Amateur astronomy: Space is pretty awesome

The Something Awful Forums > Discussion > Hobbies, Crafts, & Houses > Amateur astronomy: Space is pretty awesome

PlasticSun: Feb 12, 2002; Unnaturally Good

I don't have a scope but I really enjoy using Stress Pill's 12" reflector, I haven't found a way to rig up my DSLR to it just yet, but I do take some long exposure shots from dark sky locations when I travel around.

I've been able to get some ok shots of the moon though a 200mm lens with a 2x tele-extender:

The trouble I'm having is I've got one of these http://www.telescope.com/control/product/~category_id=photo_accessories/~pcategory=astro-imaging/~product_id=05338?atc=hofs509&id=pofs509 to hook up the DLSR to my friend's 12" reflector but I end up with an incredibly tiny image in a very small part of the frame that is typically very blurry. It seems like I need some kind of adapater that allows the camera to use the scope as a lens rather than looking through the eyepiece with another lens.

I mostly want this just for taking detail shots of the moon, so I should have plenty of light to freeze the motion but the dob mount seems really unstable particularly with a heavy DSLR attached near the eyepiece. Can anyone recommend a setup for taking shots of the moon with a dobsion mount?

# ¿ Jul 6, 2009 19:53

Adbot: ADBOT LOVES YOU

# ¿ Apr 28, 2024 20:00

PlasticSun: Feb 12, 2002; Unnaturally Good

Jekub posted:

Beautiful pictures you've got there.

Attaching a DSLR to a telescope for prime focus photography is pretty simple. If the telescope has a focuser which accepts 2" eyepieces then you get yourself a simple adapter like this. Or the second option is a DSLR T-Ring. which converts you down to a 55mm thread for which you can get all manor of adapters for 2", 1.25" and most anything else you want.

Right now I use a T-Ring, into which I have connected a Baader multi purpose coma corrector and a 2" sky glow filter. That little array slots strait into the telescopes focuser. Your only other concern is whether your focuser racks in or out far enough to achieve focus, you can get extension tubes and correctors for that as required.

Hopefully someone can guide you in the direction of a decent US supplier for the bits you need, Orion who you linked to do everything.

Astrophotography with a dob isn't something I've tried, but it can certainly be done, and for imaging the ISS they are perfect. The first thing I'd look at is balance, if you put a heavy DSLR on the scope you will throw the balance out. On my old dob I had a couple of 35mm film cannisters stuck on the back which I could put coins in to level things out. Place it slightly ahead of the object so the vibration has gone by the time you shoot and use remote shutter release so you don't have to touch anything, mirror lock up is handy as well.

My current setup, I just remounted everything.

Nice thanks! I think adapter to the focuser will work.

# ¿ Jul 7, 2009 00:28

PlasticSun: Feb 12, 2002; Unnaturally Good

Ziir posted:

I want to take pictures like this. Someone teach me .

The most important part is to find an area with dark skies. The links above are good resources but the important thing is just to get the hell away from people.

If you want to have any of the foreground lit you'll need some kind of light source, lanterns work well and the old propane style have good control over how much light they put out. Campfires are also good provide you've got a good supply of kindling. Both will give out a very warm light, if you want to pair the blue starlight with a cool light you can use flashes with reflectors.

The shot you mentioned was a really simple shot, I put a handful of kindling on the fire to amp it up a bit and had the camera on a short tripod. Lens was an 11-16 2.8 @ 2.8 and the exposure was 30 seconds at ISO 1600. Next to no post was done aside from adding a bit of brightness to the blue channel.

With your 50 this is what I would do:

1) find a dark sky spot.
2) find some sort of rise/hill/etc where the dark sky spot is.
3) setup a camera at the base of the hill with the 500 looking upwards, you should just have the top of the hill in the bottom of the frame.
4) put something cool up on top of the hill, maybe it's you maybe it's a tent whatever.
5) add some sort of light to the hill, if it's a campfire it should be off camera to the right or left if it's a tent just fire a strobe inside the tent or use a headlight in the tent.
6) Expose for 15 secs at @1.8 with ISO 1600.

You won't have the big wide field of view but you will have a subject other than the stars and with that exposure you should have more stars and part of the milky way exposed.

PlasticSun fucked around with this message at 20:11 on Feb 8, 2010

# ¿ Feb 8, 2010 20:02

PlasticSun: Feb 12, 2002; Unnaturally Good

Ziir posted:

This was taken with 50mm lens at f/1.8, ISO 100 and 15s exposure time. I found that anything longer than 15s resulted in something extremely washed out due to the moon's brightness. I read that you can stack up multiple pictures to make it look better so I took ~13 of these pictures before a cop found me and told me I was trespassing... Anyway, how do I do that? I can open them up in Photoshop as layers but then what? I'm looking for a tutorial for dummies as I just found out what a mask was the other week.

Is there anything I can do aside from buying a bigger lens or a telescope that would let me take pictures of galaxies and other cool things? I can't afford a lens or telescope with now, so the 50mm f/1.8 and kit lens are all I have.

Edit: How come I can't take pictures of the moon? I don't get it. The 50mm lens has a longer/bigger/farther (whichever terminology is correct) focal length than the human eye, so in essence everything seen through my camera should be zoomed. The moon was pretty big tonight through my eyes and I could see details on the moon, but when I tried to photograph it, nothing came out. Long(er) exposures resulted in a huge glowing orb, and shorter exposures resulted in a moon the size of a dime, even though the moon as seen with my eyes was huge (aka the lens "zoomed out?").

Shooting while the moon is out results in most of the stars getting washed out. The moon is crazy bright, also your 50mm lens has a natural field of view of 47 degrees. The moon is 29.3 arcminutes which is about .50 degrees. So it's going to be pretty small when you want to take a picture of it. By comparison telescopes that get good images of the moon range in focal length from 800-1200mm.

To get a good shot of the moon you'll need both a longer lens (even a 200mm would help a bit) and you'll want to stop down and use a slower shutter speed, like 1/4 sec at F8.

# ¿ Feb 8, 2010 20:18

The Something Awful Forums > Discussion > Hobbies, Crafts, & Houses > Amateur astronomy: Space is pretty awesome