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Lovejoy with Pleiades - 18 Jan

sharkmelley

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greglloyd

greglloyd

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Lovely picture. I like the way you catch the merope nebula in it as well.

Another interesting thing about this shot is that if you asked a non-astro person "which way is the comet 'flying'?" They would say "to the right". Even though it's actually going up!

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Psychobilly

Psychobilly

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Awesome! Just out of interest, does the f stop matter? I always thought that for astrophotography it's best to have it as wide open as possible?

I depends on the lens used - stopping down will usually result in better star shapes in the corners and also reduce vignetting focusing is also less critical. Stoiping down using the lenses internal iris results in diffraction patters on the brighter stars - the pattern will depend on the number and shape of the blades.. alternatively you can use a front aperture mask which gives round stars without artefacts - Filter step down rings can be used as front aperture masks or you can cut them using a cutting compass - just remember to cut the outer circle first....

I always focus on a star at one of the four thirds point  intersections as this tends to give optimal focusing across the full frame and will sometimes allow you to use the lens "wider open"...

Peter...

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redneon

redneon

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I depends on the lens used - stopping down will usually result in better star shapes in the corners and also reduce vignetting focusing is also less critical. Stoiping down using the lenses internal iris results in diffraction patters on the brighter stars - the pattern will depend on the number and shape of the blades.. alternatively you can use a front aperture mask which gives round stars without artefacts - Filter step down rings can be used as front aperture masks or you can cut them using a cutting compass - just remember to cut the outer circle first....

I always focus on a star at one of the four thirds point  intersections as this tends to give optimal focusing across the full frame and will sometimes allow you to use the lens "wider open"...

Peter...

But I imagine it's a trade off, because then you'd also need expose for longer, wouldn't you? Also, do you want diffraction patterns? Is that just a personal preference thing? Also also, what's a four thirds point intersection? Also also also, sorry OP for hijacking your thread :)

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Psychobilly

Psychobilly

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Imagine 2 horizontal and 2 vertical lines each line 1/3rd of the way in from the edge of the frame .. where these "imaginary"  lines cross is the 1/3rd's intersection point. By focusing  on a star at one of these points rather than the centre of the FOV you will get the best "compromise" focus across the whole frame...

Apologise to the OP for answering the question in the thread...

Peter...

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