Only Slightly Flocculent!

[Warhen]

Here is NGC 1398 (http://www.billionsandbillions.com/ngc_1398.html) in Fornax. Hope you enjoy! This is the first SSRO set's acquisition that I was in on. Our U9's sensor has over 100 legitimately bad columns (dead). PI's CosmeticCorrection does a good job, but don't look at the BG too closely (Paul ;>). Also could have used more color frames for a bit more richness. At f/11, even 6h per channel of 1,200 sec subs look weak. Definitely need >8h per. Thanks for looking guys, and enough mit de excuses already! :>)

[Tony_]

Great image Warren - no excuses needed here.
Magnificent looking galaxy - great structure.

Tony.

[SimmoW]

yes, looks great to me.

So whats the best way to fix the bad columns, is it the CosmeticCorrection you mention Warhen? I've used some iTelescope cams before and haven't been able to fix some of their shocking dead columns.

Ta!

[Warhen]

Thank you mates! Simon, what camera was that? Seems sometimes the 'better' the cam, the worse the sensor is- not cool! :>) Are you using PixInsight Simon? A combination of Superbias creation, and defining a template with the locations of all the stinkin' columns for cosmetic correction to use after calibration does most of the trick, though some residual artifact remains.

[SimmoW]

Thanks Warren, yes I have PI. Haven't got access to the iTelescope bias files, might have to ask them.

[Warhen]

Simon, look at the PI forum or my tuts. You create a Superbias from a master bias- it helps define fixed patterns. Much more important though is the CC template with all the columns defined- beginning and ending locations X/Y locations.

[RickS]

A very nice galaxy image, Warren! Fascinating structure.

My KAF-16803 develops a new iffy column every few months. I keep a bunch of defect lists/CosmeticCorrection process icons by date and have to remember to use the right one when working on old data!

Cheers,
Rick.

[gregbradley]

Stunning Warren.

Greg.

[Warhen]

Thanks Rick n' Greg! Rick, are we talking 'white columns'? That's generally just a hot pixel that spills it's charge over and those calibrate out well, especially with dithering. Now black columns, those suck. See attached guys, this is a lovely section of the U9 which I inverted for you- white are actually black/bad columns!

[RickS]

Warren,

These are dark columns (and occasionally partial columns) that don't calibrate out well. Using the defect map (and dithering) produces good results.

Cheers,
Rick.

[multiweb]

Can't stop looking at it. That's one really pretty galaxy. Superb rendition. Some serious image scale here. What FL are we talking about?

[Warhen]

Thanks Rick. Marc, 4.5 meter f.l. .41 arcseconds per pixel. Thanks for your kind comments.

[multiweb]

Just saw your rig on your website link. Didn't realise you're in Chile. Seeing must be extraordinary which explains the detail at that image scale. Hope you guys are not affected by the recent volcanic eruption.

[clive milne]

Absolute corker of an image Warren!

[Ross G]

Amazing galaxy photo Warren!

Ross.

[batema]

Stunning.