My first serious effort at star photos.

[Mr Felix]

I was way out of the city and saw Orion.

Got the tripod and pointed it.

Did a few quick calculations and took the shot.

1 Min 30 and it looked ok.

When I look on the computer screen, ALL the stars have trails.

Would 1 Min 30 be enough for the rotation to show?



Just asking.

[William]

Where's the image so we can tell ?

In answer to your question 1min 30secs will leave star trails

[jasnat]

As a general rule under 30sec with a wide angle lens will have minimal trails.

[ameerat42]

What focal length did you use? I got trailing on Orion with 15 secs and a 24 mm lens. It is at that part of the sky that seems to moves fastest. No, it wasn't camera shake. I got it on 3 shots I tried with a non-SLR camera.
Am.

[gerry]

The longer the focal length the shorter your shutter needs to be, for example, 300mm + 1.7 converter needs under a second to reduce the movement of the planet.

a recent example:

http://gerry.avernus.com.au/slide/files/2889_dsenm/lunar-eclipse-v3.jpg

[gerry]

actually here's a better example

30secs at 16mm only very slight movement on full res version.

http://gerry.avernus.com.au/slide/files/3008_i4iqm/GJB_8998.jpg


and 4 secs at 85mm

http://gerry.avernus.com.au/slide/files/3007_ymtp3/GJB_8991.jpg

[Mr Felix]

Ok folks, sorry I wasn't infront of my machine when I posted the question.

(Didn't know I had to be)

Home now and have image - see attached.

I tried a few shots before on other things and they didn't work. So I kind of guessed the time and just tried it.

After the shot I was impressed that it wasn't under/over exposed and it looked ok.

[Mr Felix]

On this, I remember where I came unstuck.

I kind of remember the "Trick" about exposoure calculation you up the ISO speed and get a shutter speed.

Then drop the ISO speed and you increase the shutter speed (or rather time) by the same number of steps.

But, this all falls appart when you run out of time for exposure.


To explain:
Say I set ISO 1600 Shutter speed 30 seconds, F7.

If that is 5 steps up from the desired ISO, what are the next steps after 30 seconds?


(Yeah, I'm gonna cop a flogging for asking.)

[William]

I think what happened, was you posted a question in the Main Critique Forum without an image, Asking for help , Still wondering if you wanted Help or critique on your image , I'm sure you got the help that you needed to try this again with different settings , Good luck for next time you try

[Mr Felix]

Yeah, well I would like to check that the "trails" were from the 1 min 30 sec exposure or movement of the camera?

I was playing with the settings because I couldn't get the exposure automatically. I had to use BULB mode.
And, without the cable release, and in the middle of a field with mosquitoes eating me alive as I am holding the camera, I wasn't sure what the picture is/was.

Now I uploaded the image, I would be interested if anyone can tell me if I am on the right track.

But the new post (18:42) explains my conundrum about how to calculate times when the shutter speed doesn't have numbers that "big".

[ameerat42]

Mr Felix. Don't flog yourself too much. 1.5 minutes where Orion stalks, near the celestial equator, is WAY to much exposure time for almost ANY lens that is not tracking the subject. OF COURSE, though I couldn't be sure, it would be a FAIR BET (you wanna bet?) that what you posted is NOT camera shake but star trailing. Think of Occam's Razor. Why invoke the less probable when the simplest explanation is to hand?

Yes, your focal length was 18mm, but as I said in the earlier post, I had appreciable trailing at 15 sec with 24 mm. Do the trigonometry: 360degrees in 24 hours is 15 degrees per minute, Over a focal length of 18 mm, 75sec (EXIF) is about 0.1mm on your sensor.

Given that it is an approx 1.5 crop sensor, that roughly translates to the trailing you have shown.

ONE Question: Is f/6.3 your widest aperture at 18mm? If you can go wider, ie, go to maximum aperture, and use an ISO of about 800-1600. Do a bit of noise reduction on the result, maybe. Keep it up, though. It's a challenge.
Am.

PS: Just read your last point. You do not "calculate" exposure times for stars. Bulb, widest aperture, most exposure time you can squeeze in before trailing is expected. Meantime, (Much later on summer nights) give the Southern Cross and Pointers a whirl. They are nearer the S celestial pole and their RADIAL motion is less than stars nearer to Orion. (Their angular motion is, of course, the same.)

