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Mosaics ???

Mav359

By Mav359
in Imaging - Discussion

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ollypenrice

ollypenrice

Posted
Posted

I model the panels on SkyMap Pro, take the central co-ordinates, slew to those and it's usually fine. I don't use long slews, though. I re-synch on a star close to the target first. It is much much easier to do masaics with the chip in portrait or landscape aligned to RA and Dec.

Olly

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ollypenrice

ollypenrice

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So your panels match a grid parallel with the DEC axis?  Hmmm... How do you do that please?  I shall have a crack at that too.

Skill and daring? No, dead easy.  :grin:

Take a 3 second sub (binned for speed) while slewing in either RA or Dec. This will produce star trails. Bring up your crosshair reiticle in Artemis Capture (or lesser programmes!!!) These trails will be at an angle to the crosshair. Rotate the camera and try a return slew. Are the trails better or worse aligned? Adjust and try again. This takes a couple of minutes and will save you a couple of hours in years to come. If only I'd known!

Olly

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kirkster501

kirkster501

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Skill and daring? No, dead easy. :grin:

Take a 3 second sub (binned for speed) while slewing in either RA or Dec. This will produce star trails. Bring up your crosshair reiticle in Artemis Capture (or lesser programmes!!!) These trails will be at an angle to the crosshair. Rotate the camera and try a return slew. Are the trails better or worse aligned? Adjust and try again. This takes a couple of minutes and will save you a couple of hours in years to come. If only I'd known!

Olly

Most ingenious. I shall investigate that one further :)

Sent from my iPhone using Tapatalk

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martin_h

martin_h

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I use Al's Reticule  http://www.iceinspace.com.au/forum/showthread.php?t=21798 to achieve the same thing, but use a 1 second looping exposue while slewing the scope in RA. And I work to a grid, If the mosaic is going to be a big one I draw a grid and number the squares, using those numbers for the file names, then pencil in the coords into the grid so I can return to that position on another session.

grid-2.jpg

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Uranium235

Uranium235

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I just find three reference points, one on the camera, one on the focuser, the other on the dovetail.

With a refractor I would (by eye) align the focuser locking screw with the bolts of the dovetail bar. Next I would align the fixed point on the camera with the locking screw  - the 383 has a centrally placed photo thread on one side of the body, I popped a machine screw in there and it acts as a perfect marker.

The newt is a little different, but I figured that one out by aligning the straight side of the 383 with the flat edge of the focuser mounting. You will know if youve got it right when you start calibrating your mount via the camera, if its off then you will see your calibration stars coming in at a slight angle from what the reticle says.

From there I use the markers function in Atremis, saving markers in the folder for each panel. It works fairly well, but I still try to be generous with overlaps in mosaics becuase at some point you may be fighting field curvature (depending on sensor size). Also, make use of the "user objects" function on your mount  - you could store each panel (as you go along) as a user object to give you a rough framing - then tweak it using the markers - its useful if you have to slew away to bright star to refocus after a filter change.

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Gina

Gina

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I like EQMOSAIC which I've used once only due to cloud and other bad weather and various other problems.  I found it very easy to use and it will keep a record of which panes you've already done so you can carry on next time.  That plus AstroTortilla go get me exactly in the rioght place to start and I'm good to go as they say :)  I too set up my camera(s) with the axes along RA and dec axes.  It may be a while before I do another mosaic though as I have new gear to set up.

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Gina

Gina

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I've only tried Canon PhotoStitch (useless) and Microsoft ICE (much better) as yet but plan to try PixInsight when I get a decent set of panes.  It looks complicated but very powerful and I shall probably end up buying it.  It will do things no other software can do.

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Gina

Gina

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..and there ly'eth the problem.  So few nights to practise that you want to get on with astronomy and AP and not fiddling with kit.

Yes, that's exactly how I felt last night.  A clear and half decent sky and I hadn't done any imaging for a long time (or it seemed like it).  So although I knew I ought to get my PA better, I did imaging instead.  AND I'm quite glad I did because the data was rather better than I had expected :)

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kirkster501

kirkster501

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Yes, that's exactly how I felt last night.  A clear and half decent sky and I hadn't done any imaging for a long time (or it seemed like it).  So although I knew I ought to get my PA better, I did imaging instead.  AND I'm quite glad I did because the data was rather better than I had expected :)

http://www.harrysastroshed.com/Mosaic.html

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ollypenrice

ollypenrice

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Cheers guys

Deffo want to have ago at some mosaics.

Can i assume Olly that the star trails should appear parallel to the X-Axis of the cross hairs on the screen.

Or the y. If it's right in x it has to be right in y. But, yes, just get the trails aligned with the sides of the frame or the crosshair.

Olly

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