Travel Photography - Trouble Shooting the Night Sky

I've made 4 attempts to capture what is arguably one of the most stunning night sky displays accessible in the world - the summit of Mauna Kea.

Every time I try and shoot, I end up with crap - a black image with nothing, a bunch of colored pixels or just star trails.

I've tried every possible combination of bulb exposure times, wide open to partially closed apertures, being careful to avoid long exposures at high angles that would cause trails - but I never capture any detail in the sky.

The camera is a Canon Digital Rebel XT with a Sigma 18-200 lens, and I use a tripod and remote control trigger. Bulb settings from 30 seconds to a full minute, and apertures from 5.6 (the widest) to the low teens.

Any suggestions or ideas? Is it just a limitation of my camera and lens? I have a Canon S90 I can use as an alternative, which I can hook to a tripod, but it won't shoot RAW and I'm not sure if I can set it for a long exposure.

not sure exactly what it is that you are trying to capture. But maybe shoot at higher ISO for shorter shutter speeds and see what happens?

I'm trying to capture the stars - which from the summit of Mauna Kea would look like daytime weather clouds, but of stars instead of vapor, it's that intense - yet my camera captures nothing.

I tried up to 400 ISO, but still nothing but a few spots - and anything higher would result in nothing but noise.

Have you tried it in Auto or P mode? What did the exposure meter to? Do you have long shutter noise reduction (takes a "black" frame right after the real one and subtracts them)?

Are you focused to infinity?

Have you tried it in Auto or P mode? What did the exposure meter to? Do you have long shutter noise reduction (takes a "black" frame right after the real one and subtracts them)?

Are you focused to infinity?

I think I tried P mode before and it did almost 30 seconds of exposure - same result - a black frame with a few colored dots.

I didn't try the black frame because there is no noise after the first exposure - the frame is just black with some dots or pixels.

I've made 4 attempts to capture what is arguably one of the most stunning night sky displays accessible in the world - the summit of Mauna Kea.

Every time I try and shoot, I end up with crap - a black image with nothing, a bunch of colored pixels or just star trails.

I've tried every possible combination of bulb exposure times, wide open to partially closed apertures, being careful to avoid long exposures at high angles that would cause trails - but I never capture any detail in the sky.

The camera is a Canon Digital Rebel XT with a Sigma 18-200 lens, and I use a tripod and remote control trigger. Bulb settings from 30 seconds to a full minute, and apertures from 5.6 (the widest) to the low teens.

Any suggestions or ideas? Is it just a limitation of my camera and lens? I have a Canon S90 I can use as an alternative, which I can hook to a tripod, but it won't shoot RAW and I'm not sure if I can set it for a long exposure.

The S90 definitely shoots raw. Not sure about it's bulb setting, though.

I'd set the focus on your Rebel to infinity, aperture to 8, and start shooting with 30 seconds, then increasing 30 seconds each successive step until I'd start getting something decent. Then you can decrease or increase the time by a little bit for finetuning.

Cheers,
T.

Your exposure times and or ISO are way too short. Try ISO 800 (minimum) and at least a 2 minute exposure. It will be difficlut to not get trailing on your stars without a drive system (clock drive) to compenstae for the earth's rotation during your exposure. Using a short focal length lens may help. 50-85mm should give you a great shot.

I tried shooting with longer exposures - up to 1 full minute. Still no star detail, just a few more blurred dots (caused by trailing).

I checked online and found some incredible night sky photos taken with the Digital Rebel XT - so I'm not sure what's going on with mine. Maybe the lens is crap? I have been pretty disappointed in the Sigma 18-200 lens.

I'll check on the S90 to see how to do nightsky photos with that device and compare.

I tried shooting with longer exposures - up to 1 full minute. Still no star detail, just a few more blurred dots (caused by trailing).

I checked online and found some incredible night sky photos taken with the Digital Rebel XT - so I'm not sure what's going on with mine. Maybe the lens is crap? I have been pretty disappointed in the Sigma 18-200 lens.

I'll check on the S90 to see how to do nightsky photos with that device and compare.

One minute at 5.6 is not going to give you any detail from a totally black sky, even though the stars emmit enough light for the human eye to see, the camera is not near as sensitive as the human eye. Keep upping the exposure until you see some detail. Could be up to 5 minutes a get anything substantial. Check here http://tonypatta.com/Site/Astro_and_Wildlife/Pages/Astronomy.html

Most of these are 5-7 minutes at 2.8 and 1600 ISO with the 300mm.

