PF Photography: Tips, Tricks, & Photo Sharing

[lisab]

Shanghai from the highest observation deck in the world:

Maui, that shot made me dizzy!

 

[Maui]

Maui, that shot made me dizzy!

Hold on, there's higher!

120x, hand shot

The moons of Jupiter(hand shot, no tripod):

 

[Kinase]

here's a photo from the jersey shore after sandy tore it up.

 

[Maui]

 

[Andy Resnick]

Finally- the first clear night in (what seems like) months. First image: 15/4, 8s @ ISO 800, background subtraction post-processing. Second image: 1:1 crop of 800/5.6, composite of 1/100s ISO100 and 1/4s ISO400.

http://imageshack.us/a/img191/6586/resultofdsc02785filtere.jpg

http://imageshack.us/a/img826/7623/dsc027793.jpg

 

[fluidistic]

Nice photos Andy! I'm curious, can you take such photos from a big city? I ask this because I'd think it's hard to see that many stars in the sky in a big city due to "light pollution".
Also for the second photo, you made a composite of "1/100s ISO100 and 1/4s ISO400". I am curious... shouldn't 1/100s ISO 100 be almost a fully dark photo?!

 

[Andy Resnick]

Nice photos Andy! I'm curious, can you take such photos from a big city? I ask this because I'd think it's hard to see that many stars in the sky in a big city due to "light pollution".
Also for the second photo, you made a composite of "1/100s ISO100 and 1/4s ISO400". I am curious... shouldn't 1/100s ISO 100 be almost a fully dark photo?!

Thanks!

To the first question (light pollution): it's all about increasing the signal to noise ratio. What I did here was simply subtract the background- the slowly-varying intensity. Any location with a rapidly-varying intensity (starts, tree branches, etc) is left alone. It's easy to do- duplicate the image, blur one of them (I used a Gaussian blur radius of 100 pixels), and then subtract the blurred image from the original. Another method is 'image stacking', where multiple images are added together. There are lots of subtle details that go into optimizing a particular strategy, and there are folks here with a lot of experience who can help you.

As a point of reference, I have been able to consistently pull out magnitude +15 objects from the background. I think I can do even better once the weather warms up and I can spend more time outside.

To the second question, the answer is that I am using a lens with a large aperture; the lens is a 400/2.8 (with an optional 2x extension tube) which means for astrophotography it's a 6" refractor. This let's me use short shutter speeds, but more practically it let's me aim the camera by eye; I can 'star hop' to a particular faint object fairly quickly.

 

[Drakkith]

To the first question (light pollution): it's all about increasing the signal to noise ratio. What I did here was simply subtract the background- the slowly-varying intensity. Any location with a rapidly-varying intensity (starts, tree branches, etc) is left alone. It's easy to do- duplicate the image, blur one of them (I used a Gaussian blur radius of 100 pixels), and then subtract the blurred image from the original. Another method is 'image stacking', where multiple images are added together. There are lots of subtle details that go into optimizing a particular strategy, and there are folks here with a lot of experience who can help you.

I'm assuming that the background subtraction doesn't actually increase the SN ratio, it just removes the background light from the sky without affecting the abrupt changes where something blocks out the background light, such as the tree limbs you mentioned, along with the sudden increase in signal from stars? That way you can still see the tree limbs and such, thanks to the "glow" around them, and at the same time you can see the stars as well.

 

[fluidistic]

Thanks Andy for the explanation.

 

[Andy Resnick]

I'm assuming that the background subtraction doesn't actually increase the SN ratio, it just removes the background light from the sky without affecting the abrupt changes where something blocks out the background light, such as the tree limbs you mentioned, along with the sudden increase in signal from stars? That way you can still see the tree limbs and such, thanks to the "glow" around them, and at the same time you can see the stars as well.

That's a good point. My intention was to describe ways to stretch the contrast between star and sky.

 

[Drakkith]

That's a good point. My intention was to describe ways to stretch the contrast between star and sky.

Got it.

 

[Borek]

Spring is in my backyard. Definitely.

 

[fluidistic]

Have you seen this video borek?

By the way, nice photo. Do you know whether it's a toad or a frog? Probably the former...

 

[Borek]

Have you seen this video borek?

Sigh. I thought I already know what it is about and then... Now I have coffee everywhere.

By the way, nice photo. Do you know whether it's a toad or a frog? Probably the former...

Check the file name.

 

[fluidistic]

Sigh. I thought I already know what it is about and then... Now I have coffee everywhere.

lol.

Check the file name.

Ah, I didn't know that was possible. Nice... According to wiki:

When alarmed, it emits a very loud call (alarm call) and it can exude a noxious secretion which smells like garlic, hence the common name "garlic toad".

. So your specimen was around 6 to 8 cm?!

 

[Borek]

So your specimen was around 6 to 8 cm?!

Perhaps even larger.

 

[fluidistic]

Perhaps even larger.

