M81 from Tuesnoad

[MarkS]

Saturday at DSC was pretty good.  The sky was not very transparent for most of the evening but it was very still - even Sirius was hardly twinkling.

This is a preview of the image I took.  I squeezed as many subs in as possible before the clouds came over.

My guiding was the best it has ever been (I'm not quite sure why) and the C11 was precisely collimated on the Friday evening with an artificial star halfway across the field!  The reducer to CCD distance is still not correct because I'm waiting for some spacing rings - therefore there is residual coma in the image.

Details:
40 x 5min (i.e. 3hr 20min) modified Canon EOS 350D on Celestron C11 with F6.3 focal reducer. 2x2 binned in software and cropped to 1280x1024.

The fullsize image is here:  http://gallery.orpington-astronomy.org.uk/albums/userpics/10046/m81dsc.jpg

The smaller one is below.


For comparison, the one I took in Sidcup with a CLS filter appears in this thread:
http://forum.orpington-astronomy.org.uk/index.php?topic=4306.0

I think you'll agree, the DSC image is much less noisy and brings out more detail in the spiral arms.  Some of the tiny stars are also very sharp - probably because of the good conditions.

Mark

[JohnP]

That is really excellent Mark - Very smooth & detailed & you even have some faint fuzzies in the background.. A great result especially like you said transparency was not the greatest last night.

John

[Fay]

That is a greart image, Mark, so focused & guided well. It shows how much better images are when there are a lot of subs

[RobertM]

Very nice for a preview Mark.  Much more contrast and shows lots of promise for the final version.  Could be your guiding was down to the conditions, I've noticed differences from day to day and have put it down to just that.

[Fay]

Gosh, Mark, if that is a preview!!!

[Rocket Pooch]

Very good Mark, will look great when its complete.

[Carole]

Excellent image as usual Mark.

[Whitters]

Nice one Mark, you can see so much more structure in the fainter areas of the arms. Great image

[Mac]

excellent and no signs of the rockets

[Tony G]

So thats what you were doing all night. 

Great image Mark and seems like it was well worth the wait, and thats only the preview image.

Tony G

[Mike]

Superb M81 Mark.

[Rocket Pooch]

Very nice Mark.

[MarkS]

I've finished tinkering with the image now.  Removed the background gradients; improved the overall sharpness (by deconvolution) and enhanced the contrast in those weird dust lanes.

Full size here:  http://gallery.orpington-astronomy.org.uk/albums/userpics/10046/m81dscv2.jpg



Mark

[Fay]

Mark, that is superb, one of the best!!! You must be very pleased

[RobertM]

Mark, that's absolutely superb.  You've just sharpened it enough that the stars don't look too artificial and brought out excellent detail in M81, can't see any noise either.  The faint Holmberg IX galaxy has shape and detail and there's a hint of  M81 arms filling the void between the two.  You should submit this to one of the astro mags, it's got to be a good candidate for image of the month.

There's a small amount of coma and perhaps toning down the core a tad might improve it further (I know that't tricky!) but they're fairly minor niggles.

Well done!

After seeing what difference the dark sky has made to your M81 I may take a couple of nights at that new campsite before the next DSC.