My First Recognisable Horsehead

[Jeff]

I thought it was about time I re-attempted the Horsehead after a wowefully unsuccessful first attempt about a year or so back.

I'm stoked to have finally captured a likeness of the little beast from my back yard in Melb, but am a little stumped by the "streakiness" in the image ... maybe light pollution?

Captured on Jan 9th through ED80 with 450D ... before the moon arrived.
93 minutes of data (31 x 3min) at ISO 800.

Followed my usual processing approach with Photoshop...
- levels/curves/colour balance
- a few Noel Carboni Photoshop actions (less crunchy, noise reduc, lighten DSO & dimmer stars)
- brightness & contrast

Would welcome any tips from more experienced folks on how to improve, especially with the processing.

:thanx:
Jeff

[AG Hybrid]

I like it! The nice round stars from your refractor are nice. Its amazing how effective an ed80 is for AP. :) Try using some narrow band filters if you think its light pollution. Looks more like camera noise or something?

[spearo]

Hi Jeff,
I had a quick play with your image hope you dont mind.

Do you use Deepskystacker ? it's very good and free (i always use it for dslr shots).

I couldnt just raise the black point in PS without losing too much of the faint neb so I used apply image. Basicaly this will create an imag of the background noise and remove it from the main image. There are sophisticated ways of doing this but here' a very basic process for it.

here's how: (crude instructions, adjust to taste...)
duplicate your image twice
first copy use gaussian blur pretty much max
second copy: selection tool , select highlights (stars mainly), modify by expand by 4 pixels, modify feather by 2 pixels, invert selection (so everything BUT the stars is selcted) adjust levels-black point- to make everything dissapear except the stars. deselectuse a very mild guaaussian blur to softer if you wish this is now your mask. may increase contrast a tad if you wish

(all these steps require a bit of experimenting and playing with settings)

then go back to main image, lick on it so it is the one that is active
go image and click on "apply image"
inthe new window in the drop down select the first copy
in the bottom of the window click on mask and select the copy 2

then in the setting boxes you'll probably want to use subtract , i changed the offset to 3 to get the attached pic.

hope this helps a bit

longer exposures will probably get rid of the streaks but you'll need good guiding

cheers
frank

[sheeny]

Looking good. More data required I suspect.

Al.

[lesbehrens]

good work.:thumbsup:

[bloodhound31]

That's an outstanding image for one of your first. The stripes are definitely NOT light pollution. It will be a glitch somewhere in your stacking. Try to set your stacking program to use the best 80% instead of all of them, or manually go through the subs and ditch any suspect ones.

Either that or it's a very dirty sensor...

Baz.

[RobF]

Great effort Jeff. I was expecting to see a faint horse, but he's clearly there along with a great rendition of the flame and the curtain behind the HH.

Nice going for city shooting!

[Astrobserver99]

I had the same problem a few weeks ago. The cause was faulty USB cable. You could use a card reader and compare the results...

[Jeff]

Thanks everyone for the encouragement and helpful suggestions. I’m gradually learning that when people suggest more data, they mean hours (rather than larger portions of an hour). ;)

Regardless of seeing conditions, my images always seem a bit noisier in warmer weather – no doubt from sensor thermal noise, but possibly also due to some increased sky glow after long hot summer days.



That’s great Frank – I really appreciate the time you’ve taken to help me cut some more baby teeth in Photoshop. It’s impressive how the background noise from DSLR sensor heat and light pollution can be reduced or removed with the use of layers. I followed your steps this afternoon on another image, with reasonable success.

I’ve combined my Jan 9th data with some more captured on Jan 6th to give a total of 3 hours (DSS stack of best 60 from 77 3min frames).
Following the gist of Frank's suggestions, I blurred the background a little in another layer to reduce noise, and made the stars a little crisper. I'm much happier with the result, and no longer afraid of horses. Thanks Frank!

Fresh image attached ... which is better than I expected to get from the burbs with current equipment.

Jeff

[telecasterguru]

Jeff,

I think you have done very well.

Keep on learning.

Frank

[spearo]

well done Jeff,
it's the "Dark Arts" of processing...
no one recipe just lots of variations.
Keep experimenting and have fun!
I couldn't get anything out my new camera until I was shown how to use curves differently in the past few weeks.
there's so much to learn and so little time...
keep up the good work and keep the pics coming
cheers
frank

[multiweb]

Excellent shot. Just needs more data. You got everything else nailed. Keep'em coming. :thumbsup:

[Hagar]

Looks pretty good Jeff. Taking images from your backyard you need a medal as far as I am concerned. Down the road a bit at my sisters place I wouldn't bother even setting up.

This is pretty good. I am afraid the streaks just look like thermal noise, one of the problems with a DSLR and hot weather.

Well done.