TheSkySearchers

We have a treat for the July TSS Astrophotography Processing Challenge.

Carol (Carastro) has submitted her Narrow Band data captures of NGC7822.

From Wikipedia:

NGC 7822 is a young star forming complex in the constellation of Cepheus. The complex encompasses the emission region designated Sharpless 171, and the young cluster of stars named Berkeley 59. The complex is believed to be some 800–1000 pc distant, with the younger components aged no more than a few million years. The complex also includes one of the hottest stars discovered within 1 kpc of the Sun, namely BD+66 1673, which is an eclipsing binary system consisting of an O5V that exhibits a surface temperature of nearly 45,000 K and a luminosity about 100,000 times that of the Sun. The star is one of the primary sources illuminating the nebula and shaping the complex's famed pillars of creation-type formations, the elephant trunks.

Taken at Kelling Heath Star party in Norfolk UK Sept 2019

Total Ha 19 x 600secs half and half 7nm and 3nm Baader filters
Oiii 6 x 300secs
Sii 5 x 300secs
Total 4 hours 5mins
Mapped SHO + some RGB stars

The tif images have been calibrated and stacked ready for processing and can be downloaded from here:

https://drive.google.com/drive/folders/ ... sp=sharing

Please download the files and process using your preferred software. Then post an image of your results with a description of your methods for discussion.

You can also just join the discussion with some input for us all to learn from.

If you have data to submit for a future challenge please email a download link to a cloud storage location to tssapchallenge@theskysearchers.com

Have fun!

Regards

Graeme

I've never processed before, not even sure where to start, I wonder if I should give it a go..hmmmm

I struggle with my OSC files!

Many thanks Graeme for putting this together.

I am looking forward to what “develops “ here!

Good luck everyone!

SirTalllPaul wrote: ↑Wed Jul 01, 2020 6:45 am I've never processed before, not even sure where to start, I wonder if I should give it a go..hmmmm

A lot of people here have never processed an astro image or (me included) have only ever processed single file colour images, so you're in good company.

Give it a go!

Regards

Graeme

Juno16 wrote: ↑Wed Jul 01, 2020 10:49 am I struggle with my OSC files!

Many thanks Graeme for putting this together.

I am looking forward to what “develops “ here!

Good luck everyone!

Same as that! This will be my first go at NB processing. I'm looking forward to seeing what I can learn too.

Regards

Graeme

i'll give it a go, the ha looks fine but the oiii sii looks like it has some noise reduction or something done to it while stacking .

did you bin the oiii and sii and then drizzled them ?

This should be interesting. A chance to play the narrowband arena! First pass is really weird.

Bob

took about 15 mins to process , just basic stretch of each frame, scr green removal, hue shift on the stars,star mask,psf,lum mask, deconvolution 50 iterations, tvgdenoise,crop.

i didn't do background extraction, i've notice lately that it has been removing some faint signals in my images .

some questions, badder has 3nm ? how did carol stack the 7nm and 3nm , did she do this for the nii data ?

also do you have a link to the original image ?

Thanks for the enthusiastic responses Yobbo!

yobbo89 wrote: ↑Wed Jul 01, 2020 1:26 pm i'll give it a go, the ha looks fine but the oiii sii looks like it has some noise reduction or something done to it while stacking .

Not sure about that. Perhaps [mention]carastro[/mention] can shed some light.

yobbo89 wrote: ↑Wed Jul 01, 2020 1:55 pm did you bin the oiii and sii and then drizzled them ?

Carol's original post doesn't mention binning or drizzling.

yobbo89 wrote: ↑Wed Jul 01, 2020 2:19 pm took about 15 mins to process , just basic stretch of each frame, scr green removal, hue shift on the stars,star mask,psf,lum mask, deconvolution 50 iterations, tvgdenoise,crop.

i didn't do background extraction, i've notice lately that it has been removing some faint signals in my images .

some questions, badder has 3nm ? how did carol stack the 7nm and 3nm , did she do this for the nii data ?

also do you have a link to the original image ?

Carol's original post is here:

viewtopic.php?f=66&t=7044&p=60541&hilit=NGC7822#p60541

If you mean the individual capture files then I'll have to go home and check to see if Carol submitted those. I'm at work at the moment.

That's a great first try at the image Yobbo. Great depth. I'm going to have a go tonight.

Regards

Graeme

Thanks for sharing your data, Carole!

Here is my attempt. I am very new to multi-channel narrowband processing. I spent a lot of time trying different palettes. I finally settled on H-HO-O.

