# Photographing the night sky **URL:** \ **Category:** Factual Questions\ **Created:** [June 21, 2006, 7:57pm UTC](https://boards.straightdope.com/t/photographing-the-night-sky/361621 "2006-06-21T19:57:36Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [June 22, 2006, 6:58pm UTC](https://boards.straightdope.com/t/photographing-the-night-sky/361621/21 "2006-06-22T18:58:06Z")
> [@Chronos](#): > > the Moon’s proper motion relative to the stars is much slower than the stars’ daily rotation through the sky, and in any event, it’s in the opposite direction (so the Moon will actually move a bit slower through the sky than will the stars). The background stars move at about 14.96 degrees per hour, while the moon moves at 14.45 degrees per hour. Both are close enough to 4 minutes per degree as to make no difference to a stationary camera. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 22, 2006, 7:19pm UTC](https://boards.straightdope.com/t/photographing-the-night-sky/361621/22 "2006-06-22T19:19:52Z")
[quote] The moon lights up the entire sky and wash away all but the brightest stars. So even with multi-exposures and other tricks, there’s no way to get a decent photos of stars on a moonlit night. [quote] Well, you could take a shot of the stars, with the Moon overexposed, and merge it with a shot exposed for the Moon, which I presume could show you as many stars as you can see with the naked eye on a moonlit night. Or you could take one shot of the Moon, and then go out again at the same sidereal time a week or two later, and get a shot of the same area of sky without the Moon, to be sure to get all of the stars. **Squink** , I didn’t mean to imply that the difference between the Moon’s speed and the stars’ was significant, just that, even if it were, the Moon would be easier. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [June 22, 2006, 7:23pm UTC](https://boards.straightdope.com/t/photographing-the-night-sky/361621/23 "2006-06-22T19:23:36Z")
> [@Chronos](#): > > **Squink** , I didn’t mean to imply that the difference between the Moon’s speed and the stars’ was significant, just that, even if it were, the Moon would be easier. Yeah, I’d just forgotten what the numbers actually were, then figured someone else might want them too. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [June 22, 2006, 7:44pm UTC](https://boards.straightdope.com/t/photographing-the-night-sky/361621/24 "2006-06-22T19:44:14Z")
> [@NoClueBoy](#): > > Good idea for the trails, then. A neutral density filter can also help, as with your recco of staying with slower speed film. > > I don’t have it available online, but I once took a photo of a Houston freeway exchange during the middle of an overcast day with an ASA/ISO 12 B&W film that I pulled to be a stop slower in processing, stopped down to f/32, with a 2X and a 4X ND filter and the resulting long shutterspeed rendered the moving cars invisible. All you could see was the empty freeway interchange with downtown buildings in the background. (1977 or so, can’t remember exactly) Yes, I had some vignetting, but I cropped that out of the prints. A motorcylce cop pulled up as he was curious what I was doing. I made an extra print for him. Neat! I’ve always wanted to do this, but somehow have never gotten around to it. It would be lots of fun going around a normally busy city and rendering it as some sort of post-apocolyptic ghost town. Surely, someone else must have done a project like this, right? Anyhow, if you do by any chance find those prints, I would love to see them online. ---
**Author:** ![AncientHumanoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ancienthumanoid/32/278_2.png) [@AncientHumanoid](https://boards.straightdope.com/u/AncientHumanoid)\ **Post date:** [June 22, 2006, 7:53pm UTC](https://boards.straightdope.com/t/photographing-the-night-sky/361621/25 "2006-06-22T19:53:28Z")
> [@pulykamell](#): > > Neat! I’ve always wanted to do this, but somehow have never gotten around to it. It would be lots of fun going around a normally busy city and rendering it as some sort of post-apocolyptic ghost town. Surely, someone else must have done a project like this, right? Anyhow, if you do by any chance find those prints, I would love to see them online. I got the idea from a large format photography show I went to (mid 70s) and talking to some of the artists. Who knows where the guy who told me that got his idea. But his work was of building fronts in NYC, iirc. Perhaps that might help a serach. I’ll look for mine. I have, quite literally, THOUSANDS of images stored. Some negs, some prints, some chromes, and of various different formats. But, I’ll give it a go pretty soon. Been meaning to catalogue everything for quite some time now anyways. Plus, I now have my Dad’s collection to sort, so I have that motivation, too. ---
**Author:** ![UncleBeer](https://avatars.discourse-cdn.com/v4/letter/u/977dab/32.png) [@UncleBeer](https://boards.straightdope.com/u/UncleBeer)\ **Post date:** [June 22, 2006, 9:03pm UTC](https://boards.straightdope.com/t/photographing-the-night-sky/361621/26 "2006-06-22T21:03:51Z")
> [@Chronos](#): > > The fact that the Moon is closer is irrelevant: As far as any Earthbound optics are concerned (at least, any optics smaller than a few hundred meters), the Moon is an infinite distance away. And the Moon’s proper motion relative to the stars is much slower than the stars’ daily rotation through the sky, and in any event, it’s in the opposite direction (so the Moon will actually move a bit slower through the sky than will the stars). Thanks for correcting me. And thanks to Squink, too, for putting some numbers to the motion. Obviously, orbital mechanics ain’t my strong point. > [@NoClueBoy](#): > > I don’t have it available online, but I once took a photo of a Houston freeway exchange during the middle of an overcast day with an ASA/ISO 12 B&W film that I pulled to be a stop slower in processing, stopped down to f/32, with a 2X and a 4X ND filter and the resulting long shutterspeed rendered the moving cars invisible. That does sound pretty nifty. ---
**Author:** ![Omphaloskeptic](https://avatars.discourse-cdn.com/v4/letter/o/bcef8e/32.png) [@Omphaloskeptic](https://boards.straightdope.com/u/Omphaloskeptic)\ **Post date:** [June 24, 2006, 10:07pm UTC](https://boards.straightdope.com/t/photographing-the-night-sky/361621/27 "2006-06-24T22:07:05Z")
One annoyance not yet mentioned is airplanes. I have quite a few nice pictures of constellations with dotted red lines running across them. Joshua Tree, for example, is pretty close to the LAX approach path, so careful timing and framing is necessary to get good images. ---
**Author:** ![dwc1970](https://avatars.discourse-cdn.com/v4/letter/d/a183cd/32.png) [@dwc1970](https://boards.straightdope.com/u/dwc1970)\ **Post date:** [June 24, 2006, 10:23pm UTC](https://boards.straightdope.com/t/photographing-the-night-sky/361621/28 "2006-06-24T22:23:24Z")
Hey, **panache45** , can you post links to your photos once you have them ready to share? I’d like to see them. [Previous page](https://boards.straightdope.com/t/photographing-the-night-sky/361621.md?page=1)