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Finally... (Nearly) a clear night on NGC7023

AndyUK

By AndyUK
in Imaging - Deep Sky

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AndyUK

AndyUK

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I wouldn't normally post this as it's a "Work In Progress", but as it's been SUCH a long time, I was just greatful to get out last night!

Unfortunately the clouds hadn't looked at the BBC weather forecast so they didn't realise that they were supposed to be taking a well-earned rest after having turned my garden into part of the Amazon basin, but at least it didn't rain. Consequently I was only able to capture 20x600s luminence, but the guiding was just about the best I've ever had :).

Obviously I need some more data on this before I can then move on to the RGB... but the forecast is now looking not quite so good again, and with the nights now getting shorter, I'm just hoping this one doesn't turn into another project I need to return to next year :)

However, this was "first light" for my repaired moonlite focuser (long / embarrassing story :headbang:) which I obviously had to refit/adjust and go through collimation from scratch (not one of my most favourite tasks!) - I think I still need to do a little more work on the scope, but I'm hopeful that I can get her singing again soon and hopefully the clouds will get fed up of covering my back garden and visit some other country for a few months...

post-18819-13387777357_thumb.jpg

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Anweniel

Anweniel

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Wow a stunning Iris there Andy, lots to look at even in the dark stuff and it certainly gives that three dimensional feel, I'm sure the colour channels will add much but I always enjoy these luminance only from deep shots like this.

but as it's been SUCH a long time, I was just greatful to get out last night!

I think we all felt like this and I am now glad that it was enough to convince you to give us a sneek peak at this work in progress - lovely :)

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Gina

Gina

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Oh yes! That's looking very good :headbang: I was hoping to have another go at it last night but couldn't even find it - don't know why, other objects I slewed to were well in the frame - very puzzling and somewhat annoying :) Oh well... Maybe we'll get some more clear skies again soon...

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Uranium235

Uranium235

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Good start, you might want to think about starting the RGB next because from what I remember, you need tons of it (unbinned) to get the brown stuff (think NGC1333, but not quite so mind-meltingly difficult!).

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AndyUK

AndyUK

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Anweniel - Thank you...! This will be my 3rd crack at this - Last year with a DSLR, and a few weeks back I had a go with the Equinox 80. I never got enough data with either, and I should probably have tried to add some more data to the Equinox 80 image, but I've been itching to try the MN190 out again for nearly a month, and this is really the best placed object for me at the moment...

Gina - I had a problem with this a few weeks ago and that was with a wider FOV scope (400mm FL). I never did get to the bottom of it - I was on it and then slewed away to Alfirk (the nearest named star) to check focus, but when I tried to slew the few degrees back... it had gone :). I ended up packing up for the night and creating a false green channel instead, but thankfully it didn't happen last night. Very odd... but obviously user error! :headbang:

Uranium - I still want to come back to that NGC1333 (now that I have the TRF working!), but I think you're right about not binning the RGB on these dark nebulae. I'll admit I was tempted though as 2x2 binned resolution with the MN190 will still gives 2.64 arcseconds/pixel, but that exercise on NGC1333 certainly taught me quite a few lessons. I don't think it's possible to ever get too much data on these dark nebulae, and thankfully I should be able to get to this for quite a few months now so hopefully I can keep topping it up over the summer from the back garden... If it hadn't been for the 2+ hrs clouds last night, I'd have had c. 50% more luminence, but even then I was expecting I might need to allow 2 nights... and then probably at least 1 full night each for the R, G and B.

(A far cry from my first images when I thought 15-20mins would get me something worthwhile - I'm now looking at 15-20 hours! :))

Mark - (I wonder who really wants the weather we've been having? I thought about suggesting somewhere, but then remembered this is a global forum so decided against it!).

These dark nebulae fascinate me, but I've yet to really do one justice - The noise has always beaten me to date... or to put it another way, my processing skills aren't up to it! I keep coming back to the dark nebulae images that Harel and Olly post, but I don't think I'll ever get to that level...

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ollypenrice

ollypenrice

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Terrific. You have a bucket of data there, Andy.

You are beginning to lose the core but that's very easy to sort out. I'd just do a new stretch looking only at the core. Stop stretching when you have that right, the star still looking like a star. Then either

- paste the short one underneath and use a well-feathered eraser to remove the saturated parts from the top (starting with a larger brush at low opacity and repeatedly erasing a little more with diminsihing brush sizes...

Or

-do it the hard (but proper) way, pasting the short one on top and following Jerry Lodigruss's technique. http://www.astropix.com/HTML/J_DIGIT/LAYMASK.HTM

Although I try to avoid noise reduction I accept it as a fact of life on the dark stuff, so I selectively noise reduce only the faint areas. I think most people do that.

Olly

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AndyUK

AndyUK

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Thanks again very much everyone for the encouragement!

I can't believe that we had ANOTHER clear sky last night, but things didn't quite go as planned...

To answer Catanonia's question, I was indeed considering 2x2 binning as that way (I thought) I might be able to get 60 x c.90s on each channel and that would be it in one night... But then I changed my mind and decided to go unbinned and get 35 x 240s per channel (I haven't done my G2V calibration yet) and accept that I'd then have one more night at getting the Green. Fortunately I set the sequencer to take 60 frames (I don't know why) and started with the red filter... and then promptly forgot to set an alarm to remind me to change the filter about 1am... and woke up at 0315 :)!

So I'm now on Plan C and will pray we get another 2 nights reasonably soon so that I can get 60 G and B on separate nights...

Olly - Thanks for the suggestions re not blowing the core - I've tried to do the "Lodriguss proper way" 2 or 3 times (with varying degrees of success) and will have another go once I 've got all the data. Even though I think (with Plan C) I'm going to have a reasonable amount of data, I'm still dreading trying to process it - I wasn't too successful with NGC1333, but that was with somewhat less data, so I'm keeping my fingers crossed - My "consolation" from last night is that the Red doesn't look that shabby...

Catanonia - As mentioned above, I certainly did consider binning, and I may have got away with it (at 2.64 arcsecond/pixel resolution) but this inadvertant Plan C means that (hopefully) I also have the option of seeing what a straight RGB will reveal as well - I'd like to say that was my plan all along... but it wasn't (it was the Jack Daniels!)

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Catanonia

Catanonia

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LOL @ Andy, Mr Daniels has a lot to answer for ;)

Good luck with getting the rest of the data, at times I love my F2.8 for that very reason with this horrid British weather :)

Looking forward to the final result, looks like it will be a corker.

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AndyUK

AndyUK

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I think you're more confident than I am, but thanks anyway! If newts didn't need collimating, then I'd have one of those f2.8 jobs like a shot - This would have been finished 2 nights ago! :)

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