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Solar Analemma. This outstanding image from Alexandra Hart taken over a period of 4 years charts the midday position of the sun in the sky throughout the year. The north–south component of the analemma results from the change in the Sun's declination due to the tilt of Earth's axis of rotation. The east–west component results from the nonuniform rate of change of the Sun's right ascension, governed by combined effects of Earth's axial tilt and orbital eccentricity.

Merry Christmas, Happy New Year and looking forward to a great solar cycle 25!

Welcome to Solar Chat! The best forum for Solar Astronomy
Moving forward from solar cycle 24 to 25

Search found 628 matches

by GreatAttractor
Sat Jan 11, 2020 10:09 pm
Forum: This is SolarChat !!
Topic: Visual Solar Observing
Replies: 17
Views: 330

Re: Visual Solar Observing

I observe quite rarely, but here's my advice: once you max out with the 'scope (& double-stacking options), I strongly recommend getting a binoviewer. I have a Baader Maxbright with 2x 15 mm Plössls (just regular ones) and the views with the 50 mm and 90 mm H-alpha setups are wonderful. I also had j...
by GreatAttractor
Wed Jan 08, 2020 5:31 pm
Forum: This is SolarChat !!
Topic: Gong showing new feature
Replies: 7
Views: 170

Re: Gong showing new feature

I use helioviewer.org, which shows the current SDO images among others.
by GreatAttractor
Thu Dec 26, 2019 10:59 am
Forum: Solar Software
Topic: New version of ImPPG: faster processing on the GPU
Replies: 23
Views: 616

Re: New version of ImPPG: faster processing on the GPU

To those who downloaded the Ubuntu package: I've uploaded a corrected one, which also installs an ImPPG application shortcut (so it can be selected in "application launcher" of your desktop environment). The same goes for building under any Linux (or alike) system. Pull the latest source code, and t...
by GreatAttractor
Wed Dec 25, 2019 10:22 pm
Forum: Solar Software
Topic: ImPPG version 0.6.0
Replies: 9
Views: 293

Re: ImPPG version 0.6.0

I'd miss out the wavelets and go straight to ImPPG for sharpening Indeed! It will work best with raw, unprocessed stacks. Though one could do the primary sharpening elsewhere (e.g. wavelets in Registax) and then just touch up in ImPPG (probably with L-R disabled, just apply unsharp mask and modify ...
by GreatAttractor
Wed Dec 25, 2019 8:22 pm
Forum: Solar Software
Topic: ImPPG version 0.6.0
Replies: 9
Views: 293

Re: ImPPG version 0.6.0

Hi Rainer,

That's right, ImPPG is for post-processing of stacks. So you must stack your AVI first (e.g. in AutoStakkert), and then you can open the resulting TIFF in ImPPG. On the home page you'll find links to a few tutorials:

http://greatattractor.github.io/imppg/
by GreatAttractor
Wed Dec 25, 2019 12:41 pm
Forum: Solar Software
Topic: New version of ImPPG: faster processing on the GPU
Replies: 23
Views: 616

Re: New version of ImPPG: faster processing on the GPU

GPU mode will be activated by default when you first start ImPPG 0.6.0. The current mode is indicated in the status bar in the lower right:
imppg_back_end_info.png
imppg_back_end_info.png (96.9 KiB) Viewed 424 times
You can switch between CPU/GPU modes in the menu:
back_end_selection.png
back_end_selection.png (36.8 KiB) Viewed 424 times
by GreatAttractor
Wed Dec 25, 2019 1:05 am
Forum: Solar Software
Topic: New version of ImPPG: faster processing on the GPU
Replies: 23
Views: 616

Re: New version of ImPPG: faster processing on the GPU

Wow, great to hear this! Thanks for checking. I must get me one of those high-end babies one day... ;)
by GreatAttractor
Tue Dec 24, 2019 12:28 pm
Forum: Solar Software
Topic: New version of ImPPG: faster processing on the GPU
Replies: 23
Views: 616

