M8 M20 Widefield @ 280mm FL

[dugnsuz (Doug)]

Originally Posted by Craig_L

Great stuff Doug - love it wide. Makes you want to see whats to the right and down below.

Craig

Thanks Craig and welcome back!
Perhaps I ought to try mosaics?
Tricky enough just getting one image sometimes!!
Doug

[Craig_L]

Hey Doug,

It would be good to see a version without the 1.4 extender just for comparison.

Craig

[spearo (Frank)]

good widefield mate!
Dont hang up the camera just yet!
play the guitar while imaging!
frank

[Tilt (Michael)]

Hmm, I'm kind of new to imaging. How do you keep from over exposing the core of the Lagoon Neb? I am imaging right now and the shots coming in look to be a little bright in the center. I am using the 350D on the 70-200 set at f/2.8, ISO1600, 120sec exposures. Should I knock back the ISO? Or set the aperture to f4? I'm dont have any guiding, but it seems to be tracking well on the EQ6.

Michael.

[dugnsuz (Doug)]

Originally Posted by Tilt

Hmm, I'm kind of new to imaging. How do you keep from over exposing the core of the Lagoon Neb? I am imaging right now and the shots coming in look to be a little bright in the center. I am using the 350D on the 70-200 set at f/2.8, ISO1600, 120sec exposures. Should I knock back the ISO? Or set the aperture to f4? I'm dont have any guiding, but it seems to be tracking well on the EQ6.

Michael.

Hi Michael,
That image was done at f4, perhaps that stopped core burn-out to a degree, but I did a little PS magic in curves (just a little) to pull back the core brightness on that pic. Certainly stopping down the lens will sharpen up the stars and nebular detail (but I do autoguide so I can push my exposure times to compensate for this, although for me f4 is the fastest I've got!!!)

As to iso setting - not sure, experiment.
I've found since getting the 40D modded I use iso1600 all the time - I think it's a "maximum from the camera" type of attitude - I try to suck the marrow from the bones of my imaging sessions (YUK!!!!)

You could also try shorter exposures at f2.8 to reduce core burn then combine the shorter and longer exposures with a layer mask technique to save the core but bring out the faint nebulosity too as per this tutorial...
http://www.astropix.com/HTML/J_DIGIT/LAYMASK.HTM
Cheers
Doug

[Tilt (Michael)]

Thanks for the link Doug, I will have a go next time with taking some shorter exposures on the image run and try the layer mask technique.

[jase (Jason)]

This one almost slipped through the cracks Doug. Pleased I didn't miss it. Great composition. Colours are perhaps a little too saturated or they maybe indeed be ok, but lacking green to counteract the magenta hues. Lovely display of detail. Good stuff.

[Bassnut (Fred)]

Nice Doug, a tad wide field for my tastes, and a bit over exposed in the core, but louder than a 18"/quad 10" stack with a 1Kw Gallien Krueger on top and drop tuned low B 5 string axe. Mmmm, then again, I see what you mean, is tempting.

[dugnsuz (Doug)]

Originally Posted by jase

This one almost slipped through the cracks Doug. Pleased I didn't miss it. Great composition. Colours are perhaps a little too saturated or they maybe indeed be ok, but lacking green to counteract the magenta hues. Lovely display of detail. Good stuff.

Cheers jase and congrats on your Malin stuff!!!
Processing, yes!!!
I'm afraid I'm the incremental king - a bit here, a bit there, an extra bit added there!!!
All a bit of a white knuckle ride if truth be told!
I have a core initial processing regime that I follow...
star minimisation, gradient removal, Levels/Curves Stretch then the world according to Noel Carboni is my oyster!!!
I experimented with layers on that pic - the added layer being a 25% star reduction and processing to extend the nebulosity. Merged in at around 40% opacity. Didn't play around too fanatically with colour - so that is pretty much what's coming out of the 40D.
Any tips - do you have a processing workflow that might help?

Doug

[dugnsuz (Doug)]

Originally Posted by Tilt

Thanks for the link Doug, I will have a go next time with taking some shorter exposures on the image run and try the layer mask technique.

No worries Michael,
Check out my first attempt running through that tutorial ( I think it turned out well)just followed it step by step...
http://s231.photobucket.com/albums/e...nt=M42-IIS.jpg
Doug

[dugnsuz (Doug)]

Originally Posted by Bassnut

Nice Doug, a tad wide field for my tastes, and a bit over exposed in the core, but louder than a 18"/quad 10" stack with a 1Kw Gallien Krueger on top and drop tuned low B 5 string axe. Mmmm, then again, I see what you mean, is tempting.

Cheers Fred you like to get up close don't you!!!!????

