(Viewed 8,420 times)

[Chicago Astronomer - Astro Joe]

13 Dec 2006 - Evening Practice Images

I ventured out to my garage roof with a nice eastern vantage to catch the Geminds, but got dissapointed when only two faint ones entertained me. So I decided to concentrate on developing my new camera skills at nighttime astrophotography.

--------------------------------

This first one of the crescent Moon was nice. With full 12x optical zoom, mid-level aperture and a 1/30 shutter speed, not a bad shot.

------------------------------------

Sirius was staring me down in the south, and I took this zoomed in, out of focus airy disk to check optics. Looks pretty good to me, and appears similar to a microbe.

----------------------------------------

Overhead was Auriga and it's bright star Capella. Wide open, ISO 400 and about a 10 sec exposure, I was able to see stars in the result that I could not see with the naked eye.

-----------------------------------

Here zoomed in all the way with the additional 4x digital, 8 sec exposure and wide open is a Capella star trail.

Lastly is Auriga again, with a 15 sec exp, ISO 800, wideopen. Nice star trails.

============

Considering my very light polluted skies and alley lights surrounding me the shots are not half bad.

[starbux]

Pretty good first shots. You will note how Capella turned out better at 400 ISO (much less skyglow) than at 800. If you check out my just posted Orion-Taurus shot (shameless plug), you will see how the settings for an urban light-polluted sky can go against the norm for dark sky shots.

Nice moon shot too. Was it mounted to a tripod, or did you use the IS feature?

[Chicago Astronomer - Astro Joe]

Malcolm,

For the Moon shot, I used a tripod, legs splayed wide and very low to the ground to minimize vibration.

The IS (Image Stabilizer) was on. I set the option for "Shoot only" mode instead of continuous. It will save on battery power.

What are you using for the average sampling for available light? Center weighted, spot or something else? And you are observing any difference in quality from the size of the initial image? Meaning are you finding any improvements from a 640x480 saved image from a 2816x2112 saved image?

I think I'll try a binocular shot this evening and see how it comes out.

[starbux]

So far mostly Matrix. But metering will be pretty much useless for anything fainter than the Moon and planets. You should also use the camera's 2 second (or custom) self-timer to avoid any possible shake from pressing the shutter when mounted to a telescope --- the IS feature probably won't help much in those circumstances.

The higher the resolution, the cleaner the results when processed with an image editor. After which you can reduce the image to a web compatible size.

[Chicago Astronomer - Astro Joe]

Malcolm,

Yes. I have been utilizing the timer option for astro shots, and for the reason you specify.

When you zoom in all the way, (without a telescope), are you getting pin-points for the stars?

I'll post some pics in just a bit where the stars look nice, but are not razor sharp pin-points.

[starbux]

My constellation shot had pinpoint stars, but I wasn't using the zoom. And I was using a driven mount. If you use any significant level of zoom on anything more than a few seconds you will have star trails.

Several years ago I took dark-sky constellation pics with an SLR and Konica 3200 film (alas no longer available). Without zoom and on a fixed (undriven) tripod I was able to keep the stars more or less round with exposures up to 30 seconds or so.

Try various exposures at 15 seconds with various ISO settings. If there is too much skyglow you can either lower the ISO or close down the camera's aperture (experiment with different f-ratios). A slower (long focal ratio) system will record images better under light-polluted conditions than a fast system. This applies to telescopic imaging too -- though in that case you need not narrow the camera's aperture -- just increase the magnification which effectively increases the f-ratio of the entire system.

[Chicago Astronomer - Astro Joe]

Two nights of Astro Imaging

For the past couple of nights, the heavens have been good to us and provided astronomers in the Chicago area clear, (albeit light polluted), skies. I took advantage to set up the camera again and refine my astrophotography skills.

On Dec 14th, I ventured up to my slanted peaked roof and halfway out of the roof hatch...lodged the tripod over the crest and targeted Orion. Thursday night was a windy one, but I stayed the course.

