best camera for all sky use

[Cath]

any thoughts on a dome wiper?

You can get spray on/wipe/on coating for glass for that problem Huw.

Plus their are new coatings coming out from time to time that improve on it, althought this particular one is not the best  ..

Youtube link

[Cath]

I know it might seem like a silly idea, but have you guys ever thought about doing away with your domes, and thus removing some of the problems you guys experience ?

[JamesF]

I know it might seem like a silly idea, but have you guys ever thought about doing away with your domes, and thus removing some of the problems you guys experience ?

Some sort of protection from the elements (not to mention insects, birds and other fauna) surely must be necessary?

James

[Cath]

Some sort of protection from the elements (not to mention insects, birds and other fauna) surely must be necessary?

Indeed

 ......

[Horwig]

I always love those rotating round windows on ships to spin water way. There's even a company that produce a device for television cameras based on the same principle. Wonder what a dome spinning at 10000 rpm would work like. Gina, get your thinking cap on

Huw

[pete_l]

I know it might seem like a silly idea, but have you guys ever thought about doing away with your domes, and thus removing some of the problems you guys experience ?

Some sort of protection from the elements (not to mention insects, birds and other fauna) surely must be necessary?

James

Not silly at all. That's my way of doing it.

Briefly, concentric plastic tubes. The outermost with a rectangular slot cut in it. The camera and other sensors are mounted on a fixed platform facing up. The outermost sleeve is attached to a motor at it's centre. The sleeve is usually orientated so that the hole is at the bottom.

Every 10 minutes the arduino inside rotates the sleeve to expose the camera and it takes an image. After that it rotates back down again.

The electronics contains sensors for cloud that is exposed when the sleeve has been partially rotated (to determine if there's any point to going for a photo), water, temp, humidity and light level.

The advantage is that there's nothing to spoil the view as it's very difficult to get a glass / perspex dome that has no optical flaws and will stay clean. The camera is only exposed for a few seconds and only if conditions are suitable. Therefore there's no chance of the lens getting dirty or dewed.

The Mk1 used drain pipe which was just about big enough for my old camera. However the Mk2 is made out of an old plastic paint container and a custom fibreglass outer sleeve . It's bigger (to accommodate a larger camera) and heavier so I'll have to use a bigger motor to rotate the sleeve.

[Gina]

Hmmmm...

[JamesF]

Any chance of a photo of it, Pete?  I think I understand what you mean, but I'm not absolutely certain.

James

[Gina]

Maybe some sort of cover that could be remotely removed might be possible.  The main problem I have with my CCTV cameras is spiders.  A hood keeps the rain off and there is no problem with dew but the spiders seem to think this is an ideal place to build their webs for catching flies etc.  The web I can tolerate though it reflects the IR light at night, but a blooming great eight legged monster in the middle of the picture really does spoil the view!!

SO... any cover has to be bug proof - and bear in mind that spiders can be really tiny and get through very small gaps.  Then there's flies and the excrement they leave behind

I have given this a fair amount of thought in the past without coming up with a solution but I do have one idea.  Credit goes to Steve alias steppenwolf for his flats panel flap idea   A dome could be hinged with an actuator operated by a micro servo to open right out of the way which means 180 degrees.

[JamesF]

I think with opening the dome that way you probably couldn't really be sure it would close tightly.  I think you need some sort of "positive" closure mechanism rather than just relying on the dome's weight.  Perhaps some sort of "sliding" rather than "flipping" arrangement would be better?

James

[Horwig]

Interestingly, have gone back to the motherboard USB, I needed the usb3 card for work. Back to square one, camera drops out, even though its fed from a powered usb hub, ho hum.

Huw

[Gina]

I think with opening the dome that way you probably couldn't really be sure it would close tightly.  I think you need some sort of "positive" closure mechanism rather than just relying on the dome's weight.  Perhaps some sort of "sliding" rather than "flipping" arrangement would be better?

James

I wasn't planning on just using the weight of the dome, it would be driven by the servo motor.  Or if that wasn't strong enough, it could be driven by a stepper motor.  A bit of spring in the drive could ensure that the dome was firmly closed.

It isn't possible to slide the dome because the lens is in the way!

OTOH the acrylic dome I'm using is pretty free from optical defects (it was specified for use with CCTV cameras) and cost just a few pounds.  Reminds me, I ought to order a spare or two in case they disappear from sale.

[Horwig]

Another nice day

New PCi USB card installed, everything working so far.

Also got the focus and orientation a lot better, North straight down, West left, now to wait for some stars.

Zoomed in a bit, weather normally comes in from the West, so  don't really care about losing extreme North and South.

Huw

[Gina]

That's strange Huw, I would have thought the Fujinon lens would have covered the sensor

[Horwig]

That's strange Huw, I would have thought the Fujinon lens would have covered the sensor

It does Gina, the sensor has a more oblong aspect ration than the QHY5, so there's a lot of black left and right, I'd rather see more sky, so I'm willing to sacrifice North and South.

H

[Gina]

Ah, I see.  I wonder why so many astro cameras have an oblong aspect ratio when so many things are better with a square sensor.

