Nikon 50mm 1.8 D or Cheaper Wide Angle

So I am looking to get into Astrophotography. Im shooting a d5200. I have a 50mm 1.8 D and the kits lenses. I was wondering if it'd be worth picking up something like a used Rokinon or Samyang 24mm 1.4 starting out or is the 50mm a good enough lens for learning and trying? Its something I plan on doing at least every other month (living in the city is not fun). Hopefully in the summer get out more regularly.

Is there any tips you guys have to someone just starting? I am visiting home for the holidays and am going to go out and play with the 50mm if its not to cold.

IMO you are doing the right thing by starting with the equipment you have and seeing what it can do. You may find that you want to image the rings of Saturn which would lead you into a different direction than a wide angle lens, and become more interested in steadier mounting, trackers, higher magnification, etc. Or you may find that the 50mm lens isn't nearly wide enough for the Milky Way shots you seek, and that Rokinon looks more tempting. "Astro" can mean lots of things, the lens FL choice is mostly a choice of field of view, you can use the 50mm lens for experimenting and learning how to focus precisely, playing with foreground light painting or blending multiple exposures for the foreground, and to learn what you are interested in to set priorities for our budget. Were astro my priority, my next purchases would be tripod/tracker related because I am fascinated by what is out there beyond our normal view...

You can use the 50mm without a tracking head, but you'll find that the maximum exposure time is limited to about 8 seconds before you'll start to notice that the stars are elongated due to the rotation of the Earth. If you use a tracking head then you can image much much longer and bring out quite a bit of detail (8 seconds isn't very long).

The 24mm would let you double the exposure time.

If you want to shoot nightscape shots (landscape + sky) then probably you want a wide lens without a tracking head.

Ordinarily the tracker rotates at 15 arc-seconds (that's the angular rotation amount) per second of real time. That's the rate that the Earth is spinning. So as the Earth spins from west to east, the head rotates from east to west and they cancel each other out -- which is what allows you to take long exposures. That rate (15 arc-seconds per second) is also called "sidereal" speed (it looks like "side" "reel" but it's pronounced "sid EERie al").

But many trackers have a mode for shooting landscape astrophotography (aka "nightscape" shots) and in this mode it tracks at half sidereal speed. This lets you double the exposure duration (double what you could do with no tracker) when shooting nightscape images by splitting the difference between a blurred foreground and blurred sky.

If you do NOT want landscapes... and just want to feature deep-space objects, then a tracking head is what you really want and then you can later add lenses such as Nikon's 135mm f/2. I've never tried to shoot at 200 or 300mm but there's a point at which it's better to move to a telescope than trying to get away with a long heavy lens on a tripod (due to tripod flexure.) When you use a tracking head, you want a strong beefy tripod. Lightweight tripods can flex and vibrate and that would trash your images.

Very helpful. Thank you. Is 2.8 enough? Im looking at a 70-200 2.8 for portraits anyway. I do want to just do the sky and deep space, at least mainly so I see a tracker in my future.

gmm213 wrote in post #18217640
Very helpful. Thank you. Is 2.8 enough? Im looking at a 70-200 2.8 for portraits anyway. I do want to just do the sky and deep space, at least mainly so I see a tracker in my future.

Yeah, if you're on a tracker than you can take very long images (I've gone 8 minutes with my 135mm with no problems at all).

Make sure the tripod is solid (this is one of those times when you don't want the lightweight tripod.)

I'd check out the Sky Watcher brand "Star Adventurer" tracking head. I think it's around $300 USD but definitely get the equatorial wedge option (it lets you fine-adjust the altitude angle to get a precise polar alignment) and also pick up the counterweight bar if you're planning to use a 70-200 f/2.8 lens. It's a heavy lens, so the counterweight bar balances the rig so the motor isn't under load if it's trying to "lift" the lens while tracking. Those accessories will add to the price tag -- but not by much.

iOptron makes a tracking head as well, but it doesn't offer a counterweight option.

The idea behind these trackers is that you point them toward true north (or south for Southern Hemisphere observers) and set the altitude angle on the wedge to be equal to your latitude on Earth. This points the tracker directly at the north celestial pole (it's very near to the North Star... technically the star is about 2/3rds of a degree away from truth north, but it is close). The better job you do aligning it, the longer you can image with no issues. The camera can be attached to a ball head so you can point the camera anywhere you want.