Nighttime sky

In article <4g3k9l$ @tlaltec.tezcat.com>, john @tezcat.com says...
: > I'd like to photograph the nighttime stars using ASA 100 film and an

The poster asked about taking a photo of the night sky without a tracking
device.  To render stars as points, exposure must be kept under a minute at
most.  I don't think you will get much of a photo at F/8, except maybe
with 3200 ISO film...  Sometimes the increased amount of light more than
makes up for a slight decrease in image quality, especially in
astrophotography.  

- Ken

: I'd like to photograph the nighttime stars using ASA 100 film and an
: aperture of 3.5 the lowest my lens will go. How long should I expose
: the film. My Ricoh XR-10M can co as slow as 16 seconds (1 sec, 2, 4,
: 8, then 16) withouth a bulb setting. I do in fact have a plunger. I
: plan on going out into the desert where there is no light pollution
: and during a full moon. I want to use the highest speed I can get away
: with so the rotation of the stars won't streak the photo. Any
: recommendations?

If you really want to make some nice pictures of the nighttime sky, why
don't you make a device to follow the stars.  I did this once and the
pictures were fabulous.

It takes a little construction but anyone with basic construction
abilities should be able to do it.

All you need to do is make a hinged camera support to be mounted on your
tripod.  I used 2 one foot 1x4 pieces of wood.  You fasten a 4 inch stove
bolt to the top part and have it move freely through a small hole in the
bottom.  Us a ruber band on the ends, maybe over screws or nails in the
end grain to hold tension to the closed position.  Put a washer and nut on
the bolt in the inside.  You may have to bend the bolt to make it move
freely, trial and error will tell you how much.

Now the rubber band will close the device and the nut will hold it open.  
Turning the nut will increase or decrease the angle.  Simple math will tell
you how much turn is required to follow the stars.  I set the bolt on
mine at a distance from the hinge so that one turn of the nut was required
every minute.  A quarter turn every 15 sec. resulted in streak free images.

On the top to mount the camera you screw on a ball joint mount and you
are ready to go.  The hinge must be in line with the north star

I can't remember the speed of film, but I too 3 - 6 min. exposures.
Truly amazing results.

If you want to make one and need more details, I will be glad to tell you
more.  Just email me direct at:  s @magin.com

In article <4fmcbg @news1.goodnet.com>, rept @goodnet.com says...

Are you using an equatorial mount/platform to track the stars?  If so, a
really dark sky can usually take an hour or more of exposure without fogging
up, with ISO 100 and F/3.5.  You should experiment with different exposure
times though, since this is very dependent on the site.

If you are not using a tracking device and still want to have the stars
appear as points (without streaking), you should keep the exposure under
one minute at most for a standard lens (<50mm).  You won't get much with
an ISO 100 film though.  I'd try 1000 or 3200.

By the way if you want to take the photo of stars, go on a moonless night.
The Moon is a big source of light pollution when it's larger than half
full.

- Ken

If you want to see the stars in your photos, do not shoot when the moon
is full. it will completely overwhelm the stars. Go instead on a
moonless night. Any shutter speed that doesn't overexpose the moon will
never capture stars.
--
Dennis Andrews

from the description and ideas I read do I take it that it is best to
experiment with ones camera?

What is a good test range to use - I'm a beginner and am putting
together lots of basic test prints - i.e.: all the shutter range and
it's effect --yes, as basic as that.

So, if I want to potgraph at night should I simply take 3 roles at
differing condition/light etc?

Is this what most people do?

Cheers-Glen.

The latest copy of Outdoor Photograher has all these details well laid out.
Try your newsstand

Mike writes

My last 2 portfolios for my photo classes here at Stanford were all  
night photography. I used my Canon 20-35L/3.5 lens and TRI-X 400 film. I  
can give you the following rules of thumb:

Full moon, or lots of light pollution: 30-60 sec
Half moon, some light pollution: 2-5 minutes
New moon, out in the desert: 30+ minutes

Once I used a TMax 100 film, stupid me, with lots of light pollution,  
and got one shot right -- at about 2 minutes. All others were way under.  
The problem is reciprocity failure, and it gets worse the longer the  
exposure is.

So for your particular application, full moon but no light pollution, I  
would go with 45 sec - 3 minutes, to be safe. Again, that's with TX, and  
other films may vary a lot.

Good luck, don't forget to bring warm, very warm clothes and lots to  
read :-)

- Stan
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