Gina

Yes it's a Newtonian telescope.

Left the image capture running overnight. This is an image from just before dawn with a bit of curves processing.

I can't see anything wrong. Sorry Paul.

Not dew.

Cloudy earlier but now the clouds have gone and there's just the moon high up in the sky. Dew heater has been on since well before dusk but there's a ring round the moon which is not there when viewed with no.1 eyeball! Not sure if this is dew or just image sensor overload.

Been thinking about the question of the humidity level in the ASC. What matters most is that the camera doesn't get wet and fail (like the last one did) but I think I've done everything possible to prevent this. The camera itself is in a sealed casing with silica gel beads to absorb any damp, this casing is also well above the bottom of the outer casing so there would have to be lots of water inside before it even reached the camera casing. Damp in the lens would be the next problem though I have had condensation in the lens before and it dried out fine so not a critical problem. In fact I think this would be a good indication of failure of the outer casing sealing and well before water could cause a problem with the camera I reckon.

I ran the image capture overnight until dawn. The dew eventually went from the dome but the clarity wasn't as good as the previous night and cloud came in just before dawn so no Milky Way visible in this set of images. More dew heating is definitely needed and it wants turning on well before sunset to stop dew forming. I shall leave the ASC as it is for now as there are other projects I want to work on. The inside is staying dry so far and while that remains the case, I probably wont touch it. Next clear night that's moon free I'll try tweaking the imaging settings to see if I can improve the results.

I think I may arrange to switch the dew heater on from the outside RH rather than manually via the INDI Control Panel. I'm planning to measure RH and temperature outside the observatory anyway. I can show whether the dew heater is on with a light on the control panel maybe with a manual override. Also, I think it would be interesting to measure the temperature at the bottom of the dome inside (higher up would obscure the FOV).

Yes, it looks like it. I'm currently running the dew heater at 12v - I can run it at 13.8v or I can add more heating.

Gamma reduced to 30. FITS image enhanced in PixInsight and saved as PNG.

Well I didn't see any before but now the oval is just a tiny bit smaller.

The dew appears towards the SE where the breeze was coming from so that makes sense. There was some dew around the bottom of the dome earlier but that cleared after the dew heater had been on for a while. There is no sign of the central dew dispersing.

Taking a few images tonight but I'm suspicious of the image - it would seem to show dew or condensation. Now this could be on the outside of the dome and of little concern but it could be in the "dry" zone, maybe in the lens. The silica gel was still orange this evening so maybe I'm concerned unnecessarily. Dew heater is on. Exposure 90s, gain 0 and camera temperature -1.6°C.

Oops, this Blog wants more... All the works with lots of pictures. Found it!! HERE. It's pretty big - 46 pages.

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.

Installing the main control software on the Client computer This is KStars and includes Ekos which connects to the INDI drivers in the remote RPi via LAN. Go to the KStars web page for instructions. For Linux there in Synaptic Package Manager from the Administration menu. Search for "kstars" to select for installation. Once KStars has been installed, run it from the Education menu and choose Tools > Ekos You will get a window like this but without anything in Profile. In the Profile section click on the + to bring up an editing box fro your connection details, looking like this. Give your remote device (imaging rig) a name and if you are connecting over LAN, check the Remote option. Check Auto Connect. In the Host box put the computer name you gave to the RPi when you set it up (or alternatively, the IP address if you set up a fixed address). You can select your devices from the drop-down lists but it worked without in most cases for me. When finished choose Save. If all went well you can now choose Start INDI to connect to your astro imaging rig RPi. Full instructions on using KStars can be found hers :- The KStars Handbook. There are also tutorials on YouTube. Google KStars (other search engines are available).

