HI,

Taken with a canon D6 at 15secs Tv and 2.0 Av Focal Length 7.2mm.

Enjoy !



Regards,

Paul

Attached Images

Orion forum.jpg (42.8 KB, 161 views)

Very nice shot of the Orion region. you did very good Paul. Clear Skies

Very good photo. Keep them comming!

Kind regards
Matt

One of my fav constellations. Very nice shot.

Thank you for the knid comments.

I was wondering if anyone out there could take a similar photo of Orion with the same settings as me(see above). It would be really helpful if you were located in a light polluted area as I would like to see the difference light pollution would make to these types of photos.



Kind Regards,
Paul

Hi Paul - The camera(s) that I use are Canon DSLR types - the newest one that I use all the time now is a 40D. The only lens I have that can go as wide an aperture as your camera is my 50mm f/1.4. I should be able to shoot a widefield image of the constellation Orion using that, and hopefully get the same image scale as the image you posted above.

Do you know what ISO setting your camera took this image at? My camera can be set between ISO 100 and 3200. I suspect ISO 400 will give me an image that may not be too much over- or under-exposed from my location here 25 miles northwest of Los Angeles.

If the high clouds in the sky clear by tonight, I think I can get a shot or two with close to the same composition as your shot. I think, with all the light pollution in the San Fernando Valley I live in, that the sky is close to Mag 2 or 3 - pretty badly light saturated, making a lot of deep sky imaging harder. Planets and Lunar imaging is not a problem, because most of these are bright enough to spot naked-eye.

I will shoot Orion at 15 seconds exposure, aperture f/2.0, and whatever ISO speed you shot your image at, and then post the results here.

Clear skies!

Paul

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Dear Paul,


Thank you for your reply. See below for full details on photo graph.
File Name
Orion forum.jpg
Camera Model Name
Canon PowerShot G6
Shooting Date/Time
08/02/2008 20:51:55
Shooting Mode
Manual
Photo Effect
Off
Tv (Shutter Speed)
15
Av (Aperture Value)
2.0
Light Metering
Evaluative
ISO Speed
400
Lens
7.2 - 28.8mm
Focal Length
7.2mm
Digital Zoom
None
Image Size
3072x2304
Image Quality
Superfine
Flash
Off
White Balance
Tungsten
AF Mode
Manual Focus
Color Space
sRGB
File Size
42KB
Drive Mode
Self-timer Operation
Owner's Name

I will post the original when I get home from work for better comparison.


Kind Regards,

Paul

Attached Images

Forum Image raw orion.jpg (77.5 KB, 15 views)

Orion is my favorite constellation. Whenever I'm out on a date with a girl and we're looking up at stars I point that one out to her. I explain the belt and sword and how he's stabbing Taurus in front of him. Makes me seem knowledgable and the ladies love it. That's also one of the few constellations I know so in the summer I'm out of luck.

[quote=JesusSaves;1173492]Dear Paul,


Thank you for your reply. See below for full details on photo graph.
File Name
Orion forum.jpg
Camera Model Name
Canon PowerShot G6
Focal Length
7.2mm

Paul:

You have figured out something that few people appreciate: The the Sony 7.1 Mpixel 1/1.8" CCD is very decent for light-duty astrophotography. Your 7.2mm focal length is the equivalent of f=35mm for a 35 mm film camera. I still have the Olympus SP310 with the same CCD, which I used to make some neat pictures of the galactic plane by stacking 20 pictures (15 seconds each) on site at 10,000 ft elevation and a very dark sky using the IRIS software.

The bad news is that the aperture on your G6 is only 7.2mm/2 =3.6 mm and you are limited to iso400.

If I were to take the same shot with my Nikon D40 and a Nikkor 28 mm f/2.8 (equivalent to f=42 mm), almost the same large field of view, but with a 28/2.8=10mm aperture (gained factor 8 in area) and you can go to iso1600 with less noise than the G6 at iso400 (gained another factor of 4). While you don't gain a factor of 32, the results are stunning, even under light polluted conditions. This was first shown by Christian Buil ( look for the IRIS web site and his name). The IRIS software is free. Try stacking some of your G6 pictures. You will be amazed.

I have stack 20 exposures at 30 seconds each using the D40 with a 105 mm f/2.5 lens. From my backyard (visual condition +3.5 on a good night) I get to stellar magnitude +14. Pretty neat for satellite, astroid and comet hunting.

hha

Hha,


Thank you very much for taking the time to post I appreciate it!

I would like to quickly say a big thank you to all the people who make up this forum, as a complete newbie every one has been really supportive and helpful .