[Mr Felix]

6.5 is not the widest.

I couldn't focus the stars (obviously) and so gave myself a bit of DOF before taking the shot.

It was DARK, and I wasn't really wanting to take it, but I saw the opportunity and so took it.

A few bad shots, then I guessed about 1.5 minutes.

Took the shot and was pretty happy.


I didn't realise I have the lens at 18mm. It is the 18 - 135 (IS) lens. I thought I zoomed in on Orion to frame the constellation first.

Dunno if the ZOOM is sent to the camea. But..... Anyway.


I didn't want to use higher ISO settings as they give noise and I am not wanting to start learing about that just now.

[Mr Felix]

6.5 is not the widest.

I couldn't focus the stars (obviously) and so gave myself a bit of DOF before taking the shot.

It was DARK, and I wasn't really wanting to take it, but I saw the opportunity and so took it.

A few bad shots, then I guessed about 1.5 minutes.

Took the shot and was pretty happy.


I didn't realise I have the lens at 18mm. It is the 18 - 135 (IS) lens. I thought I zoomed in on Orion to frame the constellation first.

Dunno if the ZOOM is sent to the camea. But..... Anyway.


I didn't want to use higher ISO settings as they give noise and I am not wanting to start learing about that just now.

[MarkChap]

Mr Felix, it is simple exposure calculation, if you halve your ISO, then you need to double your shutter time.

Unless you can achieve ISO 50 on your camera, which i doubt, if I remember correctly you have a rebel ?? then you won't have 5 stops of downward adjustment in your ISO any way.
SO ISO 1600 = 30sec -> 800 = 60 sec -> 400 = 120 sec -> 200 = 240 sec -> 100 = 480 sec.
So as you see, you could only achieve 4 stops adjustment

[ameerat42]

...I couldn't focus the stars (obviously) and so gave myself a bit of DOF before taking the shot...I didn't want to use higher ISO settings as they give noise and I am not wanting to start learing about that just now...

The 1st bit is interesting. You couldn't focus the stars? A 550D and live view? Doesn't it also have some sort of live view magnification? Did you set your camera to Manual and set focus to "infinity"?

"Normal" conditions don't really apply for astrophotography, so you have to take more control of your settings.

This is early in your astrophotography, and you got a fair result, not a bad one by any means. I'm only saying what to look out for. Another thing has occurred to me: did you take it from somewhere in Sydney? If so, you are really battling the light pollution and unclear skies. As such, the result is as good as you can expect for a static exposure as you took it.
Am.

[ameerat42]

Mr Felix.
After the foregoing posts, here's the result I got recently for Orion, as described above. Look at EXIF for details. Magnify it and you will see just the beginning of trailing. Now the only PP done on this was to sharpen it in the RAW converter.
Am.

Orion, Dec 2011.

https://public.blu.livefilestore.com/y1ppWOcSQXTVoZz7I5-BUJF1unqr7tOiaQM_y3CSH5hr5B3eNjGaxYP7lmItzz7LBDzr1ntsZyMQdmf3HIMtaeE5Q/SDIM0078.jpg?psid=1

[Mr Felix]

Mr Felix, it is simple exposure calculation, if you halve your ISO, then you need to double your shutter time.

Unless you can achieve ISO 50 on your camera, which i doubt, if I remember correctly you have a rebel ?? then you won't have 5 stops of downward adjustment in your ISO any way.
SO ISO 1600 = 30sec -> 800 = 60 sec -> 400 = 120 sec -> 200 = 240 sec -> 100 = 480 sec.
So as you see, you could only achieve 4 stops adjustment

Hi Mark.

I have the 550D - or that is what I used to take the image.

Yes, I sort of remember what you explained about ISO/shutter speed. But have forgotten the "extra" numbers.

So where I went unstuck is when I pushed the ISO to a high level, and got the shutter speed to 30 seconds, then wound the ISO back to a less noisy level, but then I didn't know the shutter speed time.

But thanks, now reading your reply, it is "double" if I read it correct.

So if I have ISO 400 and 30 seconds, and take it back to ISO 200, it becomes 60 seconds - right?

[Mr Felix]

The 1st bit is interesting. You couldn't focus the stars? A 550D and live view? Doesn't it also have some sort of live view magnification? Did you set your camera to Manual and set focus to "infinity"?

