Originally posted by Pete_XL: It would be great if we could keep this topic cooking here in this forum until we all know what Sequator really can and for whom it is worth it.
I don't think that I will give up DSS altogether either, but DSS does create some headaches to me every now and then. Now, I haven't been able to get new data since this thread started, but working with older data has brought up some 'features' of Sequator that to me speaks in favour of this software:
1. Colour
Working mostly under heavy light pollution, for me DSS tends to desaturate my files (whether PEF, DNG, TIF or JPG) almost entirely. Sequator seems to have an edge here in preserving colour better. I wonder, if anybody else has similar experiences?
2. Star Counts / Star "recognition"
Not only is my city sky light polluted - it is also very turbulent = lousy seeing most of the time. Now, I have always been fascinated by the tiny pixels of the Pentax Q and Q10 (pixel pitch = 0.00154mm) and the Pentax Q7 and Q-S1 (pixel pitch = 0.00185mm) for photography of the smaller Deep Sky Objects, such as M51, Ring Nebula etc. But, alas, these tiny pixels also magnify the effect of turbulence on my star images, as in this rather typical example:
With my Q10, I cannot see the diffraction pattern of a Bahtinow mask, at least not under my city sky, but I can do the second best and photograph the pattern until I am satisfied that focus is OK.
Fig. 1: Pentax Q10 Image - Diffraction pattern of star Rigel in constellation Orion with Bahtinov mask on TS Imaging Star TSED70Q telescope.
That extra time and effort is well spent, and results in star images like this:
Fig. 2: Pentax Q10 image of M42, the Orion Nebula: Single exposure at f/6.74, FL = 474mm, 30 seconds, ISO 1600 with TS Imgaing Star TSED70Q telescope. Broad-band CLS filter used for this image.
The image is completely un-cropped!!!
It may not look that bad, but DSS stubbornly refuses to recognize these 'blobs' as stars and all attempts of stacking are aborted in DSS. However, Sequator has no objections in stacking and aligning 23 such images and here it would be pertinent to repeat the question of VoiceOfReason:
Originally posted by VoiceOfReason: Now, how the heck to I keep from blowing highlights out so badly?
23
Fig. 3: 23 images with same exposure details as above stacked in Sequator - using the Auto Brightness feature.
No good! As others have, I soon discovered that using HDR would be the way forward for post-processing this type of very high dynamic range scenes:
Fig. 5: 23 images with same exposure details as above stacked in Sequator - using the HDR feature
Much darker, but also much better for post-processing as we shall see below.
3. Post-processing of Stacked Images in StarTools
I have been playing with a demo version of StarTools for several months trying to find out whether I should invest in that software (MUCH cheaper than Pixinsight but not very intuitive for me to go to). One thing that StarTools requires is that the stacked images are as prestine as at all possible: No stretching, no white balancing, no nothing and DSS does hidden things to my images whatever I do. And since my SNR is usually always low, there are many features such as wipe and de-convolution that do not work and other features such as HDR and contrast that oftentimes only work so-so in StarTools for me and the kind of data that I may be able to produce.
Here is then the image in Fig. 4 processed in StarTools and with a finishing White-Balancing touch in PhotoImpact X3. Since I only got the demo version, I can show a screen dump only, but.....
Fig. 5: Stacked image in Fig. 4 post-processed in StarTools. Colours are somewhat 'arbitrary' due to the use of a broad-band CLS filter.
......maybe, I have just convinced myself that I will buy StarTools after all.
B.R. / Steen G. B.
