Equipment: Skywatcher Equinox Pro 120 refractor
HEQ5 Pro mount
Watec WAT-120N video camera
20mm Explore Scientific 100 degree FOV eyepiece
Several batteries, plenty of dew heater strips, thick coat, plenty of hot drinks, to overcome the cold! Temperature must have been around -5 C in my garden – ice was certainly crisp enough under foot.
This was my first attempt at video astronomy. I spent three hours preparing the equipment in the afternoon – lot of frustration getting drivers to work on my laptop – eventually I had it all connected – a mass of cabling that threatened to tangle up like spaghetti. Some of the cabling was bespoke – made by myself at an inspired moment when my brain was working (trying to remember when that was now) as I had the whole lot connected so that I could view the image simultaneously on a laptop and on a 7 inch LED screen bought for the purpose. This latter is sold as a screen for the back of car seats for watching DVDs on Amazon and only cost around £20. BUT it did mean my soldering iron had to come out to make cables that would connect to various sockets……..I had also spent quite a bit of time last week labelling every connector and using colour codes to show what plugged into what – a VERY good idea if you decide to do something similar yourself!
I was glad I had put everything together as I am sure it would have been virtually impossible outside in the dark.
As I was concentrating on using the camera for the first time and getting it to work, I did not manage to observe a large number of objects. The situation was made worse by a poor connection somewhere unknown in my cabling that I could not work out in the dark. Wobbling the cabling and spaghettified cabling mass got it working again but it tended to stop working each time I moved the telescope. Plus, I am still getting to grips with aligning the mount so my pointing accuracy wasn’t that great which meant I had to search around a little to find objects each time I moved the scope (not much searching required though – but I could still do with a tutorial from Pete!). In addition, the camera and eyepiece were not par-focal – I will need to use a par-focal ring to sort this one out.
Good news was that the field of view of the camera was not bigger than I expected in the refractor – I could get 1/3 to ½ of the diameter of the Moon in the image without a focal reducer. Later on in the evening, when I added in a focal reducer, I was able to image the whole Moon in one go. Great stuff!
It is also becoming very clear that the height of the hedges and trees around my garden makes aligning the GOTO on the HEQ5 Pro difficult.
On a positive note, the sky was clear and very still. The Moon was bright in the south and somewhat affected the number of visible stars. But it also made a great target for my first night with the Watec.
Having said that, the first object I looked at was NGC 662, a delightful open cluster. This allowed me to check alignment and I have a nice view in the Explore Scientific eyepiece. When I put in the Watec, I thought I could see around 10 faint stars on the image but they did no move when I moved the scope using the hand controller on the HEQ5 Pro. They also did not change with focuser position. Strange! Suddenly as I changed the focuser position, other stars appeared and I realised the original "stars" were hot pixels. The focus position for the camera had a narrow range of focus which meant it was easy to miss it. It also involves racking the focuser quite far in, demonstrating that the Watec requires more in focus than the eyepiece. Later, when I added in the focal reducer, I had to remove the diagonal to get enough in focus for that accessory to work.
The image through the Watec, once I had aquired it, was nothing spectacular. I noticed this with the images from video cameras by other folks in RAG – it is the nebulae where these video cameras really excel. Actually, my image was probably worse than theirs due to the high sensitivity of the black and white sensor in the Watec – led to bloated stars. However, it did pull out more and more stars from the cluster as I turned up the integration time on the hand controller for the camera – and that was quite spectacular to behold – stars jumping out at me with a slight turn of the wheel!
I moved to the Double Cluster in Perseus, thinking that if I am going to image an open cluster then that would be the best! In spite of what I said above about imaging open clusters this was quite spectacular in the camera, although I could not fit both clusters into the field of view. At this stage, I had not thought about trying the focal reducer so I would like to go back at some stage and use that to see if I can get both clusters together in the same image.
I was now on a role – with my initial success so moved to M31 Andromeda Galaxy. High in the sky, I could see the galaxy in the finder scope which made accurate alignment onto the chip easy, in spite of my poor initial alignment of the mount. Again, turning the integration dial to higher settings magically pulled out more and more galaxy from the image. Wow!
I tried M81 and M82 but found they were below the hedge – just – and unfortunately all those cables I mentioned above made moving the scope difficult – plus I did not want to lose my alignment, such as it was.
By the way, when I first got the scope the hand controller went off once or twice and this worried me that there might be a significant fault in the mount. However, not happened since, or event tonight in extreme cold or even when I dropped the HEQ5 hand controller and it dangled on its wire. I think the original problem might have been due to a non-fully charged battery as these lead-acid batteries lose voltage quite quickly as they discharge and the HEQ5 Pro mount has a significant current draw – or so I have read on the internet.
I tried to find M33 – but my limited success in mount alignment got the better of me here and I could not see it with the light pollution from the Moon in the eyepiece.
I was getting rather cold by now – plus needed to clear up for work – so decided to finish by photographing the Moon using the Watec. Good news was that, by now, I was finding it easier to manipulate scope and camera. My biggest problem was a surprising one!....or at least surprising to me at the time (if not to anyone else – I am easily surprised). This was that the high sensitivity of the camera meant the Moon was a whiteout even when the integration was turned off and gain turned to lowest setting on the camera. I desperately need a strong moon filter – but don’t have one. So, I put every 1.25 inch filter in my case together and just about got the Moon down to a low enough level to photograph. I was very happy with the initial results showing quite a lot of detail in craters. Really, I should have put in Barlow lenses and upper the magnification to see what I could get but that idea did not come to me at the time – probably because I was feeling rather cold.
Pete Hill had leant me a focal reducer – and I tried this and was very pleased with the results, managing the whole Moon in a single frame. I then discovered I had my own focal reducer in my case which I had forgotten about – and that worked equally well with the camera. The brightness problem was amplified by using the reducer. If you look at my whole Moon images you can see areas of whiteout I could not get rid of due to insufficnt filtering power.
The really neat thing about these video cameras is the ability to integrate in the camera and hence grab a single image of the integrated result. This is very quick and effective. I also tried video – this works well too and I would like to try it with Registax at some point.
I have debated whether to finish this report on a high or low point. Going out with a bang is good – but on reflection I would make a note of caution. My Dobsonian telescopes are in and out in a few minutes – easy to use. This current setup requires a lot of boxes, plenty of time to set up and pull down, and that is made worse with all the gear for the camera. Not a grab and go arrangement!
From: Peter Hill
Sent: 29 December 2014 13:57
have got more snow up in Barton, need to clear a pathway and viewing patch before can make most of good viewing, have also been away doing the Christmas rounds.
Welcome to the club!
Glad the focal reducer worked.
I found turning the integration down and using a Bahtinov mask helped to focus the video camera, make a note of position for future ref, on the moon, as well as turning down the integration , have you got control of the exposure?, this worked on the PD camera, without need for filter.
As you say , definitely not grab and go, I also do the alignment with a illuminated reticule eyepiece to make sure image is centred, if I'm planning to image, image is usually in view in camera even if only on edge of fov, otherwise it’s a lot of frustrating tweaking and searching.
You'll also have to trim the trees and bushes!!