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Trying to catch the tail
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Another attempt to capture “Comet Lovejoy” with it’s tail visible. Light pollution & a thin layer of cloud made it really difficult.
Delighted you managed to capture this Miki g, very difficult shot imagine.
Dave.
Thanks Dave & Ballistix.
Ballistix: I’m very new to astrophotography & may not be the best person to advise, but I’ll give it a go.A fast lens is essential. The faster, the better. Clear skies are also very important. The main problem with subjects such as stars is that they are so dimly lit and that the Earth is rotating causing trailing in fairly short exposures. This results in the need to open the lens as much as possible to gather as much light as you can, in the shortest time possible. A high ISO will also be necessary, but this results in noise in the image. A wide lens will allow a longer exposure without apparent movement in the stars, but the subject may look very small in the frame. Focus is critical & should be done manually. The stars should be pinpoints of light with the lens focused at infinity (slightly less than infinity). Even a tiny amount of light pollution or a very thin veil of cloud will drastically affect how your image will turn out by reducing the contrast between the stars and the sky. It is essential therefore to shoot RAW to be able to adjust exposure/white balance etc to give the most pleasing results.
Astro photographers tend to use a technique called the 600 rule. This is your lens focal length divided by 600 to give the longest exposure before trailing starts ie A 100mm lens would give a maximum exposure of 0.6 seconds, A 17mm lens would give an exposure of 28 seconds.
Rarely will a single exposure achieve the desired result, so photographers also use “image stacking” as a way of increasing the overall exposure time. This doesn’t necessarily brighten the image, but it does increase the signal to noise ratio in the image.
This is done by taking several exposures and combining them (stacking) in software later.
All camera settings should be set to manual. Also, the camera’s meter is practically useless for this type of photography, so it takes a lot of guessing to get it right. Using the histogram can help.Astrophotography is definitely the most difficult genre of photography that I have attempted and due to living in Ireland, we don’t get many clear nights to practice our technique. Hope this helps. :wink:
This is (apparently) the most popular image stacking software and its free. http://www.astronomie.be/registax/” onclick=”window.open(this.href);return false;
I also think that some of the steps in this tutorial can be applied here too.
http://www.photographyblogger.net/shoot-the-su … tographer/Although I would not bother with taking 50-60 shots as they say, instead I would take 1 RAW and generate 50-60 jpegs from it – unless someone can tell me that this won’t work because ………….
Mark S.
markst33 wrote:
Although I would not bother with taking 50-60 shots as they say, instead I would take 1 RAW and generate 50-60 jpegs from it – unless someone can tell me that this won’t work because ………….Mark S.
The main problem with generating 50-60 jpegs from 1 RAW would be that the “random noise” that would have been generated by 50-60 shots in camera would not exist as the same noise pattern would be in all of the jpegs & would be more difficult to get rid of than random noise. The reason for this is apparently that you are multiplying the existing noise in the Raw file x50-60 times. This is one of the reasons that “trackers” are used while taking multiple shots (as well as avoiding trails in the stars). A tracker will also allow for lower ISO values to be used on longer exposures.
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