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Astro - Imaging .... Beginner


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Hello all , I ventured out tonight to image the circumpolar stars , its been very clear with the full moon , my Fuji S5700 was set at night mode with continous imaging set , the focus was on (I think Im unraveling my own question) and I imaged 247 times 8 images per minute the EXIF data per image is .....

ISO Speed ratings 200

Exposure Time 3.00

Shutter Speed 2.80

F-stop f/3.50

Aperture value f/3.50

Focal length 6.30 mm

Flash supressed

Now could be my beginner mistake but I thought this would be enough images to image the travel of circumpolar stars?

A: Did the full moon stop the imaging?

B: Did the settings?

C: Should I stayed out longer and just got alot colder??

Any info helpful

P.S I was imaging the circumpolar stars for astronomy GCSE coursework!

OH sorry I forgot to add I image stacked them on Photoshop elements 7 and it did not look diffeent the stars obviously looked bright with tiny trails - once IO can save the image I will post it up to show you all!

I can assure you thats Polaris in the middle ..... ish

Edited by johnk81
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Not exactly sure what it is precisely you are asking, but it seems that you are/were trying to get the classic image of a complete circle of the stars in their rotation around the earths axis?

If so that takes 24 hours.

And the daylight bit is going to be difficult.

Post says "imaged 247 times 8 images per minute".

8 images per minute is an exposure of 7.5 sec, data says exposure time of 3.0 and shutter speed of 2.8.

3.0 sec will not give much of a trail, 7.5sec won't either. I presume that the camera will not simply remain open indefinately as that is the usual way of getting the rotation.

You would seem to have 30.875 minutes of "rotation", this is just 7.5 degrees which is quite small.

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That answer alot yes Capricorn I have space for 750 individual images and on continuos shot its on the Fuji s5700 so it was focusing first , I only need a small trail to show the movement of the stars but I feel my settings are wrong and my time imaging was also wrong , I am asking what is the best settings as I have manual and can turn off the focus and would image stacking 700 images produce the trail Im looking for?

I dont need a full 24 hour trail but would 2 - 3 hours do it? or 700 images individually taken?

Thats what I need to know as I will need to take a bigger jacket next time.

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I've done a few startrails shots using about 50 minutes of data, in 30 second exposures and the trails are nice and clear, although they weren't circumpolar. You want the lens at it's shortest focal length, I suspect that 6.5mm probably is. You want to focus first, then turn the focus off. Shoot as many images as you can with as long a shutter speed as you can. if 3 seconds, you're going to need a very very large number of them. I'd expect that 700 images combined in starstartrails ought to show some trailling.

I can't work out whether you took 30 minutes of data or 12 minutes of data.

The trails in this thread, were over 45 minutes (but shot with my SLR with 30 second exposures at 18mm), and not pointing at Polaris you get more trailing showing...

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Really you'd you'd do better to borrow a DSLR from a friendly friend! Or have you got an old film camera that can do bulb shooting (continuous exposure?) Slide film is best but any will do. I guess such cameras are being given away these days, especially of the light meter doesn't work. I got a Canon AE 1 for nothing that way and it is ideal.

It would also be a thousand times better to wait for a dark night since the moon will kill the contrast.

Olly

PS Just to be pedantic the sidereal day is not, of course, 24 hours... (We have to watch our Ps and Qs if we have a GCSE student watching us on the forum!!)

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Hi John

I have the S5600

I have not tried taking star trail images with it but I have used it for taking some pics of the night sky.

My 5600 has a maximum of 15secs in manual mode. I would combine it with an ISO of 400 - you can use 800 if you don't have awful light pollution.

I hope this helps.

Cheers

Ian

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OK I have an oppurtunity to get a Minolta SLR film camera - £35 as it happens , so I may venture down this route , I have found my S5700 has a Manual Focus so that would solve the infinity focus conundrum. I can get an exposure time which is longer but Im not 100% sure and can get a shutter speed of 4 secs , now Im thinking leave the focus manual get the aperture and ISO right and 700 images later I should get a good trail shot ......... hopefully

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I would give further thought to purchasing an SLR film camera unless you want to go into black and white/colour photography and develop your own photos, a little extra money and a s/h DSLR could be had, which would be useful for Astronomy, depending on the model, or for all other present day photography.

John

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One odd thought came to mind, the stacking you did would that possibly mean that the software will try and lay each trail one on another not one next to another? Possibly not, but it just crossed my mind. The intention of stacking is to minimise things like trails and putting one on top of another would do this.

Assuming that you can lay each trail next to the previous image then it seems that you need more images and/or images of longer duration.;):mad:

You need a/the manual set up option where by you define the aperture and the exposure time. Going to have to read the instruction manual to see if this is possible on the camera you have. Would have thought that they supply such a feature.:):confused:

Strange that most people wanting to photograph the sky want to get rid of star trails, you don't, but cannot get any decent ones.;):D:D:D:D

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