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Another DIY all-sky camera

michaelmorris

By michaelmorris
in DIY Astronomer

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michaelmorris

michaelmorris

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For a while now I’ve been thinking about taking pictures/videos of meteor showers. Inspired by the DIY exploits of others, for the last couple of weeks (on and off) I’ve been toiling with drill, spanner and silicone mastic and have put together my own DIY all sky camera.

Here are the basic specs:

Camera - Samsung SDC-435 (already had this)

Lens – 2.1 mm board camera lens (150 degree FOV) (EBay)

Board camera lens to C mount adaptor (EBay)

Dome – 9 cm diameter dome and mount (Henrys Electronics - http://www.henrys.co.uk/)

Box – IP65 Weatherproof junction box (EBay)

TV aerial pole and mount (B&Q)

Other bits mainly from the ironmongers round the corner and from Maplins.

Cover – Small barbeque cover – (Tesco online)

The dome is (hopefully) sealed on to the junction box with a homemade rubber gasket. For ease of access, I’ve removed the original securing screws for the lid of the box and have replaced them with five toggle catches. All joints and holes are (hopefully) sealed with liberal quantities of silicone mastic.

The box is a bit wider that I would ideally have wanted, but It was the smallest one I could find that had both the depth to fit the dome on the top and the height to accomodate sliding the camera up and down when (as I eventually hope) it is fitted with an Auto Iris C mount fisheye lens.

The camera can be lowered on its mounting rail for tweaking the focus and for easy removal.

The weather proof box is mounted on a short TV aerial mast which is bolted to the side of the observatory. It's a bit 'bouncy' so I may end up having to brace it higher up.

I’m using a KWorld DVD maker 2.0 USB video capture device and will be using HandyAVI as the image capture software.

The last job is to take the camera out then put a hose on the casing it to double check it is all waterproof.

After that it’s going to be a few nights tweaking the capture settings, then full steam ahead.

Here is the completed box and dome mounted on the mast on the side of the observatory from the front and from the back.

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post-586-0-49671800-1345309195_thumb.jpg

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Breakintheclouds

Breakintheclouds

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That looks superb. What software will you be using to do the capture? Will you use a program of the sort which monitors security cameras and which stores a section of video each time it detects movement? I had the idea to use the Linux program motion for this one day.

Sent from my Nexus 7 using Tapatalk 2

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JamesF

JamesF

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That looks superb. What software will you be using to do the capture? Will you use a program of the sort which monitors security cameras and which stores a section of video each time it detects movement? I had the idea to use the Linux program motion for this one day.

I had wondered about the possibility of doing this with motion, too. Hours of images of the undersides of clouds probably isn't that interesting though :(

James

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Gina

Gina

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Maybe but I'm broadcasting hours of webcam pictures of a green shed and view across the valley with generally nothing happening. Though today the goats are in this area and may show themselves from time to time.

Should add... I'll be broadcasting images from an all-sky camera when I get round to doing it.

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Stargazing_Cliff

Stargazing_Cliff

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Looks well smart look forward to any images or time lapse video's from it :)

i shall have to get dome for cam sometime and use some kind cctv ccd and wide view lens and wire it up to me easycap.

i know they sell dome cams in some electrical shops that say ccd sensors wounder what they like allready made they cost around 50 quid from maplins

what you guys rekon to this

30 quids not to bad sony super had ccd sensor i mite get one sometime and stick the thing on me garage roof outside waterproof it little.

http://www.maplin.co...e-camera-225102

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skybadger

skybadger

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What about using allthese 300d dslr bodies that are coming available to do this work?.

I'm trying to think of how to compare these apples and oranges. Basically you need a camera of 0.003 lummens sensitivity or better to get video of the night sky in real time. With a dslr at 3200 do you get the same at a seconds exposure ?. Then you get all 12 mp to play with. I shall have to check the specs of my camera (I'm on the train).

Given a zero mag star emits one million photons per sec per sq cm into a detector, a pixel typically covers 50 millionths of a metre or 5 thousandths of sq cm so I estimate a zero mag star will emit 5000 photons into a single pixel in one second. Take that to 6th mag, a drop in intensity by *252, becomes 40 photons per sec. Maybe I answered my own question. How can I improve this?

I will do this. Anyone see theproject inS&T this month?

Cheers mike,

Mike.

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pete_l

pete_l

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Given a zero mag star emits one million photons per sec per sq cm into a detector,
That's an interesting factoid, may I ask where it came from?

These guys reckon the answer in much, much less (measured at 9.2x10**6 total into a 45cm mirror and then through to the counter. The theoretical value was > 100 times more)

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michaelmorris

michaelmorris

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What software will you be using to do the capture? Will you use a program of the sort which monitors security cameras and which stores a section of video each time it detects movement?

Yes - HandyAVI software has a meteor capture mode that captures a short rolling video and analyses this for motion. If it detects motion it saves the section of the video with the motion and a user-defined number of frames before and after the motion. It seems to work well but picks up a lot of moving clouds. I've used it for two sessions so far and the only thing 'astronomical' it has picked up is the ISS. Early days.

Here is a link to HandyAVI http://www.azcendant.com/

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skybadger

skybadger

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Mike

Have you any results on what the faintest star you are seeing is ? I am interested in seeing what exposure/frame rate you are using and how sensitive this camera is at that rate.

What are your thoughts on longer exposures/more stars vs greater time resolution ?

You have inspired me to re-awaken my project to do this too - I have a DMK41 I can use.

For times when there are clear skies but no meteors there's also widefield variable star photometry to try for too.

Looking forward to seeing a meteor.

Cheers

Mike

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  • 3 months later...
ixalon

ixalon

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Skybadger,

Slightly different equipment but on my QHY5-based allsky cam, with 30 second exposures (and 10% gain) I see down to around Mag 3.75 (e.g. I can just make out Alula Australis). If I increase the length of exposure or gain I pick up much more reflection off the dome (even with all the masking/shading!) so not really worth it.

Nightly time-lapse videos (which need to be downloaded to see the full detail) at: https://www.dropbox.com/sh/5floelgzu5adldz/fl7F5RykKE?lst

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  • 10 months later...
skybadger

skybadger

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picking up on this again, I read a paper recently where the D20a is at unity gain about ISO1200, ie one electron per photon, and where the Watec 902 gets to mag 5.4 after on-the-fly stacking and 3.4 for no stacking (http://france.allsky.camera.free.fr/test-camera-en.html), So I guess there are more data points now to work with.

If the aim of an all-sky camera is to pick up the meteor events the eye misses, then the long exposure pixel in a DSLR has to be able to record at this level to have a useful function compared to these low light video cameras.

I shall have a go tonight to see if I can work out what the instantaneous sensitivity of my DSLR is ...

Mike

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Ant F

Ant F

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i have the samsung scb2000 which is the same cctv i think. i have captured quite a few interested things, big meteors over the past few months. i always leave it pointing north out my windows and leave the laptop recording. then the next day i review what i have and make mini videos of what i have caught. ive seen some strange stuff. 

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