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Old 01-11-2023, 02:24 PM
Startrek (Martin)
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Antlia 3nm Ha Filter Test NGC 2070 Tarantula Nebula

I imaged the Tarantula at my Dark Site with a much bigger telescope back in September and wanted to see how these Antlia 3nm filters hold up when subjected to a heavy light polluted Sky with a Full Moon overhead and more importantly limited data.Same object NGC 2070 but completely different conditions.

Bortle 8
Full Moon
Suburban backyard
8 f5 Klaus Helmerich Carbon fibre Newt
SW EQ6-R pro mount
ZWO2600MM cooled to -10C , Gain 100
ZWO 7x2 EFW
ZWO EAF
Antlia 3nm Ha filter only
Orion 60mm guide scope
ZWO290MM guide camera

Ha 35 x 3 min dithered subs
Flats
Bias
EQMOD and Stellarium
APT
PHD2 Multistar guiding PPEC algorithm
Stacked in ASTAP
Processed in Startools v1.8

Again Startools Spatially Variant PSF Deconvolution did a good job at correcting atmospheric blur at these low altitudes

Ha only ( Synthetic Luminance )
Native frame version
Crop version

The result out of this Antlia 3nm Ha filter was extremely pleasing. The noise gradient from severe light pollution and moon glare was manageable and Startools did a good job at cleaning the image up ready for processing.

NB: At my City/suburban backyard I only have a 2 hour window to capture data on this object as my roof and a large tree obstruct its view below 35 degrees and above 50 degrees.

Astrobin link below for full resolution ..

https://www.astrobin.com/qlr2p1/

Original frame version 200KB
Crop version 200KB


Thanks for looking
Comments welcome
Martin
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Click for full-size image (NGC 2070 Tarantula Nebula 180sec Ha Gain 100 Crop.jpg)
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Click for full-size image (NGC 2070 Tarantula Nebula 180sec Ha Gain 100.jpg)
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Old 01-11-2023, 08:16 PM
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Ryderscope (Rodney)
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Looks like the hardware has done its job well Martin with plenty of detail coming through and handling the dynamic range quite well
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Old 02-11-2023, 11:54 AM
Dave882 (David)
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Some truely exquisite detail Martin. Contrast in those ropey tendrils is amazing. Stars are tiny (must have been pretty good conditions) and yes youve managed the dynamic range very well. 3nm filters on a 2600mm should cut through the LP quite well but still gotta nail the processing, which you have. Well done!
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Old 02-11-2023, 06:00 PM
Startrek (Martin)
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Originally Posted by Ryderscope View Post
Looks like the hardware has done its job well Martin with plenty of detail coming through and handling the dynamic range quite well
Thanks Rodney
The hardware worked extremely well, I was expecting more noise in the initial auto stretch for less than 2hrs of data. Im use to my 2600MC with a Dualband filter which exhibited far more noise for similar integration.
Gives me confidence when I image the smaller dimmer nebula.
Also no halo around that largish Star bottom left either.

Martin
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Old 02-11-2023, 06:22 PM
Startrek (Martin)
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Originally Posted by Dave882 View Post
Some truely exquisite detail Martin. Contrast in those ropey tendrils is amazing. Stars are tiny (must have been pretty good conditions) and yes youve managed the dynamic range very well. 3nm filters on a 2600mm should cut through the LP quite well but still gotta nail the processing, which you have. Well done!
Thanks Dave
Yeh that Antlia 3nm Ha is excellent. Now I can see that Mono and dedicated filters do have the edge over OSC even with minimal data.You certainly can pull out so much more detail.
The tiny stars are not entirely a result of good conditions, although conditions were Ok, its more the result of Startools Spatially Variant PSF Deconvolution Module applied during processing.
You apply a Apodization Star mask and then select 10 to 15 sample stars across the entire image based on parameters. The algorithm then attempt to reverse the effects of atmospheric blurring by analysing the stellar profiles ( spread of pixels or point spread function PSF ) of selected stars and reverses its affect. The outcome is a specific Deconvolution applied to the sampled areas or zones of the image at the required amount ( not like other software where it applies a Deconvolution at a constant value across the whole image )
The end result is a sharper detail in main structures and stars become pinpoint rather than halo looking where stars stellar profiles bleed a lot of their pixels into neighbouring areas. You can control the amount of Decon and have good control of the Stars themselves in regards to ringing artefacts etc
I love it
The better the data the more improved and natural the Decon becomes, nothing artificial there ( AI ) just complex mathematics doing its thing tracking every pixel on its way to the final image.

Cheers
Martin
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Old 18-11-2023, 09:02 PM
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AlexN
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Yep. That's fantastic!

I'm looking at the antlia 3nm Ha, I've never shot with a 3nm before, but my old astrodon 6.5nm almost completely removed gradients from local light pollution, moon glow would still creep in, but my backgrounds when the moon was over 50⁰ away from my target were always inky black..

I thought going to 3nm would make the sky even darker.
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Old 19-11-2023, 11:59 AM
Startrek (Martin)
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Originally Posted by AlexN View Post
Yep. That's fantastic!

I'm looking at the antlia 3nm Ha, I've never shot with a 3nm before, but my old astrodon 6.5nm almost completely removed gradients from local light pollution, moon glow would still creep in, but my backgrounds when the moon was over 50⁰ away from my target were always inky black..

I thought going to 3nm would make the sky even darker.
Thanks Alex,
After nearly 3 weeks of cloudy nights I managed to capture some Oiii and Sii last night , so now I can process an SHO colour image.
Its going to be interesting as the Ha was captured under a full moon whereas last night only a slither moon descending in the west.
Im under Bortle 8 in Sydney so this Ha image still had some significant gradients to mitigate with that full moon thrown in. The Oiii data was really clean and detailed but the Sii was quite faint.
See how it all processes out
My Antlia 3nm filters so far have been excellent
Cheers
Martin
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Old 19-11-2023, 07:04 PM
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Thanks for the info!
Order placed! I've already got a 10 day rain and cloud forecast so why not.
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