Second shot at astrophotography

[toruonu]

Well this time I went a bit better prepared and went outside of town for better view.

Basically I started with shooting Mars:

as this is 100% crop, then I quickly found out that it's pointless So I moved to task nr 2: Andromeda galaxy. Well I was able to find it and I played around with different iso levels and exposures, but that's probably the best I got out of the pic at the moment (still sleepy so will hack more tomorrow probably)

well at least you can distinguish the galaxy from the stars I definitely need some tripod with tracking capability

Finally I contsentrated on getting a nice shot of startrails and got this after 25 minutes of waiting:

which I kind of like and think that the trip was worth it

And finally while packing my stuff I turned on my cars headlights and liked the view, so here comes a shot called "Highway to darkness..."

Your comments most welcome (and reposts if you want). I'm still not used to the fact that the telescope erm camera won't track with the object and hence I can't get nice long exposures to really bring out galaxies etc Anyone aware of a tripod or smth for 20D that I could use which would track the motion of earth? Instructions on how to build one?

 

[Calliope]

I really like that last photo... I also like the third photo but something about that last photo kind of makes me feel like I'm being led to the unknown. Nice photos!

 

[Mike Jordan]

Not bad. I took a bunch this last winter and as soon as the time changes and it gets darker earlier I'm going to try again this fall and winter.

I didn't use a tracking mount either, but if you keep your shots at about 30 seconds you won't get trails. What you do is take a bunch of 30 second shots and then layer them together to bring out the detail and multiply the light. It won't get you the deep stuff, but it does pretty decent.

If you want to build something that will track so you can take shots for much longer periods, do a google search on Haig mount, barn door mount or equatorial camera mount. It's manually driven so you turn a wing nut or screw one turn per minute if you have it designed right. It's real cheap to make as well... even almost free if you have a lot of the parts laying around.

This is one of the shots I did... 4 or 5 30 second shots layered together in Photoshop. Taken with at about 24mm with a 24-70 2.8L, ISO 100. Not that spectacular, but gives you an idea of what can be done with no tracking mount.

Mike

 

[PlasticSpanner]

Yes a Haig mount is the way to go unless you want to spend £150 + on an equatorial mount! Cheap and cheerful and designed by a Scotsman if I recall correctly!


My friends dad was Scottish. He dropped a shilling once and as he bent down to pick it up it hit him on the back of the head! . (Might be a UK only joke! )

 

[toruonu]

Thanks for the hints on mounts

Mike: I'm using 300mm+1.4 TC to take shots of deep sky objects like the Andromeda Galaxy. If I'd like to take shots of even more deep sky objects I'd really need even longer lenses. And as the time the stars remain as dots for such a configuration is a bit less than 1 second, then I'd have to do hundreds of shots, reposition each to be just on top of the other one and then add them. That's a hellava lot of work. That's why I consider getting a tracking mount.

 

[PlasticSpanner]

You wouldn't need to re-position to get multiple shots. PS will align the images for you or you could download a program like Registax or K3ccd tools to stack the images. I sometimes use a video camera to record an AVI file that is then split into 5 frames/second and a total of 5,000 seperate images are then stacked together!

 

[toruonu]

Ok, how do you let PS align the images? Maybe a slight description of the process. You also have to understand that 99% of the shots I take are camera RAW so I have to postprocess them anyway and I shoot as RAW to give me a better exposure compensation ability. Should I instead shoot in JPEG in such instance to allow for better and easier stacking?

 

[PlasticSpanner]

Might be best keeping the images as RAW files & getting the PS plugin to handle them. Either that or BMP files. Jpegs tend to make the black sky a little blotchy. Also save the files in as large resolution as your computer can handle and reduce the file size after you've done all the processing.

If you open each image and copy/paste as new layer into your first image, reduce the layer opacity to 50% and blending to Multiply. Then use the transform tools to stretch, rotate and move the layer to fit the one below it, increase the opacity back to 100% then merge it down. You could use the automated PhotoMerge but I'm not sure how you set the blending mode in that!

There are links to post processing tutorials here http://thephotoforum.com/forum/showthread.php?p=303249#post303249

 

[toruonu]

Well I have read that article That's how I postprocessed these pictures as well to remove light pollution however if I take shots every 1sec and take around 200 of these, then each and every one will differ from the others as the actual motion of the stars is exactly 1 second per pixel. So I have to manually postprocess the pictures to align them correctly or I will just get the same startrails.

That's why I asked on how you make PS automatically align them so that it would compensate for the earth rotation automatically. If that could be done, then there is no problem shooting hundreds of shots However if I leave them in RAW, then I have to postprocess every single shot as PS can't open a RAW file without processing it. That's the tought part So I guess I'll probably have to make the investment in a tracking tripod

 

[PlasticSpanner]

PS can do it in the "File/Automate/Photomerge" option but you'll have to read up how to set the blending mode.(might even already be set!?) Also when doing it manually if "snap" is turned on most of the images will line up as soon as you paste them in!


I think Registax can only handle AVI files for stacking but I think K3CCD Tools can stack MBP and JPG files as well. (but not sure!)

If you shoot 10, 2 second frames of M31 (Andromeda Galaxy) you would only have to process those 20 images and would get a similar image as one taken at 20 seconds! More than enough for such a bright object!

 

[toruonu]

Well with 20 sec exposure (the above pic is 15 sec) you don't get the full galaxy You mostly only see the core while the galaxy itself is around 4-5 times bigger and dimmer. So It would have to be something like 5-6min exposure I guess which would bring out the rest as well. For that I'd need 180x 2sec exposures And that's a lot of manual labour.

 

[PlasticSpanner]

Have you tried shooting at a higher ISO speed?


On film I usually use 400 ISO but I know digital gets a lot more noise. You could use a dark frame (frame shot with the lens cap on) to remove some of this noise.

 

[toruonu]

The above pic is done at ISO 1600 And it's 15" ISO 1600 and ISO 800 are for astrophoto quite ok considering that they create graining, not colour noise. ISO 3200 will create awful colour noise on 20D.

 

[PlasticSpanner]

I've always thought film is more sesitive and suitable to this application although not having used a digital SLR for astophotography I have little to compare it to!


It may also be worth shooting at a lower zoom factor but higher resolution image. This will produce less trailing for a longer exposure and the res will allow you to crop to your chosen subject.

 

[toruonu]

Well I'm shooting at maximum resolution (RAW) so full 8.2MP, I never shoot on lower resolutions as CF cards are cheap and fast so no need to stroll down resolution when you can just swap cards at some point. And I always try to take shots which can be printed at least A3+ or even enlarged bigger

And as the Canon 300mm f/4L IS USM is a fixed zoom lens then no zooming I can remove the extender, but that will change exposure from 0.9" to 1.3" and that's not such a difference