All Sky Camera Revisited

[DaveL59]

so this cctv kinda works, tho stars are faint, pretty much expected given its fighting both the IR lighting and the sky lit by the moon behind the tree...

Can just make out the 3 stars in the tail of the plough at the top 1/3 in from the right, looks better with the mk-1 eyeball but hardly surprising given this module only goes down to 1/25s exposure. Was only expecting to get bright objects with this setup so fairly pleased as it goes, be interesting to see if it does any better in darker conditions but for a v low cost test rig, not a total fail 🙂

Edited May 15, 2019 by DaveL59

[skybadger]

12 hours ago, DaveL59 said:

thanks Gina, I'm currently playing with the spare kit I have, being between jobs means limiting the spend somewhat so an astro camera is a bit out of reach for now 😉

Here my back yard is not that big and with a large oak tree to SW of where I might put the camera plus houses at around 20-30 degrees above the level a 150 wide would likely do for me at the mo. Will see how it plays, I've ordered a 2.1 and 1.7mm lens so will have a play and see how they go. Might try a 5MP starvis module later on as they can be had for under £20 now, assuming that the current play rig turns out to be viable...

Ooh, where can I get a 5mp starves from, for that price ?. Sounds like you are the man in the know..

 

[DaveL59]

1 hour ago, skybadger said:

Ooh, where can I get a 5mp starves from, for that price ?. Sounds like you are the man in the know..

 

Aliexpress 😉

I tend to buy my lenses from Treeye as they tend to be good quality and prompt, and aim for the higher MP lens compared to the sensor in the module as they'd be better quality too, so for the 2MP module I go for 5MP lenses. You can also get the starlight lenses but they don't have IRcut filters, tho they will add those if you ask them. The new lenses I've ordered are for 1/2.5 sensors where this module is 1/2.8 so will see what sort of image I end up with, it may truncate but I am at the experimental stage so...

 

Thinks I should start my own thread on an el-cheapo sky camera tho so Gina's isn't sidetracked too much 🙂

Edited May 16, 2019 by DaveL59

[Gina]

My ASC project is currently on hold.  It's no use with total cloud or full moon and I feel like a break from it.

[DaveL59]

know what you mean Gina, same here. May well find out how water resistant my el-cheapo is soon lol

[skybadger]

Thanks Dave

That's really handy. It's hard finding a 5 or 8mp camera on there with starves though..

[DaveL59]

if you take a look at my "el-cheapo sky camera" thread I've listed the one I've ordered 🙂

 

[Gina]

I now have a 3D printer working again so thinking of picking up this project again.  Only trouble is, I forget what I was doing...

[Gina]

Maybe there's something to be said for starting again on the casing as I might have some different ideas.  As I recall, I wasn't doing very well in the past with sealing it.

[Gina]

What I really want is a proper cooled astro camera for this.  A home made cooler for a camera that's not designed to be cooled is really going against the tide and causee no end of problems.  Unfortunately, FLO don't sell a 1/2" cooled camera that I want for this project though one is available elsewhere :-

ZWO ASI385MC Cooled USB 3.0 Colour CMOS Camera

This is an excellent camera with exceptionally low read noise and ideal for this application.  It has larger pixels than the ASI178MC I'm currently using so more sensitive also it's a later imaging chip with higher sensitivity.  The smaller pixels are not needed for the ASC as the lens is not up to that resolution, nor do I need it.

Just checked my bank balance and I simply haven't got the funds!

Edited June 23, 2019 by Gina

[DaveL59]

3 hours ago, Gina said:

Maybe there's something to be said for starting again on the casing as I might have some different ideas.  As I recall, I wasn't doing very well in the past with sealing it.

that's kinda why I went with existing outdoor cctv housings, tho they're not really meant to be set with the dome pointed skywards. The larger housing does work ok but I may order another dome with a wider flange that hangs over beyond the casing. Not convinced that the nitrile gasket I got will cope well in the long run with the existing that is just under the diameter of the main body. So far its ok but one I plan to address down the road as the pressure of the dome bolted down causes it to dish upward, a nice little rain catcher, hmmm not what I planned for.