You have to either bump your ISO or go with a longer shutter speed. You do not have enough light coming in for a detailed shot. I would try F8-11, bump the ISO to the max before it gets grainy with a 30sec-1min shutter time. The lower the ISO is better but you might not be able to get the amount of light needed. You need a F8-11 to get detail

If I can figure out how to do long exposures on the S90 (without using CHDSK), I'll try it, but also try the recommended settings in this thread for my DSLR- F8-11, 800ISO and 1 minute exposure with a N/S alignment to minimize trailing.

Hopefully this will work and I'll have some nice results to share - although the moon might be on the bright side when I get there this weekend, so we'll need to see how things go.

I was photographing the lunar eclipse early last month. Started out with 20 second shots (500mm mirror lense) but ended up with blurred photos because the moon was moving/setting so fast! Ended up taking 2.5 second shots instead.

Taking pictures of the sky during full flight is not that difficult but you need to expose at least a few seconds and a high (1600+) ISO rating which is usually only possible by SLR or ILC (Sony NEX like) cameras.

Fortunately, the usually very poor lighting inside the aircraft allows taking night pics.

But there are some requirements:

- no turbulence to prevent motion blur (moreover, otherwise you are supposed to be seated in your own seat)
- reading lights off or, better, use one of the windows in the exit doors and wrap the camera in a blanket as otherwise the spacing of several centimeters between the glass layers of the plane window show a lot of ghost images. In a 744 you can just put your camera behind the window without holding it, most other aircraft (like a 777) you should hold the camera steadily.

Here some examples taken with the Canon 40d at 1600 or 3200 ISO (2009, 2010). I'll try again next feb.

http://sky.velp.info/extremeastro.php

It is not that difficult.

I tried it 2 years ago on a 744 from MH (AMS-KUL) and took pictures of 4 seconds at ISO3200 with a Canon 40d using Tamron 18-250 @18mm f/4 .
Fortunately, the lighting is poor during the night but the double windows may cause ghost images so wrap your camera in blankets (provided by most airlines on long haul flights), turn off AF, focus to infinity.
On 747s you can just put your camera steady in front of the exit door windows without holding the camera, provided the flight is calm (at turbulence you get motion blur and, moreover, you are supposed to be seated).
Look at "sky dot velp dot info slash extremeastro.php" for my results.

a different lens might be the best solution? can you borrow one that is more appropriate for night sky shooting?

a different lens might be the best solution? can you borrow one that is more appropriate for night sky shooting?

I don't have that option at this point :( I think to keep things simple (and travel light), I'm going to leave the SLR at home and bring the S90 and tripod to try the shoot....it can't be any worse :)

Your camera and lens is fine, it's just getting the technique right. If you don't want trails you want a maximum of a 30s shutter speed, depending on your focal length and where you're looking at the sky. Don't use any auto or programmed manual setting, set your camera to manual mode and manual focus.

30 seconds f/4 upwards at ISO 1600 18mm should be fine for wide-field astro, the hardest part is getting a good star focus. If your camera has a live view and you can zoom in on one bright star, adjust it manually that way, else take some test shots and adjust a small amount until you get it right. I tend to focus just before infinity.

This is f/4 ISO 4000 16mm 30s, on a D700 and 16-35.

http://farm6.staticflickr.com/5222/5560287966_4657e94c4b_z.jpg

Your camera and lens is fine, it's just getting the technique right. If you don't want trails you want a maximum of a 30s shutter speed, depending on your focal length and where you're looking at the sky. Don't use any auto or programmed manual setting, set your camera to manual mode and manual focus.

30 seconds f/4 upwards at ISO 1600 18mm should be fine for wide-field astro, the hardest part is getting a good star focus. If your camera has a live view and you can zoom in on one bright star, adjust it manually that way, else take some test shots and adjust a small amount until you get it right. I tend to focus just before infinity.

This is f/4 ISO 4000 16mm 30s, on a D700 and 16-35.

http://farm6.staticflickr.com/5222/5560287966_4657e94c4b_z.jpg

Thank you - looks like I need to really ramp up the ISO in order to capture anything. The trick will be the noise, but I'll just need to experiment.

You should be able to get good results from ISO 1600 onwards. You can open up the aperture on shorter focal lengths to let more light in, you only need the very long DoF if you have some close foreground objects you want in focus.

If you have long exposure noise reduction (not high ISO noise reduction, that does something else), turn that on, it'll double the length of each exposure but will remove any hot spots that develop on the sensor by subtracting that black frame from the picture you just took.

Best thing is practice, but it's good when you get it.

The pic of @cottons looks very good nice with the Southern Cross and Pointers in it !
Is is taken from the plane ?

I took this one: EOS 40, 4 sec Tamron 18-250mm, 18mm f/4, ISO 3200. With Sirius and Orion setting.
Taken in a full moon night midflight AMS-KUL @39000ft.

http://sky.velp.info/extremeastro/IMG_8068.JPG

I've noticed that some cameras have a function that maps out hot or stuck pixels so that they can be compensated for on board. Does yours?

