Can someone look at this picture and tell me if they see any stars. I did a 30 second exposure through my telescope but all I see is black. When I ZOOM in I can see little white specks and some red specks. Are these stars? http://www.coynepics.com/stars/DSC03412.JPG
Thanks Mary

Mary,

I see what you see but I do not think those are stars. They look very much like hot pixels from your camera. Especially the ones in the lower right hand corner.
Pity. But do not give up.
Phil

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I heard you the first time LOL.
I think in the bottom right hand corner is Orion. Are you sure they aren't stars?

I thought my response did not load , But it did!! In quadruplicate!! Sorry. Will go look again.
Phil

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Mary,

I have looked again and I really think those are hot pixels and not stars.
Way back when I thought I had a pic of Uranus, the same thing happened to me.
No harm in trying again and push up your ISO some more. With a 30 second exposure it is also unlikely that the stars will show up as such discrete points.
Maybe someone else will hold another view.

Phil

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...sorry - only hotties!
dietmar

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Dietmar
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www.stargazer-observatory.com

How do I take a picture of the stars. Am I able to take one with a 4.5 refractor? I have a camera that takes 30 second exposures. What should I do?

You wont be able to take pictures through your telescope eyepiece with 30 second exposure.

To me, It looks like you had the lens cap on and forgot to take it off. If you're using a normal F1.4-F4 lens, and 30 second exposure, you should get pictures of stars, but with star trails unless like you have a Nikon 10.5mm Fisheye. 8mm Peleng.

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Those must be "hotties"... I saw the Orion "stars" but the for one thing, the scale is way too small to be Orion. I had to zoom in like 250% to see these and play with the contrast, etc. Have you tried just taking pictures of the sky with teh camera alone? I have got some nice constellation pics this way using my Fuji S5000 set on auto focus, ISO 400, apparture @ 2.8, and exposure at 2 seconds (which is the longest time that camera has) and taken from a tripod and used the timer... I'll post pics if you are interested.

dana t

Yes I'd like to see the pictures. I will try without the telescope.

Hi Mary - are you able to remove the camera lens from your camera? If so, you may be able to connect your camera (with a T-ring and adapter) to the focusing tube on your telescope. That way, your telescope becomes the actual lens for your camera. You may have a problem in being able to reach focus this way. Some telescope focusers may not go in far enough to focus on stars, or may not go out far enough. I guess it depends on the type of telescope and the focuser that's attached to it.

I have a Canon 20D (DSLR) which has a removable lens. Just a few minutes ago, I took it outside and connected it behind an Orion Short Tube 80 (80 mm diameter objective {front} lens - about 3-1/8" diameter glass in front), and thereby used the telescope as the actual lens. This is called "prime focus" photography. The "focal length" of the telescope is 400 mm, which makes the scope an f/5 focal ratio. The only adjustment I have on the telescope is for focusing. Since the telescope is basically a "fixed" aperture, the only control I can have of the image brightness is either by changing the shutter speed or the ISO setting on the camera itself. I set my camera to ISO 100 (slowest ISO setting I can make), and set the shutter speed to 30 seconds. The telescope with the camera behind it were mounted on a camera tripod (heavy duty), and I aimed the camera at a few different stars and Venus.

We've had mostly clouds for the past few days, so at times tonight I couldn't even see Sirius and just barely Capella a few times. At 30 seconds, ISO 100, and with partial cloud cover and bad light pollution from the Los Angeles/San Fernando Valley area, I could see a number of stars around Capella. However, 30 seconds was almost too long of an exposure because of the clouds and light pollution; and of course, since I did not have the camera/telescope on any type of tracking mount, I ended up with star trails. One nice "advantage" of taking star trail pictures is that it is easy to tell the difference between the stars and the "hot pixels". The stars will obviously be trails (the longer the exposure or camera/telescope focal length, generally, the more trailing you will see); however, the hot pixels will show as tiny white, blue or red dots. Since the pixels are part of the actual image sensor inside the camera, they remain in the same position, in every photo you take, regardless of how much the earth rotates during the exposure. Hot pixels are usually more apparent (and prolific) in longer exposures. Hopefully this makes some sense

I believe if you are in a dark location, you should be able to see many stars in your images with a 30-second exposure. Of course, changing your ISO setting to a higher number will give you a brighter image and show fainter stars. But, you can only go as high in ISO and length of shutter speed as your sky glow/light pollution/etc. will allow before your image is washed out and overexposed.

However, if you cannot remove your camera lens, then you probably will either have to shoot through the telescope lens (afocally - see how Phil does it with his images - they are incredible for this technique! at http://home.telkomsa.net/mybirding/Afocal.htm) or you may be able to mount your camera with its own lens "piggyback" either on top of an existing scope on its own alt/az or equatorial mount, or alongside the main scope with something like a duplex plate. Piggyback astrophotography can yield some pretty incredible images, particularly if you are in a dark site and have a good, solid mount - preferably polar aligned and tracking for the longer exposures (you can probably get away with not having a mount polar aligned or without it tracking if your exposures are short); many photographers also recommend that you use a remote shutter release so you don't introduce vibrations into the image by pressing the shutter by hand. Very pleasing, wide-angle shots can be made using this method. In fact, you can probably more easily get shots showing an entire constellation than through a telescope, because the field of view of most 'scopes will be a lot less than what you will see through a normal or wide-angle camera lens.

"If" the sky clears tonight (and it's only getting worse as the evening wears on), I'll try to get another image or two and post them here so you can see what 30 seconds can do from a light polluted area. The two images I'm including here are 30 second exposures of the star Capella on an almost clouded over night at ISO 100, using the Orion Short Tube 80 in "prime focus" configuration. The "darker" image is directly out of the camera, with no modifications other than reducing in size to meet posting requirements here. The "brighter" image is the same one, only with levels grossly adjusted to show more stars (as well as noise and those nasty "hot pixels"). It's easy to spot those pixels in this image!

If you are using a 4.5" reflector, you should be able to pull in much more light than I can with this small 80mm refractor. Hope this helps

Good luck, and keep trying!

Clear skies!

Paul

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Mary,
You all got me interested now to try my Sony Cybershot T10 last night and have a shot at Orion and the Southern Cross. My camera has a "High Sensitivity" setting pushing the ISO up to 1000 and a 1/4 sec. exposure time max. The focus was on infinity. I used a tripod and the self timer. I tried Orion first but the exposure time was too short. Then I tried alpha and beta centauri ( the pointer stars) and the Southern Cross. I got a reasonable image but had to enhance the brightness and contrast quite a bit and that tends to bring out hot pixels.
It seems to me that if I could lengthen my exposure, it would have done the trick but I cannot with my camera.
Try this method with a longer exposure setting ( 2 to 5 seconds) and I am sure your perseverance will pay off. (I am limited to brighter stars alone).
I have images Alpha Centauri through my 9"Dobs with a single shot using my Fujifilm Finepix camera afocally. That came out quite well and I also post that image her.

Good luck.

Phil

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Maryccc,

see my posting of "Stars through camera - Orion".......

dana t