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-   -   Hand held Orion (http://e-group.uk.net/forum/showthread.php?t=49729)

Phill D 5th February 2019 10:44 AM

Hand held Orion
 
It was fairly warm last night and pretty clear so I decided I didn't have an excuse not to have a go at an astro shot. First off tried a few quick hand held shots of Orion with my 17mm at f1.8 just to see what I got. I did do some tripod shots later but thought I'd post this first as I was amazed it even turned out let alone looked like stars in my very light polluted back garden.

F1.8, 2s exposure at iso200 cropped about 50%, highlights and shadows at +50% white and black levels tweaked too, sharpening at 50% but no noise reduction added.

http://e-group.uk.net/gallery/data/500/P2040536-4p.jpg

Same image cropped about another 40%, is that the Orion Nebula! or just fuzzy noise?

http://e-group.uk.net/gallery/data/500/P2040536-8p.jpg

Will post a tripod shot later for comparison when I've looked through them.

Phill D 5th February 2019 01:17 PM

Re: Hand held Orion
 
Well on the tripod I used a conservative 10s as the 500 rule says max is 14.7 and 600 rule says max is 17.6s for my 17mm. Light pollution seemed much worse at the 10s exposures so I had to add a graduated filter in Lightroom to grade the exposure and also the noise was a lot worse so I added some luminance noise reduction. these are what I got at approximately similar crops to before.

http://e-group.uk.net/gallery/data/500/P2040562-2p.jpg

http://e-group.uk.net/gallery/data/500/P2040562-6p.jpg

On this rough test I prefer the hand held shots! but I suspect movement of the stars towards the street light responsible for the light pollution has had a significant effect.

Bengeo 5th February 2019 02:04 PM

Re: Hand held Orion
 
Very good. Yes, that is the Orion Nebula. Nice red colour on Betelguese.

Phill D 5th February 2019 02:18 PM

Re: Hand held Orion
 
Thanks Andy, yes I was quite taken with how red Betelgeuse came out. I didn't think that would show up.

wornish 5th February 2019 04:12 PM

Re: Hand held Orion
 
Great shots. The handheld ones are better for me.

On the tripod shots at 10 sec, you are just starting to see elongation of the stars due to the earth rotation.

Phill D 5th February 2019 08:24 PM

Re: Hand held Orion
 
Thanks Dave I like the handheld ones best too. Still can't quite believe they worked to be honest. Is it rotation at 10s? Or is it more likely to be vibration/ camera movement of some sort. Whatever it is I was quite pleased with what I got. Wish I'd realised at the time that the Orion Nebula was in view I'd have gone for a longer lens and maybe even got the scope out as well.

MikeOxon 5th February 2019 09:13 PM

Re: Hand held Orion
 
Quote:

Originally Posted by Phill D (Post 471135)
Thanks Dave I like the handheld ones best too.


So do I - better contrast overall. My method of processing (using PSE) is to view the histogram with the 'levels' control and then move the left hand slider towards the right until the background is truly black but fainter stars have not disappeared. Then I apply some sharpening (unsharp mask), choosing an amount which makes the stars stand out without any fringes appearing. Noise really isn't a problem and I prefer to use a higher ISO setting to keep exposure duration down.
There is also a good 'trick' to remove a small amount of star movement, by first creating a duplicate layer (in PSE). Then bring down the 'Layers palette' and select 'Darken' in the drop-down selection box (which initially contains 'Normal'). Next, drop down the 'Filters' menu and, under 'Other', select 'Offset...'. You will now find controls for shifting the duplicate layer relative to the original and the shifted pixels will be darkened. Just a few pixels lateral shift should restore slightly elongated stars to round.
Below is a crop from a shot of the Orion nebula, taken with my 75mm f/1.8 lens, using 2 sec exposure at ISO 1600. (on a tripod). The original image is on the left, while the right hand image shows the effect of a 2 pixel horizontal shift, when using the method described above.



http://e-group.uk.net/gallery/data/5...hiftLayers.jpg

MikeOxon 5th February 2019 09:27 PM

Re: Hand held Orion
 
Quote:

Originally Posted by MikeOxon (Post 471141)
...the right hand image shows the effect of a 2 pixel horizontal shift, when using the method described above.


Since my last post, I have checked by using 'Stellarium' that the star towards the bottom right, which still looks slightly oval after processing is, in fact, a close double: HIP26197 and HIP26199.

wornish 5th February 2019 09:44 PM

Re: Hand held Orion
 
You both are doing great stuff. Phil and Mike.

Even at 10-sec, you begin to see star elongation it's not noise, just physics ;)

With a longer lens, rotation gets even more noticeable.

Phil, you captured four really good targets in your shot.

The Great Orion Nebula, The Running Man, Horse Head Nebula, and The Flame Nebula.

If you get a chance, have a go with a 200mm or longer lens.

I have been really lazy and not got out because of the temperature for the last two months and I am missing the challenge.

Phill D 6th February 2019 10:47 AM

Re: Hand held Orion
 
Didn't realise Orion had so much to see. Just looked up all those targets Dave, all pretty close, relatively that is :). Just need a clear night now and will give them a go with the 40-150 +1.4tc to see what I can get. Probably need to be around 1s or less I guess for that. I used iso 200 before but notice Mike you used 1600iso, is it better to use higher iso for things like this?

wornish 6th February 2019 10:55 AM

Re: Hand held Orion
 
The higher the ISO the shorter the exposure needed to capture the same amount of signal, but there is a noise trade-off.

Many people shoot astro shots at ISO800 or ISO1600 beyond that the noise becomes a real problem.

If you shoot with the 40-150mm + 1.4TC at maximum aperture and ISO800 then a shot of 5 - 10 secs on your tripod should be OK. Even 20 secs for fainter objects but you will see a little elongation.

Have fun.

raichea 6th February 2019 12:12 PM

Re: Hand held Orion
 
Nice thread... enjoyed the pics and the info.

Phill D 6th February 2019 02:15 PM

Re: Hand held Orion
 
Thanks Dave I'll definitely have a go.

MikeOxon 6th February 2019 09:24 PM

Re: Hand held Orion
 
Quote:

Originally Posted by Phill D (Post 471180)
Didn't realise Orion had so much to see....

Orion is surely the most striking object in the night sky and has fascinated observers since ancient times. The Pyramids of Giza are, apparently, aligned on the model of the belt stars. It has a different appearance in the Southern hemisphere, where the sword in its scabbard becomes a more erect appendage. The photo below, taken from the South Island of New Zealand, was made using my 45mm lens with an exposure of 1/5s@f/1.8 ISO 1250.

As Wornish has already written, I find a higher ISO is preferable, as it allows a shorter exposure to minimise the effect of the earth's rotation. Of course, for 'deep space' objects, a powered mount can be used, to keep the subject apparently 'fixed', but that's another story....

http://e-group.uk.net/gallery/data/5...nd20161201.jpg

Phill D 7th February 2019 10:35 AM

Re: Hand held Orion
 
That's an impressive shot Mike but it looks weird upside down :) I'll definitely try higher iso next time.


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