Gina's DIY All Sky Cam - Complete Redesign

[Xplode]

Interesting but I can't find a source in the UK.

I found them for sale in Germany and the US.

[Gina]

It's now just about dark enough to go to 60s exposure.  Dew heating ie. dome temperature is about 3C above ambient and so far no dew.

[Gina]

Reduced the gain a little and the image is better.   I caught a brief glimpse of The Plough just before this image.  I'm recording an overnight AVI file now so single shots have to be screenshots rather than PNG saves.

[RLWP]

Have you got a saw to remove that unsightly post?

Richard

[Gina]

I don't need a saw - just a screwdriver to undo the jubilee clip that secures it to the fence post   I shall be moving it but it might still be visible in the all sky camera - it's my weather station mast for the wind instruments.  I shall be producing a new weather station sometime.

[Gina]

I was going to attach the weather station mast to the observatory but my observations from trying to mount the all sky camera on a pole/mast attached to the building show this to be impractical.  And, as you say, it obstructs the ASC view where it is let alone a few feet closer.  So it's going soimewhere else - probably on the corner of the goat shed some 15m away to the north.

[Gina]

Here is a photo of the copper heat radiator that I'm using as a dew heater.

[Gina]

Have you got a saw to remove that unsightly post?

Richard

I won't be taking the current weather station mast down until I have something else to show me the wind direction and strength - I can see the wind instruments while I'm sitting on the settee in front of my desktop PC through the smaller east facing window, so I get the info even without the electronics working

[Gina]

Here are some photos of the cables fed into the observatory.

Cables enter the roof near the apex.

Held out from the side to avoid catching on the storm fastening as the roof opens.

Passing through the partition wall. 

The roof partly open with the cables curling and looping all over the place.  The piece of cardboard stops any loops catching on the corner.  I think maybe the cables could do with holding together somehow.

Roof fully open.  The cables straightened out again across the roof of the warm room.

[Gina]

Some clear sky forecast for tonight and everything is set up and working using the Asus laptop running Win 7 64bit Home Premium.  Imaging with Sharpcap and control using the Arduino IDE with Serial Display.  I'm planning to develop a Python based GUI for control rather than the MS Visual Basic front end developed earlier.  I am not bothering to use VB any more as command line is adequate until I do the Python version for Linux.  That's even if I bother with a graphical front end just for myself as I'm quite happy with a command line version.

[Gina]

Not dark yet but an interesting cloud pattern

[Gina]

2015-05-16-T2230

[Gina]

2015-05-16-T2253

[Gina]

I got a little misting in a band across the top of the dome in the early hours so it needs a bit more dew heating.  I think the best option now is probably to add extra dew heating with resistors with on/off control.

Here is a still screenshot from the overnight video, flipped the right way up and cropped in Photoshop.

[Gina]

Here is a screenshot of an image just captured with the lens aperture just very slightly open.  This can hardly be called a proper aperture control (iris) as it has only two blades and it isn't quite centred nor in the best position in the optical path as it casts a shadow.  Maybe it's adequate at larger apertures.  This lens is not designed for use in an all sky camera with the enormous light intensity range that I'm trying.  It is a CCTV lens presumably intended for surveillance use. 

As seems usual for me, I'm pushing things well past their intended operating conditions   I don't know if there is a lens with a more standard iris capable of closing down enough for this application but with the large aperture needed for nighttime and very short focal length, I think it would probably be very expensive.  With this design of all sky camera, I'm not using either the most suitable imaging device or the best lens.

A bit later...  Been thinking about the image below and I'm sure I was doing better a while back with daytime imaging.  I think something has changed.  One thing I know of is the zoom - this affects the focus and it could well affect the aperture control as well I would think.  Anyway, I'm leaving it for a while and looking at some of my other projects.

[Pan Euro]

Gina, thanks for sharing this, I have found it fascinating following the iterations of this project.

Ed

[Gina]

Completely overcast tonight - no stars to be seen   I won't bother recording.

Spoke too soon

[Gina]

I shall be having a rest from further development of this project - I need a break and I think it's working well enough for night skies for now.  I have a few comments on the performance I'm currently getting.

Firstly for night sky :-

1. Camera covers the full 180 degrees with reasonable resolution but...
2. Stars elongate the further they are from the centre - this seems to be a lens problem.
3. Dark noise is adequately eradicated with the Peltier TEC cooling.
4. Dew heating seems adequate for most conditions but more heating would be good.

Secondly for daytime :-

1. Old QHY5 is too sensitive.
2. Aperture control on lens can't quite allow for the above.
3. A colour camera is more suitable for daytime to distinguish between blue sky and dark clouds.

Conclusion :-  ASC is adequate for night use but is failing for daytime.

Possible further development :-

1. Add extra dew heating.
2. Add LDR input to Arduino to reduce aperture during daytime.
3. Consider a different camera for image sensing to cover daytime use.

Regarding 3. above, the QHY5L-II-C (or the ZWO equivavlent) seems a far better option than the old QHY5.  See my post in best camera for all sky use, post #219 (bottom of page).

[Gina]

Tried PHD2 instead of Sharpcap for daytime imaging - much better   Makes daytime imaging work!  I need Sharpcap with it's long exposures for night sky use.  I'm looking forward to having oaCapture available for longer exposures   Not really pressing you James

[Starlight 1]

Have you giving up and taking up golf it look like a golf ball . lol

[Starlight 1]

Gina, put some rain x on the cover ,that move it.

[Gina]

Ah yes, must look into that   Doesn't distort the image doe's it?

[Starlight 1]

Water is like a magnifier .

[Gina]

Yes, I know, I meant rain x doesn't distort the image does it?

[Starlight 1]

No bike riders use it. some use it on car.