Gina

The light is only just inside the FOV and I think I might be able to exclude it from the lens by tilting the ASC & mast a few degrees.

I might see if I can arrange some sort of shield to block that light, at least from the lens if not the whole dome.

Yes indeed. To both. Stars a lot better than last night but still not quite in focus. It could do with motorised focussing to get that last bit. Won't do that immediately though, I'll wait for the new dew heater to arrive at least.

Exposure 60s, gain 200, temperature -14°C. Next door have turned their quadrillion candle power floodlight on ? I expect they'll turn it off later - they don't usually leave it on.

Exposure 60s, gain 0, temperature -13°C. Plenty of stars showing now and very much better than last night but they are out of focus, not a lot, but...

Ah, a handful of the brighter stars and maybe a planet of two. Exposure 20s, gain 0, temperature -14°C.

A few lights but where are the stars??? Exposure 10s, gain 0, temperature -13°C.

Some redness in the sky.

A bank of cloud to the south, a few contrails and the sun shining on the sheds... Lots of wispy clouds.

It's showing signs of mistiness - the hills to the south are looking decidedly murky ?

Not too long until sunset and possibility of seeing stars now. Looking forward to seeing if I've conquered the focus. Exposure still 1ms and gain 0. Camera temperature -16°C. Not that it needs it - still running test setup.

Having used ROI for manual focussing it occurred to me to use it for normal imaging to cut out all the black outside the sky view. That will save some disk space when saving images.

Exposure increased to 2ms to show the ground level. Second image shows the north view rotated to show "normal" view - sheds and bungalow.

Everything back on and in observatory. The focus is tons better than last night. Here is a far hill on the edge of the view at full zoom. This is the best I can do with manual focus. Tonight will tell assuming it remains clear as forecast.

Need more dew heating and got fed up with messing about with resistors or nichrome wire with all the mounting problems so bit the bullet and ordered a proper dew heater. Dew Heater Module - All Sky Camera

Flat glass will give you a lot of distortion as well as internal reflections. Ultra thin glass might work or possibly Baader film clear (rather than the sun blocking sort).

Using ROI I have repeated the manual focus and this is the best I can get. TBH I think it's approaching the best the lens will do and is considerably better than last night. Maybe it's worth a test tonight. Here are some images. The far range of hills are about a mile away. This is looking out of the east window of my living room. Full view - no dome. Zoomed in - no dome. Zoomed in - with 3" dome.

Amazing what a cup of coffee can do - brain reactivated ? Had a thought for reducing the time between images - 2 possibles - binning and/or just downloading the centre part of the image (Region Of Interest). Binning made the image a bit coarse but ROI worked fine. Can also capture more images before the SSD fills up.

Thought I'd try the ON-OFF-ON-OFF dome type manual focussing but it's darn nigh impossible! May have a coffee break and try later but...

Been manually focussing and there certainly is a difference with and without the dome so that shows the need for remote focussing as it isn't possible to manually focus the lens with the dome on. That's aside from the difficulty of actually focussing by hand. OK so theoretically is should be possible to make allowance for the dome - or keep removing and replacing the dome between focussing. Maybe I could get focus nearer this way but accurate focus would be extremely difficult. I shall investigate remote focussing. Two images zoomed in to about the same extent. First without the dome and second with. I tried to get the focus fairly near without the dome but with the frame capture period of several seconds this is not easy. Note focussing on the horizon, not the bird feeder or nearby trees, though the bird feeder does illustrate the difference the dome makes.

Removed ASC et al from observatory and brought it indoors. It's still out of focus so I'll reset the focus and think about giving it another try tonight.

The colour change silica gel is still showing bright orange so the sealing has worked. By this time the colour would have changed to green even indoors in lower humidity. The water in the saucepan I'm temporarily using as a reservoir is still cold. I do have a radiator if needed to cool the water but looks like this may not be needed.

Thank you both for those comments. Seems the dew heating wants increasing as there is some dew around the edge of the dome. Now surprising as we has a frost and the observatory roof was covered with frost at 7am, now melted in the morning sunshine.

It's certainly a bit off but maybe not quite as much as 15°.

Even though the focus is way out, this has not been a totally wasted night's imaging. I have shown that the coverage of the sky is fine - there is a thin ring of ground round the whole circumference of the image. There is no point in covering any more as an all sky camera. I have also shown that the camera cooling system is well able to kill any hot pixels and remove noise - it has performed well beyond expectation. This last image is showing some noise in the image but the signal to noise ratio is adequate even with the cooling running at half power. Getting the focus right will increase the signal from the stars considerably. Dew heating is necessary to prevent the formation of dew on the outside of the dome. I shall probably alter the dew heater to run off the full 13.8v of my observatory power supply.