"Normal" conditions don't really apply for astrophotography, so you have to take more control of your settings.

This is early in your astrophotography, and you got a fair result, not a bad one by any means. I'm only saying what to look out for. Another thing has occurred to me: did you take it from somewhere in Sydney? If so, you are really battling the light pollution and unclear skies. As such, the result is as good as you can expect for a static exposure as you took it.
Am.

As much as you may be correct, you have to understand a couple of other factors.
1 - it was a grass field and it was cool and wet. The mosquitos were eating me alive.
2 - Yes, setting the lens to "infinity" would have worked - probably. But in the past when I have tried, "infinity" is too far and I get blurred images.
3 - the lens focus isn't marked. I am still stuck knowing which way to turn it manually to focus close and far. Yeah, I'm an idiot. I've been told, many times.
4 - it wasn't the main objective of the mini-trip. I was taking images of the moon, some buildings and a party which was going on, and some planes.


No, this photo was taken in the Hunter Valley so the light was not a problem and it really was a nice clear-ish night and I looked up and saw Orion and thought I would "give it a go".


And don't mis-read my reply as upset or annoyed. I am not. I'm just mentioning things - which I maybe should have earlier.

I've got a whole heap of images to go through from other things done those three days.

[ricktas]

So if I have ISO 400 and 30 seconds, and take it back to ISO 200, it becomes 60 seconds - right?

Yes, as long as you do not adjust the aperture at all.

[I @ M]

As much as you may be correct, you have to understand a couple of other factors.
1 - it was a grass field and it was cool and wet. The mosquitos were eating me alive.


A couple of tips ----

You have been given correct advice on the photography side of things, absorb it and put it into practice.

Wear gumboots.

Carry a torch.

Take Aeroguard at anytime you might venture into the great outdoors.

Stop dwelling on the irellavent side issues of mozzies, darkness and damp and concentrate on learning about the correct way to use a camera.

[mikec]

Mr Felix try doing a search on the rule of 600 for doing star shots. It works really well and have done it many times myself. It does require knowing where infinity is on your lens but you can work that out easily enough even with the kit lenses.

Basically you;

Set f/stop wide open
ISO to 2000 to 4000
To calc the shutter speed take the focal length then calculate 600 / focal length
Focus to infinity
Ensure you've got mirror lock up on and are either using timer or a shutter release

[Mr Felix]

MikeC,

One thing I did do was activate the live view to stop the mirror shake.

Point 3 is handy to know.

Thanks.

[arthurking83]

Mirror lockup isn't so important with very long exposures(Eg. > 10 sec exposures), and if you don't have a remote of any kind, then locking up the mirror is a redundant setting anyhow.

Some cameras feature a setting called exposure delay, which is a pseudo mirror lockup(MLU) setting, whereby when you press the shutter with one action, the first stage is to raise the mirror, the camera waits about 1 sec and then makes the exposure. For a short focal length this can work very well, as in general an 0.5s delay is sufficient to stop camera shake caused by the mirror.

Does the 550D have liveview feature?
If so, the best way to find the point of focus for an infinity setting such as stars is to use liveview.
The other issue with infinity focus is the weather/temperature of the time.
It shifts as the temperature changes. This is why most lenses will focus past infinity, to compensate for this.
So while focusing to the infinity mark on the lens may work one day, it's not guaranteed to work the next.
With a very very wide angle lens this is less of an issue.
Best aperture setting to use is the most open setting, that gives the sharpest, most contrasty rendering of the scene .. not so much stopped down to get a deeper DOF.
If this 18-135 lens is the main lens you want to stick with, have a look at any test/report on how this lens works at various aperture settings, specifically looking for the aperture setting where it peaks in terms of sharpness(but watching for other aberrations such as CA and suchlike) and stick with this value.
All ISO and shutter speed settings should really be calculated around this value.

[William]

Quote Arthur : Mirror lockup isn't so important with very long exposures(Eg. > 10 sec exposures), and if you don't have a remote of any kind, then locking up the mirror is a redundant setting anyhow. :confused013

Morning Arthur, I'm confused about this , On my old 30D I rarely use a remote on my Sunrises, I regulary take 20 -25 sec shots, I set Mirror Lockup, set Timer and with the lockup activated it gives a 2 sec delay , The mirror is definately up cause you cant see anything through the viefinder at all , Remember I dont have Video or live view and I do only use it on a short focal lenght 11mm to 12mm , Maybe the newer cameras have this pseudo function :umm: - Cheers Bill

[Mr Felix]

Ok, I'll ask first.