Re: New version of ImPPG: faster processing on the GPU

Hmm, by the looks of it, it's not "too strong", rather the processing went completely bonkers :) Standard OpenGL has no provisions to choose the active GPU (though there are AMD- and NVidia-specific extensions, as I've now googled), it's up to the operating system/driver configuration. I wouldn't th...
by GreatAttractor
Mon Dec 23, 2019 11:44 pm
Forum: Solar Software
Topic: New version of ImPPG: faster processing on the GPU
Replies: 23
Views: 616

Re: New version of ImPPG: faster processing on the GPU

Thanks for feedback, Marty. When you switch to CPU mode, does everything look OK? Also, in GPU mode please try with View/Scaling method/Linear. And check if a saved output image also looks bad. I tested on 3 different GPUs (Intel, NVidia, AMD), each under Linux and Windows, but yeah, there might be ...
by GreatAttractor
Mon Dec 23, 2019 10:43 pm
Forum: Solar Software
Topic: New version of ImPPG: faster processing on the GPU
Replies: 23
Views: 616

Re: New version of ImPPG: faster processing on the GPU

Hard to compare GPU-CPU performance, I'd need many data points. As for a desirable GPU, even my ancient Intel HD Graphics 5500 (integrated) benefits here; generally, the more powerful, the better. I'm wondering if the current highest-end GPUs could apply L-R in real-time for, say, a 1 Mpix image (if...
by GreatAttractor
Mon Dec 23, 2019 9:53 pm
Forum: Solar Software
Topic: New version of ImPPG: faster processing on the GPU
Replies: 23
Views: 616

New version of ImPPG: faster processing on the GPU

ImPPG version 0.6.0 has been released . After some architectural cleanup, I added a GPU/OpenGL back end, that is, almost all processing (except image alignment) is now performed on the GPU. In practical terms, on most computers it means: processing is faster by a factor of several or more for quite ...
by GreatAttractor
Mon Dec 23, 2019 9:52 pm
Forum: Solar Software
Topic: ImPPG version 0.6.0
Replies: 9
Views: 293

ImPPG version 0.6.0

ImPPG version 0.6.0 is available at: https://github.com/GreatAttractor/imppg/releases New features: GPU (OpenGL) back end for much faster processing Enhancements: View scrolling by dragging with the right mouse button (previously: with the middle button) Zooming in/out with the mouse wheel (previous...
by GreatAttractor
Wed Dec 18, 2019 3:45 pm
Forum: This is SolarChat !!
Topic: Full Disk 2019-12-17
Replies: 14
Views: 235

Re: Full Disk 2019-12-17

Good job, Jochen! To tease the max resolution out of these 50 mm, I suggest you make a 2x2 mosaic. I have similar pixel pitch (3.75 µm) to yours, and such mosaics work very well for me with a 2x Barlow's lens element screwed directly into camera's nosepiece (giving ~1.6x), e.g.: https://astrob.in/22...
by GreatAttractor
Tue Dec 17, 2019 8:23 am
Forum: Solar Software
Topic: Processing Solar Proms Autostakkert 3 vs Registax 6
Replies: 9
Views: 315

Re: Processing Solar Proms Autostakkert 3 vs Registax 6

And I still use AviStack 2 (for those cases where Stackistry fails). Seems OK on prominences too.
by GreatAttractor
Sat Dec 14, 2019 9:38 pm
Forum: Solar Scope Modifications
Topic: D-ERF in converging beam?
Replies: 26
Views: 807

Re: D-ERF in converging beam?

Then how do we calculate the rise in temperature along the converging beam of our OTA? There's certainly some of that, but probably less important than one would think. The air (over the kind of distances we have in telescopes) is after all quite transparent to solar radiation. Consider this: Lunt ...
by GreatAttractor
Sat Dec 14, 2019 10:36 am
Forum: Solar Scope Modifications
Topic: D-ERF in converging beam?
Replies: 26
Views: 807

Re: D-ERF in converging beam?

