Crux Colours

[sheeny]

I thought I'd have a go at doing my own version of David Malin's famous image of the colours of the stars in Crux, so this was taken and processed tonight.

Captured with the Oly E-510, 1600ASA, 15 sec (to limit star trailing), Zuiko digital 40-150 zoom at 40mm (80mm eq) and f/4, ICNR on (standard), IS off, manual focus using live view.

The image is a stack of 8 photos, stacked with blending mode "lighten", image flattened and saved for the web in PS CS3. No other processing.

I took 12 photos in 15 minutes, and had a few problems:rolleyes::whistle:... like the remote ceased to work after the first image, so I had to go to cable release and start the sequence again, and it looks like I must've bumped to zoom on the second or third image in the sequence:rolleyes:... there could be some movement in the tripod as well as I was too slack to get my big tripod from my binoculars to put the camera on... the lens was entirely dewed up at the end of the 15 minutes. It was -0.7C and 85%RH outside at the time.

I will have to do this again. Next time:
sturdier tripod
fixed focal length lens (Zuiko f/1.8 50mm)
try to take images at more regular intervalsAl.

[edwardsdj]

Very nice colours Al.

I'm sure that if you can sort those three things you mentioned next time you will get a great image.

[iceman]

Wow that's awesome, Al!
I agree with Doug, next time that'll be very nice indeed. What you need is an computer/handpad controlled focuser on the camera lens though, so you can do it in one long exposure instead of several short ones.

I know Bert has a setup on his camera lens that could do that.

Looks great!

[Dennis]

A very fine effort indeed Al, that is certainly worth repeating after you have sorted out the gremlins!

I have found that a Kendrick dew strap kept my camera lenses clear of dew all night long, even under quite wet conditions.

I look forward to the Mk II attempt!

Cheers

Dennis

[sheeny]

Puzzle time guys... (maybe not too:P:lol:)

What's happening with Gacrux? why should it have a dark spot inside the out of focus star image? It's the only star in the image with this. In some of the less out of focus images it looks like it could be another close star, but why should the dark spot appear as it goes out of focus... I would expect it to lighten (ever so minutely)...:shrug:

Al.

[bindibadgi]

Dust bunnies?

[sheeny]

Thanks guys.

I do have a dew heater for my lenses, but I wasn't fully set up last night.:P It was really just a token effort:rolleyes: after a big day working around the property... I just had to do something (but not too much:lol:).

Bert's focus setup would be ideal - no doubt!

Al.

[sheeny]

It's not a dust bunny on the sensor because it moves with the star image. I suppose it could be dust in the lens, but I wouldn;t have expected this to show up as such a small dark spot... I just checked the lens... can't see anything front, back or looking through it...:shrug:

Al.

[JohnG]

Hi Al

Gacrux is an optical Double Star, the A/B distance is 110.6 arc secs and the Visual M is 1.6 for the A componant and 6.7 for the B star. There is also a 3rd star but it is fainter again.

Interesting effect though.

Cheers

John G

[dcalleja]

Al
Great to see some different imaging being done - very nice colours.

[sheeny]

Ok here's the second attempt.

Olympus E-510, Zuiko 50mm f/1.8 OM lens stopped down to f/2.8, 1600, 15s, ICNR on (high), IS off, manual focus, 21 frames stacked with blending mode "lighten" and saved for the web in PS CS3. No other processing. More robust tripod and no zoom to mess up:P:).

I note the artifact on Gacrux is absent!;)

Just for fun (some might say art's sake:whistle:) the second one has the sharpest 4 images hidden for that stylised look:P:).

Al.

[iceman]

That is absolutely awesome, Al!

Well done!

[jase]

Great work Al. I've often admired this technique to present the star colours. You've done a lovely job of bringing them out. Well done.

[gaa_ian]

Nice effect Al !
I always knew there were wormholes behind all of those stars :P

[edwardsdj]

Absolutely beautiful result Al :)

[Alchemy]

the little thumbnails didnt do it justice, it looks superb.... glad i had a look.