:confused013

I took a "nice" picture of the moon through some trees.

Should I put it here, as it is a image of the moon (and/or and wooden tower) and not stars as the topic is?


:confused013

[ricktas]

Ok, I'll ask first.

:confused013

I took a "nice" picture of the moon through some trees.

Should I put it here, as it is a image of the moon (and/or and wooden tower) and not stars as the topic is?


:confused013

If you want to post it to ask questions relevant to this thread, then yes, post it here. If you want to post it just for CC on it, post it into the relevant Member Photos Forum (http://www.ausphotography.net.au/forum/forumdisplay.php?5-CONSTRUCTIVE-CRITIQUE-Members-Photos)

[Mark L]

I didn't want to use higher ISO settings as they give noise and I am not wanting to start learing about that just now.
See am's post, #16. ISO 3200, not to much niose.
I've had to force myself to learn not to be to worried about pushing ISO up if that's what's needed.

[Mr Felix]

Hi again.

Dunno if I am just stupid, or am missing something.

My picture was 18mm and of Orion.
It was 75 seconds.
Ok, low ISO.

Gerry's picture was so much brighter.

His was F1.4 for 4 seconds.
High ISO.

Ok, I read 3200 isn't a "high" speed for night shots.

I guess there was a lot more "exposure" in Gerry's shot than mine?

[ameerat42]

Mr Felix.
(BTW, where's Gerry's pic? In another thread?)
I see you're trying to get your head around this type of photography, and that's good. No self-deprecation is needed: there are some tricky ideas in it.

A couple of points for your next efforts at star photography.
1. "The stars" - but not the moon, sun, and planets - are regarded as "point sources of light" for most earth-based pursuits. That means, no matter what "magnification" you view or photograph them with, like say, a 2000mm telescope, you can never resolve them past a point. (Most un-ideal optics, though, will smear the "point" out somewhat, not to mention what the atmosphere does and adjacent pixels on a sensor.)
BUT, it also means that they respond well to large diameters of glass. That is, the wider the diameter of the objective lens the more light it will collect. This holds for any means of "observing" the stars. You can even see more stars when you use a pair of binoculars than you can with the naked eye. That's because the eye lens is much smaller than those of the binoculars.

2. If you have a lens with fairly large aperture - that is, area of glass, you will get a much brighter image than with a smaller aperture. You may not then have to worry about increasing your ISO to extremes, say, 3200, but you might get by with much less, like even ISO100. But this depends on how bright the stars are that you want to photograph. For example, going from f/2 to f/1 (how nice if...), or from f/4 to f/2, this represents a doubling of lens diameter and a X4 of glass area. That means four times the amount of light will reach the sensor, reducing the need for high ISOs.

3. When your lens is of short focal length, say f=18mm, they are often also of "fairly high" maximum aperture, like about f/3.5 or f/4. This means that when you divide the focal length by that ratio, f/3.5 or f/4, you end up with a very small aperture to let the starlight in. For the examples, the apertures will be about 5 or 4.5 mm. It is in these cases when you have to bump up your ISO, and so introduce noise, and so have to remove it in PP, and so lose potential information. It becomes a bit of a compromise.

4. Star trailling is a problem when you D :(N'T want a picture of star trails. Stars appear to wheel across the sky more quickly near the celestial equator (Orion-ish) than near the celestial poles (S. Cross-ish, Polaris in N Hemisphere). 15 sec of exposure just showed incipient trailling in my f=24mm shot of Orion above, and no detectable trailling in my S Cross shot (some other thread) using the same exposure time and f=16mm. Of course, the two factors are involved in this comparison, but it's all I've got.

5. Serious non-trailling star shots require the use of a tracking (equatorial) mount, and all that's required to do that sort of stuff.

And lastly,
6. I feel like Arthur King after this.

Am (?)

[Mark L]

^Thanks Am, feeling like Arthur, I found that a useful post (yes I learned some things).


Mr Felix.
(BTW, where's Gerry's pic? In another thread?)

Posts #5 and 6.

[ameerat42]

Ta, Mark L. I was whizzing down MOST PROBABLY before the screen fully appeared and didn't see them . Now I can. (Talk of being observant:rolleyes:!)

