Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: RobertM on Feb 14, 2015, 14:57:28

Title: M42 with Sony A7
Post by: RobertM on Feb 14, 2015, 14:57:28
Severe vignetting meant I had to crop nearly half the frame but it was half expected due to the crappy adaptor.

M42, from Orpington
59 x 60s
ISO 2500
Baader L-Booster filter
GSO 10" RC at f/8
Basic processing in PI to gauge the attempt.

(https://farm8.staticflickr.com/7381/16527691905_1477ac431b_b.jpg)

Title: Re: M42 with Sony A7
Post by: MarkS on Feb 14, 2015, 15:13:09
That has come out very nicely indeed.  An excellent first light for the camera and very nicely processed.  The camera really looks like it will be a great full-frame performer with its excellent sensor. I'm very tempted by it's smaller sibling, the A6000 (which is much cheaper!).

When did you get a clear night for this?

Mark

Title: Re: M42 with Sony A7
Post by: Kenny on Feb 14, 2015, 16:07:03
The image looks fantastic Robert.
Title: Re: M42 with Sony A7
Post by: RobertM on Feb 14, 2015, 16:37:07
Quote from: MarkS on Feb 14, 2015, 15:13:09
When did you get a clear night for this?

Mark
Sunday 8th.

Edit.  It's a long way from being processed correctly but at least it shows promise.
Title: Re: M42 with Sony A7
Post by: MarkS on Feb 14, 2015, 17:14:36
Did you process it as a single HDR image - i.e. none of the Photoshop overlaying mullarky?
Title: Re: M42 with Sony A7
Post by: RobertM on Feb 14, 2015, 18:23:24
I used PI for the whole process but wished I'd done it properly with calibration frames and processed it carefully after having seen how it turned out.  For the HDR I think I just increased to layers to 8 or 9, everything else was default.  The output from the stack was surprisingly clean so only a little NR was applied to counter the deconvolution.

Robert
Title: Re: M42 with Sony A7
Post by: Kenny on Feb 14, 2015, 23:04:51
What language are you speaking because it's not one I recognise. ;) :D
Title: Re: M42 with Sony A7
Post by: The Thing on Feb 15, 2015, 11:19:18
For a test run I think this is a really nice result .
There must be a high dynamic range available even at ISO 2500 as you've nearly been able to reveal the Trapezium without recourse to shorter subs.
Title: Re: M42 with Sony A7
Post by: RobertM on Feb 15, 2015, 11:28:47
Quote from: Kenny on Feb 14, 2015, 23:04:51
What language are you speaking because it's not one I recognise. ;) :D
PI = PixInsight astro processing software
HDR = high dynamic range
NR = Noise reduction.

You'll be speaking da lingo soon enough ;)

Duncan,
Thanks, the trapezium was visible in the 30s subs so perhaps that was a better length.  The histogram was well up as you can imagine so I could certainly try that next time.

Robert
Title: Re: M42 with Sony A7
Post by: Carole on Feb 15, 2015, 11:56:24
Very nice test image Robert.

Carole
Title: Re: M42 with Sony A7
Post by: Fay on Feb 17, 2015, 09:26:57
Very nice Robert, how is the Sony with computer software etc? did you use BYE or APT or capture just using the camera?
Title: Re: M42 with Sony A7
Post by: JohnP on Feb 17, 2015, 16:38:04
Well that looks pretty amazing to me for 60 sec subs - I'd be really interested to see a single 60sec sub (warts & all) full size without the crop...

John
Title: Re: M42 with Sony A7
Post by: RobertM on Feb 17, 2015, 18:28:36
Fay,  I used one of those cheap timer things that plug into the accessory port so capture was to SD card.  There won't be much software support for automated capture till APT version 3 is out and even then it's not guaranteed.

John, will do but it will be a JPEG, I can make a Sony 'RAW' available if needed.

Robert

Title: Re: M42 with Sony A7
Post by: RobertM on Feb 17, 2015, 18:49:34
The full size JPEG can be found here: https://farm9.staticflickr.com/8598/16375138830_4ea85850ca_o_d.jpg (https://farm9.staticflickr.com/8598/16375138830_4ea85850ca_o_d.jpg)

A 2.5" field flattener came with the scope; I'll use that as soon as the focuser adaptor arrives from Telescop Service.

Robert

Title: Re: M42 with Sony A7
Post by: Fay on Feb 17, 2015, 18:56:25
I thought BYE supported the camera?
Title: Re: M42 with Sony A7
Post by: RobertM on Feb 17, 2015, 21:47:47
Quote from: Fay on Feb 17, 2015, 18:56:25
I thought BYE supported the camera?

I don't think so, that's for Canon EOS cameras.
Title: Re: M42 with Sony A7
Post by: Mike on Feb 17, 2015, 22:51:18
Robert why did you choose a Sony camera?
Title: Re: M42 with Sony A7
Post by: RobertM on Feb 18, 2015, 08:20:42
Hi Mike,

It was the particular camera that interested me.

1) Full frame
2) mirrorless so no mirror box shadows
3) exceptional ISO performance (I can see the trapezium and surrounding nebulosity in live view).
4) in camera apps that mean less reliance on a computer.
5) no back focus issues with almost any lens.
6) no stupidly small pixels.

And more importantly, it came in at a good price converted.

Robert
Title: Re: M42 with Sony A7
Post by: The Thing on Feb 18, 2015, 09:43:22
Quote from: Fay on Feb 17, 2015, 18:56:25
I thought BYE supported the camera?

I think all software is about to start supporting the Sonys, but BYE has a Nikon version at present but not Sony.
Title: Re: M42 with Sony A7
Post by: RobertM on Feb 26, 2015, 13:21:54
This is a link to the full size (after cropping), the one originally posted is a flickr resized version.

<link>https://farm8.staticflickr.com/7381/16527691905_ac64ce0365_o.jpg</link>
Title: Re: M42 with Sony A7
Post by: Mike on Feb 26, 2015, 13:29:44
Absolutely stunning.
Title: Re: M42 with Sony A7
Post by: JohnP on Feb 26, 2015, 15:02:38
That is amazing Robert - are all the little light coloured bits (all over the image) jpeg compression artifacts...?
Title: Re: M42 with Sony A7
Post by: RobertM on Feb 26, 2015, 17:54:35
John, that's me being careless with deconvolution and noise reduction - I got both a bit wrong !  Some may be faint stars but not that many.

Robert
Title: Re: M42 with Sony A7
Post by: MarkS on Feb 26, 2015, 23:58:55
I've just compared it with an old one of mine:  http://www.markshelley.co.uk/Astronomy/2008/m42_2008.html

Yours has got far more detail in it - better colouring as well.  I suspect my guiding wasn't much good though - guiding with a Philips Toucam back then!

Mark