Reddit mentions of Nikon 25395 MC-DC2 Remote Release Cord (1 Meter)

Hey, I have the same camera and intend on doing the same thing, only on Tuesday (8/14) night. I'll miss peak by one night... :/

I've never shot a meteor shower, though.

Anyway, I use the camera more with my refractor, but I do wide-angle shots sometimes, including one of the ISS I keep meaning to post (and hope to remember to do when I get home today). Here's things I've learned in my short time in astrophotography; remember, this is general stuff, as I've never shot a meteor shower:

• I put the lens in manual focus, find a decently bright star, turn on live-view, zoom in on the screen all the way, and focus. It's still kind of tricky, but it gets better with practice.
  
• While it's a nice lens, the kit lens has a terrible little focus ring. To keep it in focus, I use gaffer tape. I keep a couple feet of this stuff rolled up around a toothpick in my camera bag. It's awesome. It's like duct tape, but won't leave a residue on the camera. Don't use it on or near the optics, and take it off before putting the camera away. A tiny piece will do to hold the focus ring in place (1/2" square or less).
  
• I trust you have a tripod; a good solid tripod is a must.
  
• I think the answer for which ISO setting is this: Set it as high as you need it to get the shot, but as low as you can to avoid noise. Sorry for the vague answer, but it can change depending on what other settings you use. I like to start at 800 and go up or down.
  
• Your exposure length should give you a histogram peak somewhere in the middle. The big picture is: you don't want your histogram too close to either the left or right sides. To do that, you'll adjust exposure length, ISO, or aperture.
  
• I've heard people say to stop the aperture down a little to make sharper stars. It's a balance between that and actually capturing the stars as points, unless you want star trails... For a meteor shower, star trails might work. (I keep mine wide open, but I do more shooting with my telescope, not a lens.)
  
• Using a remote of some kind is a good idea to keep the camera stable while controlling exposure. There's also a setting to add a delay of 2 seconds before taking the exposure.
  
• There's also a thing called "the hat trick", where you cover the lens with a hat (or something), open the shutter, give the camera a second or two to stop shaking, then move your hat (starting the real exposure). Reverse to stop the exposure. I haven't done it, but it sounds reasonable.
  
• Take dark frames to eliminate noise, or use the built-in high-ISO noise reduction. This person said why better than I can.
  
• There's also a setting in the menus to dim the display. It'll keep from blinding you too much while using live view at night.
  
• I stick with RAW. It's not lossy. I like jpeg for everything else, because I'm not a pro. But for AP, I stick with RAW, since there are much fewer photons involved.
  
  All right, I feel like I'm missing some things. It's late, I'm working the night shift, and I don't have my notes with me. Also, I might be rambling. I really like the D5100, though, and I feel like there's a lot of tricks to learn. That's half the fun, though, right? :D

I have a Nikon D7000, and I just use a little wired shutter release that duplicates the two-stage shutter button on the camera exactly, with the added feature of locking down to trigger the "bulb" mode for as long as I want.

The Cannon Magic Lantern solution is one option, but personally I use the wired remote anyway for any longish tripod photography because it doesn't shake the camera when I press the button. Mup mode + off camera trigger = no shake even with the longest lenses.

However, as /u/zeFinn pointed out elsewhere, it's a good idea to stack photos for long exposures instead of just taking one long picture; it helps cut down on noise from the camera sensor heat as well as normal noise because it can be filtered out in the stacking process. I only got away with this because it was about 20°F out, if it had been warmer the picture would have hot pixels everywhere. (if you look at that image in full resolution, the hot pixels are really obvious. That was nearly 20 minutes in t-shirt weather, so it turned out really badly.)

Well, depending on his interest: starscapes vs telezoom celestial bodies, I would buy him a good prime lens (50mm or 85mm) that is used. Look for f/1.8 or less (the 1.8 is way more affordable). The other great thing about these two lenses are they're very versatile. He can use them just about anywhere that he goes and they are excellent in low light situations. He will definitely, more so than the lens, need a tripod. You cannot get a good shot without something to hold the camera still.

He'll need a good remote release cord so that he'll be able to keep the shutter open and get that great shot.

Again, I don't know much about the telescoping zoom lenses but this one happens to be in your price range. You could do this and the remote release but he'll still need a tripod of some kind. Do you know if he has one?

What justifies the high cost of the Manfrotto tripods? The legs cost ~$150 and the Ball head is another $100 or so. Also, would a fisheye lens be suitable for astrophotography?

Comment: The D3100 does not have an IR receiver, thus a cord release is necessary:
http://www.amazon.com/Nikon-MC-DC2-Release-Digital-Cameras/dp/B001F6TXME/ref=sr_1_4?s=electronics&ie=UTF8&qid=1346031587&sr=1-4&keywords=nikon+remote

I also have a D3100. To keep the shutter open for an arbitrary amount of time, you need to use the Bulb shutter setting. Go into Manual mode and "slow" the shutter speed to the setting past 30" (30 seconds). In Bulb setting, the shutter stays open as long as the shutter release button is depressed. If you want to do long exposures without camera shake, you're going to need to buy a shutter release cable. I use the Nikon MC-DC2, and I think that's the only one that works with the D3100.

As for seeing Live View (or the viewfinder) while the camera is at ground level, there are accessories you can buy, like this expensive one. I don't know of any others off the top of my head. I'm sure you'll be able to find something with a bit of searching, though.