It's been so long since I posted a new image that it may seem like I gave up on it; but, nothing could be further from the truth.  This has just been a temporary pause in processing.   A lot has been going on since I last posted an image but we'll get to that later.

About NGC 1300
NGC 1300 is a barred spiral galaxy that was first discovered by Herschel in 1835.  At a magnitude of 11.5 and an apparent size of 6.2' x 4.1', it's a good target for larger, longer focal length telescopes located in the Southern Hemisphere.  It has a morphology classification of (R')SB(s)bc, showing two distinct arms spiraling from a "grand-design" nucleus that is about 3,300 ly long.  The diameter of the entire galaxy is estimated to be about 110,000 ly.

About the Data
I love a good galaxy project and this seemed like an excellent target.  I started on this project earlier in November as the spring seeing began to improve.  During the period that I took this data, the observatory monitor never showed conditions getting much better than about 1.5", which aligned with the quality of the data that I measured.  I set a threshold of 2.1" FWHM for my acceptance criteria which produced a yield of 50%-60% and around half of that fell into a range of 1.5" - 1.9".  As expected, the red channel is always the best and the blue channel is always "less-good".  I'm almost afraid to say it, but ever since my "tune-up visit" last April, the 20" has been working flawlessly...and in spite of my lapse in processing, I continue taking data every clear night, which means that I have gobs of unprocessed subs to play with whenever time permits.

About the Processing
This entire data set contained gradients.  So, to create a master local normalization image, I averaged all of the images that I took on Nov 13, which was new moon.  To my amazement, those integrated images still showed moderately strong gradients and they were different for every channel!  I am pretty sure that Nov 13 was perfectly clear with no clouds and I made sure that all of the images were taken well outside of astronomical twilight so I can't explain what caused the problem.  Either way, I've been having excellent luck with the AutomaticBackgroundExtraction (ABE) tool in PI for removing gradients.  In this case, a 3rd order fit worked perfectly to remove the gradients from each channel (which were all different).  

I used the SCC tool to calibrate the colors and that produced a very credible looking result. However, I felt that the overall color balance was just slightly biased toward the yellow so I wound up tweaking the color temperature to very slightly cooler colors.  Remember that my system incorporates a dichroic mirror in the ONAG, which is not precisely modeled in the SCC tool so I'm not sure that it produces 100% accurate results for my system.  It's close, but I'm not reluctant to make minor adjustments.  As always, I do about 90% of my processing in PI, but I still find that I am more comfortable doing the last 10% of the finishing touches in PS.  This image is a cropped, sub-sampled (by 50%) version of the original processed image.

Hopefully I Can Find More Time
Even though I run both of my imaging systems every clear night, I just haven't had the time since last since last summer to process much data!  One of the things that chewed up a lot of time this summer was my effort to finish up a commercial helicopter rating.  It has been a bucket list item for a very long time and I've been working on it every summer for the last 3-years and this summer, it finally all came together.  I did the check ride in late October, which required a LOT of practice and study and that pretty much chewed up time that I might have otherwise used for image processing.  Still, it was totally worth it.  I know that not everyone can do these kinds of things and I feel very fortunate to be able to pursue these kinds of dreams.  Helicopter flying is both hard and very addicting, but unfortunately it's not cheap!

The other "little project" that I've been working on is a bigger scope.  Last summer I decided to sell the 20" and move to a 24".  We just completely the optical testing on the new scope and there's a whole story behind that project, but I'll do a seperate post with some images to tell the full story.  I had hoped to commission it in early January but the new observatory building won't be done until nearly February.  So right now it looks like I'll be heading down to Chile again during the second half of February to get it all going.  In the meantime, there have been a lot projects related to this new imaging system but I'll save that for another, more appropriate post.  I've also been working a little bit to help Adam Block with his 24" project as well so we've been comparing a lot of notes. You can see more about Adam's project here:  https://www.patreon.com/user?u=80004680.  It will be cool to be able to compare imaging performance with Adam when we finally get our two scopes set up and running at Obstech.

Feel free to provide feedback.  C&C are always welcome .

John