Unless you’ve been hibernating all winter, you know that Comet Lulin
is on the move!
Comet Lulin is zooming past Saturn, and pending wind and clouds, and seeing and the typical weather gremlins we have round the world, we have a very good viewing and photo-op for recording this once in a lifetime sight.
So, get your camera batteries charged and your film loaded for this great opportunity. Round up those memory cards too!
Or just get your binoculars and telescopes at the ready and watch the show.
Personally I like to shoot wide field shots of things like this so the surrounding star field is visible and you get the idea that space is BIG!
I use ISO 400 at f/4 and mount the camera on a tracking mount in order to keep the stars from making trails.
Star trails make a neat effect too if you don’t have a tracking mount. Just let the exposure go for 15-20 minutes or so for an interesting photo. YOu can go hours too if you like. Sometime I let my shots go all night long!
The image above was a 4 minute shot. It looks like everything is racing into the Sun, but the simple reality was there were clouds illuminated by the skyglow of Albuquerque zooming past while I was out shooting the comet and Saturn early this morning so the movement made this crazy effect. It’s kinda cool don’t you think? You can see all of Leo in this shot and as soon as I wake up again, I’ll figure out where Ceres is in the image and let y’all know. Or be a super sleuth and find it yourself before I tell you where it is.
ISO 400 Nikon D70 on Losmandy mount
rinky dink 28mm lens
I also shot a lot of film, (you remember film) and should have that back this afternoon.
One last thing, the comet is the smeared turquoise colored star looking object on the left of the frame.
Top image was enhanced a bit by tweaking PS. An adjustment in levels brought out the dim stars and streak left by the Shuttle and ISS as they passed by the Pleiades on the left. Bottom image is right out of the camera. Nikon D70 on tripod. Photo above in the collection of the STS-120 Discovery mission astronauts.
Twilight has never been my favorite time to photograph an international space station or shuttle pass but it has rewarded me with some favorites and a couple of unusual shots.The important thing is to embrace the challenge and use every opportunity to practice and pretty soon you’ll just “know” what to do.
Civil Twilight is when the Sun’s altitude is 6 degrees below the horizonThis is the limit at which twilight illumination is sufficient, under good weather conditions, for terrestrial objects to be clearly distinguished; at the beginning of morning civil twilight, or end of evening civil twilight, the horizon is clearly defined and the brightest stars are visible under good atmospheric conditions in the absence of moonlight or other illumination. In the morning before the beginning of civil twilight and in the evening after the end of civil twilight, artificial illumination is normally required to carry on ordinary outdoor activities.
Nautical Twilight is defined when the Sun’s altitude is 12 degrees below the horizon.At the beginning or end of nautical twilight, under good atmospheric conditions and in the absence of other illumination, general outlines of ground objects may be distinguishable, but detailed outdoor operations are not possible, and the horizon is indistinct.
Astronomical Twilight is when the Sun’s altitude is 18 degrees below the horizon.Before the beginning of astronomical twilight in the morning and after the end of astronomical twilight in the evening the sun does not contribute to sky illumination; for a considerable interval after the beginning of morning twilight and before the end of evening twilight, sky illumination is so faint that it is practically imperceptible.
***above definitions excerpted from the USNO site
These periods of twilight occur before dawn and after sunset and are usually about 20 minutes apart.You can check <http://www.heavens-above.com> or any astronomical almanac type reference for exact times at your location.
By looking at the times of twilight, you can begin to make a more educated guess on how to prepare for an image that really stands out from the crowd!
Finding a Happy Medium
Don’t let the exposure run too long since lingering or imminent sunlight will wash out the image in a bright sky.
Use a small aperture and low ISO.Be mindful that this combo has a two sided edge.
If your exposure is too short or you’re using too small of an aperture, you also risk not collecting any of the light left behind by the ISS at all.This is not what you want happening so finding a happy medium is the challenge.
Bracket, Bracket, Bracket!
Practice using different exposure lengths, apertures and changing the ISO.It will take some trial and error to get the hang of it since light is always changing and is never the same from moment to moment.
Practice your bracketing technique using airplanes.I know this sounds corny, but you can learn a lot about your camera settings this way.Keep a small note book and use it to make detailed notes about the exposure length, aperture, ISO and time of day.
Compare the images to determine what worked best and use that as a starting place for making an image of the ISS flying by.
Check Heavens-above.com for twilight times and then use it as a guide for maximizing your exposure lengths.
As an example if you are planning to make an image of an ISS pass that occurs at 6:20 a.m. and twilight time tables indicate that civil twilight begins at 6:22 a.m. the light is not ideal for making a long exposure.You can practice a couple of mornings before the pass day to determine just how long an exposure can run before it is washed out by the bright sky.
Ideally you want to make long exposures before astronomical twilight begins each morning or after it ends each evening.
Yeah, this is a drag, but once you get the hang of it, it’s bucket loads of fun!
Another thing to consider is the direction of the pass you are imaging.Try to plan your shots aimed away from the rising or setting Sun’s direction.The sky will be darker opposite the Sun and may give you just a few more precious seconds to expose the pass.
Make a few quick exposures and then stitch them, or make a short exposure when the ISS is by a pleasing target, like Venus.
Give your photo context and thoughtfully begin your exposure when the ISS is near a recognizable target in the sky.
Use a photo software adjustment program to enhance an image on the edge of being just about right.
You can adjust the levels of contrast, brightness, etc. to bring out faint traces of the ISS without going overboard and making your photo look garish.
Images from the morning of Feb. 5 show Comet Lulin is on the move.
These two photos were made 20 minutes apart. Note the slight movement toward the bright star at the upper right of the frame. That’s Zubenelgenubi in Libra. Tomorrow morning the comet will be much closer to it. Stay tuned!