Then to answer Mr Felix, yes, they got more exposure because of the higher ISO used.

[Mr Felix]

Mark L beat me.

Yes, thanks Ameerat.

I shall hae to wait until another clear night and when I am out in the country to try again.

[jjjnettie]

It's a pretty steep learning curve, this night sky photography.
Best tips I can give for tripod based work is....
1. if you don't have a remote timer, use your built in timer, set it for 3 seconds to give the camera time to settle after pressing the button.
2. for short exp. 30 secs or less, make use of your ICNR
3. ISO 800-1600 is best. Though ISO 3200 will give ok shots.
4. If the region of sky you are shooting in, has no bright stars to focus on, swing around to a bright star and focus, then gently bring the camera back to the region you are going to work on.
5. To frame your shot, set the camera up to ISO 6400 or higher and take a couple of test shots. Then don't forget to change back to the lower ISO. LOLOL
6. Always knock your F stop up a couple of notches, your stars will be sharper and it should tame any coma inherent with the lens.
7. It's OK to have slight trails. You're shooting fixed objects from a moving planet, it's inevitable :) . Pin point stars are only to be expected if you're using a EQ mount with guiding.
8. If you want to end up with a bright picture with plenty of detail, you will need to stack your images. Take as many photos as possible, fill your card even. Reframing as you go, so the object you are shooting stays in frame. Then put all those photos through a program called Deep Sky Stacker.
9. If you have any questions at all re. astro imaging, just PM me. :)

[Mr Felix]

Thanks for that.


Shall try those ideas as soon as we get some clear weather.

Sydney has been terrible for night shots recently.

[Mr Felix]

Recently I tried some more night shots pointing as far south as I could.

I didn't know exactly where the south celestial pole is/was, but I tried.

Alas I still got a lot of problems focusing on those little blighters!

Even putting it on live view so the screen at the back of the camera was the display and setting MANUAL FOCUS, the lens's focusing system is touchy to say the least.
Only a SLIGHT touch and the star goes in/out of focus like that!

Is there a way to "cheat" with this?

My only thought was to build a "venere" thingy which gives me a thing to turn and it is geared down to turn the focus ring so SLIGHT adjustments are possible.

How you people with "normal" lenses manage such fine focusing on stars?

(Maybe I've just got a dicky lens with a fickle focus ring?)

[ameerat42]

Well, Mr Felix, for star shots can I hazard a guess that you are using a fairly wide lens? Perhaps 30-50mm range. Does it have a short focus "throw"? That is, hardly any turn between closest and infinity?
Yes, they can be touchy. But you can try to focus on a largish, brightish distant object, like the moon (hopefully setting and not very full), or a street lamp. If your lens goes "past" infinity, swing it back and forth so that you end up with the sharpest image. You can only go from there. And I seem to remember that you have a late-ish Canon camera. Does it allow a magnified Live View? Use that to you advantage, like on the bright distant objects.

All of this is in Manual focus mode, of course.

Otherwise - and I have only heard about this - you set your lens to AF, focus into the night sky (and hope it has focused at infinity), then switch back to Manual focus.
Good luck.
Am.

[Mr Felix]

Well, honestly: No I am using the 18-135 which came with it.
Or maybe the 90 - 300 Canon lens.

Stabaliser off, manal focus.
(the 90 - 300 doesn't have stabaliser anyway)

I try to zoom in on the actual star I want to see.

Like Mars was in clear view but when I too the shot it was a red line.
I accept that was the rotation.

So I went to the southern cross and tried to get the diamond part (the main 5 starts) in the shot.

As "good" as it was, I feel it was our of focus.
I shall upload a image when I can.

I tried a few more times, which is when I realised HOW sensative the focus ring is.

I sat there for a while with the torch, tripod and other things but had little sucess.

I shall try the wide angle idea but the 18-135 at 18mm is the widest I have.
Well, acually it isn't. I bought one of those wide angle converter things. But: Didn't have it with me.
D'oh!

Ah, well. More things learnt.


So, let's say Jupiter is up. Or Saturn. Ok, a 135 isn't going to really going to let me see the rings, but it is a "big" object.

I want to have it in the picture as the "main" thing. Sure the long exposure will bring in other fainter stars which make it more than a "white spot on a square of blackness", but the MAIN thing woudl be Saturn/Jupiter.

