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I made an acquisition and processing tutorial a while back (3 years ago? Yikes!) and it is fairly dated in terms of what I'm doing these days. I've been asked for a long time to make a new one showing what I'm doing these days. Specifically how I'm processing a single shot image for both the surface and prominences and how to process them together to show prominences and the surface at once. I've abandoned doing split images and composites and strictly work from one image using layers. Acquisition does not use gamma at all anymore. Nothing terribly fancy, but it's not exactly intuitive so hopefully this new video will illustrate most of the fundamentals to get you started. Instead of an hour, this time it's only 18 minutes. It's real time from start to finish. I'm sorry for the long "waiting periods" where I'm just waiting for the software to finish its routine, it lasts 1.5 minutes and 30 seconds tops typically at first. The first 4 minutes is literally just stacking & alignment in AS!3. I typically will go faster than this, but wanted to slow down enough to try to talk through what I'm doing as I do it. Hopefully you can see each action on the screen. I may have made a few mistakes or said a few incorrect things or terms, forgive me for that, this is not my day job. I really hope it helps folk get more into processing as its not difficult or intimidating when you see a simple process with only a few things that are used. The key is good data to begin with and a good exposure value. Today's data came from a 100mm F10 achromatic refractor and an ASI290MM camera with an HA filter. I used FireCapture to acquire the data with a defocused flat frame. No gamma is used. I target anywhere from 65% to 72% histogram fill. That's it! The processing is fast and simple. I have a few presets that I use, but they are all defaults in Photoshop. A lot of the numbers I use for parameters are based on image scale, so keep that in mind, experiment with your own values. The only preset I use that is not a default is my coloring scheme. I color with levels in Photoshop, and my values are Red: 1.6, Green 0.8, Blue 0.2 (these are mid-point values).
Processing Tutorial Video (18 minutes):
RAW (.TIF) files available here to practice on (the same images you will see below as RAW TIFs):
Video for Acquisition, Focus, Flat Calibration and Exposure (20 minutes):
(Please let me know if any links do not work)
Results from today using this work flow method.
SSM data (sampled during 1.5~2 arc-second seeing conditions):
Equipment for today:
100mm F10 Frac (Omni XLT 120mm F8.3 masked to 4")
Baader Red CCD-IR Block Filter (ERF)
PST etalon + BF10mm
SSM (for fun, no automation)
If I have one solar panel, and four 12v batteries I need to be charged, two pairs of equal age and capacity (60 amp hour x 2, and 50 amp hour x 2) and the pairs have the same resting voltage and seemingly the same capacity, and I can get a solar charger unit which can charge two batteries (see link below), I was thinking of charging each pair in parallel.
I've read about the risks of charging in parallel, with the weaker battery having the dominant impact and bringing the other battery down to its capacity, but in reality, how likely is this to be a problem in the course of 5 years, where the batteries won't be used that much anyway, maybe discharged 20%, just 10 times a year?
I'm conscious there is scope to discuss lots of things around this, like "buy pairs of new batteries rather than starting out with old ones" and "buy larger capacity new batteries etc", but this is the set up we have and will be sticking with.
Thanks for any replies.
I recently bought a 2nd hand Lunt 50PT Ha (on a different platform). The vendor said he had only used it a handful of times since buying it and it shipped in the original box. It seems fine, focuses well (although I find the helical focuser a bit of a pain compared to crayfords). But it doesn't show any Ha features on the surface of the Sun!
Long story short, I completely opened up the pressure tuner and found a bizarre thing. Its well greased, there's no detritus (and it doesn't lose pressure). But there was only one O-ring in it?! The tuner itself has grooves for two o-rings and the video on Lunt's website (on how to replace o-rings) shows a tuner with two o-rings when it comes out. And they ship replacements in batches of two.
So I'm guessing that somehow the original scope shipped with only one o-ring fitted? (It wouldn't make sense for the vendor to have removed one?).
I'm hoping that's what it is, b/c then the inability to resolve Ha features may just be insufficient pressure building up? In which case, does anyone know where I can get these replacement o-rings please (Lunt's US website has them but that's only for shipping to the US)?
If it's not that, and the scope is only meant to have one o-ring, any ideas on the problem? The ring & tuner seem well greased.
(EDIT: in the meantime, the next time the sun comes out, I'm going to try moving the current o-ring from the higher groove to the lower groove in case that longer distance from the base is why the pressure isn't building up sufficiently?)