Hha, I feel such an idiot it did not occur to me that you could get some software to stack your pictures by star aligning, I was under the impression I needed some kind of tracking mount and a bulb setting for long exposures. Thank you for pointing this out to me. I shall have hours of fun learning to use the Iris software and stacking some pictures.

My first project is going to be the seven sisters. However, I need to wait for the new moon so I can get lots of dark pics. In the meantime I will try the Orion pictures I have and I will post the results soon.

Kind Regards,

Paul

Paul:

Attached is a single 30 second shot of M42 with my Nikon D40 at iso400 and a Nikkor 28 mm f/3.5 at f/3.5, taken on the evening of 2/15/2008. The top of a tree illuminated by street lights is visible in the lower right, and the moon was in the Pleiades, just outside of the upper right corner. The camera was attached to a tracking mount. Other than rotating and saving in a more lossy jpg to allow uploading to this forum, no processing was done to the original photo. The 28 mm focal length has a similar field of view as you 7.2mm focal length on the G6. This picture will give you an idea of what you can expect from the G6.

hha

Attached Images

m42.28mm.f3.5.30sec.rot.DSC_0538.jpg (123.1 KB, 28 views)

Here's a pic of orion, 15s exposure, f7.2 in the extremely light-polluted area known as my backyard (it's a townhouse complex with a very well-lit parking area in the back...can't complain when parking the car, but it makes for poor sky viewing).

Attached Images

orion.jpg (90.3 KB, 24 views)

Orion is my favorite as well
This sounds nuts I know, but I have a beauty mark set on my arm that is the exact lay out of the orion constellation

Hi,

Follow up image of just the belt and sword photographed with A Canon G6 mounted on tripod using 19 light frames + dark, flat and offset masters.

Focal length 28.8, Tv 4, Av 3.0 and ISO 400

Processed using iris and then Photostudio 5.5.

I hope you enjoy!

Regards,
Paul

Attached Images

Orions belt&sword forum Draft 1.jpg (135.2 KB, 24 views)

I've not tried to use Iris yet, but I have looked at the website. It looks like it probably has a steep learning curve. DeepSkyStacker is much easier. Registax also works pretty well, but I prefer DSS.

I just thought I'd mention that there are other programs that you can use (that are free)

Paul:

You are on your way to serious astrophotography. However, there are limitation to what can be done with a G6. I am attaching a picture which I processed
so you can see the difference. You took 19 frames at 15 seconds each + dark etc. The attached picture is from three 30 second exposures with my D40 at iso400 and a 28mm f/3.5, taken from my backyard with the moon in the Pleiades and +3.5 visibility. The images were stacked together with IRIS, no darkframes or noise suppression. The attachment, cropped from my original to show the same area as your picture, shows that the two pictures reached comparable stellar magnitude depth.

Keep plugging away.

hha

Attached Images

M42.d40.3x30sec.28mm.G6.19x15sec.compare.e.jpg (26.9 KB, 17 views)

Sigh... I'd be seeing that if it wasn't so darn cloudy here. K'yek.

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Hi Hha,

What do you use for noise suppression and does it make alot of difference?

Kind Regards,

Paul

Paul:

[quote=JesusSaves;1185505]Hi Hha,

What do you use for noise suppression and does it make alot of difference?

Kind Regards,

I presume you refer to my post from 23-February-2008, 05:49 PM
which shows the 3 x 30 seconds with the D40. An earlier post (with the tree branches visible in the lower right hand corner) showed just how bright the sky is in a single shot. The d40 CCD has no hot pixels and is extremely low noise and the photos I take are totally suburban ligh pollution limited. I make no dark frame or internal noise subtraction in the camera. The sensitivity is set to keep the background at less than 50% of the dynamic range (based on the histogram). With 30 seconds and and my 85mm f/1.8 lens, iso200 is typical, at with my 105mm f/2.5 lens I can use iso400. My slowest lens is 400mm f/5.6, for which I can use iso1600.The images are registered using IRIS and the background is subtracted using the subsky3 function. Call the registered images mr1, mr2 and mr3. Using the command line interface

add2 mr 3
save image1
bin_down 150
save mask
load image1
subsky3 100 mask
save final_image

The bin_down function determines areas with stars which will be excluded from the background fit. The parameter 150 in bin_down has to be determined empirically. A good mask will look like a black on white star map.

The G6 CCD is prone to hot pixels, so you have to enable to internal noise reduction, which automatically takes a 15 second darkframe and subtracts it from the image. Each 15 second exposures takes 30 seconds of total time.

Hope this excplanation helps.

hha