All Sky Camera Revisited

[Gina]

Currently have USB cable for the camera, 4 way ribbon cable for the focus motor and 4 core power cable for the dew heater and Peltier TEC though only the Peltier TEC needs much current (2A).  If I put an Arduino Nano in the ASC housing for the DHT22 I shall need to get the data down to the RPi - power is already available for the dew heater (12-13.8v main observatory supply).  Several possibilities occur to me for transmitting the data - USB, Tx/Rx serial or parallel output.

[Gina]

Since there are clear skies forecast for at least part of tonight I decided to put the current ASC casing back together with new silica gel and plenty of silicone sealant.  There certainly isn't a leak on the dome now - it's well sealed!!

[Gina]

Doesn't half take a long time to get dark now we're on summer time!!!

[Gina]

Nice lot of stars now and I'm pushing the exposure.  This is 90s and beginning to show elongation of stars well away from Polaris.  Gain still at 0 and minimum camera cooling and +0.5°C.

 

Edited April 8, 2019 by Gina

[Gina]

90s exposure, gain 100, camera temperature -6°C.

[Gina]

I'm satisfied with the focus achieved with the remote focussing system.  Ursa Major at full digital zoom.

[Gina]

Clouds are rolling in, lit by the light pollution.   ?

Exposure 90s , gain 100, camera temperature -14°C.

Edited April 8, 2019 by Gina

[Gina]

Almost total cloud coverage now.

[Gina]

That was it for last night and no better today  - overcast, dull and misty.  It did brighten up a bit earlier but decidedly murky now.  A plus point is that the ASC is currently working fine linked by WiFi to client software indoors and was last night too.  The silica gel is still orange (dry).

[Gina]

I've printed a new outer casing top to take the 4" dome with a window/pod for the colour change silica gel but whether I use it will depend on whether the casing stays sealed and the silica gel stays orange.  The colour change silica gel is a far easier way of showing that the inside is dry than the DHT22.  I'll just see how things go.

Edited April 9, 2019 by Gina

[Gina]

After all the rain yesterday and overnight, the silica gel is still orange (dry).  Sunshine and a few clouds now and not looking too bad for tonight, particularly later in the night.

[Gina]

Here come the clouds!

[Gina]

A crescent moon at 28%.  Maximum digital zoom

[Gina]

Stars are starting to show.  Exposure 90s, gain 0, minimal cooling giving -0.5°C camera temperature.  The moon is overloading the sensor and spreading.

[Gina]

Exposure 90s, gain 200, minimal cooling giving -1°C camera temperature.

[Gina]

Exposure 90s, gain 300, minimal cooling giving -1.5°C camera temperature.  Beginning to see some noise at this gain so going to switch camera cooling to HIGH.  Unfortunately the moon doesn't set until 01:45 tomorrow morning.

[Gina]

Exposure 90s, gain 300, HIGH cooling giving -14°C camera temperature.  I think I may have picked up a satellite (vertical streak).

[Gina]

Exposure 90s, gain 300, gamma 40 (was 50), HIGH cooling giving -21°C camera temperature.  The reduction in gamma increases the contrast and I think this is as far as I can go with this camera and lens.  The thermal noise has been eliminated by the very low temperature but other noise remains.  This is shown by the fact that the very low temperature hasn't reduced the noise compared with -10°C.

Edited April 10, 2019 by Gina

[Gina]

The moon is near setting and I'm staying up to see it.  I don't have to get up early in the morning.  Watching BBC4 about black holes currently anyway.

[Gina]

Moon set.

[Gina]

Aircraft produce a pretty trail ?

[tekkydave]

Here's a crop from mine, currently still on the bedroom window sill. I think the local police were out looking for someone last night.

 

[Gina]

An image from just before dawn.

[Gina]

High resolution PNG file saved from PixInsight following Curves applied.  Milky Way is showing but not very well and not much colour definition.

[Gina]

I get the feeling that this version of my ASC is not as good as the last one but I'm not yet sure I'm getting the best out of this one.

This is from 9th July last year.  I know summer is reckoned to be better for the Milky Way.

Edited April 11, 2019 by Gina