First Stacking Attempt Question

[bradinusa (Brad)]

Hi Guys,

I been messing with my camera, no great shots yet but I have a question about stacking.

I have taken 5 shots of Orion from a tripod. ISO 1250 6 Sec Exp on 2.8 (50mm Prime)

I bring them into Deep Sky Stacker and when its finished...I see a picture that looks nothing like Orion.

My question/s -

1.Best way to stack constellation pictures
2.Is 6 seconds to long for a stacked image as the last image the stars will be in a different spot.
3. Do i manually try and reframe Orion everytime?

Any info would be appreciated.

Thanks

Brad

[tilbrook@rbe.ne (Justin Tilbrook)]

Hi Brad,

It sounds like you may trying to stack raw images. At ISO 1250 sounds like you running a Nikon?

Just to start with convert your images to tiff files, I presume you have some software to do so?

Won't matter how long your exposures are, DSS will stack them together. You may need to change register settings for stars, if you have a lot you can set it to 20% or more. If there's not many you may need to set it to below 10%
I know it sounds back to front but that's the way it works.
No need to re-centre with short exposures.

Hope this helps.

Cheers,

Justin.

[rogerco (Roger)]

If you are using a 50mm camera lens or there abouts (30-70) then yes 6 sec is about right, anything longer and you are going to get star trails. I don't have a lot of experience yet in stacking but as I understand it the stacking program will handle the stars moving a bit. You don't say if you are tracking and/or guiding the mount.

One thing you should check is are you using JPG files or RAW files. Another post elsewhere here says that it is pointless to stack JPG files.

[bradinusa (Brad)]

Thanks guys.

I am using a Canon 60D, but i took this pictures out my backyard just to practice and learn DSS before i go out bush.

I just watched a tutorial on DSS and I have noticed something very weird.

When I import my pictures (RAW) the image size is wrong.

The original image is - 5184x3456

When imported in Deep Sky Tracker it is 1336x3516 so its long and narrow!

[bradinusa (Brad)]

Not using a guided mount. Just a couple of quick pictures.....but if i take more than 20 do I have to keep the constellation in the exact same part of the frame?

UPDATE: DSS 3.3.3 Beta supports 60D Raw Files.....some bug in 3.3.2!

[smader (Stacy)]

I have a Canon 1100D and found the same problem - my CR2 files displayed as partial strips in the current version of DSS, but I used the beta version 3.3.3 and I was able to see the full images.

Beta from here: http://tech.groups.yahoo.com/group/DeepSkyStacker/

Cheers,
Stacy.

[bradinusa (Brad)]

Got the Beta, Thanks :-) i have noticed after stacking the image is very grey in DSS.

Not sure if it is light pollution but it does say 16-bit Grey.

[LewisM]

They always are grey - well, nearly always. You can set the saturation slider to increase colour. I would NOT leave it at 0% before saving, as I have RARELY been able to extract colour when processing if the saturation is left at 0%.

You can also fiddle with the sliders for the RGB. Link them, and slide left (darker) or right (lighter).

I wouldn't fiddle with the shadows, highlights and midtones unless you know exactly what you are doing.

Also, when stacking, I always set the Light files to Median Kappa, with 25 to 50 iterations. Takes longer, but usually worth it.

[bradinusa (Brad)]

Thanks guys for the info. I am working on the image again and see how it goes.

I will post if it looks ok.

[bradinusa (Brad)]

Ok, here is a cropped image. Stack of 5.

Not sure if it looks ok?

http://imgur.com/wvK8NeM