Veil Mosiac - 2 July 2011

[MarkS]

A mosiac of the veil nebula taken last night at DSC.

This is a mosaic of 4 pieces, each piece is 5 x 5min at ISO 800.  Taken, as usual, with a modified Canon 350D with a CLS filter on the Tak Epsilon 180ED.



Bigger version is here:
http://www.markshelley.co.uk/Astronomy/2011/veilmosaic02072011.jpg
This bigger version is 2x2 binned then cropped.

It's a work in progress - I want to shoot a lot more data for this and process it more carefully - removing some of the background gradients.

Mark

[Rocket Pooch]

That looks like a fab start, are you going to do the part further down as well?

Chris

[mickw]

yep very nice

[Carole]

Very nice Mark, looking forward to see this progress.

Carole

[Fay]

5x5 mins, that looks really good Mark. Will be great wen finished

Fay

[MarkS]

That looks like a fab start, are you going to do the part further down as well?

Probably not - no.  I think aesthetically the image is quite balanced as it is.

[Mac]

Very nice.

Just a thought,

will you get better data, by mosaicking?
or would you get better data by using a shorter lens, i.e. a 300mm or something that will give you the same field of view?

Mac

[PhilB]

What a great result. Just spent some time cruising the full size image - fabulous!

[JohnP]

Nice one Mark - Nice structure captured - The top 1/4 or so of image looks brighter to me - is that just down to the nebulosity or is it a gradient of some kind..?

Nice,  John

[MarkS]

will you get better data, by mosaicking?
or would you get better data by using a shorter lens, i.e. a 300mm or something that will give you the same field of view?

A very good question - I've thought about this a lot.  The Tak is 500mm at F2.8   By doing a 4 piece mosaic (with overlaps) I cover an area roughly the same as using a 300mm lens.  I'm binning the data down 2x2 during processing which, broadly speaking, means that the 4 x 5 x 5mins I took is equivalent (in terms of photons captured per pixel in the final image) to 20 x 5mins on a 300mm lens a F2.8  Hence, for an equivalent signal to noise ratio, there is no difference in total integration time between the 2 approaches but I would suggest that unless you pay a fortune for the 300mm F2.8 lens then the mosaic will give a much sharper final image.

The top 1/4 or so of image looks brighter to me - is that just down to the nebulosity or is it a gradient of some kind..?

It's a gradient that still requires removal.

Mark

[RobertM]

That's a great start Mark, with an incredible amount of detail showing for that exposure time.  Can't wait to see the final result.

Regarding using a Camera lens,  you wouldn't need to go for one of the same f/r.  Since you're capturing four times the area you could use an f/4 lens instead of f/2.8 if you kept the exposure times the same.  Alternatively if you want to spend mega dosh then you could use f/2.8 to do it in a quarter of the time.  Either way you would loose resolution over the Tak.

Robert

[Mike]

Looking great Mark. Can't wait to see the final result.

[MarkS]

I added another 5x5min for each of the 4 pieces on 3 July at home.  So each piece is now 10x5min.  This has certainly improved things.  I'm still not entirely happy with the mosaic itself because the joins are fairly obvious from the changes in background gradient.   I clearly need to play around with this a bit more.



Here are the medium and large versions:
http://www.markshelley.co.uk/Astronomy/2011/veilmosaicv2_medium.jpg
http://www.markshelley.co.uk/Astronomy/2011/veilmosaicv2.jpg

Mark

[PhilB]

It's starting to look very tasty indeed, Mark.

[The Thing]

Aaaahhhh!!!! Too many stars! Awesome. Hope you can sort out the joins without too much bother.