Lagoon Nebula ~ NGC 6544 6553 6520 ~ Kaus Borealis ~ M28 ~ Star Cloud & Dust Lanes

[JBW]

My color shots are more dramatic and some will think more beautiful. The black and white shot is what a four to eight inch reflector would show a good observer from a really dark site.

ISO 3200 ~ Shutter Speed 3.2s ~ F/3.2 ~ Stacked In DSS ~ 130 Brights ~ 20 Darks ~ 15 Bias ~ Hand tracked.
Sony Alpha a58 ~ Tamron 90mm 272E

[NorthernFocus]

That's pretty cool looking, Brian. I'm becoming intrigued.

[JBW]

That's pretty cool looking, Brian. I'm becoming intrigued.

I'm using the same gear I use for my garden shots. The secret to this type of shooting is stacking. Every camera and lens combo works differently but they all follow the 500 rule. Whatever your FL is, in my case 90 divide 500 by it and that will be close to your maximum exposure before star trails become a problem. So with my 90 4 seconds is a maximum and I like it better at 3.2. The above shot had @140 color frames, 20 dark (same settings but shot with lens cap on) and 15 bias (leave the lens cap on and up your shutter speed to as fast as it goes)

Work on the raw color shots in your favorite pp software and then put them all three types into something like DeepSkyStacker. When it comes out as one shot do some more pp.

I do my tracking by hand but there are some excellent camera mounts in the 500US range that will automatically track for you. Skywatcher is one of the top 3. B&H sells all three.

The other necessity are clear stable nights. Which means you will either be standing outside in an Alaskan winter manually controlling everything or hooking everything up to a computer.

Having done a bit of both I can assure you that astrophotography can be as expensive as boating if you get carried away with the tech end.

On the other hand I'm not doing too bad and I haven't spent for any new toys.... yet

[NorthernFocus]

Oooofff. Sounds complicated. Plus you have to stay up after dark. And living someplace where the sky is visible once in a while would probably help. Yeah, I'll just look at your photos

[Cantab]

Brian, fascinating information in post #3: stacking 140 images, many with the lens cap on. I agree with Dan: "I'll just look at your photos."

[Shadowman]

Nice images.

[JBW]

It is quite the learning curve and I've just started up the hill. Thankfully the results are (at least to me) worth the effort.

[Rainforest]

I'd sure be happy to master half of what you described ;-), which I appreciated very much.

[JBW]

I'd sure be happy to master half of what you described ;-), which I appreciated very much.

so would I

[Stagecoach]

The above shot had @140 color frames, 20 dark (same settings but shot with lens cap on) and 15 bias (leave the lens cap on and up your shutter speed to as fast as it goes)

Brian, at what point during the 140 colour frames do you take the Darks, start, during or at the end?

Also, on what basis did you determine 20 darks?

And, for the darks, would it be feasible to just shoot one and copy it 20 times?

[JBW]

Brian, at what point during the 140 colour frames do you take the Darks, start, during or at the end?

Also, on what basis did you determine 20 darks?

And, for the darks, would it be feasible to just shoot one and copy it 20 times?

I leave it to the end of the shooting to add my dark and bias. They both require the same camera temperature as when you are shooting and to me it just makes sense to add them at the end. They are not subject specific so if you shoot multiple subjects they can be used for one and all.

I have done some reading and it was pointed out time and again that more is better but there is a point of diminishing returns. When I tried 4 or 5 darks there was still a lot of noise. I tried 20 and the noise was pretty much gone. One night I shall try 40.

from what I have read they need to be individual darks. Each dark is just that little bit different than any of the others and it is the slight differences that eliminate the noise. At least that is how I understand it.

I'll see if i can find the web page that helped me.

[Stagecoach]

Thanks for that Brian.

Next chance I get, and it's not looking good here at all for a while, I'll shoot far more off. My last play I just did 2.

[JBW]

Thanks for that Brian.

Next chance I get, and it's not looking good here at all for a while, I'll shoot far more off. My last play I just did 2.

my pleasure. After all the advice I've been given here it feels good to be able to be able to give some back.

