Talk about good timing. The Sony arrived on Thursday evening, just before I was due to go to the dark site on Saturday! Both UPS and JTW Astronomy were excellent in progress updates and being concerned about good delivery.
So a few test plans were written and away we all went, among the glorious blue skies of the Victorian country. First decent clear skies many of us have seen for a month or more.
Pleasingly the astrophotography field wasn’t that busy. In the end I turned up far too early and got a little sunburnt chatting to my new astro buddies for hours. At least the crew mowed the grass!
The camera looks and feels incredibly small and light! (see my last post for comparative size pics) I showed the camera to one of our club’s imaging experts, who has a cooled 5D and he laughed when I showed it to him. Especially the depth of the camera, it’s so thin! Despite this, it is built supremely well and feels solid. A real retro feel to it. Being so light, I had to revisit my scope balance.
Handling at first was fiddly, being used to the Canon world so long. But after a fair bit of use in the dark, I can say that the controls are really nicely set out, easy to find by touch. Especially the play button and review zoom buttons. The folding screen is a fantastic asset, making review on the screen so much less back breaking. Well, until APT supports the camera, then I can control and view the cam from the PC.
One quibble – if you set the drive mode to anything other than single shoot, the camera refuses to let you use BULB mode. Took me awhile to work out why I couldn’t do shots over 30 secs!
The E mount to Canon T mount adapter I bought from B&H Photo is really solid, gives an excellent firm connection to the Takahashi scope.
Is a dream to perform! With the firm connection to the scope, a full range of focus was quickly verified, thankfully. I slewed the scope to the first alignment star, using the camera to centre it. Woah, what a field of view! The full frame sensor gives you so much more screen view that centering object is a breeze.
Then focusing, another revelation. Set at ISO 3200, I could so easily focus during live view, adjusting my Tak focuser until the stars were very, very small on the high res screen. Then I took a pic, zoomed in on that pic and assessed the focus. Spot on first go. THAT is pretty hard with my f3.3 scope, I can tell you.
Ok, enough waffle, lets get to the test shots. And heeeere we go –
Single shot at 6400, 30 seconds, already starting to bloom, though it was early in the evening and I was able to use 2 mins at 3200 later. Remember, these are raw shots, no darks or flats to remove vignetting. Click and zoom in to see the very even noise. Pixinsight handles this supremely, the noise is so random that it’s smoothed right out without image degradation at later stages of processing:
12800 for 30 secs, levels adjusted to balance for overexposure. And this is a dark site:
As the camera is generally know to have a good balance of quality and sensitivity at 3700, I kept the ISO at 3200 for the rest of the night. This proved to be correct I think, very impressed with the smooth, correctable noise, no banding finally! So here is a single sub at 3200, 30 secs, by this time the sky was darker:
I could see the faint luminosity emerging, so extended the subs as follows. Firstly, 1 min:
Then finally, used 2 mins, beyond which I think the cam was so sensitive that it was starting to overexpose the background. Not bad eh, 2 mins!
Here’s a one minute dark at 3200, stretched to a similar amount to the light images. It was cooler than the other time I showed you some darks, with pleasing results:
And a flat, very pleased with the vista through my scope that is designed for full frame sensors:
One very clean sensor kiddies. Shows the superior quality control at JTW.
So below are the results for ISO 3200 after quick stacking and basic stretching/editing of the images, these edits were not exactly patiently done!
First, a stack of 60 by 30 seconds:
Cropped version, showing the versatility of such a wide Field of View:
Next, a stack of 30 by 1 minute subs. Already more definition and nebulosity emerging:
And lastly, a stack of 30 by 2 minutes. By far the best results:
By then the 60% moon was rising and our targets rapidly bleaching out. So I slewed across to the opposing sky and imaged a magical part of our southern skies, the Large Magellanic Cloud. It was getting towards 3 am, I was tired, so couldn’t be stuffed selecting more targets. So I thought I’d do a silly stack for later experimentation. Took 120 (one hundred and twenty) pics, at 30 secs. Went to bed in the car, with the comforting ‘click’ of the shutter every 30 seconds lulling me to sleep, such a calming sound…
When I get time, I will try stacking just 80, then 40, and assess the differences. It’s convenient that such a sensitive camera allows us to conduct such experiments:
Plate solved version, via Pixinsight:
I have the go ahead to go back to the country on Saturday, so stay tuned for more fun experiments from Simmo! I might try a direct comparison between 1600 and 3200 ISO, although I am already being reliably informed not to bother, that 3200 is the sweetspot. But I need to prove it for myself.
I’m expecting delivery of a 12nm Ha filter from Astronomik this week, so I hope to test it at ISO 6400 as well.