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Hi all and HELP please!!!!

Carpn

By Carpn
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Carpn

Carpn

Posted
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I'm a complete newbie and going through a steep learning curve at the moment.

I've started astrophotography with my DSLR on a tripod (Sony A580 with 70-300mm zoom) set to 150mm , my problem is having taken some shots of the orion nebula (M42 i think it's called) looks all ok on camera. i load the raw files into DSS (lights, darks, flats and bias files) checks stars at 2% result no stars?????????????

ISO set to 3200

Shutter set to 2s

Ap F5.6

200+ frames (lights)

20 darks

20 flats

Bias ISO100 at 1/4000

Camera set to manual, manual focus, stars appear round when zoomed in

Sorry for the numty here i'm self learning any help would be really appreciated.

I've done the same trick several nights with the same result it's driving me nuts, i change lens 28-80mm lens, change the ISO setting same result - ARGGGGGGGGGGGGGGGGGHHHHH.

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Andy_E

Andy_E

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Hi, welcome to SGL. Don't worry, LOADS of people have this problem at some point or another. I suspect this may be due to trailing in the stars... in your images are they pin points or slight streaks? You may need to zoom in to 100% to see this. DSS doesn't recognise trailed stars as 'stars'. Having said that, this will be a fine line between stars/trails with 2 sec exposures @ 150mm.

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Carpn

Carpn

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Hi and thanks 

Andy pictures look  ok no streaks i would attach is i can see how?

Tinker - ok will  try this too, but as im still using a fixed tripod won't i get star trailing, im in the process of making a barn door so hopefully i can then take longer exposures, but first this numty needs to be able to take a least a few half respectable shots.

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Andy_E

Andy_E

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Hmmm, if the stars look ok then that's probably not the issue. At 150mm there should be enough stars in frame for DSS to be latching on to as well. The only thing I can suggest is try fiddling with the parameters a little. Quick tip; try doing this with just a handful of light frames to start so you're not spending ages waiting for it to register all 200+ frames... try something like 5 frames. When it finally starts recognising stars, stack the lot!

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nmoushon

nmoushon

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Try changing the ISO to 800 and the exposure to 10 seconds.....

This would only induce star trails. If anything I would try it at 70-100mm FL and then increase exposure to 5-10 sec. Also try going the other way in DSS with the slider to increase the star detector. Sorry for the bad description can't quite remember as i dont have DSS load on this computer.

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JamesF

JamesF

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Welcome to SGL

I'd agree that it's probably a good plan to start with some longer exposures at shorter focal lengths and then work your way up.  Star trails would have been my favourite reason for DSS failing to find stars, but I wonder if with such short exposures there's insufficient contrast for it to pick them out.  Anyhow, going back to a simpler setup and going from there seems like a good plan.

James

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Carpn

Carpn

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Thanks all for the warm welcome :laugh:  :smiley:

I've attached a JPEG of the raw file (cropped)

anyway clear sky at the mow so going to get cold and try again smaller lens, different iso settings etc etc - in other words going to learn from you lot :Envy:

post-33709-0-14201400-1386794971_thumb.j

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