Sky glow and moisture and star trails.

[Grandpa Ron]

After an annoyingly long period of cloudy nights, the clouds parted. Unfortunately, sky glow has encroached on my once rural area. Just to see the impact, I set up on the North Star. As you can see, there was way to much light scatter in the air. I also was trying 400 ISO film.

The next night I turned the camera up towards a darker parts of the sky. Still to low to avoid sky glow, but it is interesting to see what crosses the field of view in three hours.

I used 400 ISO film to catch the weaker star light but it also capture the sky glow. My next objective is to find a dark skies area nearby.

Arista EDU 400
4x5 film format
127 mm lens
3 hour exposure

 

[wfooshee]

I've never tried star trails with film... I could wish you had a film scanner instead of digitizing from your Rebel camera. Shooting a print or negative with a digital camera introduces a whole level of artifacts that are probably not actually in the film. See this post I made in another thread, comparing a flatbed scanner to a film scanner, and comparing DSLR duplication to film scanning. I was working with a slide in my camera vs. scanner comparison there.

 

[Grandpa Ron]

wfooshee.

I certainly would like to have a scanner. However, I am shooting a 4"x 5" negative, so no magnification is required for a 4x6 drugstore print, or digital camera download.

35mm is handier. But as you mentioned, when enlarged the negative and digital conversion issues become noticeable.

 

[smoke665]

used 400 ISO film to catch the weaker star light but it also capture the sky glow. My next objective is to find a dark skies area nearby.

Interesting. I've never tried this with film and only a few times with digital.

 

[Grandpa Ron]

Interesting. I've never tried this with film and only a few times with digital.

Smoke.

I like film because you can open the shutter and get some sleep, then come back in 3or 4 hours to close the shutter. The max shutter time on my digital is 30 sec. I know some folks have found a way around this issue by stacking the digital frames in post process. However, my digital has no way of tripping the shutter every 30 seconds except manually.

 

[RacePhoto]

Smoke.

I like film because you can open the shutter and get some sleep, then come back in 3or 4 hours to close the shutter. The max shutter time on my digital is 30 sec. I know some folks have found a way around this issue by stacking the digital frames in post process. However, my digital has no way of tripping the shutter every 30 seconds except manually.

Digital: Set the camera to 30 second exposure, with a wide lens, 1600 ISO, f/4 (just for starting) I use a 14mm Rokinon and on a crop camera, that's not going to get points of light, well maybe, but it's at the limits. Full frame you're fine. I also have an 8mm but there's light fall off and color aberrations. Suggestion, set camera to Incandescent for a nice blue sky.

Lock the shutter with cable release. The camera will take a 30 second exposure, as soon as it's finished, it will take another 30 second exposure, until the card fills or the battery dies. Must be set to multiple images, not single [ ] , at least for mine I need to do that to have it continuous.

In effect you now have an exposure, every 30 seconds.

Combine with: https://startrails.de/ free

I start mine after dark, but often it's still too light and I get up shortly after Sunrise and it's too light. Throw out anything that's not dark night sky or the lighter frames will overwhelm the dark ones. There are also suitable pairs and single frames, but since this is about trails,...

Below is two frames.

I like the idea of film and the 4x5" sounds like good fun.

Oh and yes, I use old 10-D or 20-D and I made one setup with a 40-D that I picked up at an auction, cheap.

The 8mm and 14mm are a little more complicated for the heaters. They are wound with #38 enamel coated copper wire. Length depends on the diameter of the lens. I started with one that was 58mm for an old kit lens, then wound these two. The project was to have 12V camera power, so the heaters are also 12V.

I wanted to be able to walk in to a dark sky site and set up, shoot all night, and pick up the camera in the morning. No AC in the woods. Eventually I found that I'd either need a larger battery pack or two small ones. The cameras are powered by 12V continuous adapter in a grip with one standard battery.

Now I'm working on shorter heater wires on the filters, that run on 7.4V so they can share the output. A 12V heater (calculated length) on 7.4V doesn't keep the dew off the center of a 14mm lens. So eventually still 12V power, buck converter to 7.4V and in my long term, maybe a solar powered camera. But that's complicated because of needing a pretty large solar panel. Not very stealth?

Good clear night and Perseids is my goal. Testing 12V portable above.

Longer lens works as well.

 

[Grandpa Ron]

I thought about using my digital and long exposures, but I am not sure the sensor on an entry level camera would handle continuous use without overheating. I have used the digital camera for northern lights and constellation photos.

It is a "chose your poison", type of adventure. You can spend your time and effort on the front side assembling the gear you need to power the digital apparatus, then combining the images in post process. Or, you point your camera and walk away for a few hours, then spend your time developing film. which you will eventually digitize to share with others.

If I were starting out, I would probably go with digital. It is fast, not messy and the images are easily manipulated. However, film is what I know and am comfortable with, plus I have all the gear. It is a real hands-on adventure, kind of like driving a stick shift over an automatic transmission.

My biggest concern is the continuing increase in sky glow.

 

[RacePhoto]

Real simple, if I'm going to do an hour exposure, it would be film. If I'm going to do digital, they would be individual shots and software.

Yes about that sensor heating up or who knows what. Although I never took a really long digital exposure. I suspect there would be the main problem you mention, which is fogging and light other than what is desired, ruining the shots. "sky glow"

The sky and time lapse and other projects are just that. Someone could do night sky, really easy, without anything but a cable release and if they wanted more than the life of the batteries, external power of some sort. Even a grip will give a pretty good long time.

Put it out, turn it on, go watch a movie. With mine that I worked up to combat dew and made an all battery power version so I can walk in to a dark spot, I start it up at dusk, go home and come back in the morning. The alternative to that is, I shoot from the back yard and use AC.

Double yes to what you said though. I'd really worry about an hour long exposure with a digital camera. Not only burning up something or power, but there's go to be some limit to how the data gets collected or what it looks like.
If you like film, you'll like looking into film reciprocity.

You'll have to read for a much smarter version that what I'm going to write. But over time of the exposure, the film becomes less sensitive to light. It's not as simple as 10 minutes being half of 20 minutes.

Above all HAVE FUN! Or what's my other one? Don't be afraid to experiment just to see what happens?

 

[Grandpa Ron]

Yep, people have done many things when they set their mind to it. Back when I was chasing stars and planets (late 1990's to early 2000's) I built a reflector telescope with a 6 inch mirror. I had quite a bit of fun with it, coupled my camera to it a few times etc. but again light pollution and civilization arrived. A friend of mine in Missouri had built quite a telescope set up with photo multipliers and a TV monitor. He shot some ready neat deep space stuff. Basically, I am an incessant tinkerer so there are always new things to try. Lately I inherited a lot of camera and darkroom gear from the 1940's. There is a unique feeling when you have fire up some old piece of gear, knowing that some long-gone craftsperson created it by hand. I love that stuff.