DIY All Sky Camera

[steppenwolf]

Before I start running my fully automated observatory from a remote location, it is useful to know what the weather conditions are like at the observatory site and an all sky camera is a great way of seeing what is going on in conjunction with my AAG CloudWatcher that 'measures' the weather conditions.

Unfortunately, commercial all sky cameras have a pretty hefty price tag and I had a very limited budget for this project so I decided to make my own. The camera is the easy part and the excellent ZWO ASI 120mm was an obvious choice - it even comes with a 150° wide angle lens. However, the key to a reliable all sky camera is the enclosure it operates in. A camera and lens combination like the ZWO will work very well on its own for this purpose right up until the dew forms on the lens or even worse, it starts to rain so a waterproof enclosure with its own heating system is a prerequisite.

Before I even started to think about the enclosure itself, I gave a lot of consideration to the heating aspect. The solution was sitting in my bits and pieces drawer - the components that I'd bought in a couple of years ago to make a dew-band for my 28mm camera lens when I wanted to capture a meteor shower! I never did make the dew-band but the Nichrome wire and pulse width modulation (PWM) power supply were perfect for this project. I calculated that I would need up 8 watts of heat for a 'de-frost' but a lower output for general use.

With the heater resolved, I looked around for a suitable transparent dome for the enclosure and found a 100mm diameter dome for under £10.00 on Ebay. All I needed then was a suitable box to match the total width of the dome and again, Ebay came to the rescue.

Awful skies mean that I have used it very little but I have enjoyed making time lapse videos of the night sky and I ended up buying a fisheye lens for the camera to give me a full 180° view.

So here's the camera enclosure in all its glory

Click here to view my first light timelapse video

[bingevader]

Nice timelapse.

[steppenwolf]

Since posting this, I have received an outraged email from a member on SGL accusing me of stealing his design.

This is not the case although it would appear that we have used the same components. I would just like to publicly apologise to a member called 'Olly' (not Penrice!) - and I don't know his SGL alias - if he feels that I have in any way copied his design but he is mistaken, I carried out my own independent research but have apparently reached the same conclusion as to the choice of the components used.

[Gina]

Hmmppfff...  In my opinion any design posted here or anywhere else on the internet becomes public domain (unless specified otherwise).  If someone doesn't want their design used they shouldn't publish it!!  "Simples".  Have to say, I'm disgusted that anyone who posts their design on here should grumble if anyone publishes a similar design.  A direct copy should acknowledge the original poster I agree but this isn't the case here.  In fact any ASC is going to use much the same design - there are olny so many ways of doing things.

Personally, I reiterate that anyone is very welcome to copy any of my designs or ideas - they are freely published into the public domain.  Indeed I post my ideas and designs in the hope that others might benefit from them though admittedly, I'm always glad of other people's thoughts or suggestions and that benefits me - it's a two way exchange. 

[Dave Lloyd]

That's so right Gina, it's a camera with an ebay dome on top. What other way is there of doing it?

[ncjunk]

I´d concur most designs I´ve seen look like this it´s not likely you´d come up with something different.

Dome, Heating element and box er....perhaps add a picture of a fruit and call it an iskycam thus infringing on at least 2 copyrights!

Nice video and graphics on the video.

 

Neil C

[mcsheffield]

I think you have done what anyone else would do, research will show only certain components needed for the job, only certain components available on the bay, conclusion: most will end up with a similar result. 

Anything put on the web is free game as far as I'm concerned, if you don't want anyone to admire/copy/learn from what you have done, don't put it on the web!

Great bit of time lapse footage, good detail, you should be very happy with a great job completed.

These are all my own views not copied from anywhere else.

[martin_h]

Nice camera solution, shame about the rest. You do realise that your dome and mount have been done before as well, shame on you!?

[Stub Mandrel]

In the original thread he seems to be encouraging people to copy the idea:

I think he was probably upset as he thought his idea had been copied without giving him credit. Who knows, Steve may have seen it and been subconciously influenced, although a sealed electrical case, perspex dome and acrylic sealant are a fairly obvious way of doing it.

Stranger things have happened in Led Zeppelin.

 

[Gina]

Yes, that's the way I did my first one.

[steppenwolf]

Quote

I think he was probably upset as he thought his idea had been copied without giving him credit.

Thanks for posting the link to his thread because I couldn't find it when I looked yesterday to see what the fuss was about - what is strange is that the same person reported my post to the moderators BUT his alias wasn't 'MagnaMan' which is why my search didn't find it. It is the not giving credit that has apparently caused the upset.

Without doubt I have purchased the same box and most likely the same dome but as for copying the design, well, my conscience is clear on this as my research was rigorous (as always) and having located a suitable dome, I looked for some time for a square box as I wanted the camera to be as compact as possible but I was unable to find one of around 140mm that didn't have a curved top! However, the 140mm dimension did bring up a supplier who sold a suitable external use box that was rectangular but with a 140mm short side so that is what I eventually went for. Anyone who has followed some of my other much more complex original projects would surely realise that I don't need to copy anyone's designs but am more than capable of original thought!

I don't think this member is being malicious and I can see why he has mistakenly assumed that I have copied his design but I didn't so no credit was required, end of. It is a matter of record that I give credit to others in my projects and elsewhere (for example my false coloured mono images on Facebook where I credited Sara Wager for the idea) and there is a list of names credited in my automated observatory thread so if I had used this earlier thread as my source for all sky camera components, it would surely be unlikely that I would fail to give credit this time.

