Recently Browsing 0 members
No registered users viewing this page.
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.
NGC281 - The Pac-Man by Chris Kennedy, on Flickr
35kph gusts of wind, and REALLY bad guiding due to a lack of drift align and the star being "blown away", but managed to get a little something out of 30x360s light frames, also a new target for me, one I want to come back to under better conditions and with other wavelengths of light to make a full colour image.
While I am waiting for enough astrodark to make it worth while up here, I have revisited my Pacman nebula data from November last year, since I had the feeling that there were more nebulosity there to bring out. Most Pacmans I have seen posted on the web are processed quite hard and only bring out the central parts - maybe to emphasize the Pacman figure. However, I just saw a Ha image of Pacman at Astrobin that reveals a lot of surrounding Ha-nebulosity, particularly to the right of the nebula (http://www.astrobin.com/full/144610/0/).
So here is my revised version showing more of that surrounding nebulosity. Below it I post my old version for comparison.
Processed in PS CS5 now also using the APF-R technique (http://www.cedic.at/apfr/) to bring out more faint stuff and a round of Hi-pass filtering to bring out more structure in the nebulosity.
Equipment: ES 127EDapo with a Canon 60Da on an EQ8
29 x 360 sec, so totally about 3 hours.
Any comments and suggestions most welcome - I am sure it can be improved