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DaveL59

el-cheapo sky camera

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very nice Pete, is that a USB camera or IP and what speed is the lens, f2?

The limitation I have with the IP ones is slowest shutter is around 80ms hence going after as fast a lens as I can reasonably get hold of. Am wondering too how much light pollution you have, looks nicely dark there 🙂

 

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8 minutes ago, DaveL59 said:

very nice Pete, is that a USB camera or IP and what speed is the lens, f2?

Yes, it's an IP camera. This one. I have no idea what the FR of the lens is, but the image circle is about 6mm, which is a shame since the sensor is too narrow to fit it all in.
Like you, I can't find a way to get more than the programmed maximum exposure time which is purportedly 80mS, hence the stacking. The camera does get quite warm in use, which is where the noise comes from. It looks like it might be possible to separate the imaging part from the SOC which handles the connectivity.

As for the LP, it varies with atmospheric moisture. Usually around an SQM of 21.5 and occasionally down to an SQM of 21.8

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I see the croatian meteor network reckon they can get Mag 6 stars at 25fps using an Imx291 camera. Have to find the sauce.

I have a camera and the software. Let's see if I can get it to work....

 

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Posted (edited)
20 minutes ago, skybadger said:

I see the croatian meteor network reckon they can get Mag 6 stars at 25fps using an Imx291 camera.

That's interesting :)
The image I posted has some 4.5 Mag stars just about visible near U Maj's "tail" (the handle) - if you give it an extreme stretch. I guess the lens is a big part of that sort of sensitivity. As would be reducing the thermal noise in the sensor.

This link: https://www.meteornews.net/2018/12/16/the-2018-geminids-from-croatia-with-raspberry-pi-meteor-systems/

Edited by pete_l

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hi Pete,

yeah getting a lens to give the whole circle isn't easy, the 1.7mm I have clips top and bottom but isn't bad otherwise, except the f2.0 meant a drop in what stars show compared to the previous 2.8mm F1.4 which wasn't bad at all, hence looking for faster. Looks like to get below F2 at 1.7mm means a jump into the £90-200 price bracket tho which I might think about once I've an income again, but I think te ones I've found this far are aimed at larger sensors so may not be worth trying as that'd be a similar result, full screen and losing the full wide view.

Just tested the new CS 2.5mm F1.2 and 2.1mm F1.8 indoors on a spare IMX291 camera module, will be a step backward to a more full-chip image rather than the fisheye circular view. When I get a chance I'll pull the 5MP IMX335 module from skycam-2 and rebuild that into a different enclosure with the CS lenses and see if that improves what can be seen. At least then I can have a better idea what's worth spending on regarding a better lens. 

Agreed they do run warm so with yours having the sensor on a ribbon cable it might be worth increasing the space between the ccd and the rest as the 3516C and similar chips get quite hot on their own. I glued a small heatsink onto the bare board one to shunt some of that away, just superglued direct onto the chip package 🙂 At least the warmth keeps condensation and dew at bay and hopefully will do so during colder months too, the module doubling as a dew heater, maybe.

Haven't tried stacking anything from these as yet, with so little being picked up it didn't seem worth the time just yet. Like your image, ursa major is pretty much directly overhead but of late with clouds even on the clearer nights I'm barely seeing more than 2 of its stars where on good nights I might see them all. What I have done on the 5MP was to adjust the max/min shutter speed to the furthest value they'd go to and then set the camera to bias to slow shutter. Does make the sky more washed out (pale rather than deep blue) during the day but that's fine by me.

camera settings.JPG

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Posted (edited)

ugh bleedin british weather! so after lots of rain sky went nice and blue and clear. OK thinks I, ladder out and fit the new dome housing. So just as I'm putting in the camera module sky goes dark and spits of rain. managed to bolt the module base in and just got the dome on before it started heavier, phew! Still need to open it up again tho to adjust the aim and drop a silica gel pack in, plus a dab of silicone around the dome screws.

Oh well, its up with the 2.1mm F1.8 CS lens so if it doesn't get drowned I can at least see if there's any improvement 🙂

Had to switch the IRcut trigger too as it was working the wrong way with the CS filter, thankfully the camera module has an option for that 🙂

 

Edited by DaveL59

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ok, another dry spell so was able to go adjust things, kinda. Had to swivel Cam1 around as it was obscuring and can still see the base, oh well I can move that later. Canted the 5MP camera on its gimbal so its tilted toward SE, so it should hopefully be able to pick up the moon etc as they transit and hopefully will still see Ursa Maj above. Now just need a clear dark night to see what can be seen. Doesn't have full sky view now compared to the 1.7mm lens before but am hoping the little bit extra aperture will improve what it sees, time will tell...

Noticed too that Cam1 had some condensation under the dome. Looks like moisture seeped by the seal under the dome edge where it isn't smooth. Pasted some dielectric grease under the edge after drying it out and will see how that fairs. These CCTV domes really aren't designed to be used upside down but heck they seem to work reasonably well 😄 Left cam1 with the previous lens since the CS ones won't fit into that tiny housing unless I file the lens opening a long way wider.

So the new dome (cam2 IMX335) is aimed toward SE and the mini dome (cam1 IMX291) toward EW in terms of widest part of the view which looking at it means it'll catch my IR lighting, such is life.

