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A friend ask me about filter size, I already had a Excel sheet with that calculation. But I did a new web calculator.
It's the first version but it looks to calculate it correct, have a look:
It's not any high precision calculation, but gives knowledge enough I think.
Too small filter gives vignetting, too big filter empty the wallet.
The weather has been so bad I have had the time to finish a video on using astro filters with the Nikon Z bodies and Nikon camera lenses. There is a manual alternative to the FTZ allowing 1.25 inch filters to be fitted between camera and F-mount lenses, and for some lenses and end of lens solution make sense. FAstroTZ is described here:
I scrapped all the Oiii and Sii data I previously took during a full moon (about 15 hours worth) and retook it all when the moon was a bit smaller at 76%. Ha was taken during 98% and 67% moon. All the lights were taken on the following nights: 12th, 19th and 20th September 2019.
Integration times, all in 600s subs unbinned:
Ha = 28.33 hours
Oiii= = 5.67 hours
Sii = 5.67 hours
The Ha data is really nice, and unsurprisingly the Oiii and Sii is not as strong (or nice).
I'm missing that (vital) step in my processing routine of getting the Sii and Oiii properly stretched to match the Ha, before combining. I dont really know how to deal with the weaker data properly. Any pointers would be appreciated.
What I do currently:
All the data is loaded into APP into separate channels/sessions.
The data is stacked and registered against the best Ha sub
This produces individual stacks of Ha, Sii and Oiii that are all registered
Each channel is processed with DPP in APP and then saved as a 16bit TIFF
Each is opened in PS
Stars removed with AA and any remnants removed and tidied up
I then open a blank RGB document in PS
I paste Ha into Green, Sii into Red and Oiii into Blue
Adjust the selective colour settings to get 'Hubble palette'
Adjust levels, curves, saturation until looks ok
All the Ha Sii Oiii data is then combined together in a single 'super' stack in APP using quality weighted algorithm to create a 'luminance'
That luminance layer is adjusted using levels, curves, and NC tools such as local contrast enhancement and deep space noise reduction (using masks to apply as required)
The luminance is pasted onto the above colour layer, and incrementally added using gaussian blur
Cropped and saved.
Here it is anyway I haven't intended on any more exposure time for this one, but will consider it, if the expert opinion dictates otherwise!
I'm working with some recent data of a new(ish) camera, and my Ha data is pretty good, but the oiii has these strange artifacts around the borders.
If I use any kind of local normalization then it pretty much ruins most of the image, as you can see below..
First the Ha:
Oiii with local normalization:
oiii local normalization map, see how it fits with the artifacts:
Oiii without any local normalization:
These edge artifacts, could they be related to a bad filter or is it a processing artifact, has anyone seen anything similar?
I am using Astro Pixel Processor for calibration and stacking.. Im kind of stumped on this one, and I am going to yank out the Oiii filter this weekend to have a looksie.
THIS ITEM HAS NOW BEEN SOLD.
This listing is for my personal narrowband filters (Kayron from Light Vortex Astronomy). They are the Astrodon Hydrogen-Alpha (HA), Oxygen-III (OIII) and Sulphur-II (SII) 3nm 1.25" narrowband set. These are considered the highest-end narrowband filters money can buy, able to produce images of exceptional quality and incredible sharpness, cutting through a vast amount of light pollution. The 3nm variants featured here are fantastic for pulling out fine nebulous structures clearly above background. For more information, please see Astrodon's website:
Please note that these three filters together currently retail at just over £1,710 from UK suppliers, €2,180 from European suppliers or $1,690 from US suppliers. Payment is preferred via bank transfer but PayPal is OK with an extra 2.9% to cover PayPal fees. I'll cover postage to you via tracked Courier.
I welcome any questions you may have regarding this listing. Thank you for looking.