How do I take a 30 second time exposure for Northern Lights tripod

Although your manual des not say what the maximum time is your shutter can be open, try the M setting on the main dial.
Then you an chose time your shutter can be opened. On my powershot the maximum time is 15 seconds.
If that does not give you what you want, try the scene mode for fireworks, because then the shutter should be open several seconds too.

When you want to use the time exposure with your remote control, you need to be in the M mode (Manual) then you can select time Bulb. One step farther then 30 seconds. Then you can press the ML-L3 to start and again after some time to stop the exposure.

Is there any way you could post one or more of these pictures so we can see it? From the verbal description alone it could be lens flare, caused by reflections from the internal surfaces of the lens. Without actually seeing it...

Okay lets put some "joy" back into your photo's The reason you aren't getting anything is because your shutter speed is to fast. Your setting I think you are trying to say are F5.6 100 ISO and 1/100 shutter speed "M" manual setting. Actually if you looked closely on your "nothing there" there would be something. Anyway, Moon shots as simple as they look are anything but simple. The earth is moving and you are trying to take a still shot. I don't know where you are on this earth and every star system is different. Starting with a good solid tripod, next the lens needs to have a great enough focal length so the moon covers 2/3rds of the view (first shot) ISO 100 is good. In manual mode look at your light meter try to have your F-stop at F8 or F11 and adjust the shutter speed for proper exposure, you may need to adjust your aperture up or down once you have a "normal" exposure either increase your shutter speed or preferably stop down the lens two stops.
Your camera will meter down to 30 seconds if it goes below this then this is where you take your start (first shot) meter reading and count how many stops of light you require beyond 30 seconds.
For practice though attempt to stay within the 30 seconds by increasing the aperture but not wide open say F8 is as low as you go, need some speed adjust the ISO up to ISO 200 then ISO 400 don't go beyond this because other factors come into play at this point. the thing is you need to establish a metering point then stop down two stops and see what you have as far as exposure.

I know this may all sound really complicated but it's not the most important thing is to have a good tripod use F8 as your widest aperture don't increase beyond ISO 400 and keep your shutter speed at 30 second or above. Another problem that will occur is focus actually the lack of, your camera requires contrast to focus one you have established this shift the lens into manual and recompose your scene. What we aren't done yet don't touch the camera when your release the shutter. Use the 2 second time delay to give the camera time to stop vibrating after the shutter has bee depressed remove your hand DON'T touch it until the picture is finished. If it were me I'd be looking at doing a few landscapes at night to get use to all this stuff then tackle the moon so to speak. In the mean time here is a picture of The Fork Of the Thames in London Ontario Canada.
Picture here

Photographyat night can be used to create mysterious and amazing photos. When I sayphotography at night I mean the hours from around sunset until when the starsare clearly visible. The long exposures associated with low light can createunique effects and unusually sharp photos. And when I say long exposures I meanexposures lasting from half a second up to even 30 seconds. An exposure thatlong would seem impossible to prevent shaking, so my technique that I use veryoften is to compose the photo like I would normally and then to set theself-timer so the camera takes the picture on its own and I don't even have totouch it.
EquipmentOptions For lowlight photos, a tripod (or some kind of substitute) is very necessary. I almostalways keep a tripod in the trunk of my car or carry a miniature tripod aroundon trips. A miniature tripod can be very handy because it is typically smallenough to fit in a pants pocket so it can be taken anywhere. Some photographerscarry around a bean bag or something like it so that can set their camera downand tilt it in any way they like. Some of my best pictures I have taken simplyby setting my camera down on a newspaper stand and setting the self-timer.

Many photographers are convinced that they need a cable release to take longexposures but the self-timer release option on just about all cameras worksjust as well. All you have to do is set the camera up, configure theself-timer, press the shutter button, and wait the specified amount of time(usually 10 seconds) and the camera will take the photo automatically. And youdon't have to touch the camera so the photo won't be blurred from hand shaking.

Night Photo Opportunities
Landscape Photos - My favorite kind of night photousually includes a landscape with some kind of foreground element, some sort offraming element, and lots of lights throughout the scene. Adding some kind offoreground item to the frame helps to create a greater depth of field, thistechnique works for any kind of photo but I have found that it makes nightlandscape photos much better. Another tip you should keep in mind is that themain subject of a night photo should probably be the most well lit. Lots oflight is good for a night exposure but there should still be some focus appliedto the major objects in a scene.
CapturingMotion - A verypopular kind of night photography includes a steady camera with some sort offast moving object streaming through the frame. When cars are photographed atnight with a long shutter speed, the headlights make a bright pathway of lightand in most cases the car can't even be seen. Another option would be to set upyour camera next to a lighted area with lots of people moving like a night clubor an illuminated street. Just about any kind of motion captured with thecamera steady produces a very interesting photo.

Balancing Aperture and Shutter SpeedWhen taking photos at night you should keep aperture in mind as well asshutter speed. It is without question that you will need a long shutter speed,but the aperture that you choose will provide the depth of field. When I takenight photos I usually have a very long shutter speed (5-15 seconds) and a verynarrow aperture (high f-stop). This combination creates a huge depth of fieldand makes everything very crisp and in focus. Of course sometimes you will notdesire a great depth of field and in those situations you should widen theaperture (small f-stop).

Calculating the ExposureFiguring out what exact shutter speed and aperture you should use can bevery challenging in Manual Mode. I would recommend that you just try manydifferent combinations for each scene and eventually you will refine thesettings that you prefer. Another technique I use is Bracketing, if you bracketall your photos so the camera takes multiple exposures at different settings,you are more likely to end up with a photo that has a satisfactory brightness.
Conclusion There is no exact science to night photography; I hope some of these tips willguide you in the right direction. But the best night photographers are usuallythe people who experiment a lot when they are taking low light exposures andeventually they figure out the best scenes and best exposure settings to match.Just remember that you need a very long shutter speed setting, and that youneed to keep the camera very steady.