Stacking multiple AVIs

[jambouk]

This website suggests it is possible ti image Saturn for 10-14 minutes, which makes sense as there is so little in terms of sharp surface features I can't imagine it makes much difference, unlike Jupiter.

http://www.rkblog.rk.edu.pl/w/p/saturn-imaging-tips/

Anyway, if I imaged for say 10 minutes, the AVI would be massive, circa 25GB. I've found registax stops being friendly at about 5GB, so if I broke the AVI up into five 5GB AVIs, how could I go about stacking them all? If not in registax, in what software? (I'm capturing in Firecapture now, previously Sharpcap)

Could I some how stack one 5GB file, then use that processed image as the template for the next 5GB AVI to stack on top of it?

Give the cloud and forecast I don't think I'll be doing any of this in the near future

Thanks for any replies.

James

[cgarry]

Firstly, I have to say I disagree with that advice. Saturn does have some surface detail (sometimes there are more features than at other times) but you will never see this detail you use such long capture times.

A few thoughts if you do want to try long AVI captures though:

* Use the 'Extended AVI mode in the latest versions of Firecapture to ensure you generate valid AVI files. You can also enable lossless compression to keep the file sizes down.

* Run you large AVI through PIPP (or several shorter AVIs in join mode) to centre, crop and quality select the best frames. Then process this AVI with RegiStax.

* Use AS!2 instead of RegiStax as this is better with longer AVIs.

Rather than use one long capture I would recommend taking multiple captures back to back, stack and sharpen each one individually and then combine them together with WinJUPOS.

Cheers,

Chris

[jambouk]

Thanks chris.

What are the advantges of doing say 5 x 2 minute AVIs and then joining them, rather than one 10 minute clip?

I'll have a look at the other software you've talked about. That's really useful, thank you.

James

[cgarry]

What are the advantges of doing say 5 x 2 minute AVIs and then joining them, rather than one 10 minute clip?

The advantage is WinJUPOS derotates each image so any surface details do not get smeared. WinJUPOS is a great piece of software, though does have quite a learning curve.

Here is an example of using PIPP to produce a smaller AVI file with only the better quality frames in it:

http://sites.google....uasge/example1C

Basically lots of software to play with on cloudy nights once you have some AVIs under your belt.

Cheers,

Chris

[jambouk]

It's the computer side of things i find tedious! If there was a software package i could just load the data into and it churned out a nice image, i'd probably pay £500 for that!

I'm still working on collecting good data too. It's all very much a learning curve.

I'll check out those programs. Thanks again.

James

[jambouk]

Why would the images need derogating if taken using an equatorial mount?

James

[cgarry]

It removes the planet's rotation, not the rotation introduced by an alt-az mount.

Chris

[jambouk]

I am on my phone in a costa in bournemouth so can't check that link above which would probably answer my question, but surely the only way to remove the rotation of the plant around it's north-south axis is by selecting adjacent frames over the shortest time frame possible. Or am i missing the point?

James

[cgarry]

I am on my phone in a costa in bournemouth so can't check that link above which would probably answer my question, but surely the only way to remove the rotation of the plant around it's north-south axis is by selecting adjacent frames over the shortest time frame possible. Or am i missing the point?

James

Yes, that pretty much used to be the way it was done but did lead to some frantic imaging, especially with RGB filters. WinJUPOS has been something of a game changer in that respect, derotating the planet in software.

Chris

[Daddystu]

Saturn rotates quite quickly on its axis although not as quickly as jupiter. This may effect a long avi capture (certainly a number of consecutive long ones if stitched) although your stacking program may be able to compensate to some extent.