Focusing on them would be painful the way I have things now.

I'm guessing I need a bigger lens?

[ricktas]

most lenses go past infinity. So in manual focus turn focus ring right out to infinity, and then bring in back, just a touch, a wee bit, not much at all. Generally that will give you a good focus.

[ameerat42]

For planetary detail - like, disc and bands on Jupiter, rings of Saturn - you would really need a quite good, stably mounted, preferably tracking telescope. For "telescope", substitute lens at least f=1000mm.
Then you would have to attach you camera to it in one of several methods, usually prime focus, afocal projection, eyepiece projection.
After all that you will start to get a big(gish, relatively speaking) image of the said big object.

Anything less than that, like f=135mm, will only give you varyingly bright/coloured dots. This is OK, because many astro shots are wide-field and are taken to show various dispositions of the stars/planets in the sky at the time.

Focusing will not necessarily get any easier no matter what optical system you are using. Again, if your camera has magnified Live View, then this is what you should try to use. But, do not zoom in to focus and then zoom back out to a wide view, as this may change the actual focus.

From experience, about 15 seconds exposure at f=18mm focal length is about as long as you can go without getting any (just noticeable) trailing. (And this gets less as you move nearer the celestial equator.) So you will have to open up your aperture to maximum (what, f/4?) and maybe give it an ISO of about 400 but not any more than that. Once you nail that focusing you'll be 1/2 way there. Bonus: make that 3/4.

In summary: Focusing, there's no easy way. Once you get it right for that lens (at that focal length), make a note of it.
Am.

[Mr Felix]

Well, here is the effort:

I am not sure if the focus is as good as it can be and there is some rotational distortion visible.


87909

[ricktas]

that blur is caused by either camera movement of rotation of the Earth.

Looking at the EXIF, it says it was a 30 second exposure, so the blur is being caused by the Earth's rotation. You need a shorter exposure time.

[Mr Felix]

Granted and it suffers the same problem as my initial effort.

Because it is such a "narrow" focus there is less light and I need the longer exposure.
Back on page 1 someone showed me their effort of Orion and the meta-data showed a short lens, but the image was pretty well only the main body of Orion and it was quite bright.

Ok, I shall have to wait until I am getting to the outback where it is darker and try the settings shown from that picture.

It just seems a bit confusing to what I am reading and what I am getting.

No worries. More trial and error.

Thanks.

[ricktas]

Increase your ISO, to get a faster shutter speed, open up the aperture, and then do some noise reduction in post processing.

[ameerat42]

Nothing particularly "wrong" with this shot. It's the Southern Cross slightly trailled. If you didn't want the trailling, then OK.
Your EXIF data shows you used f/6.3 at f=200mm for a 30sec exposure time at ISO200. If that is your widest f-stop OK, but as in my previous post, try upping the aperture - see if you can get an extra f-stop - and (in this case) even up the ISO to 800. But then to stop trailling, expose for only 10 sec.

Alternatively, for a nice trail, stop down to about f/8, drop the ISO to 50 if you can, and shoot for about 2 min (if your camera lets you). Shoot a series like this and use a star stacker to make a nice, long trail.

(After all that, go inside and have a cuppa.)
Am.
Am.

[ameerat42]

...Because it is such a "narrow" focus there is less light and I need the longer exposure...
...Back on page 1 someone showed me their effort of Orion and the meta-data showed a short lens, but the image was pretty well only the main body of Orion and it was quite bright...

...No worries. More trial and error...


Mr Felix. Somehow I missed this post of yours before I wrote my last one.
I would like to point out how lucky you are that you are QUITE WRONG in your first line quoted above.
It is NOT because of your narrower angle (of view) that you need more exposure. Know this: When photographing stars - which are considered "point sources of light" - ONLY the aperture of the objective lens matters.
That translates to "the wider your objective lens (including the aperture you have set it to), the brighter the image of the star". I am saying "aperture" and not "f-stop".

To try to explain: this is because ALL of the light received by the objective (lens or mirror) is concentrated into the "resultant point" on the sensor. It is not the same for when you are photographing the likes of the moon. In that case "f-stop" matters in what exposure is required.

It might be a bit of a concept, but try looking up "photographing point sources of light". It's an important idea if you are to succeed at it.

Other factors still apply, like how dirty the atmosphere is, and how much skylight is reflected.

