Topic: General Discussion / Startrails help

Hi,
Iv’e recently taken an interest in startrails. I’ve finally located polaris to get the circular effect.

I was messing about with the camera settings and a fairly gusty wind was blowing hence the less than perfect alignment.

The first problem i have is that polaris is very high in the sky at the moment and I can’t encorporate any foreground which is a shame. Doe’s anyone know when polaris is at it’s lowest point? I’m in the UK.

My second problem!

Admitting defeat I instead decided to get star trails without polaris but with foreground. I didn’t have much time to play with at this point so this shot is made up of 58 30 second exposures giving a total 29 mins.
There was no moon last night so no light source.
I started the shots at f3.5 and then incresed to f5.0 all taken at ISO 400. I then used flash for the last 6 exposures to light up the foreground.
My biggest problem here is noise. The photograph is way to pixelated and grainy and I’m really not sure how to overcome this. The cameras built in noise reduction facility wont let me continue while it’s working so I miss 30 seconds between each exposure which results in dots rather than lines.
I’m using canon 400D 18-55 lens @18mm and startrails.de software for stacking with 2 darkframes.

Topic: General Discussion / Is this ok in the group?

Sorry, not obviously. And I think it’s fair to say that it isn’t the main element of the image.

Topic: General Discussion / Is this ok in the group?

What, you can’t see the southern cross at the top of the tower a little to the right?

Topic: General Discussion / Is this ok in the group?

I’m not seeing any astronomy in the photo so, probably not.

Topic: General Discussion / Is this ok in the group?

Hi All

i was wondering if this image should be in the group or not?

Puggs

Topic: General Discussion / Where are we from and what are we into with Astronomy?

Hello everyone
I am an amateur Astronomer from the Central Coast, NSW, Australia. I have been interested in Astronomy for over 30 years. I am into observing rather than Photography with regard to my Astronomy. I have 3 telescopes to observe with, an 18" f4.5 Obsession called Pluto, a 20" f5 dobsonian called Hector, and a 25" f5 Obsession called Ptah.
I perfer Deep sky observing to Luna or Planetary. The best things I have seen include the Solar Eclipse in South Australia, The impact and resultant plume of Shoemaker levy into jupiter, the Leonids from Nyngan with about 1 meteor every few seconds and attending the Texas Star Party in Fort Davis Texas.

Topic: General Discussion / Uploading Images

I reckon you should do it how you like it mate.

I’ve seen a few instances on Redbubble where very similar artworks from different artists are upped at the same time.

With out a date, no one knows who was first and it gets a bit suspect.

Topic: General Discussion / Uploading Images

I am in the habit of including a title, date, and my name in the corner of my images, but I’ve noticed no similar identifications on the images shared here. Should my uploaded images not include any personal identification directly on the images?

Topic: General Discussion / Digital technology and Night Photography

you need a much longer exposure than 30 seconds to capture star trails. the aperture of your lens also has something to do with it. shoot with the widest aperture as possible for as long as possible. film also has something called reciprocity failure, meaning the film won’t adequately expose a scene the longer the exposure, even though the “math” says it should. also, your stars may be lost in the film grain. fuji pro400 isn’t that grainy unless you’ve got crap scans or developing, so I don’t know what to tell you there.

Topic: General Discussion / Digital technology and Night Photography

I’m using a SLR with 400 asa fuji pro neg film.

Now I set the camera up on a tripod and timed 5 shots of the stars on a very clear night from 10 to 30 seconds.

When I had the film developed nothing came out. What did I do wrong. Any ideas?

Topic: General Discussion / submission from a new member!

What’s your ’scope Samuel?

Topic: General Discussion / submission from a new member!

Hello, I am excited about this group! I have been interested in Astronomy for quite some time and recently upgraded to a newer and more powerful telescope! I have included a photogrph here that I would like to submit to the group!

Title – Blood Moon

Topic: General Discussion / Digital technology and Night Photography

Have a look at this image by Geoff Coleman. Geoff may be able to give you additional advice.

Interesting contribution from David – that’s certainly how pro astronomers tackle this problem (although they also chill their chips).

Canons use a CMOS chip, rather than CCD, which (I believe) produces lower noise levels.

I’ve yet to try digital night shots, lacking a capable digicam. For me it’s film, for the time being :)

Topic: General Discussion / Digital technology and Night Photography

On this type of subject, which method would people recommend for astrophotography using a dSLR – a super-long exposure, or multiple short exposures of, for example, 30 seconds each? Also, how does each affect battery power? I don’t yet even own a dSLR (saving for a Canon 400d), but I plan to by the time I travel to rural Scotland in the summer, and I’m keen on learning as much about startrails as possible before I go in order to reduce the pain once I get there. :)

Topic: General Discussion / Digital technology and Night Photography

OK, a late entry to this thread, but I have some experience with amp glow and have a solution. This is for my Nikon D70, but the technique is valid for most I should think.

