ASTRO: Three small PN: NGC 6884, IC 5217 und "Footprint" Nebula
In the nights when I collected the data for Abell 80 (http://ccd-astronomy.de/temp12/Abell80colourneugut.jpg) the seeing was quite good, so I imaged some small but bright planetary nebulae in between.
All three pictures were taken on my Berlin rooftop terrace with a 10" Meade ACF at 2050mm focal length on G11 mount and ASI1600MMC camera.
With the small pixels of the ASI1600 I get an image scale of 0.38"/pixel. I show the pictures in 100% size, even if it's not always crisp and sharp. These small nebulae cannot be downsized any more if they should be larger than hot pixels.
I had some difficulty with the enormous dynamic range of these objects. The stars had to suffer a bit in order to show the nebulae in a reasonable way.
All three images consist of approximately 80-120 images at three seconds per channel. IC 5217 is a pure RGB, the other two are LRGB. I didn't sort the images by hand but combined them all with sigma stacking.
NGC 6884 in Cygnus had the best seeing. Despite the large image scale the stars in the unprocessed stacks looked nice sharp.
NGC 6884 is a quite "normal" planetary nebula, it is similar to NGC 6826 and has an outer halo which in my picture it was only seen by extreme stretching of the blue channel and didn't make it into the colour image.
IC5217 in Lacerta has a very unusual shape. It has two bright centers and is rectangular in shape.
The most famous of the three nebulae is certainly the Protoplanetary Nebula Minkowski 1-92, better known as "Minkowski's Footprint Nebula".
Just like the "Egg Nebula", the footprint is a bipolar nebula.
Unfortunately, the seeing was not quite as good here.
Nice job on those little guys. The low read noise of the new CMOS cameras allows short exposures that make for nice resolution but sure eat up disk space like crazy.
I just replaced my imaging computer's 1tb hard drive with a 2tb one as I was getting tired of needing a second drive to keep my current stuff. Bit the bullet and got an SSD drive. Made a big difference when I search the drive for something. With far more stuff to search through it still goes many times faster than before. Saves me a ton of time, should have done it long before. I'd hate to think what I'd need in drives with a CMOS camera. None with a chip my size yet in mono but that will soon change I assume.
I only have a small SSD but I am sure stacking up external harddrives ;-)
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