Also, back on Page 1 that was me, and the exposure was bright because I was using the widest (meagre) aperture I could, and I think I had the ISO up a bit, too.

Correct about trial and error, but also helpful is Q and A.
Am.

[Mr Felix]

Ameerat42.

Thanks.

Actually I looked and thought it was anothe name which posted the shot of Orion.

Jerry.

Anyway, doesn't matter.

I shall read what you posted and try to put it to use. Alas living in Sydney makes dark nights difficult.
That latest show was taken in Wanaka on a cold night.

[arthurking83]

OK, from what I understand of what it is that you want to achieve, the only real solution for you is either a very very expensive camera kit upgrade or a tracking tripod.

With a modern camera body that has reasonable detail level at ISO25600 you can shorten the shutter speed to a reasonable time, and you would also want a much higher quality lens to match it too.
Something that shoots with superb quality at the fastest aperture setting(in Canon world I believe this may be something like a 135/2).

I think you can find a tracking mount for about $500 - $1K which then allows you to shoot 10 mins exposures or more as the camera is automagically rotated to track the stars.

I think in this case you have a few elements working against you: too slow exposure time, and a lens with a too small aperture.

[jjjnettie]

I've already given the best tips I can earlier on in this thread. If you follow them you will be able to get a good night sky portrait.
PLease go back and read them.
For fixed tripod shots, your 18-55mm kit lens @ 18mm is going to give a good wide FOV and will give minimal trailing at say 30-40 seconds.
Use ISO 1600 or 3200.
Yes, focus can be a right pain, but you have the luxury of live view, it's a breeze compared to using early camera models. There are plenty of bright stars out there to focus on. Don't zoom in and focus, then go wide again. The focus point changes.

A tiny wad of blue tac overlapping the focus ring and the lens body may help if the ring is sloppy.

Buying a better camera and lens will NOT make you a better astrophotographer.
If I bought a 7D, does that mean I automatically become an outstanding Wedding Photographer? I don't think so.
Learning the skills necessary to create the photos will.
I use an elderly 20D and a 550D for my imaging. For wide field work, I use the Canon kit 18-55mm lens and the el cheapo Canon Nifty 50mm f1.8. ( I love my nifty 50 )

The learning curve for astro imaging is long, hard and frustrating. There is no easy way around it.
It's entirely different to terrestrial imaging.

As for a tracking EQ mount, I wouldn't recommend one at this stage. It's not just a case of plonking it on the ground and turning it on.
It needs accurate polar alignment, (do you know what the constellation Octans looks like and it's relative position to the SCP? ), and if you intend to go beyond a couple of minutes exposure time, you will need to learn drift alignment and guiding. Which means additional purchases of guide cameras, guide scopes and relevant software.

[jjjnettie]

The sky cleared for 20 minutes tonight so I grabbed the camera and tripod and headed outside.
I used my new Tamron 18-200 lens to take these. So it's by no means a high end lens.
Checking through the view finder, I focussed roughly on the Pointers, then I activated Live View and refined focus. Then I swung over to the Sagittarius region (our Galactic centre) and took a couple of test shots to frame up.
The images I posted are all 30 second exposures, taken with the lens @ 18mm and @ f3.5.
They are taken at ISO800, ISO1600 and ISO3200. Just to show you the difference it can make.

[jjjnettie]

I'm sorry for hi jacking your thread, but I'd love to see you out there imaging the stars too. :)

[Mr Felix]

No, that's quite all right.

It gives me food for thought.

Me, alone, taking pictures, I have nothing to compare them to.

Seeming more and more examples helps establish for what I am aiming.



Now, you are in QLD. I am in NSW.

Would the different latitudes have much bearing on star trails and long exposure?

[ameerat42]

Good shots jjj for such poor conditions.

Mr Felix, to answer your (two) Qs about latitude:
1) No for terrestrial latitude
2) Yes for celestial latitude.

The No answer is the one you were looking for, the Yes answer is the one you should be considering in stellar photog.
Am.

[jjjnettie]

:D There is no substitute for just getting out there and practising.
Use the widest lens you have.
These were taken at 18mm. The bigger the lens the more trailing you will get, therefore your exposures will be shorter and your images will be dimmer and less detail will be captured.
If you're really keen, you can download some star maps and see what interesting Nebulae and Clusters you've have in your picture. :)