Installing the Operating System and Astro software The Raspberry Pi uses a micro SD card as its main drive and this behaves the same as the hard drive on a computer except that this card can be removed and data read from it or written to it. In fact the way the operating system is installed on it requires it to be out of the RPi. This tutorial will describe how the operating system is written to the card, the system set up with computer name, user name and password and then further software installed to permit remote control via LAN and the astro software to capture images and control the hardware such as filter wheel and mount. You need an SD card reader attached to your main computer. First job is to download the operating system on the main computer and write it to the micro SD card. Go to the Ubuntu MATE download page, choose the Raspberry Pi 3B+ version of Ubuntu MATE 18.04 (takes two clicks) and download it. Next is to unzip it and write the image to the micro SD card. In Windows this can be done with Win32 Disk Imager. For Linux I recommend Etcher which works well (my main PC uses Linux Mint). Etcher unpacks and writes the OS to the card in one go. Plug card into reader (with adapter if required), run Etcher and select the micro SD card - careful here not to select you HD or other device. Also select the downloaded file. Set Etcher going and a few minutes later the OS is written to the card. With Windows, install Win32 Disk Imager, unzip the downloaded file and chose the image file (.img) and SD card in Imager and follow the onscreen instructions to write the OS to the card. There is a script that has been written for installing the INDI drivers onto the card in the RPi that covers what we are trying to do. This is AstroPi3 and pretty much does it all. The instructions given repeat what I have written above. The lines of code can be copied and pasted from the web page into a Terminal window on the RPi. Applications > System Tools > MATE Terminal. Use Firefox on the RPi to go to the AstroPi3 page and copy/paste each command line to the Terminal window. Hint, 3 clicks selects the whole line for copying. The script installs INDI and a few other items of astro software but you don't have to accept it all if you don't want it. The script may be edited to comment out unwanted items but you need to be careful and know what you're doing though "it's not rocket science" It also turns on SSH so that further command lines can be added from the main PC through its Terminal window and SSH. At this time the human interfaces can be disconnected from the RPi. With this script you end up with a usable system that will capture images and control most of the astro equipment on the market. Controlling DIY equipment is another matter and one I've worked on successfully - this will be another Tutorial. The script takes an hour or more to run and has a few y/n responses needed. We now should have a working system on the RPi but to use it we have to run indiserver. You need to choose the drivers for your equipment, for instance, I have a ZWO ASI astro camera indi_asi_ccd and EFW indi_asi_wheel and a SkyWatcher mount (EQ8 but same for NEQ6) indi_eqmod_telescope :- indiserver -m 100 -vv indi_asi_ccd indi_asi_wheel indi_eqmod_telescope ADDENDUM :- I have had a problem with the AstroPi3 script reporting the "dpkg is locked...". To stop this edit the script file to comment out the appropriate lines. The location of the script file and the lines to comment out (with #) are shown in the screenshots below. I shut down the RPi and edited the SD card in my desktop computer before returning to the RPi and continuing. Next will be to install and use the software for the main computer indoors (or maybe warm room).

INTRODUCTION This is a tutorial explaining how to install an operating system and software into a micro SD card to use in a Raspberry Pi 3B+ for astro imaging and control of the relevant hardware. The software to capture images, control camera cooling and other things such as the mount etc. is called INDI and provides a set of drivers to control all the hardware. The Raspberry Pi will run in what is called "headless" mode - meaning that no human interfaces are directly connected to the RPi - instead the RPi is connected to the local area network (LAN) using either Ethernet (preferred for speed and reliability) or WiFi. Everything is then controlled from indoors on a computer also connected to the LAN. This computer is called a "client" and the Raspberry Pi a "server". This tutorial will detail all the steps involved in installing the operating system and software - there are rather a lot of them, hence the need for a tutorial but there is a script that is downloaded that does all the difficult stuff. I believe that anyone with some knowledge of computers should be capable of following these steps and setting up a working Linux based astro imaging system. The Raspberry Pi can be put on the pier (or tripod) or even directly on the telescope mounting and would replace a laptop for instance, reducing the use of long cables etc. The operating system used is Ubuntu Mate and involves using a monitor, keyboard and mouse (or trackball) in order to set up the operating system and enable remote control before the RPi can be used headless in the observatory or on a tripod. The Raspberry Pi is a "proper" computer though a bit slower and with less storage space that a desktop or laptop. When powered up the operating system goes into a setup routine and you just have to answer the questions, same as when setting up any computer. Near the beginning there's an opportunity to set up WiFi so you'll need your WiFi password.

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

An image from just before dawn.

Aircraft produce a pretty trail ?

Moon set.

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.

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.

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