in the entire sweep together. Not sure if I'm fully understanding how to use registax properly either though, so back to the drawing board. I may try and split the file up (using virtualdub) into smaller sections, as mentioned above, and seeing if registax likes that any better. I guess I wont get as many frames for each section as the scope was drifting, but its a start, unless anybody else has got any other suggestions of the best way to proceed.

Thanks