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M45 The Pleiades/Seven Sisters... 1 year on


TakMan
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Hello again....

Had a bit of a cold (man flu) over the weekend, so it allowed me some processing 'free time' to have a first go at sorting my next lot of data out... my longest combined exposure to date of six and a half hours! :p

This time I was able to nail the focus using my newly purchased RoboFocuser and the 'auto focus' V-Curve routine from within the Equinox Image software I use.

I've added a comparison to a first attempt - Imaged on the 22nd Dec 2009 - with the focal reducer in place (taken off for now while I'm still learning the basics): 38 x 300s lights, and posted on here Jan 2010 - my, how quickly we all improve (and become more competent at processing! :)

Details:

RGB One Shot Colour

39x 600sec light exposures - Taken over three nights, and my first meridian flip as I usually get a few hours tracking past it... just wanted to see what was involved...! The final image did require about 10% cropping to accommodate my poor alignment over the three separate sessions.... and my slightly misaligned meridian flip data...:p

Flats(+Bias), Darks processed

Tak FSQ106-ED @ native - 530mm/f.5

SBIG 4000XCM - OSC self guiding @ -20c

IDAS-V2 filter

Tak EM400 mount

Control via 17" G4 Apple Powerbook running MicroProjects Equinox 6 (mount control) and Image (camera control/image acquisition).

Pre-processed, aligned and stacked in Nebulosity2.

Post Processing in PhotoShop CS3 + Noel's Actions

Thanks for looking....

Damian

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Love to see these skill evolution shots as it gives newcomers hope for improvement, the depth and noise control are fantastic in the first image clearly a big improvement.

John.

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Clearly the new image is much smoother and more attractive but be aware, maybe, that there is faint detail in the old one that isn't in the new. M45 lies in some faint dust which is not being much illuminated by reflection and I think a few wisps of that show in the rougher image, notably lower right.

However, the new one is very classy!

Olly

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Thanks everyone for the comments!

What I should have added:

how quickly we all improve (and become more competent at processing!

is to say that I would still be floundering at 'stage 1' if it had not been for the encouragement, help and advice offered so freely (and patiently), by the members of this forum.... especially; Peter Shah, Olly, RobH, Kevin 'BeyondVision', TJ and SteveL to name a few... thanks guys! :p

What was the meridian flip like :(

An unnecessary pain really...! The Tak mount is not troubled passing the meridian - I just keep an eye on the guiding figures as the weight shifts and make sure the camera is not about to hit the mount... :p That means I can get a few hours extra in if needed. To be frank, after that time has elapsed, the target is descending into the murk/light pollution anyway so it would be time to call it a day anyhow.....

If memory serves, the star I was using for focusing was well past the meridian (hence the flip) so that's partly why I thought I'd try it! Obviously, once I'd selected the star, the mount 'did it's thing' automatically and to be perfectly honest, the resulting re-framing was quite close.... I chose to have a fiddle though :headbang: and of course all the slew commands were then back to front - so I made it worse....!

I have changed my process now.... rather than slew back to my original 'focusing' star, I keep a running log of a non-bloated star within the image, about 1/3 out from centre and check the FWHM figures shot-by-shot. I don't jump if they start to slide as I'm sure you're aware that the focus can shift with atmospheric disturbances etc. I just keep an eye on it and after I start to see a trend, I give the RoboFocuser a nudge and check the next shot against my tally.....

be aware, maybe, that there is faint detail in the old one that isn't in the new. M45 lies in some faint dust which is not being much illuminated by reflection and I think a few wisps of that show in the rougher image, notably lower right.

However, the new one is very classy!

Olly

Olly, I'm sure you're right.... I just thought that the image was starting to break down, so tried to resist the temptation to keep pushing (as I thought you may take me aside for being too agressive with the old levels/curves too!) Perhaps I'll get another 5-6 hours on it later in the year (it'll soon come around again! :D ), and then push it a bit further....

The actual image is slightly lighter/less contrasty - black clipped.... this has had to be 'tweeked' to try and get it to display on here....:headbang:

Thanks Fay It's quite scary to see how far you've come in such a short space of time isn't it!? How's the new camera performing them....? Just so you know - this is NOT your Robo unit (the one on the FSQ is one I purchased new from the States), I got yours for a 'future project'.....('right price at the right time!')... just got to keep that bit under wraps from the wife for a bit :)

Thanks again everyone....

Attached are some screen caps showing the focusing routine and my focus logging as I image - for those that are interested, especially any Apple Mac imagers who are somewhat limited in the software department....

Damian

Oh, just remembered - the very faint edge on galaxy (left edge - in the centre, 2cm in) is UGC 02838, 17.29 mag.... but can't find any other data on it...?

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Edited by TakMan
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It's a killer, choosing between noise and the faintest signal, I know!! But a guy on the French forum and Dennis (Roundycat) over here encouraged me not to fear a bit of noise - texture, if you like - and I see what they mean. I leave it in now, though not shouting too loudly.

Olly

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I am thinking that this "flux" everyone wants to capture now, used to be known as noise, what do you think?

Fay

Noise is transient - for the same image alignment the pattern changes between exposures, regardless of exposure length.

Flux is fixed in distribution in an image with the same alignment, the pattern only changes between exposure length or through atmospheric churn/cloud.

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