I appreciate the support that several of you have given over this but would ask you not to let this episode cloud your judgement of the other party.

[steppenwolf]

To get half reasonable star shapes towards the horizon in these ultra wide images I had to employ 'off axis focusing' whereby instead of focusing on a central star, I focused on a star about half way between the centre and edge of the FOV to distribute the focus more evenly. This results in more bloated stars in the centre of the FOV but to my eye is better than the horrendous comets achieved normally!

However, I noticed that Martin Lewis has used a range of different lenses in his all sky camera project in the search for imaging Nirvana, one of which was not too expensive so with some difficulty, I purchased an Arecont 1.55mm f2 fisheye lens and produced this short time-lapse video  which shows much better formed stars across the whole FOV but at f2 rather f1.4 I am going to have to take much longer exposure subs.

So much for my low budget .........

[Gina]

I have already come to the conclusion that an ASC is not a low budget imaging system and still being a bit dissatisfied with mine I expect to spend more on it - not that we've had any decent clear night skies to test it properly.   I have been using colour cameras to date because I like to see a bit of colour im my images but I'm beginning to think perhaps I need to go to mono for better sensitivity.  The ZWO lens that came with my ASI185MC camera has good focus down to the edge but doesn't give me 180° except on one axis.  The Fujinon zoom lens gives full coverage but as you've found Steve, doesn't give good focus over all the FOV.

One reason for spending more on the ASC is that the weather has not permitted any "normal" astro imaging for ages so I'm reluctant to spend on that but the ASC can catch any short period of clear sky and the Milky Way is in a good position at this time of year.  I think I shall look at ZWO cameras with a larger image sensor.  Pity they don't do square ones - rectangular sensors waste a lot of pixels!

[martin_h]

Like all things astro related the "low budget" is a starting point for deep pocket syndrome .

[Gina]

That is SO true!!

[ChrisLX200]

It depends which camera you intend to use, but those 1.8mm fish-eye lenses sold by Bern at Modern Astronomy are pretty good for this job. Not cheap at around £80 though. I wanted a better camera so had the brilliant idea of buying an ASI174MM to replace the QHY5L-II I'm currently using, but it just dawned on me the 1.8mm lens won't cover the sensor!

ChrisH

[steppenwolf]

Quote

but it just dawned on me the 1.8mm lens won't cover the sensor!

That would also be an issue with the otherwise excellent Arecont lens if you used it on a sensor larger than 1/3" - you would get a 'porthole' view.

Quote

I have already come to the conclusion that an ASC is not a low budget imaging system and still being a bit dissatisfied with mine I expect to spend more on it

Sadly, this has been my experience also but it has been great fun and continues to fascinate me! I guess that we should not lose sight of the fact that this is still AP so expect bank balance depletion as a matter of course........

[Gina]

I'm having the opposite problem with my ASC.  I'm using the ZWO 2.5mm FL f1.2 lens and the image is too big for the ASI185 camera I'm using.  I've just been looking the the ASI174MM camera and that would seem to make the circular image just fit in the sensor frame with a Y axis of 7.2mm (I estimate the image circle as 7.1mm diameter - the 185 sensor is 7.3mm x 4.6mm).  One thing that puts me off the 174 though is that it says amp glow may be a problem with longer exposures.  It depends on what they call long - I'm unlikely to go beyond 60s AFAICT.  The 185 colour camera is fine at 60s exposure.

[Gina]

Those 1.8mm fish-eye lenses look interesting Chris.  Cheaper than buying a new camera at "half-a-grand" or so!!  Do they have good focus over all the FOV?

[Gina]

Can't see any 1.8mm lenses on MA.  Only ASC lens is 1.25mm but no info on focal ratio.

[Stub Mandrel]

The dome must affect focusing unless the focal point of the front element of the lens is dead in the centre in 3 dimensions. Perhaps you could use angled flat glass a few inches across at 150 degrees?

[steppenwolf]

The dome must indeed affect the focus but I'm not sure that a flat glass would help even with the 150° as the further away you get from the centre axis, the greater the distance the light will have to pass through the glass.

I do think these systems are a compromise which is why they are best suited to a 'quick look' to test the sky at a remote location or to produce time-lapse videos which by their very nature 'hide' many of the optical deficiencies! 

[SilverAstro]

Would it be a daft idea to wonder about the compound eyes of insects ? ! maybe they have it sussed

I know there is software to make mosaics and panoramas and that is usually done 'one camera many pics' but the software wouldnt know that many cams had been used ? Not sure how it would be done on the fly (< oh, sorry bout that )

[ChrisLX200]

2 hours ago, Gina said:

Those 1.8mm fish-eye lenses look interesting Chris.  Cheaper than buying a new camera at "half-a-grand" or so!!  Do they have good focus over all the FOV?

Yes it offers a sharp image over the whole field - but that field only covers a 1/3" sensor (it is a CS lens). In comparison most C-mount lenses cover a 1/2" sensor but larger than that it's difficult to find anything suitable. ZWO sell a Canon EOS lens adapter but then you need to find a wide-angle camera lens.

ChrisH

[ChrisLX200]

2 hours ago, Gina said:

Can't see any 1.8mm lenses on MA.  Only ASC lens is 1.25mm but no info on focal ratio.

Apologies - I just checked my lens and it is indeed 1.25mm f/l

ChrisH

 

Oh, and I think they are f/2 - you're talking mega-bucks for a fast fish-eye.