Lets say for the sake of argument that you want to take a five minute exposure.

1) first, switch OFF any built in noise reduction the cam may have

2) take the five minute exposure BUT, 2 seconds before the time is up, switch the camera OFF – this will force the camera to save a completely un noise reduced frame.

3) when that frame has been saved, put the hat / lens cap back on the camera and take another five minute exposure BUT, 2 seconds before the time is up, switch the camera OFF again. This creates what we call a dark frame.

4) now in Photoshop, simply subtract the dark frame from the live shot and all amp glow will be gone.

I do requests too if I can help anyone :)

David

Topic: General Discussion / Digital technology and Night Photography

I’ll be interested in knowing how you get on. It’s kind of remiss of me not to have tried this out for myself before now but, as someone who works with computers all day, and who has an interest in astronomy, I tend to keep the latter low-fi (so-to-speak) for whatever reason.

Topic: General Discussion / Digital technology and Night Photography

Thanks Dave. I actually ordered a remote a couple of days ago so I will give that a try.

Topic: General Discussion / Digital technology and Night Photography

I’ve yet to try it myself, but it’s my (possibly incorrect) understanding that you need to get a remote to allow this. I seem to recall that, when using bulb, it’s a two press operation — one to start the exposure and one to stop it.

Topic: General Discussion / Digital technology and Night Photography

Hi…just hijacking this thread with a question on long exposures.

Basically I am interested in capturing star trails but I have absolutely no idea how to set a long exposure. I have a canon EOS 400D. I’ve been through the book but found nothing. I’ve tried the bulb setting but I don’t fancy sitting with my finger on the shutter for 15mins. Am I missing something???

Topic: General Discussion / Digital technology and Night Photography

Thanks guys!

Topic: General Discussion / Digital technology and Night Photography

peter.
i have a d350canon.i tried many different exposure times,even up to15 min. and never had noise in the corners.you might want to do a little experiment to see whether its your camera or the limited technology for what you want to do.set up your camera as for a night shot,tri-pod ect.make sure its a moonless night.the darker,the better.go wide on your lens and maximum open on your iris.set your asa as low as possible.ie.100 or 50 if your camera can.expose for ,say 10 minutes on absolutely nothing,just black,and see if theres corners.i will send you a photo as soon as i figured out how,and will give you all the technical info with it so that you can compare.
good luck!

Topic: General Discussion / Digital technology and Night Photography

I read somewhere that you can use the D200’s (I own one too) Multiple Exposure function to shoot star trails, then you can combine it in-camera or Photoshop. This method may yield less noise, since you expose less per frame. As others have said, using the lowest ISO helps reduce noise, but you can’t avoid it. I have not tried the Multiple Exposure trick yet, but will post it up when I get a chance.

The purple glows at the corners are known as “amp glow”, common in digital sensors, especially with exposures around and greater than 15mins.

Topic: General Discussion / Digital technology and Night Photography

Hi Peter,
I have left a comment on this Picture that points out the failings of a digital sensor in long exposures.
It is real problem that cannot be easily solved.
In short-

Keep your exposures to a minimum.

Use the lowest ISO your camera has.

The darker the frame…the worse the noise. Try, as you have in this, to have an outside source of light (the moon for example)

Another tip (if you have access to a film camera.) Is take a photo with the digital one, and apart from the noise, if it looks ok… replicate the settings on the film SLR and take the shot. That way you will guarantee the photo will be a success.

Topic: General Discussion / Digital technology and Night Photography

Although I’m very much interested in astronomy, and I’m a keen observer, I’m not much of an astrophotographer (especially not when it comes to digital equipment) so can’t answer your question with any confidence. However…

What sort of ISO would you have been using for that shot? Also, what was the temperature like when you took it? The reason I ask is that I’m sure I read somewhere some time back that temperature within the body of some dSLRs can be an issue and can cause what look like light leaks (as you’d have seen them on film). It seems a little suspicious that it’s the two right-hand corners.

As for the general question of film vs digital. Most of the well-known astrophotogs I know use digital with great results. Take Damien Peach for example, or Pete Lawrence.

Topic: General Discussion / Digital technology and Night Photography

So a question for the night owls – in my limited experience with night photography I’ve been let down by my DSLR sensor. After only a relatively short exposure the sensor noise starts to become quite evident (I’ve got a D200). Do most night photographers stick with film? Or can digital be made to work? Here’s an example of the noise I’ve experienced (look to the corners):