[dem]

Hi Brian. Thank you for providing details of the process you used. I was toying with the idea of having a go at astro myself while on holiday. Not sure it is going to materialise though as it is always too cloudy and misty.

Thanks for reminding about the 500 rule. I realise it needs to be adjusted by the crop factor:

https://petapixel.com/2015/01/06/avo...wing-500-rule/

and can probably be pushed a bit if photographing the North star with a long lens.

[JBW]

Hi Brian. Thank you for providing details of the process you used. I was toying with the idea of having a go at astro myself while on holiday. Not sure it is going to materialise though as it is always too cloudy and misty.

Thanks for reminding about the 500 rule. I realise it needs to be adjusted by the crop factor:

https://petapixel.com/2015/01/06/avo...wing-500-rule/

and can probably be pushed a bit if photographing the North star with a long lens.

my pleasure. hope you find some clear skies

[ajohnw]

Neat shots Brian. I have a number of telescopes I did peer through but recent street lighting changes have wrecked that and as you mentioned photo's though a telescope make things more than a touch more complicated. If I do that now I need something really portable that also works. This might interest you. It's been an ongoing project for a long time now.
https://www.cloudynights.com/topic/5...rophotography/
There are others based around indi - that can also be PC based but it seems to be more complicated to me. You might also like to spend some time googling barn door trackers. Design's vary. The main thing they need is a rigid hinge.

Thanks for reminding me of the 500 rule. I did try this once only to find that the camera I had with me went into a strange mode and stacked itself rather than actually using the exposure I had set.. I wasn't sure what camera settings to use so when I have a go again I'll try yours just accounting for the lens focal length.

One query though. I thought that the stacking software also aligned so tracking can be extremely rough ??

John
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[JBW]

Neat shots Brian. I have a number of telescopes I did peer through but recent street lighting changes have wrecked that and as you mentioned photo's though a telescope make things more than a touch more complicated. If I do that now I need something really portable that also works. This might interest you. It's been an ongoing project for a long time now.
https://www.cloudynights.com/topic/5...rophotography/
There are others based around indi - that can also be PC based but it seems to be more complicated to me. You might also like to spend some time googling barn door trackers. Design's vary. The main thing they need is a rigid hinge.

Thanks for reminding me of the 500 rule. I did try this once only to find that the camera I had with me went into a strange mode and stacked itself rather than actually using the exposure I had set.. I wasn't sure what camera settings to use so when I have a go again I'll try yours just accounting for the lens focal length.

One query though. I thought that the stacking software also aligned so tracking can be extremely rough ??

John
-

I'll take a look.

DSS allows you to pick a % of your shots ie: the top 80%. How bad can your tracking be and still be stackable? No idea. But mine is not pin point so it does allow for some error.

[ajohnw]

I shouldn't have posted the cloudynights link Brian. Might get you into buying telescopes which is a bit of a minefield.

The barndoor trackers as far as I'm aware are all diy items but do extend exposure times. I recollect seeing one design that was fitted with a finder scope which eases alignment problems. Some just have sights. For use with a camera they start to make sense as the focal length goes up and exposure times get too short when they are derived from the 500 rule. These days no one takes extremely long exposures as they used to when film was used. It's all stacking with an exposure long enough to register something. Your iso, f ratio and exposure time combination looks pretty good to me. Stars showing trails and or defects - lot depends on how small the final shot is.

I'm not sure what lenses will work well for this sort of use. Years ago I bought a telescope of some one who was shooting film. He gave me a very old F2.8 longish range tamron zoom lens and reckoned that the results were good. Pass as I didn't see any shots but I'd guess that simpler glass arrangements may help, maybe old film primes.

You didn't mention taking flats to correct light fall off. I just did as some people seemed interested in this general area. There is plenty of info about on the web.

John
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[PRSearls]

Those are gorgeous shots, Brian. I love the color.

[JBW]

Those are gorgeous shots, Brian. I love the color.

Thanks, they were also educational. I had to crop off the bottom because I didn't think the power line was in the shot. Next time I shoot from under the power line instead of behind it