Nice :)

 

[Andre]

Wow, that must be Touchwood from Catweazle

http://www.nostalgie.webpark.cz/wp-content/gallery/caryfuk/cf9.jpg

http://www.nostalgie.webpark.cz/caryfuk-1970-catweazle

 

[Andy Resnick]

This is a chip from the paleolithic era: a circa-1968 RCA CD4012 (dual 4-input NAND gate) device.

http://imageshack.us/a/img835/803/dsc05788i.jpg

I've found a stash of TTL devices (and a lot more) dating from 1962 (!), I will be posting images of these on my lab blog as they become available.

 

[Andy Resnick]

M57, the Ring Nebula, is currently in the small patch of sky visible from my backyard:


A 1:1 crop


technical: stack of 800/5.6, 20s, ISO 2000 frames

 

[astroboy12]

just a picture i took randomly during a car ride. no preperation at all just with a camera on my phone :) though it looked rather nice.

 

[Andy Resnick]

A photo montage of a recent ISS flyover. Tech: 800/5.6, 1/1600s ISO800. Maximum elevation angle was 60 degrees, and there is no motion blur.



It looks much cooler as an animated GIF, tho...

 

[Drakkith]

That's awesome Andy!

 

[Andy Resnick]

That's awesome Andy!

Thanks!

 

[Andy Resnick]

The constellation Cygnus is in a favorable position now, and I took some interesting images of the galactic plane using my normal and wide-angle lenses- here are 100% crops.

http://imageshack.us/a/img841/6418/y4ll.jpg

http://imageshack.us/a/img9/7271/sv2w.jpg

Here's a crop using the telephoto for comparision:

http://imageshack.us/a/img46/5808/3dmm.jpg

Shameless self-promotion: full images and analysis on our lab blog.

 

[lisab]

Beautiful, Andy - I especially like the second one, it's so sparkly.

Afraid I don't have enough imagination to see the goose though .

 

[Drakkith]

Nice, Andy.

 

[ABD EL HAMEED]

Just some photos I took...

 

[drizzle]

Beautiful ABD EL HAMEED. I don't know, but I would like to do captions for these photos;

3rd photo: One afternoon in the Middle East.
2nd photo: The sun is back.
1st: Shine on you crazy diamond.

 

[ABD EL HAMEED]

Beautiful ABD EL HAMEED. I don't know, but I would like to do captions for these photos;

3rd photo: One afternoon in the Middle East.
2nd photo: The sun is back.
1st: Shine on you crazy diamond.

Thanks,but it was the sunset in the 2nd picture so I think it should be called "fare away sun" or something like that :p

 

[Enigman]

Pardon my intrusion.

The Lofty Diamond

The Last Flash

An afternoon in the Middle East

Or perhaps the third could be called 'The Eye Of Egypt'

 

[Andy Resnick]

Beautiful, Andy - I especially like the second one, it's so sparkly.

Afraid I don't have enough imagination to see the goose though .

Nice, Andy.

Thanks, guys. You can't see the constellation because it greatly overfills the frame using either the 85mm or 400mm; the brightest star in the 15mm is Deneb. The 400mm shows NGC 6910 while the 85mm is near HD 193702.

 

[ABD EL HAMEED]

Pardon my intrusion.Or perhaps the third could be called 'The Eye Of Egypt'

Ya you're right it would be awesome
Here's another one I took in a road trip I just came back from

 

[drizzle]

*inhales the air of that place*

 

[ABD EL HAMEED]

*inhales the air of that place*

Ya nothing's better than clean,fresh and cool sunset air
If only I had a better camera than my galaxy s2's...
I feel like there's lots of noise in the picture when I zoom in

 

[Borek]

Looking for a sunset?

 

[drizzle]

It's humid and smells fishy out there, Borek.

Nonetheless, it's eye pleasant. :)

 

[ABD EL HAMEED]

Looking for a sunset?

It looks beautiful

It's humid and smells fishy out there, Borek.

Nonetheless, it's eye pleasant. :)

Where was it taken?

 

[drizzle]

Where was it taken?

I don't know, close by the sea?

 

[ABD EL HAMEED]

I don't know, close by the sea?

Kinda figured that part out

 

[Borek]

Check the file name.

 

[Borg]

Another view of the ocean. Life was tough for me last week.

 

[davenn]

Dang, I would far sooner be there than here at the " salt mine"

turn off the phone and the computer ... pass me a Pina Colada and let me relax Dave

 

[lendav_rott]

Return to the Blue Lagoon xD

 

[ABD EL HAMEED]

Another view of the ocean. Life was tough for me last week.

Lol I'm sure it was...:p

 

[Andy Resnick]

Another view of the ocean. Life was tough for me last week.

Nice! jealous = me.

 

[Andy Resnick]

Beautiful, Andy - I especially like the second one, it's so sparkly.

Afraid I don't have enough imagination to see the goose though .

<honk, honk>
http://imageshack.us/a/img18/3011/ycrf.jpg

 

[Borg]

<honk, honk>
http://imageshack.us/a/img18/3011/ycrf.jpg

Taking pictures like this makes me jealous. Another fine shot Andy.

 

[Andy Resnick]

Thanks!

 

[Borek]

On Saturday I went biking - and saw these people:

Nothing extraordinary, but berkeman was on the EMT shift during SWAT competition, or he was training as a part of this competition, or he was doing both at the same time - so it was hard to not think about him