Impossible shot (I think)

[mikerault]

Disabuse me of the idea.

I need to photograph the North Star through this bore hole through a 4 foot thick slab of granite:

[markjpcs]

One has to ask.

WHY??? :D

[mikerault]

Because it is there! I am documenting the features of a specific monument and this is one of them. Sunset through a slit, noon through a peep in the capstone and the North Star through this bore...The others are easy.

[Nighthound]

How large is the hole? The trick will be to get the star to focus and then to be able to tell what it is you're shooting through, if that's an important factor. In manual you can focus on any star in the sky not blocked by the granite and then swing the camera into position. You'll be focused at infinity so you can move the camera back some to position the camera if necessary but obviously be careful not to knock the lens out of focus in the process.

You could also shoot this with point of focus being the star in one and the hole in the second and do a composite in PS. Just a thought.

[mikerault]

I thought of the composite idea, maybe I'll try that.

[A.S.I.G.N. Observatory]

With manual focus and a tripod it should hardly be a challenge at all. You should be ale to do it in your sleep. A simple task really.....

[Celestron]

Let me ask the most likely worse question . Probably will get slack over this . You say you want to shoot the North star throught this hole in the wall ....? Is this hole pointing due north and at an angle that will allow you you see stars at your locations latitude ? Otherwords i'm saying that if your latitude is for example 32-degs , the hole allows you see at most 20-degs and the angle of the hole is parallel to the ground ... your not going to see that North star reguardless , unless the hole is big enough to allow projection of the lens to see at the proper latitude angle . So now i've asked and no harm meant but inquiring minds want to know :D !

[Jeff]

Don't the normal guides for depth of field still apply? A very small Av setting gives dof to infintity. Neither the camera (on a tripod), the slab of granite, nor Polaris will move so you can use as long of a shutter speed as necessary to get the right exposure.

- Just wondering -

[mikerault]

Clestron,

yes this was designed for this purpose, of course they set it about 2 degrees off so you end up with an elliptical field of view.

I tried to use infinity and long exposure but the noise was to high (or perhaps my focus wasn't infinity enough!

This as at f5.6 30 second exposure at 85mm. Unfortunately before I could try a longer exposure with a smaller arpeture a bunch of people on motorcycles showed up where I was shooting and between their questions, the lights of the bikes and general stress I didn't get a chance to reshoot.

[mikerault]

This is were I am shooting, the monument has a "noon" indicator hole in the capstone, a North Star sigt hole through the Genome (central) stone and, as you see here, a sunset slit.

[SwingBopper]

Your Polaris shot looks very OOF to me. I'd make sure your infinity setting of your camera was correct, tape it down if necessary and try again. I'd use the self-timer and shoot at f8 or f11 to try for the sharpest image.

[Celestron]

IF you want the shapest image point your camera at the bright planet Jupiter . Put the lens on auto , push your focus button down half way til the green focus light stays lit , switch back to manual focus and don't touch the lens any more . Point camera at Polaris and shoot . You should get a good focused image of Polaris throught the hole . The outside of the hole will be totally out of focus so don't worry about how it looks . Make sure your in manual mode and choose at least 25-30 secs for exposer . Throught such a small hole tho you may have star trails .

[mikerault]

Swing,

I agree, especially considering to get that size image of Polars I would need a heck of a bigger lens! :)

MIke

[SwingBopper]

Swing,

I agree, especially considering to get that size image of Polars I would need a heck of a bigger lens! :)

MIke

I think you'd need a FTL Spaceship actually. Let us know how you solve this one would you?

[Adrena1in]

My technique for getting good focus on a star is to find the brightest one in the sky, which I can generally see pretty easily through the camera eyepiece. On MF I just rack the focus back and forth until I get it just right. Might be a little off, but in a photo it won't be too bad.

If you want it really close, then set the tripod up for the bright star, set the focus, and take a shot of 3 or 4 seconds. Adjust the focus a tiny bit and take another shot. Hit play and compare the two images. If the second is better, adjust the focus a tiny bit in the same direction and take a third shot, then compare the 2nd and 3rd shots. Repeat until the most recent image looks best. Takes a minute or two and you'll get really sharp, focussed shots.


That looks like an interesting monument...I hope you get what you want and show us.

[Pete]

There's a far simpler solution.

Basically, you shoot the hole in the monument and don't bother shooting the start through it, just let it be black.

Then shoot a star (and star at all in the same general piece of sky at the same general time).

Then in post processing, just copy the star (and bit of background) into the vacant space in the hole photo and patch up the boundaries so it's not an obvious cut and paste.

Shooting the impossible doesn't have to be impossible. It only has to look like you've done it. After all, you're only illustrating the point here, you don't have to go through the pain of shooting it all in place.