[Cath]

Ah, I see.  I wonder why so many astro cameras have an oblong aspect ratio when so many things are better with a square sensor.

Square sensors are basically custom made for the scientific/pro astro world of telescopes and satellites. They cost somewhat more than your consumer/commercial sensor.

[Horwig]

Agreed Cath, square sensors make much more sense, I have an old Hasselbled, which lives on a shelf these days, but a superb piece of kit, and no need to ever hold  it sideways!!!

Here's the Moon and Jupiter, Venus is in the burn out from the sunset.

The obsy pc is still not 100% ok with this camera, EZP will still freeze at random, but I can start a new instance, and then quit the old one. I wonder what in this pc it doesn't like?

Huw

[Cath]

Sounds like EZP is buggy and needs fixing.

[Horwig]

All last evening it would freeze, but I could launch another instance.

So I left it running and went to bed.

Got up to have a look at it at 4:15 this morning, it was still running! but the auto exposure had not opened up, it was at 1.7 seconds. 50% gain.

I set this manually to 30 seconds, showing dawn breaking. With Cassiopea bottom right, and Cygnus centre right. It's too bright to show the Milky Way.

It was still dark to the naked eye.

Focus is a lot better. Now to sort out dark frame subtraction.

Huw

[Horwig]

EZP still keeps freezing, but what's interesting is that it's only the display that freezes. I can adjust the controls, and there's a histogram and preview window, both show the adjustment, and I can save the image. This is very strange.

Time to ask the question on the QHY forum.

Huw

[Horwig]

Hmmmm, I'm still clutching at straws on this one. The camera is back indoors. it was very hit and miss outside, and I was getting fed up of trying to get to the bottom of it.

So here we are indoors in my study. I've got it running non stop all evening into my home pc (a high end HP xw8600) on a 1.8m cable into the native usb2, and I then tried it into my obsy pc, an HP Pavilion, still no slouch (again initially into the native usb2). After a while it ground to a halt on the Pavilion Pc, but I then tried it into the pci usb 3 card on that machine, and it's been good as gold for the last hour.

Interestingly I read this on the QHY forum in the last hour:

Any requirement of the length of USB cable?

Yes , shorter USB cable is recommand for QHY5-II series camera. Because QHY5-II works close to the max limit of USB2.0 (apporx 39MB/s) . Long cable will cause the USB packet damaged and bad frame increased and even cause all frame lost. The software looks like halt with zero FPS.  If must use long cable. the sepcially USB extender cable is required.

Now this might explain why some pcs work and others don't. And why the pci usb3 card made my obsy pc work, but why when I connected a powered hub it started acting strangely again. I wonder if I'm going to have to use a powered usb 3 hub, and an usb 3 cable to the pci usb 3 card in my obsy pc?

This probably explains why the other night it would crash so often before it got dark, but then ran all night, short exposure duration = high frame rate, darkness =30 second exposure.

Watch this space...

Huw

[Gina]

Interesting...

[JamesF]

I'm not sure I can give credit to that explanation unless one end or the other is a poor implementation of the USB standard or there's a fault with the cable.  The USB2 spec. requires that high speed devices allow a given latency for the connection which should allow a maximum cable length of five metres.  I'm fairly sure there are limits on interface response times etc. too.  If something is stuffing data down the connection too fast to allow for the maximum latency on the response from the receiver, or one end doesn't respond as quickly as it should to the other, then it is operating outside the USB specification.

Obviously that doesn't really help in this situation, but I think if you're going to make a device that doesn't operate strictly within the USB spec., or can sometimes operate outside the USB spec. then you shouldn't make it sound like a cabling issue.  It ought to be possible for the user to ensure that the device always operates within the spec and therefore have confidence that a device will work with the rest of their kit, otherwise what's the point of having a standard?  If under some circumstances it's possible to make a device operate outside the spec. the manufacturer should at worst take it on the chin, define that situation and explain that in that event a shorter cable may help.  Saying "Oh, well, you can't do some of the things the USB standards say you can do because the USB device we've sold you doesn't actually operate within the specification required for it to properly be called a USB device" doesn't really cut the mustard.

Anyhow Huw, have you tried playing with the "USB Traffic" control at all?  As far as I can ascertain this is a particularly hideous feature on some cameras (not only QHYs) that attempts to increase the frame rate by reducing the "flyback" time on the sensor readout or something similar.  Perhaps if you twiddle with that a bit you might slow the readout time down sufficiently to allow it to work with your obsy pc.

James

[Horwig]

Thanks for your insight James, I'll admit to my lack of knowledge about USB protocols.

I've now tried the camera on some different cables, it appears that the 2m one I was using was marginal. I tried another 1.8m length which was stable overnight, now I'm running it through a 3m length, and its been going for a few hours.

Interestingly, when it was installed on the roof I was getting some very strange results, to the point that no PC would see the camera at one point, the only difference between that and the indoor test is that there's no dew heater running, I wonder if the switched mode psu for the 12v was putting splats on the usb. both cables were bound tight to each other, and the 12v was a simple figure 8 cable.

Huw