Monday, August 6, 2007

Milky way project -- Test Image (take 2)

Milky way picture, same as the last one, but a better scan. (Click for larger)

15s Fuji Provia 400F, pushed 1 stop, on a tripod. with a 50mm Normal lens at F2.0.

Sunday, August 5, 2007

Milky way project -- Filters

Deap Space objects including the Milky Way in general are pretty low contrast objects. So filters seem to be a good idea if one can be found to pass the correct parts of teh spectrum. It appears that a Kodak 3x3" (75mm) #32 Magenta Special Color Effect Wratten Gel Filter
will do the trick. According to various sources I found it will pass 320-500nm and 600nm plus thus removing much of the green parts of the spectrum. The green range includes a lot of light polution and sky glow from O2 in the high atmosphere. This should bring out milky way nebulosity and structure though it may reduce stars a bit.

I need to figure out what the best way to attach one of these to the camera is, but I expect its not too complex.

Friday, August 3, 2007

Milky way project -- Focus

The critical factor in the milky way photo atlas will be getting the best possible focus out of the camera. At F5.6 the ground glass is not that bright, but 0th magnitude stars can be seen with help from the loupe. The nice thing is a star forms a clean point at proper focus. So assuming that the film plane and the ground glass really are at the same place (Something to check) it should be possible to establish a clean photo.

Film buckling may be a problem, so a vacuum back film holder will be useful. (see link). At least 3 film holders would be a good number to be able to work in the field. Even that will require a changing bag. Quickloads might be better.

Thursday, August 2, 2007

Milky way project -- Film Choice

After camera selection for the Milky way project the next more important thing will be film choice.
The "perfect" astro film would combine a few characteristics:
  1. No reciprocity failure
  2. Fine grain
  3. sensitive to H-Alpha at 656.4 nm
  4. Sold in 4x5 format
  5. Fast
  6. E-6 positive development
  7. Handles push processing
However there is as far as I know no such film. Fuji's provia 400F is gets 1,3 and 5, and not bad on #2, but is not sold as sheet film, so that kills that idea. So what is left

  • Provia 100F
  • Astia 100F
  • Velvia 100
  • Velvia 100F
  • A Kodak film
It looks like Velvia 100 might do a bit better on the red, Astia has a bit finner grain, and I think Provia will push better. I think they will all be fine on the other points. Kodak's datasheets are not as easy to understand as Fuji's, so I will stick to Fuji.

I may have to buy a few rolls/boxes and take them out to test and see what does best.

Milky way project

In the early 20th century Astronomer EE Barnard composed a photographic atlas of the milky way, this work was done at the Lick observatory in California and was at the time a rather technical venture. However with the advances in film and camera technology it should be possible to take similar pictures today with amature level equipment.

With modern films such as Fuji Provia 400F it is possible to get quite a lot of milky way detail in as little as 15 seconds at F 2.0. With an equatorials mounted telescope and a camera mounted piggy back wide fields can be captured of much of the northern milky way, from Sagatarius up across to Cassiopea and down into the winter sky. This will take many sessions probably over a course of several years.

The first question is what type of camera to use:

The Options:

* 35mm (Pentax K-1000)

* Easy to use
* Easy to get lens for
* F2.0 Lens
* Light weight
* Film is reasonably cheap


* Small Negatives
* 50mm Lens leaves a pretty small plate scale

* 120 format, Rolleiflex F2.8 80mm

* Film is larger
* High quality optics, probably can be shot at F2.8 or F4.0
* Film is still not very expensive
* Not too heavy


* Camera is flakey and needs repair
* only one lens (but at least is a really good one)

* 120 Format Pentacon 6 or the like with 250 mm lens

* Same size film as the Rollei
* Long lens will bring out more small details,


* Unknown mechnical and optical quality
* Would have to buy camera (1200NIS or so)
* Weight?

* 4x5 format, Sinar F1

* High end 150mm APO lens
* 150mm Lens will bring many smaller details above the grain of the film
* 4x5 film is much bigger allowing for a lot of detail


* Provia 400F is not made in 4x5 would have to use Provia 100F
* Lens is only F5.6, so exposures would have to be in the 5-10min range
* Camera weight
* Camera flex could be a problem
* Film flatness could be an issue, with luck quickloads would fix this, or if not we can build a vacuum back

For now I plan to start trying with the Sinar, this may get swapped out for a flatbed camera, however if the project can be made to work with a LF camera the result will look amazing.

Milky way project -- test image

This is test shot of the milky way near sagatarius. I think the double stars are due to a bump of the tripod. The shot was taken bya 30 eyar old Pentax K1000 camera with Fuji Provia 400F film pushed one stop, 15s on a fixed tripod from outside Mizpe Ramon Israel.