I know it doesn't look like much but the black is black and the focus is good

[JBW]

With thin to thick stratus floating past there was no chance of a classically beautiful DSLR deep space shot. I settled for some much-needed focus practice and checking out some new camera settings; 3.2s shutter speed, F/3.2 and 3200 ISO.

Very little noise, minimal artifacts and better focus. Now if it will just clear off, so I can get a good star field to shoot.

PS the bigger white blurry thing in the center is Saturn and directly below Saturn is the pulsating star 42Oph

[Stagecoach]

I agree Brian, the focus is good and the black is black.

Is it cheating to bring more stars out, or have I introduced noise into it?

Hopefully this pic is visible

[JBW]

Its visible and how did you do that. It's not quite deep well black but it 's not bad.

[Stagecoach]

Its visible and how did you do that. It's not quite deep well black but it 's not bad.

I put it into ACR, increased exposure by 50% and clarity by 25%. This made Saturn a bit too bright so I did the same thing again using a method where I could mask those overall changes from affecting Saturn.

Then later I answered my own question and checked on Stellarium that those are in fact real stars and found 420ph, Garafsa, I'm learning a lot here

If only the clouds would clear here and the rain stop:mad

Edit : I'm impressed with the sharpness you are achieving and the result you are getting at ISO 3200. What I would be really interested in is to see one of the frames used for this image with no pp having been done

[JBW]

I put it into ACR, increased exposure by 50% and clarity by 25%. This made Saturn a bit too bright so I did the same thing again using a method where I could mask those overall changes from affecting Saturn.

Then later I answered my own question and checked on Stellarium that those are in fact real stars and found 420ph, Garafsa, I'm learning a lot here

If only the clouds would clear here and the rain stop:mad

Edit : I'm impressed with the sharpness you are achieving and the result you are getting at ISO 3200. What I would be really interested in is to see one of the frames used for this image with no pp having been done

I can get you one.

[Stagecoach]

Thank you Brian, that gives me a good example of what I need to aim for.

[JBW]

Thank you Brian, that gives me a good example of what I need to aim for.

I find that at 6400 there are a lot more stars but also a lot more noise. I also put in a custom white balance. This was shot at 4500K. 4800 is the other K I am trying out.

[TonyW]

I don't understand why you need such a high ISO here. It is usually said that exposure time can go up to around 20s before there is noticeable star movement. Am I missing something?

[JBW]

I don't understand why you need such a high ISO here. It is usually said that exposure time can go up to around 20s before there is noticeable star movement. Am I missing something?

I live slightly less than 10* off the equator. There is noticeable star movement at 4s.

[Dave Humphries]

I don't understand why you need such a high ISO here. It is usually said that exposure time can go up to around 20s before there is noticeable star movement. Am I missing something?

Also, if you think about the shots they say that about, they are fairly wide angle (say 35-50 mm FFE), these are (I suspect) a somewhat narrower field of view (longer focal length), so that'll magnify the movement.

I live slightly less than 10* off the equator. There is noticeable star movement at 4s.

I hadn't even considered that having an effect, but I suppose it must.

[JBW]

Also, if you think about the shots they say that about, they are fairly wide angle (say 35-50 mm FFE), these are (I suspect) a somewhat narrower field of view (longer focal length), so that'll magnify the movement.




I hadn't even considered that having an effect, but I suppose it must.

Yup my Tamron 90mm. Being near the equator we do spin quite a bit faster. Our colorful sunsets and sunrises usually last less than half an hour.

[Wavelength]

The scanty distribution of stars and planets seen has its own beauty..a more realistic feeling too

[TonyW]

I live slightly less than 10* off the equator. There is noticeable star movement at 4s.

I suspect that the difference is not the latitude but the declination, i.e. the distance of the star from the polar axis.

This example was a 30 minute exposure (ISO 100) looking south (in the southern hemisphere). It is clear that the stars off the axis move further.



This example is a 20 second exposure, ISO 2500. The tree was lit by a torch very briefly. There was some light pollution, especially in the lower left corner. Both these examples were at 24mm focal length.

[JBW]

The scanty distribution of stars and planets seen has its own beauty..a more realistic feeling too

it is certainly what I was seeing

[JBW]

and I'm shooting with a 90mm which when you apply the rule of 500 gives about a 5s maximum.

[TonyW]

and I'm shooting with a 90mm which when you apply the rule of 500 gives about a 5s maximum.

Yes. I understand about the focal length. And I don't think I could get your black without the stars disappearing.

[Shadowman]

Nice shot and good edit by Grahame.

[James G]

Hi Brian, you are certainly getting sharp focus these days... You are probably aware, but if not, there are masks that you can construct (or buy) which can help with getting pin-point sharpness.

Specifically Hartmann and Bahtinov masks.

http://www.iceinspace.com.au/index.p...63,187,0,0,1,0

http://www.deepskywatch.com/Articles...inov-mask.html

As regards High ISO discussions there are two excellent links below which cover settings etc for Astrophotography by Jerry Lodriguss and a review of issues around Noise/ISO when capturing images. The Lonely Spec article is particularly though provoking and 'explains' why an high ISO eg 3200 is effective.

http://www.astropix.com/html/i_astrop/toc_ap.html

https://www.lonelyspeck.com/how-to-f...nge-and-noise/

On a final point, I do wonder, given the sharpness you have achieved if maybe stacking 10 or so shots of saturn might just have shown a more defined disk.... just a thought.

All we have had here recently are overcast skies and rain and when clear, there has been significant moon! That said I've been getting some Moon shots with good detail this last few nights!

[JBW]

Hi Brian, you are certainly getting sharp focus these days... You are probably aware, but if not, there are masks that you can construct (or buy) which can help with getting pin-point sharpness.

Specifically Hartmann and Bahtinov masks.

http://www.iceinspace.com.au/index.p...63,187,0,0,1,0

http://www.deepskywatch.com/Articles...inov-mask.html

As regards High ISO discussions there are two excellent links below which cover settings etc for Astrophotography by Jerry Lodriguss and a review of issues around Noise/ISO when capturing images. The Lonely Spec article is particularly though provoking and 'explains' why an high ISO eg 3200 is effective.

http://www.astropix.com/html/i_astrop/toc_ap.html

https://www.lonelyspeck.com/how-to-f...nge-and-noise/

On a final point, I do wonder, given the sharpness you have achieved if maybe stacking 10 or so shots of saturn might just have shown a more defined disk.... just a thought.

All we have had here recently are overcast skies and rain and when clear, there has been significant moon! That said I've been getting some Moon shots with good detail this last few nights!

Hi James, later today I'll see if higher number stacks will help with M4.
DSS has a star mask option.
I'll check out those links.