Here's the mistake: 1 m² = 100 cm × 100 cm = 10 000 cm². Assuming irradiance of 1000 W/m² (0.1 W/cm²), a 15 cm-diameter objective gathers only π × 7.5² cm² × 0.1 W ≈ 17.7 W.

(Or in other words: if the unfocused irradiance is 1000 W/m², you can't have a mere 15-cm lens gather > 3 kW ;)).
by GreatAttractor
Wed Dec 11, 2019 7:10 am
Forum: This is SolarChat !!
Topic: Introduction and small question
Replies: 12
Views: 317

Re: Introduction and small question

JochenM wrote:
Wed Dec 11, 2019 4:32 am
I have the Moonlite CM-Mini fitted instead. I'm guessing that pretty much covers that?
Yup. This just leaves pointing the telescope possibly a bit sideways and finding the best camera position/orientation.
by GreatAttractor
Tue Dec 10, 2019 9:58 pm
Forum: This is SolarChat !!
Topic: Introduction and small question
Replies: 12
Views: 317

Re: Introduction and small question

Hello Jochem, welcome to Solarchat! I can see two (not very serious) issues in your image: - drooping focuser (most likely); the on-band FOV area ("sweet spot") should be more or less central, but you have it shifted downwards; you can read about it here: https://solarchatforum.com/viewtopic.php?t=1...
by GreatAttractor
Mon Dec 09, 2019 9:55 pm
Forum: This is SolarChat !!
Topic: Introducing myself
Replies: 23
Views: 527

Re: Introducing myself

Hello Salvo, enjoy the forum!
by GreatAttractor
Sun Nov 24, 2019 9:22 am
Forum: Solar Scope Modifications
Topic: "Magic" distance of Lunt LS50PT etalon from focal plane?
Replies: 15
Views: 550

Re: "Magic" distance of Lunt LS50PT etalon from focal plane?

Roel80 wrote:
Sat Nov 23, 2019 12:02 pm
That 140mm is measured from the focal plane to which part of the etalon unit?
I suggest you measure it precisely yourself. Here's a simple method I used: viewtopic.php?f=9&t=19238
by GreatAttractor
Sat Nov 02, 2019 10:34 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: 3D printing and SHG
Replies: 15
Views: 712

Re: 3D printing and SHG

And here's a successful build of the LOWSPEC spectroscope (in Polish): https://astropolis.pl/topic/68522-wydru ... ektroskop/
First light: https://astropolis.pl/topic/69238-widmo ... o%C5%9Bci/
by GreatAttractor
Sun Oct 20, 2019 5:27 pm
Forum: Solar Software
Topic: Stackistry: algorithms summary
Replies: 0
Views: 439

Stackistry: algorithms summary

With a small (2-year) delay, I've finally added a description of algorithms used by Stackistry/libskry (an open-source cross-platform stacker):

link to PDF
toc.png
toc.png (104.55 KiB) Viewed 439 times
by GreatAttractor
Wed Sep 11, 2019 5:53 am
Forum: This is SolarChat !!
Topic: First animation with the Intes
Replies: 13
Views: 630

Re: First animation with the Intes

Thanks, Bart, glad you like it.

As for your setup - this is with a PST etalon, correct? So the Intes can manage the required 200 mm backfocus, or is it some other approach?
by GreatAttractor
Tue Sep 10, 2019 4:31 pm
Forum: This is SolarChat !!
Topic: First animation with the Intes
Replies: 13
Views: 630

Re: First animation with the Intes

Great result, the high resolution is immediately noticeable.
by GreatAttractor
Wed Aug 28, 2019 5:01 pm
Forum: This is SolarChat !!
Topic: Weekend Sunshine and OaCapture testing for Apple
Replies: 13
Views: 706

Re: Weekend Sunshine and OaCapture testing for Apple

I wrote the FlyCapture (i.e. "native" PGR) and IIDC drivers for PlanetaryImager (IIDC a.k.a. DC1394 is a universal protocol supported by all PGR's USB cameras). Marco (PlanetaryImager's author) does publish macOS builds (.dmg files) in the Downloads section, but likely they do not have FlyCapture su...