Zodiacal Light

[ollypenrice]

I'm embarrassed to say that I have never attempted to observe this before. However, I have the great priviliege of having Rene to stay at the moment. Now 80, he is a retired professional astronomer whose research career was largely devoted to this and he wanted to have a look at it again. Well, dang me, there it is, plain as day when you take the trouble to look. It was rising in the dawning sky this morning, passing straight through Regulus and on up into the Milky Way near Orion. It was nearly as bright as the Milky Way and showed easily in a quick DSLR shot of 2 mins unguided.

As I say, why did I never make the effort before? Well worth it, and Rene's enthusiasm and excitement was an inspiration to younger (but more sluggish) minds like mine.

Olly

[Ant]

I've never seen it either. But I, like you, haven't really ever tried.

Can you post the picture? It'll be nice to know what I'm looking for.

Also is there a "best" time of year like NLC's?

Cheers

Ant

[Talitha]

I'd like to see your image too, Olly.

The ZL's delicately beautiful, isn't it?

Ant, the ZL is best before sunrise in the Autumn, and after sunset in the Spring. It's a faintly illuminated cone of light near the horizon, caused by the Sun's reflection off of interplanetary dust.

Here are a few 30 second, ISO 400 images from the days of yore (film ). Color seems to distract from the contrast, so i also converted them to B&W. As you can see, the cones of light are leaning south during both seasons.

The first one was taken after sunset on 15 March 2002. You can see Comet Ikeya-Zhang, a setting crescent Moon and the Pleiades.. IIRC Mars was in there, too.

The second one was taken six months later, prior to sunrise on 15 September 2002. Leo is rising, and leading it are Jupiter and the Praesepe cluster.

[JCJC]

I was lucky enough to see the Zodiacal Light during a weeks stay at AstroAdventures!! It was a great sight...

Jordan

[brianb]

Wonderful images, Talitha! Just note that, for those of us living in northern latitudes, the angle the cone makes with the horizon will be less steep than those shown.

Quick query - did you make flat field images & subtract them? I've tried a few times (long ago, using real film) to image the ZL and the Gegenschein but never managed to capture anything that was convincingly not a result of vignetting (illumation falloff towards the corners).

[ollypenrice]

I think Talitha's images are so mch better than mine that we'll stick with hers! They really are lovely and POW material in my book. (Unfortunately our German Equatorials are not in a position to reach down to the horizon at that point. I sited them out of the wind as a priority. So my images were unguided.)

The Gegeschein is visible here, too, but as Brian says, exctracting it from vignetting artifacts etc would be darned difficult. Our Guest Rene Dumont did his doctoral thesis on the problem of separating the Zodiacal light from the surrounding contributions made by light polution, the integrated stellar flux, atmospheric dispersion and absorbtion, etc. etc. It was quite a problem by the look of the thesis!

Olly

As regards the apparent angle with the horizon, it just goes with the ecliptic.

[Talitha]

Thank you.

My clear night transparency is rated as being average 99% of the time, which is probably about the same as you have in the UK, so the ZL is definitely do-able provided you have a clean, dark horizon. The ZL cones were 'just' visible with direct vision, but averted vision showed about 1/3 to 1/2 of the glow you see in the images.

"Quick query - did you make flat field images & subtract them?"

I've no idea what that means, Brian.

I think it refers to digital images? These are 35mm film captures.. 30 seconds from a stationary photo tripod.

[ollypenrice]

I'm in France, not the UK, Talitha so I do have a darker site than is probably possible there. There was certainly no need for averted vision to see it. It was nearly as bright as the Milky Way into which it disappeared. For anyone looking for it, the ecliptic goes through Regulus.

Brian's mention of flats can still apply to a slide image once it is digitized. You could shoot a palin white surface in film, digitize it, and apply it in an astro software. A plain white image should look like just that, but it won't because your lens will more fully illuminate it it in the middle. 'Flats' calibrate this effect out of the final image.

Olly

[Talitha]

Brian's mention of flats can still apply to a slide image once it is digitized. You could shoot a palin white surface in film, digitize it, and apply it in an astro software. A plain white image should look like just that, but it won't because your lens will more fully illuminate it it in the middle. 'Flats' calibrate this effect out of the final image.

Still no idea, sorry. My 'imaging' is usually done with computer paper and graphite.

[AztecastroMcJ]

nice pics

and info

James

[Dangerous-Dave]

I've only ever once seen the zodiacal light and that was from the south of France too. For several nights I assumed it was light pollution from a nearby town. Luckily I got a shot of it, because it "looked pretty" reflected off the swimming pool - it wasn't until several months later that I realised what it was I had photographed.

It's certainly an amazing phenomenon and well worth seeing.

Great pictures carol.

[Astro_Baby]

I saw in in Greece earlier this year - I was also convinced on the first night it was some silly fool with a floodlight

I actually got out of bed 2 hours before dawn to have a second, third and fourth look

[ollypenrice]

Astro Baby, what were you doing in bed at night? On second thoughts, don't answer that!

Olly

[Talitha]

Astro Baby, what were you doing in bed at night? On second thoughts, don't answer that!

Olly

Olly, this is the observing zone.. please stay on topic. Many thanks!