After a very basic noise reduction using ATrous Wavelet Transform, I did a Masked Stretch on each image. I don't like doing background extractions on images that are mostly nebula, because they lose too much data.

For the narrowband data, I did a Linear Fit, then used those three images to try the various palette combinations, including SHO, Hubble (modified SHO), CFHT (HOS) and a few others. As I said, I settled on the H_HO_O palette.

I used Starnet++ to remove the stars, then did a bit of contrast tweaking with Curves and sharpening with ATrous Wavelets. I finished up the nebula with a pass of ACDNR noise reduction.

With the RGB data, I used Starnet++ to extract the stars. I did a Morphological Transform to reduce the star sizes, followed by Curves to adjust their brightness and saturation.

Finally, I used Pixel Math to combine the nebula and stars. The last step was to reduce the image size and convert to jpg for posting.

I couldn't find a way to reduce the star haloes, which escaped Starnet++ and ended up in the narrowband image. Had they been on a dark background, I might have tried harder to reduce them, but with bright nebula as the background, I thought it prudent to leave them alone.

Very nice rendition Kathy. That pallet gives a very different feel.

When you say you chose H-HO-O, does that mean you didn't use the Sii in your image?

Regards

Graeme

Graeme1858 wrote: ↑Wed Jul 01, 2020 10:02 pm Very nice rendition Kathy. That pallet gives a very different feel.

When you say you chose H-HO-O, does that mean you didn't use the Sii in your image?

Regards

Graeme

Thanks.

Correct, I didn’t use the Sii data. I used it in several of my palette tests, but I didn’t find that it contributed much.

I took a quick crack at the data in StarTools and used the Hubble palette. I loaded the Sii to the red channel, Ha to green and Oiii to blue. Processing consisted of using the Develop module to stretch, the Color module to apply SHO, a touch of deconvolution, and some noise reduction.
It was fun to play with something very out of the ordinary for me. I may try to do some more natural color processing and incorporate the RGB for star colors at some point.

Bob

yobbo89 wrote: ↑Wed Jul 01, 2020 2:19 pm also do you have a link to the original image ?

Just the four tif files.

KathyNS wrote: ↑Wed Jul 01, 2020 10:51 pm Correct, I didn’t use the Sii data. I used it in several of my palette tests, but I didn’t find that it contributed much.

What software did you use for trialing the palette combinations and the final merging of the Ha and Oiii files?

That's an open question to anyone that knows how to do this!

Regards

Graeme

bobharmony wrote: ↑Thu Jul 02, 2020 3:14 am I took a quick crack at the data in StarTools and used the Hubble palette. I loaded the Sii to the red channel, Ha to green and Oiii to blue. Processing consisted of using the Develop module to stretch, the Color module to apply SHO, a touch of deconvolution, and some noise reduction.

That's a great go at it Bob.

Will Startools let you use the other palettes to create an RGB image with the same data?

Regards

Graeme

Graeme1858 wrote: ↑Thu Jul 02, 2020 5:47 am What software did you use for trialing the palette combinations and the final merging of the Ha and Oiii files?

D'oh! I should have mentioned that. I used PixInsight. The Channel Combination tool makes it easy to allocate the different monochrome images to different colour channels. In the cases where I tried combined channels, like the HO that I eventually used, I used PixelMath to do a weighted average of the two mono images.

Graeme1858 wrote: ↑Thu Jul 02, 2020 5:54 am

bobharmony wrote: ↑Thu Jul 02, 2020 3:14 am I took a quick crack at the data in StarTools and used the Hubble palette. I loaded the Sii to the red channel, Ha to green and Oiii to blue. Processing consisted of using the Develop module to stretch, the Color module to apply SHO, a touch of deconvolution, and some noise reduction.

That's a great go at it Bob.

Will Startools let you use the other palettes to create an RGB image with the same data?

Regards

Graeme

Thanks, Graeme. StarTools allows for any combination of the data by associating each of the data files with any color channel you choose. It's all new to me, but very interesting to learn some of the new capabilities. For an RGB image I would assign the Ha data to the Red channel, and so on. We shall see!

Bob

So this looks kind of neat, and fun.

I understand all of the words you are saying separately, but when you put them together like that - I have no idea what's going on.

KingNothing13 wrote: ↑Thu Jul 02, 2020 2:38 pm So this looks kind of neat, and fun.

I understand all of the words you are saying separately, but when you put them together like that - I have no idea what's going on.