More on webcamming doubles.....

[chiltonstar]

Any hints on how to best stack webcam images of complex doubles like epsilon Lyrae? I've noticed that the stacked image (eg see below) is not really sharper than some of the individual frames, and has a lot of "mess" around each pair due to the complex diffraction ring structure being stacked oddly - I used Registax 2, choosing each pair as an alignment point. I can obviously remove the mess in PShop, but clearly, a better stacking approach would be preferred.

Scope 5" Mak, no Barlow, 1300 frames stacked.

Chris

[lunator]

Hi Chris

I got my best images using a 3MP camera.

The images were taken afocally. Generally I toook several images and usually one came out the best due to seeing fluctuations.

You needed an exposure of around 1 second to get the fainter stars.

Cheers

Ian

[chiltonstar]

From a resolution point of view for close doubles, isn't it better to use a webcam and Registax to catch those moments of good seeing, rather than a normal camera?

Chris

[chiltonstar]

Couldn't edit, so I've added this separately.......

I've found that post-Registax gaussian smooth seems to work well without distorting the apparent star image size, eg Epsilon Lyrae 1a and 1b, smoothed and unsmoothed:-

Chris

[lunator]

Chris

Fom my experience, the seeing affects both stars the same and so the benefits of capturing the good seeing moments are less I am sure this is to do with the stars being point sources as opposed to planets that are a disk that have details within it that can be affected by seeing more.

I found that a 15 second exposure gave me 11th mag stars. I am not sure how faint a webcam can go. This is why I stuck with afocal as my preferred method of imaging doubles.

The results you have got are good

Keep them coming as I am interested to see how effective webcam are.

Cheers

Ian