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DIY all-sky cam?


msinclairinork

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Why didn't I think of an old voltmeter, ideal solution. the shutter would be a piece of tinfoil between the rear element of the lens and the sensor, doesn't need to be more than say 6mm sq. and it could be powered by a tiny solar array

Got the lens from here: http://www.buythis.co.uk/open_product.asp?pid=2920&catId=133&source=Froogle

Huw

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The simplest solution is usually the best :grin:

I like the idea of the garden light - removes the need to put a PV cell in the dome to keep it dry. Plus you can locate it in the best position to pick up the sunlight and run a wire to the meter/actuator/whatever.

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How feasible is a daytime all-sky camera, I wonder?  Not necessarily using the same camera as for a dark sky.  Somehow I suspect filtering the Sun might be hard without completely blocking all other details.

James

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In theory, if I strip the board out of the qhy5 housing, and mount it under a 90mm circular plate with a c thread in it, I should have room to mount just the stripped out meter movement by the side of the camera, with a piece of foil glued to the meter pointer.

Hopefully at f1.4 the light cone is steep enough that the sun won't be focussed on the foil.

Now it would be good at times like this that work would simply go away so I can play.

Huw

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You could use a small piece of Baader solar film and see the solar disc moving across the image during the day.

I can see a requirement for a large dome housing three cameras now.  One for night time, one for white light solar with Baader film and one for daytime visible light :)

James

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Ultra cheap board lens purporting to give 170 degrees with 1/3" sensor but no mention of the aperture. £2

1.8mm Wide Angle Fisheye IR Megapixel CCTV M12 Board Lens for Security Cameras  Aperture: f 2.5 - Horizontal field of view: 170 Deg for 1/4" format. - £41

I suspect that both of these might be rather slow.  That Fuginon at f 1.4 looks much better but two and a half times as much cost.

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Ultra cheap board lens purporting to give 170 degrees with 1/3" sensor but no mention of the aperture. £2

1.8mm Wide Angle Fisheye IR Megapixel CCTV M12 Board Lens for Security Cameras  Aperture: f 2.5 - Horizontal field of view: 170 Deg for 1/4" format. - £41

I suspect that both of these might be rather slow.  That Fuginon at f 1.4 looks much better but two and a half times as much cost.

The reviews for the first don't look encouraging, though I guess mounted in a board lens mount rather than a security camera it wouldn't be a major problem.

I've bought some stuff from Stock Optics (the second one) before.  They seem competent.

James

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The fisheye I bought for the qh5 initially was f2. something, and was initially promising, but the camera was far too noisy to make it of any real use, so went for the f1.4

H

The original QHY5 is rather noisy unfortunately.  Might be fixable with darks though.

James

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Hmm...  I agree about the QHY5 being noisy - why I went for a Lodestar :D  Now I've upgraded again to the Lodestar X2.  I was going to use the original Lodestar for guiding my widefield rig (which I hope to get going sometime this decade :D)  But I could try it out for a nighttime all sky camera.

As far as a lens is concerned I think my inclination would be to go for the Fujinon later on.  ATM my finances are very pricarious and I dare not really buy anything over a ton.

I have tried to get a night sky camera working in the past but apart from the moon I got nothing :(  Camera not sensitive enough (think I used a webcam and also a CCTV cam) and lens not fast enough (CCTV board lens).  I would rather like to have another go :)

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This is where I got to two years ago, before giving up for more rewarding projects, mainly my big Newt

Nice to know I'm not the only one still playing with this. I've just bought a fujinon 1.4mm f1.4 lens, not as expensive as the other fujinon, and it's a cs mount,

YV2.2x1.4A-2 | Vari-Focal | Fish-Eye | Security | Optical Devices | Fujifilm USA

I've mounted it onto the qhy5, and it works well compared to the the cheap little lens I previously used. I then went silly and tried the lens on my Starlight Exprss lodestar, now this is so far in advance of anything I've managed with the qhy5, In the image shown, you can see the plough on the left, and the bright glow is a crescent moon in light cloud, now that is dynamic range.
I just need to justify buying another Lodestar....

Now where did I put that lottery ticket

Huw

Here's the lodestar in action, no dark frames, and lots of stars, and only 10second exposure

post-6754-0-77295500-1406218851_thumb.jp

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This is where I got to two years ago, before giving up for more rewarding projects, mainly my big Newt

Here's the lodestar in action, no dark frames, and lots of stars, and only 10second exposure

Thank you Huw :)  That answers my query about using a Lodestar - very promising :)

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The only downside I can see to using a Lodestar is the solar shutter would have to be in front of the lens, it's a CS mount, so very little space to play with behind the back element.

That and that the great case I've got for the qhy5 is too shallow.

Oh yes, I've also got to find nearly 400 quid for another Lodestar. As I've said before, 'now where did I leave that winning lottery ticket?'

For me, astro imaging is the new HiFi, the more you spend, the less return you get.

My wife keeps telling me that knitting would be a very rewarding hobby...

Huw

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im just putting this as it popped into my head a few minuits ago. but couldnt you use one of them filter changers between the lens and the camera?  use the clear baader film for the lens, and baader solar film on all the others?  with an acuator moving it around the clock and having different F/L of lens on each filter point bar the solar film one?

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I have a new ASI120MM-S USB3 camera, so I'm tempted to use my old ASI120MM as a night-time all-sky camera.  I reckon there should be far more leeway with a daytime camera when light is rather more plentiful.

James

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im just putting this as it popped into my head a few minuits ago. but couldnt you use one of them filter changers between the lens and the camera?  use the clear baader film for the lens, and baader solar film on all the others?  with an acuator moving it around the clock and having different F/L of lens on each filter point bar the solar film one?

I like the idea, but most of the lenses have very little backfocus which might make things quite tricky.  I reckon it would be easier if you wanted day/night cameras to have two separate cameras with the nighttime one completely shielded between sunrise and sunset.  Or for daytime white light, move a piece of Baader film in front of the lens of the night camera during the day.

I'm not sure that having the film in front of the lens really matters -- that's effectively what we do with a telescope anyhow.

James

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Great thread guys and well done, just love the work being done. Seeing the 900nc put to good use has made me start on one myself, you guys are a true credit to the DIY astronomer. Will post up a pre modded 900nc I got off a sale ages ago in another thread and see what you guys can make of it and hopefuly it will see it self in a dome soon. RobertCL that is one fine setup and preying i can pull the same here as light pollution isnt to bad.

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Just had another great idea for the sun shade. Use a cheap clock movement on its side to rotate a circular cardboard shade around above the lens. Cut out a segment where the lens is to be exposed at night. The beauty of this method is that it automatically keeps good time, requires no electronics/processing and you can have different sized sectors at different times of the year to adjust for the differing sunrise/set times. You could even use solar film in the daytime sector.

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Don't forget to gear it down 2:1 to give a 24 hour rotation period.  Unless you've got an extremely rare 24 hour analogue clock, of course :D

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