--------------

I had the ISO at 800, shutter at 1.6 sec and f-stop about 2.7.

-----------

Here I shot Orion again with an exposure of 6 seconds, F-2.7 and ISO 800

------------

Here I zoomed in optically, (12x), into M42.

ISO 200, F-7.1 and 10 seconds.

--------------

On this one, I zoomed in all the way and used the 4x digital zoom too.

ISO 800, 10 seconds at F-3.5

Saved it as a 1600x1200 image

--------------

This is capturing Saturn among stars.

ISO 80, F-2.7 and a 8 second exposure

I used the "Vibrant" setting on these shots.

-----------

The following night, I ventured out to the Chicago lakefront just south of the Adler Planetarium, where there is a good eastern view. I set up about 7:45 pm Friday on a rather chilly night. I had my tunes playing, binoculars and was ready for a spirited astrophotographic session.

Orion was well above the horizon and quite brilliant.

A lot of aircraft in this area of the sky, as there is an vector pattern to O'hare airport. I used a ISO of 200, 8 second exposure and an F-stop of 3.5

------------

Zooming in all the way optically (12x), on the Pleiades, I was pleasently surprised on what I could see on the LCD screen.

ISO 200, F-3.5 and a 5 second exposure.

------------

I took Malcolm's advice and used the "Tungsten" setting on the camera, and indeed...it's does wipe out a lot of the mercury vapor light pollution that would normally blemish these last two images... ;D

I had the camera on a tripod, used the timer to prevent vibration and hoped for an educated set of images.

By 9:30 clouds were approaching from the south and astrophotography would have to come to an end this evening. You can see the bright lights of South Chicago and Gary Indiana.

----------

I then ventured to the best place to view the city of Chicago, right by the Adler Planetarium...

We have been told that Chicago has the best skyline anywhere in the world...I must agree. In the forefront of the image, is our sundial. I think it makes a nice picture...

ISO 80, 15 seconds and F-stop of 8.0

--------------

I zoomed in on the Sears Tower with just the Canon S3 digital, and got a remarkable shot of the windows and rooftop lights. Way cool!

ISO 100, 5 seconds and F-stop of 5.6

-----------

Now...

I am noticing that my star images are not pin points when I zoom in to them as they should be. I can see that they are not razor sharp on the LCD screen even before I expose the image. Is this normal, or perhaps is my camera not focusing in properly?

I manually focus to infinity, then set my F-stop, ISO and shutter speed.

Am I doing something wrong?

But regardless, a great night of digital photography...and found a dime too!..

[starbux]

Very nice shots! Seems like you're doing the right thing. Star images won't appear pin-point when you zoom, I can't explain why, but that's how it is with my camera too. Maybe a limitation of the resolution of the LCD. When I use digital zoom for focusing on a bright star (this is what I do before shooting DSOs) I can only try to get the star as small as possible (even though not pinpoint by any means) on the LCD, then zoom out.

You should avoid using digital zoom when actually taking the picture, as it adds no new information and actually degrades the image (like enlarging a photo past 100%). Digital zoom is fine as a focus aid, but not for the actual shooting. And with 12x OPTICAL zoom you already have a lot you can work with.

I especially like your shot of the Pleiades, almost pinpoint with lots of fainter members showing up too. Your 3rd Orion shot (zoomed at 200 iso) along with M42 also features a favorite unsung cluster NGC 1981 -- which I have dubbed either the "Armadillo" cluster, or more recently the "Dreidel" cluster.

[katodog]

Joe, it's finally nice to see the site creator is getting some time behind the lens. I was beginning to think you spent too much time at work, and not enough time at the scope. I like your pictures, but you need some practice. I'm no expert, but it's been my experience that the best shots are always taken by someone else who has much better equipment. I know the pictures I take are horrible compared to the ones taken by guys who spend $2000 on a 66mm apo. ;D

Seriously, though. I've found that it takes a bit of practice and a steady hand to focus the camera at higher magnifications. When I take shots of the moon, I zoom the camera in all the way, and then focus the scope. It works perfectly, and when I zoom out, the focus stays the same. I don't have to keep re-focusing. It has worked like this for most of the objects I photograph, but the dim stuff that you can't see too good on the screen present a harder task. The shots of M42 I took, I had to just get the stars as pinpoint as I could. It helps tremendously that I made the electronic focuser, because now I can get a more pinpoint focus since I'm not shaking the scope.

