A footprint in the milkyway

[multiweb]

As the title indicates just trying to sneak a quick M8 past Mr. Sidonio :P ;). Here's a 5 panel widefield around sagittarius that I shot with my 5" newtonian from Wiruna Tuesday and Wednesday night. Got about 75min per panel. Both nights were fine until 12:00am when it clouded over from the south east, but I made the most of it still. It was good while it lasted. :)

Smallish version here (http://www.astropic.net/WF/SAG/SAG_ssf.jpg)[1.69MB]
Bigger version here (http://www.astropic.net/WF/SAG/SAG_sf.jpg)[3.50MB]
... and finally a full version here (http://www.astropic.net/WF/SAG/SAG_lf.jpg)[6.81MB]

I also made a more user friendly zoomable version here (http://www.astropic.net/WF/SAG/)for the ones who have a limited bandwidth.

Thanks for looking. :thumbsup:

[gregbradley]

Superb Marc.

Greg.

[Bassnut]

whoa, epic Marc, nice (relatively :thumbsup:) to view.

[renormalised]

Great shot there, Marc. Great colour, excellent detail. Well done:):)

Only one thing....what happened up in the top right hand corner of the big piccie??

[Octane]

Marc,

Fabulous image!

That's pretty much the same field of view the FSQ/STL combination gives. : )

H

[desler]

That really is Something Marc, Thanks for sharing!



Darren

[DavidU]

Just fabulous Marc. Very tidy work.

[strongmanmike]

Lovely work Marc, the colours look good...what's that nebula on the right though, not seen that one before :question:

Mike

[TheAstroGuy]

Marc,

That's a winner, great shot mate i really like how well you've got so much out of the Trifid, loads of blue O2 around the edges.

Good shot indeed

Regards

Shane

[sheeny]

Excellent Marc!

Al.

[rcheshire]

As usual Marc, a beautiful shot. Scintillating nail polish...

[Phil Hart]

lovely.. a very nice result!

[kinetic]

Beautiful Marc!

Steve

[batema]

I agree with everything said above. I'd love to know how to do a mosaic as well as a lot of other things. Fantasic colours and what camera were you using for this as well as exposures. The weather has been fantastic on the sunshine coast for the last week so we put on an astronomy night at school last night and it rained all day but today is superb Typical. What prohram did you stich the panels together with.

Mark

[multiweb]

Thanks Greg. Glad you liked it. :thumbsup:

Thanks Fred. :thumbsup: Not too shabby for WF BS hey? ;)

Thanks Carl. :thumbsup: Yeah it's me being greedy. If I crop that corner I loose another 2 strips of stars. :lol: ?! :shrug: :P


Thanks H. Go on. You know you want to do it! :)


Thanks for the kind comment Darren. :thumbsup:

Thanks a lot David. :thumbsup:

Thanks Mike. :thumbsup: Yeah... on the right...ermmm, let me get back to you on that one. Waiting on the plate solving results. :whistle:


Thanks for looking Shane. :thumbsup: Yes the blue cloud is fairly extended around M20. If you go deeper I think it even goes further in the field.


Thanks a lot Al. :thumbsup:


Thanks - too kind mate. :thumbsup:

Thanks Phil - glad you enjoyed it. :thumbsup:

Thanks Steve. :thumbsup:



Thank you Mark. :thumbsup: Here's my work flow for this one:

Camera is an older model QHY8 (square body) at prime focus on a Celestron SLT 130. Although I did modify the scope a bit. Flocked the OTA with protostar as well as a 30cm dewshield, changed the focuser to a GSO 10:1 and also shimmed the mirror in its cell. Collimation is also razor sharp.

I have to point out this data was taken in more than optimal conditions. I was by myself at the house. No lights (at all) and no wind which makes a hell of a difference.

The subs are approx. 15x5min each. I calibrated them all in CCDStack, flat fielding (20k ADU - 80 of them) and bias (100 of them). Then I debayered in separate directories to Red, Green and Blue.

Once this is done I indentify the sub with the best FWHM in CCD Inspector and use it for registration. I then align them using Nearest Neighbourg in CCD Stack. Then normalisation by picking the darkest background area and the brightest nebula in the field. Next I run a quick Hot/Cold pixel removal and a STD reject at 2% top to paint all noise and outliers then use mean combine.

Next saved all the master channels and ran 30 iterations of deconvolution positive constraint. Then did a bit of pixel math to balance the colors and push the blues. Blues are always a problem to capture and push in with small aperture scopes in my experience. Once you have all your master colors for each panels you do a color combine in CCDStack and look carefully at the histogram while tweaking the levels then save as a scaled 16bit TIFF file.

Then that's where the fun begins. Load all those TIFF files in registar and align all of them to one central overlapping sub then use union to make the master scaffold frame. Combine using mean/median then save as combine.TIFF. Next load that frame again and register all the masters to it using union again but this time save all the registered masters to TIFF files. So you end up with 5 TIFF files with a big black background and a small square which is the position of the sub in the mosaic.

Next load all the frames in PS as individual layers and delete the black background in each layer. You don't have to align anything as they already match. Order them from top to bottom as Best to worse then select them all and use PS blending function. That will work out all the seams and gradients if any.

From there on you can go on with normal PS processing. HTH.

[h0ughy]

lovely shot and work processing Marc

[Tom Davis]

Beautiful, Marc!!!

Tom

[multiweb]

Thanks for the comments guys. :thumbsup:

[RobF]

Yep, top stuff Marc
You've certainly got access to a wonderful location there at Wiruna.

Good of you to describe the workflow in such detail to for all us "mosaic wannabes" :)

[multiweb]

Thanks very much Rob. Glad you found the broad workflow helpful. :thumbsup:

[Paul Haese]

Great field of view Marc. I like the blues but would like to see some more orange stars in the field stars. Lots of those stars look a little brown to me. Matter of taste for sure. Very nice work overall and impressive to view.

[Martin Pugh]

Very, very nice Marc.

well done indeed.

Martin

[multiweb]

Thanks Paul. I know what you mean. Those golden parts of the milkyway almost like sand that you see in most shots of the area. You do have to push the greens and reds a lot more to get that effect though. It is definitely the case in the lower right part of the field closer to the center of the galaxy where the stars are smaller, many and tightly packed, but you'll find that the top of the field and left towards M20 have a lot more blue stars and the density of the starfield drops significantly. I think I got the colours looking ok but as you said we all have different preferences about colors and shapes.

[multiweb]

Thanks for the kind words Martin. :thumbsup: Hope you get clear skies soon. Leaving Oz? What were you thinking? ;) Talk some sense into Tom as well hey? He's bailing out.

[CraigS]

Hey Marc;

That is totally stunning ...!!!
I feel like I'm sitting inside it all !!!!

Soo many stars !!!

Absolute stunner !!

Thanks muchly for sharing !

Cheers & Rgds.

[beren]

:thumbsup: Marc thats a beauty congratulations.

[multiweb]

Thanks Craig. Glad you liked it. No pressure! ;)



Too kind. Thanks mate. :thumbsup:

[suma126]

that's truly brilliant :thumbsup:

[ChrisM]

Marc, a very nice result. Thanks for posting.

Chris

[multiweb]

Thanks for the comments guys. :thumbsup: