Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: MarkS on Apr 14, 2016, 23:29:54

Title: Kelling Heath (Spring 2016) Video
Post by: MarkS on Apr 14, 2016, 23:29:54
As you know, I short circuited my mount's control board.  So unable to image, I stuck a 50mm F1.8 lens on my full spectrum Sony A7S and wandered around the pitch black campsite filming at 10 frames/sec and ISO 128000.  Unfortunately I forgot to put an IR/UV cut filter on it so it picks up a lot of longer wavelengths making everything a bit purple.  It's also hand held - which isn't ideal for stability.  It was so dark that someone walked straight at me and I only noticed them just before colliding.

https://drive.google.com/file/d/0B3Ky5pyZvsINeXFiY2dsS21TSVE/view?usp=sharing  (Download it first onto your PC for best 1920x1080 quality)

Julian made a comment to the guy with the blinding red headtorch but I cut it from the video :)

Mark
Title: Re: Kelling Heath (Spring 2016) Video
Post by: Carole on Apr 15, 2016, 00:25:24
What a fantastic bit of footage that is.  Really gives the atmosphere of an Astro camp, except your camera is so sensitive it makes everything look much brighter than it actually is, for instance my red light when I came out of my van is a really faint light, yet it looked quite bright on the footage. 

Carole
Title: Re: Kelling Heath (Spring 2016) Video
Post by: JohnP on Apr 15, 2016, 08:33:14
That's pretty cool Mark - amazing performance from camera.. So is that a bog standard A7S, 12MPx - No Ha mod? john
Title: Re: Kelling Heath (Spring 2016) Video
Post by: Fay on Apr 15, 2016, 08:38:33
Really great Mark!
Title: Re: Kelling Heath (Spring 2016) Video
Post by: The Thing on Apr 15, 2016, 09:56:34
Brilliant. A couple of years ago you'd have had to have a specialist camera to do that.
Title: Re: Kelling Heath (Spring 2016) Video
Post by: Carole on Apr 15, 2016, 10:38:19
It would be great to show this at the next meeting. I wonder whether Ivor could download it to his "meetings" laptop as I am not sure whether if will go onto a PP presentation and memory stick for Doug to show particularly as Doug is new at doing PP presentations - last month was his first ever at creating and presenting.  Then hopefully if it's already downloaded all he has to do is click on it.

Carole
Title: Re: Kelling Heath (Spring 2016) Video
Post by: Mike on Apr 15, 2016, 11:16:25
Great video Mark. Ridiculous how bright some of those torches were and I bet the guy with the caravan lights got berated.
Title: Re: Kelling Heath (Spring 2016) Video
Post by: Carole on Apr 15, 2016, 11:34:13
QuoteRidiculous how bright some of those torches were
Apart from that photographer, I don't think the lights were bright, especially my torch, I can hardly see much with it it is so dim but it looks quite bright on the footage.  Also you can hardly see any light from my laptop inside the box with red plexi glass over it, yet on the footage it looks white.  It was really dark walking around - as Mark says he could hardly see a thing and almost bumped into some-one. 

It's just that his A7S is SO SENSITIVE that the lights look as bright as they were.

Carole
Title: Re: Kelling Heath (Spring 2016) Video
Post by: MarkS on Apr 15, 2016, 13:45:35

John - it's a full spectrum modified - I forgot to put an IR/UV filter on it so it was picking up IR as well as visible light.

So, unfortunately it doesn't show everything in a true light.  The caravan light that Mike referred to was not obvious at all - I reckon it was internally lit using incandescent lamps and the camera picked up some non-visible wavelengths.  I noticed my own laptop was spewing out IR from a blinking source.  It might also explain Carole's laptop.

I have another clip (I might post it later) of someone using a Dob next to us.   His working area was very gently bathed in dim red light.  Through the camera his whole caravan was externally illuminated very brightly in white light - I guess he was using incandescent light with a red filter and the IR passes straight through.

Mark
Title: Re: Kelling Heath (Spring 2016) Video
Post by: Carole on Apr 15, 2016, 16:02:17
Just think Fay, Sue, Roy, Delphine and Ian, you slept through all this.

Carole
Title: Re: Kelling Heath (Spring 2016) Video
Post by: RobertM on Apr 15, 2016, 16:07:14
Great movie Mark.

Makes you wonder how much all that red light affects people taking broadband and Ha images.
Title: Re: Kelling Heath (Spring 2016) Video
Post by: MarkS on Apr 15, 2016, 16:59:05
Quote from: RobertM
Great movie Mark.

Makes you wonder how much all that red light affects people taking broadband and Ha images.


Indeed.  It shows the importance of a dewshield to keep out stray light as far as possible.  It also shows that it is best not to walk around with head torches.

Mark
Title: Re: Kelling Heath (Spring 2016) Video
Post by: MarkS on Apr 15, 2016, 17:45:48

Here's the link to a video clip I didn't use.
https://drive.google.com/file/d/0B3Ky5pyZvsINQlNWNWh3cDVZNzQ/view?usp=sharing

His whole tent is lit up as well as the side of the caravan.  But to the eye it was just a faint red glow.  So I'm guessing it was an incandescent lamp with a red filter.  My tent lit up similarly when I used a red bulb light that Julian kindly loaned me - again it just appeared as a faint red glow to the human eye.

Mark
Title: Re: Kelling Heath (Spring 2016) Video
Post by: RobertM on Apr 15, 2016, 19:53:54
Just goes to show how much light we can't see.
Title: Re: Kelling Heath (Spring 2016) Video
Post by: Mac on Apr 16, 2016, 09:16:28
Is it me but at 00:28 it look like a meteor going just under Mars.

Mac.
Title: Re: Kelling Heath (Spring 2016) Video
Post by: Carole on Apr 16, 2016, 09:36:33
QuoteIs it me but at 00:28 it look like a meteor going just under Mars.
Now you've pointed it out I can see it too.

Carole
Title: Re: Kelling Heath (Spring 2016) Video
Post by: Mike on Apr 16, 2016, 09:38:05
Quote from: Mac on Apr 16, 2016, 09:16:28
Is it me but at 00:28 it look like a meteor going just under Mars.

Mac.

Yep, you're right.
Title: Re: Kelling Heath (Spring 2016) Video
Post by: Fay on Apr 16, 2016, 11:24:49
only goes up to 00.18 on my screen
Title: Re: Kelling Heath (Spring 2016) Video
Post by: Mike on Apr 16, 2016, 21:02:44
First video not the second one.