From Cygnus to Orion - The Milky Way as an Ultra Widefield Mosaic - WIP

[Gina]

Using 28mm f3.5 lenses on ASI 1600MM0Cool cameras and Astrodon 3nm filters I am starting a project to cover the Milky Way in a mosaic of something like 6 panels.  Each panel will have a FoV of 36x27 degrees. I shall be taking Ha and OIII wavelengths to start with and may go on to add SII later.

This is Cygnus & Cepheus in Ha and OIII and a couple of bicolour versions.

 

 

 

Edited December 28, 2020 by Gina

[Gina]

This screenshot from KStars shows the area (FoV) of the first panel.  This seems to cover the main DSOs with little in Vulpecula or Lyra.

[Nugs]

Cracking images there Gina, good to know its possible in our locale, from a fellow Blackdown dweller. 😉

[happy-kat]

What a super project Gina. A cracking first panel. Just my sort of wild field images.

[Gina]

One of the problems of making mosaics is that the camera needs rotating from one panel to the next if the panels are going to follow on neatly.  This first panel is with the cameras at -45°.  The next panel above it needs turning to 0°.  This FoV is shown in the next screenshot.  To provide this I shall be making a dual imaging rig with remote camera rotation.  This will be the subject of another thread.

[Gina]

Next panel, +50° camera angle.  Ignore the moon - capture will have to be when the moon is out of the way.

    

[Gina]

Panel 4.  Two possible alternatives.  On the whole, I think I prefer the second.

   

[Gina]

Mosaic panel 5.  Orion.  Looks like the panels don't quite join so I may have to reduce the overlap on other panels.  I wasn't expecting to cover it in 5 panels.

[happy-kat]

Perhaps when you join panel 1 and 2 it will give a feel for what overlap and angle change works.

[Gina]

The sky was such that I was able to image the Orion area a few nights ago and here are some results.  The FoV doesn't match that for the mosaic as I didn't have remote camera rotation nor had decided how the mosaic would be built up at that time.  I'm not totally satisfied with the results - I think the OIII was overexposed.

Here are some image stacks resulting from processing a couple of hours of Ha and OIII together with a simple colour combination.  Processed in PixInsight.

Edited December 28, 2020 by Gina

[Gina]

5 minutes ago, happy-kat said:

Perhaps when you join panel 1 and 2 it will give a feel for what overlap and angle change works.

Yes indeed.

[vineyard]

This is going to be a great thread to follow, thank you.  The Ha & Oiii monochrome versions at the top are really nice.  Is there vignetting in the corners?  (I ask b/c I was tinkering w an old manual focus prime lens 50mm f1.7 - am just about to post a quick & dirty image in another thread, and I think I was getting vignetting).  If so will the vignetting increase the number of panels needed?  I'm going to learn by watching this thread! 🙏🏾

[Gina]

I do get slight vignetting but it is corrected using flats.

[Gina]

Here a link to my thread :- Dual and Triple Widefield NB Imaging Rigs with Remote Rotatable Cameras.

[JeremyS]

Super images @Gina!
 

[Whistlin Bob]

Lovely images Gina. I especially love the Ha ones- light pollution is significantly more challenging with such a wide field of view and the stronger Ha signal is really batting it down (I'm guessing the Astrodons are helping here! They're certainly doing a better job than my 7nm Baaders over a similar fov). I love the way large fainter areas of nebulosity are coming through.