Cooling tho is a different problem, as the dome is essentially a sealed unit or there'd be risk of condensation otherwise. Of course the camera generates heat plus the heat from the sun just adds to the problem. I did consider finding a way to have the lens side sealed to the dome side and then set up some sort of venting and fan assist with baffling to direct outside air over the heatsink fins to cool the camera module, hopefully that'd reduce the condensation issue inside the dome affecting the image but figured I'd test as-is and see how it fairs. So far mine seems to be coping ok but I did paint the casing white to reduce a little the heat soak from the sun.

 

[DaveL59]

thinking about it... wonder if water-cooling would work, if you are able to put the cooler part in  permanent shade...?

That way you could seal the in/out hoses with grommets and not have to be pulling moist air thru the unit for cooling.

[Gina]

My water cooling has the reservoir in my observatory where its relatively cool.  Camera cooling is by Peltier TEC and waterblock.  Water is circulated by a small aquarium pump.  It's very effective.

[Gina]

I can't afford a proper cooled astro camera unless I sell some astro kit though it has to be said the the ASC will get far more use than any other astro kit.  I shall have a good think about this.  I would like to do more astro imaging with lenses and telescopes.  Anyway, selling telescopes has the problem of carriage.

As I've said, the problem I have with my present ASC is sealing the casing and I'm going to look into the possibility of buying a sealable enclosure.  I don't think I want to mess about with pressurising the enclosure - water cooling is bad enough.

[Gina]

Decided to order a box and stop messing about!  This box from Amazon, due to arrive tomorrow.  200mm x 120mm x 75mm.  Bigger than I need but beggars (buyers) can't be choosers!  I might change my mind again and put the electronics (RPi etc.) inside rather than in a box inside my observatory - I'll think about it.

[DaveL59]

fingers crossed that works for you Gina 🙂

How you planning to seal the dome to the casing? I used a large flat seal rather than silicone it on mine so I can open it up for tilt/focus tweaks, plus any maintenance would also need it removable being its a cctv housing and that's the only way in.

[Gina]

I shall probably glue the dome to the lid.  The main seal between lid and box will provide access to the works.

[Gina]

The box has arrived and looks alright.  I won't say perfect because the seal is in the form of a piece of spongy rubbery string so will have a join.  I think I can get round this though by cutting the ends with a craft knife to form a mitre join with silicone sealant.  The top is flat so attaching the dome shouldn't be any problem.  Next to see how everything fits in and design internal 3D printed parts.

[Gina]

I have a number of decisions to make.

1. The water pipes come out of the side of the waterblock - do I just take them straight out of the side of the box then round in a curve and into the mast pipe, or a sharper bend up round and down inside the box and through the bottom.
2. Do I put the electronics in the box and provide a small fan for air circulation.  Reduces the number of connections down the mast to the observatory.   Hot weather cooling from the water cooling system - would also keep internal temperature above the outside air and help stop dew on the outside of the dome.  May still need dew heater.

Edited June 27, 2019 by Gina

[Dr_Ju_ju]

My two pennies.... no sharp bends on the water pipes, and mount the electronics inside the box, at least then its a monolithic item, that can be easily?? removed for testing....

and there's definitely no chance of the pipes freezing ??

[Gina]

I have already decided to take the water pipes straight out the side.  Little chance of freezing with circulating water.  I could add a water heater to the reservoir connected to a froststat.  And yes, seems sensible to put the electronics inside the box.  To take down and indoors means unscrew the bolts on the bracket holding mast to observatory wall, disconnect power cable and one water pipe from the submersible pump.  Otherwise, there's a multicore cable and USB cable plus water pipe.

[pete_l]

14 minutes ago, Gina said:

I have already decided to take the water pipes straight out the side.  Little chance of freezing with circulating water. 

How about using antifreeze?

[Gina]

Could do, yes.

[Gina]

Hole cut in lid for the dome with large holesaw on my battery drill, or more precisely for the lens and light to come in.

[Gina]

It works out that this box is 3mm deeper than the one I 3D printed so only minor changes are needed to fit the parts in the new box.