Ngc5128

[lhansen (Lars)]

I've yet to finish processing this version of ngc5128 and would appreciate suggestions.

This one is comprised of

L 48*5 mins unbinned
RGB 32*5 mins each binned 2*

Taken over 2 nights 17 and 18 April this year

RCOS 12.5, PME, ST8XME

[TrevorW]

Star colour maybe needs enhancement, everything else spot on, is this cropped slightly

[lhansen (Lars)]

Colours look weird to me as well, stars are sort of purplish. Perhaps the colour balance is wonky, too much blue and and red? This is a straight image with no cropping.

[gregbradley]

First off wow, high impact image. You are getting better results out of the RCOS than I did. The original owner used an ST8XME as well with it.

Perhaps an AP 67 focal reducer could be useful sometimes as well to get a wider field of view and more bang for your imaging time buck so to speak. Probably would have been a nicer FOV for this object which is quite large.

Here's my take on the image:

1. Stars are to sharpened. I rarely sharpen a whole image as the unsharp mask tool is too savage and tends to damage stars. I usually find a bit of deconvolution on the luminance is good and perhaps even on the RGB subs. You want a softer look on your stars with slightly soft edges. Hard edges on stars is a bad look and isn't generally liked. Use selective sharpening using masks to do the core areas and nothing else. Ken Crawford has the leading tutorial on how to do deconv and sharpening. Google his name.

2. You can bring up the image a lot in curves as it seems there is plenty of signal there lurking in the background to be brought out so the dust lane is not so dark compared to the star halo of the galaxy.

3. Stars as you say have a reddish halo (red subs may need a tad of deconvolution to reduce star sizes - perhaps red was a tad out of focus or misaligned in processing?). There are techniques to get rid of star halos. But your general star colour needs to come up. Easiest and very effective is to use Noel Carboni actions. He has a increase star colour action that works like a charm.

4. The dust lane has 2 very pretty sections of bluish star forming areas and I don't see that blue there. Use the sponge tool and saturate 5% and bring that area up. Or lasso it, feather it and use curves to bring up the blue in the area.

Greg.

[lhansen (Lars)]

Thanks for the constructive comments Greg, I do have the AP .75 reducer which is very effective with the RCOS but I want to perfect the guiding at longer focal lengths. Next step undoubtedly will have to be a look at getting an AO8 or similar to try to reduce the impacts of the atmosphere.

I'm quite happy with the RCOS/ST8XME combination. I do have a Takahashi TSA102 which I need to press into service.

I suspect that one of my issues is the lack of a calibrated monitor. On nearly every monitor I put my images on they appear slightly different. I'm going to have to invest in a calibration unit for sure. Having said that, I've noticed a trend bluifying (is that a word) the spiral arms of galaxies and whilst they are aesthetically pleasing, I wonder if we are not making them too blue?

I frankly dont know

Cheers Lars

[gregbradley]

I bought a laptop a coupe of years ago and took a disc of a couple of my images to check the monitors of several brands. They varied a lot.

At that time the HP pavillion series had a clear advantage.

I see now some laptops have LED screens which are clearer again.
I'd be going I7 chipped LED screen with 1 terrabyte HD memory, 8gb RAM (if possible) and a HP pavillion if I bought another computer. I have an LED TV and it is noticeably sharper and clearer than even LCD TVs so that's the way to go I reckon.

I use my HP laptop most times for processing. I have started using a Sony Vaio which is 64 bit and it tends to highlight background noise more than the HP does. Hard to say what the average viewer would see. I guess I judge it on viewer feedback about posted images to get a feel for it. The HP certainly seemed to be good for that.

Focal reducers generally speaking for the RCOS are probably not a great idea in terms of resolution and maximum result. Certainly it is useless with a big chip as it will cause coma. I used a Tak 2.7 inch reducer with that scope sometimes and it gave some coma at the corners with an STL11 but it wasn't too bad. But with the smaller chipped ST8 you should be fine. I understand the tracking point. It seems you have that nailed though.

Greg.

[h0ughy (David)]

fantastic result such detail - and resolution!

For the record i have been processing on a Toshiba Satellite Core Solo as the screen is crisp and the best laptop screen i have found over the time - sad but true. I use a Spyder3elite to calibrate all of my monitors and laptops

[lhansen (Lars)]

Now you've gone and done it! After the AO8 I will definitely invest in a better monitor and calibration sensor.

It will drive me nuts otherwise

Cheers

Lars

[Peter Ward]

This is an excellent image Lars.

You have really nailed the data, the choice of 5 minute subs is a good one for high res imaging.

I'd have some minor quibbles with the (colour) post processing ....you might want to play with RGB curves, layers etc. in PS, but you have an excellent piece of kit there and are making it work for you in an exceptional manner. Well done.

[lhansen (Lars)]

Thanks Peter

I think I have (mostly) mastered the scope and mount but have a long way to go on the processing side.

I did buy the really excellent DVD's: "Making every pixel count", but I have heaps to learn - great isnt it?

Regards

Lars

Originally Posted by Peter Ward

This is an excellent image Lars.

You have really nailed the data, the choice of 5 minute subs is a good one for high res imaging.

I'd have some minor quibbles with the (colour) post processing ....you might want to play with RGB curves, layers etc. in PS, but you have an excellent piece of kit there and are making it work for you in an exceptional manner. Well done.