Jupiter and moons

[Ian Cassell]

Maybe not so exciting an image to some, but I have never tried anything like this before and tried this tonight as Jupiter was so bright.

Canon 7D
Canon EF400mm f/5.6L + 2X TC
1 sec f/11 ISO 800 MLU

Huge crop in CS5
NR in Noiseware Pro

[Robert Amoruso]

You do have a nice diagonal with the planet and stars. If you were able to get a whole sky full of stars with this - that would be something.

[Dave Mills]

Hi Ian, Agree with Robert about having more interest within the image. The diagonal alignment is interesting...

[Ian Cassell]

Thanks for the comments, folks. These were Jupiter's moons and not stars, so a different layout would have been tough. I took this because I had never seen the moons so clearly as last night. It was a relatively starless night. I might take a trip out into the desert this weekend to see if I can get this with stars around it.

[Roman Kurywczak]

Hey Ian,
Agree with the comments above......but given your limitations.....still quite interesting. I'm impressed that you got such a good image......you had to be a good distance from Pheonix because of all the light pollution. Having more stars in would be a great idea Robert gave you!

[Robert Amoruso]

Thanks for the comments, folks. These were Jupiter's moons and not stars, so a different layout would have been tough. I took this because I had never seen the moons so clearly as last night. It was a relatively starless night. I might take a trip out into the desert this weekend to see if I can get this with stars around it.


I figured not stars after posting my response so looked it up. Thanks for the clarification.:D

[Roger Clark]

Ian,

The 1 second exposure time is too long. You've staurated both Jupiter and its moons. Also, such a long exposure time at these magnifications result in motion blur due to the Earth's rotation. Jupiter appears about 40 arc-seconds across, and the Earth rotates (on the celestial equator) at a rate of 15 arc-seconds per second. So Jupiter moves about 1/3 its diameter in one second. Try keeping your exposure to shorter than about 1/15 second.

Imaging the planets with a telephoto lens is quite a technical challenge. There is a thread in the gear forum about stacking 2x TCs. Her is my first attempt at Jupiter with stacked 2x TCs on a 500 mm lens:

http://www.birdphotographers.net/forums/showthread.php?72085-Canon-AF-and-stacked-2x-TCs-with-1D-bodies&p=570294#poststop

It is a 1/50 second exposure (I think the ISO was 200 or 400--need to check). You can faintly see 3 moons. If the atmosphere and camera were more stable, the moons would be sharper and appear brighter. So one can image both Jupiter and its 4 Galilean moons in one exposure and maintain detail on Jupiter.

For computing the exposure time, Jupiter is not quite 5 times further away from the Sun than the Earth, but its clouds are a little brighter than an 18% gray card (same with the moons). So 5 times further away would mean 25 times less sunlight, so 25 times longer exposure than sunny f/16 rule, but then a little faster than that, so 15 to 20 times longer than the sunny f/16 rule. In my image above, I was underexposing to keep the exposure time short to reduce motion blur.

Roger

[Ian Cassell]

Wow, Roger. Thank you so much! I was getting trails with 10 second exposures and thought my tripod was moving! If I get a chance, I'm going out again tonight to try your method! This was the best I got the other night. This was 1 sec, f/11, ISO 1000 and now I know that's way too long.


EDIT: I just tried controlling focus on my 7D with my laptop and liveview and it works well. I think I'm going to have to try that with the camera on the tripod tonight too.