Rosette Nebula

[jarrod_koh]

An image taken late January of this year.

ASI 1600 MM-Cool
Gain 139
HaLRGB 76:60:30:30:30
2 min subs for Ha, 1 min subs for the rest

http://www.astrobin.com/291251/

[gregbradley]

Really quite nice, a little dark perhaps.

Greg.

[Ryderscope]

I think the deep burgundy tones look good. I'm surprised by the short sub length.

[jarrod_koh]

Thanks Greg and Rodney.

I think Ray AKA Shiraz might be better at explaining this than me. I think the sensor well fills quickly and hence only short subs are required. The drawback to this is that you stack a lot of images!

I live with skies of Mag 19.5-20 and the optimal exposures at Gain 139, f5 optics is 15 seconds!

I hope that Shiraz can clarify this point.

[John W]

A really nice image - thanks. Cheers, John W.

[RickS]

Nice high impact image, Jarrod. I think you may have lost some of the fine detail by pushing it so hard, but that's perfectly reasonable if that's what you were aiming for.

Cheers,
Rick.

[jarrod_koh]

Thanks John and Rick. I think it was the combination of poor processing and lack of integration. I'll have to relook at the data again and give it another crack!

[Bart]

It is a pleasing image for sure, although I do agree it appears too dark.

It will take a while to get my head around these CMOS cameras and short exposures, but longer and/or more subs might help. The stars seem to have a blue fringe on one side and red on the other. Chromatic abberation? Not sure what to call it, but I've seen it on my own images and I try not to process this into the image.

Other than that, well done, I like it! :thumbsup:

[Atmos]

I personally don't mind the dark and broody image, it also has a very 3D feel to it. It has turned out quite well for a limited amount of exposure overall.

I've also been shooting at Gain 139 with a F/5 refractor. I haven't done a lot of LRGB imaging with it but I have found that 300-400s in Ha with a 3nm filter is optimal. 60s LRGB for your location sounds quite reasonable though, doesn't sound like the darkest of skies :)

[traveller]

Very sharp and a nice 3D look. Maybe a bit too much purple/magenta?
Bo

[Placidus]

Hi, Jarrod,

A very fine image, and in particular an excellent result for the time available.

We don't think the image is too dark - it looks great as it is.

Possibly the image is slightly over-saturated, causing some slight loss of detail.

The camera seems to be monochrome. If so, and you've used separate R, G, and B filters, then good registration and stacking software should automatically take care of any misalignment between the red, green, and blue. (Shameless plug: We of course use our own GoodLook 64. We can supply it free to a good home. Let us know by PM).

There is an amazing amount of detail in your image, and it is aesthetically very pleasing.

Best,
M & T

[strongmanmike]

Yeah I don't mind the processing either, while not as epic and schmick perhaps, it is certainly similar in look to Rob Gendlers (http://www.robgendlerastropics.com/RosettemegamosaicNMS.html):D

Nice work Jarrod

Mike

[jarrod_koh]

Thanks Bart
Definitely more subs if I didn't have to break down the equipment after most imaging sessions! And I suspect the fringing is due to poor registration.. possibly bloom from one of the filters? This, I have to nut out!

Thanks Atmos,
I'm Sky limited!

Thanks Traveler,
I do tend to lean magenta... I have to learn not to push that side!

Thanks Mike and Trish,
I think I will send you a little PM!:P

Hi Mike,
Did you know that you guessed correctly! I was using his APOD in 2007 as a reference!!! ( I didn't tweak it was Rob's image. I just googled the Rosette and saw what looked really good in the top hits). Well done!!:thumbsup:

Cheers everyone..

[strongmanmike]

Ha ha :thumbsup:...after doing this caper for quite a number of years now (and spending most waking moments looking at images :computer:), I have a whole library of images in my brain and a pretty good ability to recall who took a particular image, just by looking at it :P :nerd:...can do something similar with tenor voices too :lol:...(a somewhat useless talent but fun none the less)

Mike

[Paul Haese]

Not bad Jarrod considering this is your second or third image from monochrome imaging. Detailing is good and colour is ok, though again I think the space areas are a bit too blue, maybe the image needs a little lightening up, but still good data collection is present. Keep up the good work mate. :thumbsup:

[Shiraz]

great image Jarrod - very tidy and dramatic.

the 1600 has such low read noise that it doesn't matter all that much how many reads you do - ie you can take very short subs if you choose to. If you were imaging under moonlight for the Ha, the short subs were OK, but you could consider longer ones under dark sky - FWIW, I am getting near to sky noise limited performance using 10 minutes on Ha and O3 at f4 and gain 200.