As far as attaching the camera to the scope, I swear by my Digi-T ring. Unfortunately, Scoptronix is bye-bye. DBA Astronomy bought them, and now DBA has merged with Anttlers. I would expect that they would still carry the same products, but so far it looks like they don't have a firm grasp on their company yet. I've seen that Lumicon and Orion have similar, Digi-T ring typpe accesories, but you'd have to get in touch with them to see what would fit your camera.

In any regard, it is a pain in the butt to do anything when you're stuck looking at a small screen. When I shot M42, I could barely make out the brighter stars on the screen. Luckily, I could see enough of them to make sure they were there.

When you zoom the camera all the way, you should focus. The sharper your focus is at higher magnification, the better it will look when you zoom out. It's usually good to pick a bright star and zoom into it and focus. You will see that the camera shoots the stars the same, and if you're focused on one really good it will translate to good focus on others. When I shot M42, I bounced around to different stars to make sure I was focused. Then I went back to M42 and started shooting.

Every time I've taken any pictures, whether they were of the Moon, or anyting else, the camera always puts up the "AF" warning. That means that it is not focused. But you know from looking at my pics that this is not the case. The camera only does what it is trained to do.

Anyway, I know we have two different makes and models of camera, and I'm no rocket scientist, but if you have any questions about shooting pics, post them. I'm sure I can help, and everyone else here can, too. Looks like Starbux is becoming quite the camera expert, so he can probably help you the most.

Anyhow, keep the pics coming. They look good now, and just think what you'll get with more practice.

[astrojimbo]

I found the same basic results with the s1 is ....no pinpoint stars,at full zoom(10x)but at no zoom ,low iso,long exposure time it just completly wasted the urban sky thing and it even showed a nice orion nebula cloud when magnified in the win pic and fax viewer....I'd like to get an s3 but I haven't used up the s1 yet......astro_jimbo

[Jeanette]

Hi,
Sorry to hijack your thread.
I've posted a link to some astro images I've taken with my PowerShot S3IS.

s203.photobucket.com/albums/aa7/jjjnettie/

The moon was taken afocally through my 10" Dob, the others are taken with the camera mounted on a tripod.
Most are multiple images stacked in DeepSkyStacker and touched up a little in PaintShopPro.
Cheers and Clear Skies,
Jeanette

[Chicago Astronomer - Astro Joe]

Jeanette,

Hijack welcomed, as I am pleased others are using the S3 in astrophotography.

It is a very nice shot, sharp and good detail. The additional optics of the scope brings out good contrast. Handheld shot?

Regarding the other images in your album, please do share some details about how you took them. They look as if taken thru a scope.

Thanks for sharing!...

[Jeanette]

Hi again,

I'm happy to give some more info on my images.
The Comet McNaught photos were taken on the 20th of January. These are single shot images, like the one of the moon.
All the other wide field constellation shots were taken with the camera on the tripod using the full 12x zoom eg The Ring Nebula, Omega Centauri and Eta Carina , to very little zoom eg the Sagittarius image. Please note that the images lost a fair amount of resolution when I reduced them to a size suitable to post.

BTW, I have taken some images of Saturn and Jupiter with the camera, afocal through the scope, using the movie function then processing with Registax, but I haven't gotten around to posting them yet. Besides, they weren't all that crash hot. I get better images putting my elderly Panasonic DV camcorder up to the eyepiece.

I've built myself a Barn Door mount that I have only just started to use. I rarely use it for long exposures, I lose a lot of shots from being too rough turning the spindle, but it's real handy for keeping the zoomed in shots in the field of view.

