Star Tracer Introduction

Discussion forum for Tawbaware's Star Tracer and Image Stacker software
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maxlyons
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Star Tracer Introduction

Post by maxlyons » Thu May 20, 2010 10:28 pm

This forum is for the discussion of Star Tracer (and Image Stacker).

Star Tracer is a windows program that can be used to improve and enhance "star-trail" photographs. Its two main functions are:

1. Filling in the "gaps" in star-trails that result when stacking multiple images together to create a single star-trail image.
2. Extending the length of star-trails.

Star Tracer works by calculating the path of the stars, and then using that information to either fill in the gaps and/or extend the length of star-trails.

Star Tracer is still in a beta testing stage. Comments and feedback are welcome.

Max

luigi
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Joined: Mon Apr 06, 2009 6:34 pm

Post by luigi » Fri May 21, 2010 12:54 pm

Thanks Max!

I love this idea.


I'm posting my first attempt to see if you can help me get thru the first steps.


Is it possible to add a feature to undo trails? Often when taking a starscape the exposure needed for the foreground is very long and if I want the stars without trails I need to take 2 photos and merge them. One for the stars with a shorter exposure another for the foreground.

If I can take only one long exposure, then mark the trails, mask the landscape and untrail the stars then it would be a great tool too!

Luis

seigell
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Joined: Tue Mar 21, 2006 10:26 pm

Post by seigell » Sun May 23, 2010 9:12 pm

I'm intrigued by this addition to the Tawbaware product line. I've tried a bit of nighttime and even astrophotography in the past, and star trails have been an interesting problem - either to showcase or avoid.

In your introduction to StarTracer, you mention ImageStacker as if the two are to be considered together. Refamiliarizing myself with the latter, it is easy to see that there are various synergies between the two apps. However, being a longtime user of PTAssembler, there seem to be enough features present in PTA that it could also serve as that companion product:
Image Alignment - auto and manual
Stacking via TuFuse
Lens Distortion Correction
Mask Editor
Batch Processing
These areas of overlap between the products leads to a few questions:
Is PTA a plausible substitute for ImageStacker ??
If so, is there a best workflow ??
If not, will those features which provide the gap remain exclusive to ImageStacker ??
Will the "core" of ImageStacker be added to StarTracer ??
I've "signed on for the ride", buying a license for StarTracer, so I'm interested to know if I need more in order to make good use of it.

While I'm at it, I'll add my first feature suggestion:
Luminosity Threshold Filter - setting a threshold for pixels to be considered as "stars". While similar to that filter in ImageStacker, the result would be inclusion for the rotation process rather than setting to white or black. This would suppress some noise, exclude background light pollution or the dusk / dawn gradient, exclude high-altitude aircraft lights or satellite glow, and bring focus to the higher magnitude stars for those of us with access to truly dark skies seething with uncountable minor stars.

StarTracer opens some interesting possibilities for nighttime photography. I've used some of the other available apps - DeepSkyStacker and RegiStax and PixInsightLE - and developed a liking for the former. With DSS, I've produced nighttime images aligned to a fixed star-field and mosaics covering much of the night sky. However, a key has been to avoid lengthy exposures - avoid star trails - and stack the images to overcome the Earth's rotational effects; the result being a need to avoid any horizon or foreground elements. StarTracer would seem to allow the opposite, perhaps even requiring it in order to aid alignment.

Happily, Memorial Weekend sees me in the dark night skies of high-altitude SW Colorado. Sheesh, I'll be up all night long taking pictures (again). This will be fun.

maxlyons
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Post by maxlyons » Mon May 24, 2010 7:21 pm

luigi wrote:Is it possible to add a feature to undo trails? Often when taking a starscape the exposure needed for the foreground is very long and if I want the stars without trails I need to take 2 photos and merge them. One for the stars with a shorter exposure another for the foreground.
You should be able to do that with only a small amount of manual effort. If you rotate the image once, output as a layered PSD file, and then blend the two layers (the base layer and the rotated layer) using Photoshop's Darken blending mode, then I think you'll get the result you want.

Max

maxlyons
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Post by maxlyons » Mon May 24, 2010 7:31 pm

seigell wrote:Is PTA a plausible substitute for ImageStacker ??
I'm hesitant to say no, because I'm sure someone will find some way to use the products in a way that I didn't envision. But, my view is that Image Stacker and PTAssembler do verysufficiently different things that they aren't substitutes.
If not, will those features which provide the gap remain exclusive to ImageStacker ??
For now, at least, Image Stacker will remain as a standalone app. In fact, as part of the work I did on Star Tracer, I have made some enhancements and modifications to Image Stacker, and I anticipate releasing those as a new version of Image Stacker at some point (not sure when yet).
Will the "core" of ImageStacker be added to StarTracer ??
No...I don't plan on that. One (of several reasons) is that I think too much complexity scares away more users than extra features solicit new users. I fear that the complexity of much of the software I write scares away a lot of potential users, and I'd like to avoid that as much as possible in Image Stacker and Star Tracer.
While I'm at it, I'll add my first feature suggestion:
Luminosity Threshold Filter
I know that having the program figure out what are "stars" and just rotate those would be a great addition. And, in principle, it doesn't seem that hard. In practice, however, real world issues make this much more difficult to do well (and, who wants a half-baked feature that doesn't work very well?) than it may seem. Nonetheless, I think it would be a good idea to figure out some (at least half) automated way of only rotating the stars.

Max

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