Must admit we diverge on the amplification - I'm tending toward a narrowfield approach on that - Mark Bass CMD 121H (12" 400W Combo) Axe wise I'm looking at budget quality - Lakland 44-01! Too died in the wool for a 5 string! Perhaps a drop D Hipshot tuner (optional on the Lakland) might cure that!!?? Now before you scoff
Last bass rig was an Eden WT-400 and 210XT cab the ultimate portable "RIG" - I love a portable bass rig not something that needs a team from Pickfords to move around!

Tangential topic movement!!!

[Bassnut (Fred)]

Woose, sub action is worth the lugging, "moves" the punters .

I use a 4 string droped black Ibanez fast thin neck (geez they go out of tune quick) and Hartke/10" quad myself, but one can dream .

Ive never tried an Eden, but always thought they were fairly hot, supprised your going for a (single 12"?) combo, what!, do you do folk, or country or something? .

[dugnsuz (Doug)]

Originally Posted by Bassnut

Woose, sub action is worth the lugging, "moves" the punters .

I use a 4 string droped black Ibanez fast thin neck (geez they go out of tune quick) and Hartke/10" quad myself, but one can dream .

Ive never tried an Eden, but always thought they were fairly hot, supprised your going for a (single 12"?) combo, what!, do you do folk, or country or something? .

No BS Fred the eden amp (small enough to fit into a aluminium photo case) and 210XLT was my best rig "ever" - amazing!!
No country/ folk player either - google Mark Bass - an Italian company...don't know how they do it (12" cones with huge amounts of in/out travel) but these tiny combos can carry R.O.C.K gigs all with capitals!!!!
I'm such a nice guy I'lll provide links in an off-topic kind of way!!!
http://www.basscentre.com.au/index.p...57391234-8397#

[dugnsuz (Doug)]

Sorry all, we've gone way off topic here...

[Bassnut (Fred)]

Yes, that Mark Bass gear looks good, your a kind kinda guy, in an off topic kinda way there with that off topic kinda link, thank you. Enough they said ;-).

[jase (Jason)]

Do have some core routines, but extensions to this depend on the target. In a summarised form, the core goes something like this;

• calibrate subs (darks,flats,bias)
• remove blooms if applicable
• register/align subs
• hot/dead pixel removal
• blink all subs to check for anomalies/discoveries
• combine subs (mostly sigma reject)
• Digital development each combined images to check for gradients. This also give an indication as to the quality of data and a hint of what the end result will look like. Cancel the DD process so no stretches are made.
• If gradients are present in the individual R,G,B frames, I address this before the combine if possible. Don't want to upset colour balance. Sometimes its easier to handle later in photoshop
• Manually normalise the individual R,G,B frames using pixel math. There are some nice tools available to normalise the background on OSC cameras such as CCD's or DSLR's.
• RGB combine, then save.
• Push luminance be in L or Ha through deconvolution routine. Either maxentropy or LR. I only go as far as tightening up the stars. This depends on if the data is oversampled, but in most cases some benefits are gained.
• Save the lum, then blink the original and deconvoluted lum to check for artifacts introduced by the deconvolution routine. If found, check pixel intensities. Deconvolution works well on brighter data. If needed, the data can be scaled to increase pixel values. The run through deconvolution again.
• I then bring both files into Photoshop and commence levels and curves work. Not a huge user of DDP for stretching data. It can work well if you've got good control over your mid point.
• Sometimes use shadow/highlights tool to perform a non-linear stretch on the colour data while maintaining saturation. You don't need to do this, but if you do use levels and curves, its wise to follow up with a saturation tweak so your colours don't get washed out. If they do, you can bring them back by doing a hard DDP stretch on a separate RGB combine image, then relayer it in photoshop as soft light.
• I usually end up with a few layers doing different things such as noise invert masks, SCM, gradient removal, I'm a sucker for adjustment layers when it comes to the finer tweaks. Other than on masks, I stay away from using the brush tools. Personally, if you need to use them, you're getting pretty close to the border line of ethics. The things you can do in photoshop to mask problems and/or enhance things is rather scary. Good data is always the starting point.

There are always a few other things to throw into the mix, but depends on the data. Some data you simply can do much with i.e too noisy for example. I've been working on doing DD stretches for the Ha and Luminance data at different intensities so simply the rich highlight of the Ha data come through the luminance, but not altering the star apperances when using lighten mode. Rather basic, but effective considering Ha stars are typically tight and small compared to RGB. There are many ways to do the same thing, but most have a different effect or result in introducing noise of some sort. Anyway, that's the core for what its worth. Ask me in a few months time and I'll probably find a different method of doing something.

[dugnsuz (Doug)]

Cheers jase - lots to think about there, thanks!

[gbeal]

Originally Posted by dugnsuz

Cheers jase - lots to think about there, thanks!

Now what did you go and ask that for, LOL?

[skeltz (Rob)]

Very nice widefield doug,it did not turn out to bad at all/
cheers