Camera settings for deep sky-
Always use manual settings.
Timer set to 2 seconds to eliminate shaking.
ISO is set to 400 (ISO 800 is next to useless, too much grain)
Focus to Infinity
I use the LCD screen while I'm setting up the shot, but once it's centred, I close it to save on batteries.
If you zoom in to the full 12x, 3.2 second exposures are the maximum you do. If you don't use any zoom, you can get away with
8 - 10 seconds. Otherwise you need to do test shots to see if there is any star trailing.
Keep your F ratio as low as the camera will let you.
Don't forget to take a dark frame at the end of shooting each object.
Pop the lens cap over the working end and shoot as normal. Even if you don't use it in processing the finished image, its a good marker for working out, in ZoomBrowser, where one set of images finishes and the next one starts.

Once you have the object in the FOV, start shooting. Keep shooting until you have at least 30 images, 50 or 60 is even better. The more images you take the better.
I use the free progam DeepSkyStacker . For me it's superior to Registax because you don't get any field rotation.

I'm very happy with what the Powershot S3IS can produce.

Clear Skies,
Jeanette.
(Aussie Amateur)

[Chicago Astronomer - Astro Joe]

Jeanette,

This is good stuff, very good stuff!... ;D

The information you provided on your exposure technique is invaluable to me and other S3 users out there. Considering the large glass element of the S3, the eyepiece gets lost in all that. I have a hard time hand holding the S3 to the eyepiece and getting decent shots.

A T-mount for the S3 is of course the logical choice, and I should get one. And the free program you recommend sounds great. I will download it now.

Keep the images coming and the user technique.

Thanks for sharing.

[Mark Rushton]

Hey everybody, My new S3 IS is being delivered to me here in Mexico by a friend on Friday (just in time for a wedding, but alas, too late to catch Hurricane Dean when he splatters us on Wednesday evening).

I'm upgrading from a PowerShot A40 - so it's a big leap, and astrophotography is one of my favourite activities. I'm quite glad to have found this forum.

One suggestion regarding difficulties in finding stars / constellations on the tiny LCD: Use a big one! Using the Remote Capture application, you'll have the laptop's screen available for your use. With brightness dialed down (and perhaps the screen inverted - see Universal Access in System Prefs on OS X systems) you should be able to use the laptop as a big ol' external viewfinder. (In theory. I may be retracting this advice shortly once I try it myself!)

Thanks to all for sharing the pics above - I hope to be contributing soon.

Cheers from the Land of the Teotihuacán,

Mark.

[Mark Rushton]

errr.... Oops! As I landed here via a Google search, I've only now discovered that this is a Chicago community. Any objections to a Canadian (living in Mexico) hanging out for awhile?

And... Anyone else in here using a Macintosh? Jeanette's recommendation of DeepSkyStacker will only work for me if I go and install Windows on my Mac... (ain't gonna happen!). So - any OS X stacking programs to recommend?

M.

[Chicago Astronomer - Astro Joe]

Mark,

Welcome to the Chicago Astronomer where the world stops by and says hello.

Great to have someone with dark Mexican skies to share with us, but that Dean will mess up observing for a time. I would like to have an observing session at Teotihuacán. The ambiance would be fantastic!

I use my S3 all the time and find it a great camera. I haven't yet hooked it up to a laptop, (shopping around for one - I think after the "back to school" hype settles down), but I have used the remote feature on my desktop...and it works well.

Your suggestion in using the laptop is a good one and will be doing such after I get mine. But, I really need to get me a T-mount or build something to use the S3 thru the scope. Handholding shots is so difficult.

Hope to see you around!

[Jeanette]

Hi Mark,
There is a program called Keith's Image Stacker. Made especially for Mac.

www.versiontracker.com/dyn/moreinfo/macosx/18550

The format of the program isn't very intuitive so it might take a bit of getting used to, but if you read and follow the manual you'll do ok.
Good luck with it and let us know how you go.

Cheers and Clear Skies,
Jeanette