[sheeny]

Thanks guys. It's such a simple technique to do with a dslr. I like it on nights when I'm too tired to set everything up:P... camera, tripod and a remote...:whistle: ...15 minutes of data capture and some simple processing in PS.:thumbsup:

Maybe I should right a little article for beginners....:shrug:;)

Al.

[iceman]

Go for it Al, you've been a bit dry on that front lately ;)

There has to be a simple way to constantly adjust focus so you get a smooth transition instead of the stepped transition.

Would having ICNR off make any difference to how it looks? Less gap?

[sheeny]

I've been a bit dry on a lot of fronts lately, Mike... but that's another story...:lol:. Moving house and settling in does eat a lot of time!;)

I think a perfectly smooth transition would require a motorised focus adjustment and a single long exposure.

Turning ICNR off would reduce the turn around time between images, and so produce smaller steps, I'm just a bit wary of reducing the time so much that you lose the pin point star image in the blob of the first unfocussed image which will still be clipped for the brighter stars.

A method of moving the focus ring by the same amount every time would be a nice refinement:thumbsup:.

A variation of the theme would be to do the same process but with a tracking camera. The star images would be circular discs of varying colour from centre to outer rather than the "conical" image.

I haven't decided yet about the ICNR... when it's off, random noise will be smoothed, but hot pixels will be amplified...

Al.

[leon]

Great stuff, i do remember seeing Davids rendition of that in his book, and yours are certainly at his level, well done.

Leon

[sheeny]

Thanks, but that's a big call, Leon!:P I seem to remember David's step focus change were more consistent for a start, and he took them in one image on film as far as I know. Besides, he had the idea first, and you have to admire someone who can think "out of focus... that's the way to take a good astro photo!":lol:

With a DSLR and photoshop, this sort of image is a good starter for beginners I reckon! Right up there with star trails;):thumbsup:.

Al.

[StephenM]

Great images Al!

I thought about doing the same thing a week or so ago (while doing exposures of Mars and M44, and having the red colour of Mars mostly burnt out). I never got around to trying it, but I'll give it a go after seeing these images!

Cheers,
Stephen

[sheeny]

Go for it, Stephen. :thumbsup: I intend to do some more constellations and asterisms this way. I have a fisheye lens on the way for the E-510 at the moment... not sure if that will be useful for this method, but the steps should appear closer together at least!:P I also have a pretty wide collection of wide OM lenses so might be able to get some larger constellations with those.

Al.

[Ric]

A fascinating image Al, the colours really come out wonderfully.

It looks like a great way to have some fun with imaging, I shall have to give this a go as well.

Cheers

[niko]

Great effect!

I'd love to see a "how-to" article on this Al.

As I still struggle with polar alignment but love photography I'm up for anything that can be done with minimum set-up.

niko

[MrB]

Awesome. Particularly like the effect caused by stopping the lens down, gives it a more '3D' look than the wide-open version. Good stuff!
Now do the Jewel Box :)

[prichens]

Cool Photos
Still trying to figure out how you did it but it's a nice afect.
I recently took a 20min exposure of Crux guided with PHD taken with a Canon 400D using a old film camera lens, unfortunatly there is a bit or wiggle in the camera as it shaked from side to side as the scope it was mounted on adjusted to track the star, plus I had a problem dew on the lens.

[sheeny]

Thanks!

...but I've already done the Jewel Box!!!!:P It's there....:whistle::lol:

Actually, I think the way to do the Jewel Box would be to use a camera on a scope (or piggy backed with a long lens) and have the mount tracking at lunar rate rather than sidereal. To do it with a long lens and fixed tripod would mean the stars will probably move too far between images.

But you are right, the Jewel Box would be a prime target to develop the method on!:thumbsup:

Al.

[sheeny]

No polar alignment in this, Niko!:)

Actually the only thing that I think is missing from my first post about how to do this is to start with an in focus image and then take each subsequent image progressively more out of focus.

Al.

[edwardsdj]

Congratulations on image of the week Al :)

[sheeny]

Thanks Doug.

Al.