Andromeda revisited (LHaRGB)

[Uranium235]

carastro, on 10 Jan 2014 - 10:35 AM, said:carastro, on 10 Jan 2014 - 10:35 AM, said:

Thanks for your earlier reply regarding colour.  I did try using binning once, but I found it caused a lot more headache with extra flats, darks and bias and didn't find it easy re-sizing the images to match, so decided not to do that again, but could be my inexperience.

With the severe lack of clear skies here I am hoping to go for Mono for detail and OSC for RGB, but have yet to put this into regular practice as I was having problems with my QHY8L and disconnecting, but I've fitted a retainer clip to it now.  Just need sufficient clear skies to get down to some serious imaging and also opportunities to go to dark skies.

Carole

Ahhh, so youre running two cameras now? That will speed RGB imaging up considerably for you - the only snag I found was (with using guidescope rings) that the cameras had to be tweaked every session so they lined up correctly and didnt waste any pixels - especially if the sensors are of a similar size.

With the binning, I just used flats and bias to calibrate. The hot pixels can be dealt with using a bad pixel map and sigma clipping. Combining is straightforward - rescale your lum master to 75% original size, throw that into Registar, then register the three binned masters against the resized lum. Or you can part process and combine the RGB into a colour tiff before registering it against the lum.

I was going a bit mad with the binning myself last night, and managed to tear a three pane strip from Orion in just 2hr 15min - the equivalent exposure with the 80ED would have taken 6hr 30min. The sampling rate when binned on the 130pds is a borderline 3.4" p/p, but doing the maths using test figures for this camera - its the equivalent of running at approx f3.4. The only downside is that I have a reduced FOV at this focal length, so I have to do a few extra panes. Ive yet to calibrate the data but I will put it up later tonight when its done.

[Spoon]

that latest image makes it look like M31 is pulling material off of M110!

[Uranium235]

that latest image makes it look like M31 is pulling material off of M110!

I can explain that

Its the one part of the image (the gap between M110 and M31) when the LP reduction action (noels) didnt quite reach.... whoops!

[Spoon]

That explains it! Great image anyway, one of the best!

Sent from my iPhone using Tapatalk

[RobH]

That's a belter of an M31 Rob....the Ha data, although it's very subtle, has really added an extra dimension.