 

SkyCam_2a adj SE view.JPG

SkyCams 1 and 2.JPG

SkyCam_1b reaimed.JPG

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and looks like I got it done just in time as the rain's started again 🙂

 

 

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Well by the amount of bits you have purchased it does not really seem like an el-cheapo all sky camera... 😂😂

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23 minutes ago, StarDodger said:

Well by the amount of bits you have purchased it does not really seem like an el-cheapo all sky camera... 😂😂

haha well true I guess, tho the 5MP board was only £22 or so and lenses around £7 each, the big dome was £15 as it was no longer working, so not too pricey. The other IMX291 camera well I had a couple kicking about spare so no-cost to me 🙂

 

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so first solar body comes into view beside the tree, la luna 🙂

Dunno what's going on with the image tho as its flickering between a nice flat sky and the odd ring noise pattern

SkyCam_2a first solar body.JPG

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so now its dark and reasonably clear out, looks like an improvement going from F2 1.7mm to F1.8 2.1mm in that more stars are showing, well a couple at least. I can make out the 3 on the handle of the plough and just about the others over time but probably still not enough aperture. Will let it run this way for a while then perhaps swap the F1.2 2.5mm in and see how that does. I think any lens slower than f1.4 and this cctv module is going to struggle given the slowest shutter speed is just too fast. Might get a better result if I stack a video from it which I may have a go at at some stage, will have to figure how to take H265 stream and feed that into the stacking app unless there's a better way, capturing the RTSP stream perhaps?

SkyCam_2a first stars.JPG

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Posted (edited)
12 hours ago, DaveL59 said:

Dunno what's going on with the image tho as its flickering between a nice flat sky and the odd ring noise pattern

I get that too, with my expensive setup!  (That's if it is the same thing.)  I have no idea why.  Strange and annoying.

Edited by Gina

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14 hours ago, DaveL59 said:

so first solar body comes into view beside the tree, la luna 🙂

Dunno what's going on with the image tho as its flickering between a nice flat sky and the odd ring noise pattern

SkyCam_2a first solar body.JPG

Is something (exposure time?) in auto mode?  I wonder if it gets to the point where the dynamic range of the entire image is so great that there's insufficient to render the sky smoothly, giving you the ring effect as a result?

James

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Could be James, exposure time is set to auto but has to be else it can never reach the slowest shutter as manual mode the slowest is 1/30s or there abouts. Also it'd be totally bleached out in the day. I did try anti-flicker but that seems to turn the sky white and I've not found an adjustment to correct for that. At night anti-flicker doesn't affect it the same way, so could be an exposure related artifact. I was wondering if its a kind of heat haze rising from the module and into the dome above the lens but I don't think that's the case as I don't see the same effect on the other and its a smaller dome housing, or could that be why - less air to circulate?

The IMX291 module is Hik protocol capable, so even less I can tweak on that one via the Hik interface, will have to switch it to onvif mode at some stage and see if that opens more options but as it stands, it makes a fair day-view camera with a nice fisheye view and easier to access remote via iVMS-4200 over vpn with my mobile 🙂 Can't open the IMX335 that way as its onvif only and I'd need the pro iVMS4500 for that, not found a retailer for the license so far but isn't a major priority.

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Very cool.. the sky cam is definitely a great tool in our hobby. Is is still a "el-cheapo"?

 

 

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1 hour ago, MarsG76 said:

Very cool.. the sky cam is definitely a great tool in our hobby. Is is still a "el-cheapo"?

 

 

thanks 🙂

Well I still consider it cheap, esp considering there's 2 out there and pretty low spend to achieve. Decided this dry morning to tweak the aim and move the smaller one out of view before I head off to family commitments, forecast is v wet this evening so won't be a better opportunity with returning to work Monday. I think results for a while might be tainted with the sky not being as dark as when I started the project so plan to run with the F1.8 2.1mm lens in the 5MP for a while before I test the 2.5mm F1.2 and if I figure how maybe try a few stacks to see how the current setup performs as a reference point.

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It's certainly cheap compared with mine!

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Posted (edited)

Here's an update. I received a second IMX291 camera today. This time with a 4mm F/0.95 lens.
First results were ...... interesting

I still have lots to try with this thing, but as a taster, here's a screenshot of a single live streamed image from VLC running inthe VM I spun up to play with these cameras.
spacer.png2023006530_VirtualBox_MeteorUbuntu_20_06_2019_22_47_07.thumb.png.f7e1db2974516cb6db215804c5b0542f.png

 

The camera is this one from Aliexpress It runs rather hot, so I have bolted a little 12V fan to the back.

For those unfamiliar with the stars from southern Spain, that is Lupus and Centaurus underneath and to the right of Scorpius ;)

Edited by pete_l
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very nice Pete 🙂

Here its been all rain and clouds so not had much decent viewing at all, nor any chance to do much of anything now I'm back in a day job. Doing a road trip at the weekend tho to collect a TAL100R(s?) so I guess that means it'll be occluded skies for quite a while 😄

 

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I have a 3D printer working again and after a bit more calibrating should be able to continue with the casing for my latest ASC.

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