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Forum: Mini-Challenges, Games, and Photo Stories 07-01-2019, 06:00 AM  
Thematic Post & Discuss Your Astro Tracer Star Trails & Star Shots
Posted By MossyRocks
Replies: 37
Views: 1,220
It can be a bit fiddly until you get use to it. Smoothness in movement and limiting movement to only one axis at a time seem to be the biggest factors on getting a good calibration. The first couple of times I used it I got sub-optimal results but the more I used it the better I got. I would suggest practicing calibrating it during the day until you can consistently get it to say it completed. To check your calibration stick a telephoto lens on and do a 20 or 30 second exposure on a bright star. You shouldn't see any trails but if you see short ones redo the precise calibration, if they are long trails redo the both the coarse and precise calibrations.

I don't turn it super fast but even then a run through of all the rotations only takes about 20 seconds and I usually rotate it closer to 230 degrees back and forth instead of the minimum 180 that is necessary. Every once and a while it will state it has completed after just a rotation in one direction which I know is wrong. Most of the time by redoing that calibration it will complete after doing 3, but even then there have been a handful of times when it would just keep completing after 1 rotation. At this point just turning it off and starting fresh seems to be the only solution.
Forum: Mini-Challenges, Games, and Photo Stories 08-28-2018, 06:41 PM  
Thematic Post & Discuss Your Astro Tracer Star Trails & Star Shots
Posted By MossyRocks
Replies: 37
Views: 1,220
Nice. I keep wanting to take a stab at shooting the milky way but life or weather gets in the way. I have a shot in mind that I want but I probably won't be able to get it this year as september is about the last time I could get it but that month is already looking like it will be a zoo.
Forum: Mini-Challenges, Games, and Photo Stories 08-22-2018, 03:57 AM  
Thematic Post & Discuss Your Astro Tracer Star Trails & Star Shots
Posted By MossyRocks
Replies: 37
Views: 1,220
The weather finally cooperated and I was able to do a bit of astrophotography last night. Too bad it was a work night, but I did capture M51, so astrotracer does appear to be useful for deep sky objects. Here is a 100% crop showing M51 that was taking using astrotracer:
18x20s, ISO800, F/4, Sigma 300mm F/4 APO lens, K-3 with astrotracer


Just so people don't think it came out of the camera or stacking like this it didn't and I did do some quick processing to bring out the detail.
Forum: Mini-Challenges, Games, and Photo Stories 08-16-2018, 08:06 AM  
Thematic Post & Discuss Your Astro Tracer Star Trails & Star Shots
Posted By MossyRocks
Replies: 37
Views: 1,220
Hopefully others can learn from my mistakes and not make them. I try to learn from others so I can not go down already tried and failed paths but instead I can fail in new and interesting ways that can add to the collective knowledge.
Forum: Mini-Challenges, Games, and Photo Stories 08-16-2018, 07:06 AM  
Thematic Post & Discuss Your Astro Tracer Star Trails & Star Shots
Posted By MossyRocks
Replies: 37
Views: 1,220
Likely a sign of light pollution and regular pollution interacting but even in great areas you will still get a brightening of the black sky from noise buildup and because the night sky isn't actually perfectly black. I get similar things when first stacked in DSS (Deep Sky Stacker) but then go and do more processing to get the blacker sky, better colors, and bring out the details in things. One of the regular posters in the astrophotography group had a post that contained a links to the tutorials he used to learn how to process astro pics. I can't ever seem to find that post from Pete_XL but I saved the links and included them below. Originally I found some tutorials from other people and the results were less than stellar but I thought I was doing well. I asked for feedback, got it, learned, and got pointed in the right direction.
A series on basic DSO processing
The full series on astro image processing

If you want to see an unprocessed but stacked image of what I am currently getting for the sky in my backyard here is one I took at about 2:00 AM on Sunday. It is a stack of 14 10 second (14x10s) exposures at ISO 800 using a 17mm SCM fisheye Takumar wide open. I stacked the image using DSS and did no additional processing. Granted the sky glow is exceptionally bad in this photo but my house is in a high Bortle 8 area and there was a lot of haze from the humidity plus the smoke from the Canadian wild fires. Vertically this covers an area from just above the tree line in the park behind my house to past the zenith (the tree at the top of the picture was actually behind me). The bright dot at the bottom in the middle is Mars.



Since your series of 3 images at 120s, 120s, and 150s haven't really been processed but are basically straight out of the camera I would say you are doing pretty damn good and have a nice dark area to work in with lower humidity and less pollution than I have. So much of getting good pictures from astrophotography is in the processing of them with learning and mastering that.

My suggestions for you on how to improve would be:
1. Start stacking (get DSS it is free and will work with the raw DNG files), it will help with noise and will also allow you the chance to bring out more detail
2. Learn how to process astro pictures. I'm still not great but getting better.
3. Decrease the individual exposure time to have less astrotracer error as well as digital noise but increase the number of stacked images.
4. Combine dark and bias frames in DSS.
5. If you don't have photoshop for astro processing, I would suggest using Gimp instead as it is free and the current version will actually allow you to work with the 32bpc tiff that DSS produces.
Forum: Mini-Challenges, Games, and Photo Stories 08-15-2018, 06:54 PM  
Thematic Post & Discuss Your Astro Tracer Star Trails & Star Shots
Posted By MossyRocks
Replies: 37
Views: 1,220
Here is the first photos I took once I got the O-GPS1 for my K-3. It had to be a work night so I couldn't stay all that long but went down to one of the county parks. This is a stack of six 60 second shots using my SMC Takumar 55 F/1.8 lens at ISO 100. I probably stopped it down to F/8 as I was just figuring things out then and didn't know what I was doing. I also don't think I got a great calibration, but not too bad. Most of the stars ended up being ovals about 50% longer in one direction. This was taken april 24th of this year which in MN means early spring with things likely still frozen.

I did just reprocess the image as I am getting better at it and was able to bring out the color more. Unfortunately there is always a lot of sky glow here and this was shot not long after sundown so it hadn't gotten really dark yet. The picture before this was the waning moments of sunset and was taken 15 minutes earlier. In the full size image M42 is visible and shows some finer details but not many.

Basically I have learned that you can get 10-15x the exposure time (3-4 stops) using astrotracer than you would without out and you can expect similar results as not using it. Assuming you have a good calibration.
Forum: Mini-Challenges, Games, and Photo Stories 08-15-2018, 11:17 AM  
Thematic Post & Discuss Your Astro Tracer Star Trails & Star Shots
Posted By MossyRocks
Replies: 37
Views: 1,220
Having played with astrotracer it can provide good results but it does require a good calibration, if not things go sideways fast. I haven't figured out a good way to test if it is correctly calibrated but the other day I read that you should bring a compass and check the compass in the camera against that to see if the calibration is good. I haven't had a reason to go out with the astrotracer recently so I haven't checked that this works.

My advice when using astrotracer is to do the following for best results:
1. Don't try for the 5 min max time you will be disappointed.
2. When calibrating it stay away from cars and other large steel objects, as well as away from power lines. These throw it off, same thing when using it.
3. For best results stick to 1/4 of the recommended maximum time it suggests
4. Shoot more straight up or more straight out, near 45 degrees it seems to get off quicker

I haven't had a chance to do much night shooting lately as life and the weather haven't been cooperative but I have some shots that I played around with from early spring that I took with astrotracer (I think I still have them).
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