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First things first, apologies for posting this one out of season. A combination of no astro dark, crappy weather, and being busy at work has meant that there's no imaging getting done at all these days. So, i've had to turn to old data to re-process, and this data set was an obvious candidate as i was never happy with how it came out originally. And looking back on it now with fresh eyes, boy did it need it!
Nikon D5300, SW 80ED, HEQ5-Pro.
3 x 1200s, 2 x 1380s, and 4 x 1500s of Ha
9 x 1200s of Oiii.
11 x 480s with an IDAS-D1, for RGB stars only
7 Hrs 54 Mins in Total.
Stacked in APP and processed in PS.
Combined as SHO (using a 70/30 blend of Ha/Oiii for the Sii).
The main differences this time were, using Starnet++ to create the starless versions, using more Ha in the synthesized Sii (70% instead of 50% last time), but mostly the improvement has come from toning down the stretch a lot (ok, a heck of a lot!) before making the colour map for the tone-mapping. From then on it was immediately apparent that i'd made a massive boo-boo first time round 🙈
I've included a 1080p rotated crop too, as i quite liked the framing.
Feels like ages since i last did any NB imaging. I almost forgot how much i enjoy it! 🙂
And rather embarrassingly, here's the original. Try not to laugh too hard! 😂 😂 😂
I've always found the Pacman nebula (NGC281) very difficult to process in RGB since I always tend to end up with a low contrast image that is largely devoid of detail. So, since I prefer realistic looking colours, I decided to try out a narrow band approach with Red mapped to Ha and Blue mapped to OIII. After balancing the Ha and OIII data in Pixinsight via Linear Fit, I generated a synthetic green in PS via Carboni's actions. The result below represents 15 hours integration time and was taken with my Esprit 150. To illustrate the amount of detail revealed, I've also included a small crop of the central region.
LIGHTS: 9 Ha, 21 OIII x 1800s, DARKS:30, BIAS:1000, FLATS:40 all at -20C.
Wakka wakka wakka...
22x 600s Ha, 11x 420s L, 10x 300s R, G and B, darks flats and bias, equipment as per sig, pixinsight.
If I'm honest, I wasn't really feeling the love for this one very much and it's been languishing on my processing shelf for a while - a little too much of it being an amorphous pink blob, coupled with oddly triangular stars (I had issues with coma and collimation when I took it, now resolved, but it meant I was getting tri-lobed guide stars in my OAG and I think that fed through from the guiding to giving me triangular stars in the images. You can't really see them since Flickr doesn't zoom in enough). Still, it turned out alright, and I quite like the detail version.
The Pacman Nebula (NGC 281) is a bright emission nebula and part of an H II region in the northern constellation of Cassiopeia and is part of the Milky Way's Perseus Spiral Arm. The nebulosity is associated with an open star cluster, several Bok globules and a bright quintuple star system. It lies approximately 9200 light years away.
Pac-Man was designed to have no ending – as long as at least one life was left, the game should be able to go on indefinitely. However, a bug keeps this from happening - an 8-bit arithmetic overflow error on level 256 would mean that the game would try to draw 256 fruits on the screen rather than the maximum of 8 that it would normally draw. This corrupts the bottom of the screen and the entire right half of the maze with seemingly random symbols and tiles, overwriting the values of edible dots which makes it impossible to eat enough dots to beat the level. Because this effectively ends the game, this "split-screen" level is often referred to as the "kill screen". A perfect Pac-Man game occurs when the player achieves the maximum possible score on the first 255 levels (by eating every possible dot, power pellet, fruit, and enemy) without losing a single life, and using all extra lives to score as many points as possible on Level 256.
This was actually my second attempt at this target - this was my first one, with a modded DSLR - actually not too bad:
Hope you enjoy ! Comments and cc welcome.
My first attempt at NGC281 was with my ED 80 and taken with my colour camera - and I definitely thought the result looked liked the Pacman.
So, whilst attempting to image this object with my Esprit 150, I thought I'd end up with another Pacman, albeit somewhat more detailed. However, the more I looked at my narrowband result, the less I decided it looked like the video game character. I think this is because my eye was drawn to the various nebula details, which tend to be absent in a broadband approach but reveal themselves with a narrow-band technique. So, for this bi-colour image, I decided to try to enhance the details by experimenting with colour contrast curves and the Pixinsight script DarkStructureEnhance. The image represents 9 hours total integration time.
(If you are still interested in seeing the Pacman, then you need to rotate the image by 180 degrees).
LIGHTS: Ha:8, OIII:10 x 1800s, DARKS:30, FLATS:40, BIAS:100 all at -20C.