Yes, that is called 'long exposure noise reduction'. My 40d has it and all subsequent Canon SLRs have it and even many compacts.

I recall reading somewhere that the max number of seconds exposure you can have without creating trails with the stars is something like 600 divided by your focal length (I guess you need to adjust for crop factor). With that calculation in mind, you can then play with the other settings to get the lighting that you are after. This would suggest going into shutter priority and letting the camera play with the rest. I would then take a shot or two like that, use those as readings (check the histogram and see what ISO, aperture, etc. the camera selected) and then switch to M and set the parameters where you need them. Take as long as you can, take as many shots as you need, play with as many of the settings as you can to get a feel for what changes and keep at it till you get the shot you want.

I love this challenge, and hate it at the same time as I always spot the view I want to photograph when I don't have a camera with me, and then when I go back the light or whatever else is different (who said the best photograph is the one you take, or something like that?).
Anyway, I was playing with getting a night shot of a hill near my office, with the stars in the background, and ended up with two versions. For the first there was not much ambient light at all so I figured the way to get the stars into play was to go for a longer exposure - on some nights the moon is so bright that you can read by it, and the stars are like spot lights. In this case you could see a few stars, but nothing spectacular. The shot was taken with the camera leaning on a wall with a 30s or so exposure, and while I was happy with it after a bit of pushing in photoshop (brightness, levels), I felt I could do better.
I made a point of taking a tripod and release when I went back about a month later. Again there was little ambient light on the day there was no cloud cover, the trees had lost foliage, so the shots weren't exactly the same, but I had a go. I managed to replicate the stars as dots effect, but went a bit further for some more defined trails. I ended up at ISO200, F5, 50mm lens, 360 exposure, and quite liked the result.

Good luck!
RP

I recall reading somewhere that the max number of seconds exposure you can have without creating trails with the stars is something like 600 divided by your focal length (I guess you need to adjust for crop factor).

A better way for calculating the max. exposure time to prevent trails is 25 * (long sensor size in mm) / (focal length in mm) which means 900 / FL for Fullframe sensors (36mm) and 555 / (focal langth) for APS-C(anon) (22.2mm) and 600 / (focal length) for APS-N (Nikon DX and Sony NEX cameras) (24mm).
For compact cameras these values are much smaller with the exception of the Canon G1X (18mm sensor width).

Don't overestimate how bright the sky is at night. The human eye can open up and adapt, camera sensors can't - you need to add exposure.

I have Mauna Kea shots around somewhere, but I have easy access to this shot from Death Valley, near the same mag. -7 level of darkness according to the dark sky maps I've consulted. This is at 30s, f/4, ISO 1600. It's from a current-generation 7D and still needed some noise and hot pixel cleanup.

If your max aperture is f/5.6, and you want to keep shutter speed at 30s, you need to be at ISO3200 or higher. I suspect that with a Rebel XT, introduced over 6 years ago, the performance is going to be on par with my old 10D - lots of noise at 3200. Shooting small points of light in the blackest nights without visible movement is just very challenging for sensors today, let alone those of 4-5 generations ago.

An f/2.8 lens (17-55) or an even faster prime would help get back 2-3 stops of ISO.

EDIT: I checked my Mauna Kea shots and they were the same 30/4/1600. I tried with an 85/1.8 but the two extra stops didn't make up for the 7x longer focal length and I saw blur/trails, even at 15s/1000
http://richs.smugmug.com/Landscapes/Death-Valley-2011/Death-Valley-2011-154/1222501583_TU3ko-XL.jpg

Your camera and lens is fine, it's just getting the technique right. If you don't want trails you want a maximum of a 30s shutter speed, depending on your focal length and where you're looking at the sky. Don't use any auto or programmed manual setting, set your camera to manual mode and manual focus.

30 seconds f/4 upwards at ISO 1600 18mm should be fine for wide-field astro, the hardest part is getting a good star focus. If your camera has a live view and you can zoom in on one bright star, adjust it manually that way, else take some test shots and adjust a small amount until you get it right. I tend to focus just before infinity.

This is f/4 ISO 4000 16mm 30s, on a D700 and 16-35.

http://farm6.staticflickr.com/5222/5560287966_4657e94c4b_z.jpg


That's a really cool shot! Really clear well done

Success!

I took the Canon S90 to Mauna Kea and gave it a shot with 2.0 wide open, infinity zoom and 15 sec exposure. 700 ISO got me almost nothing so I dialed it up to 1000 and the pictures started coming out brilliantly.

Once I get the files cleaned up and converted from RAW I'll figure out how to post them here.

Thanks everyone!