Celestial hemisphere:  Northern  ·  Constellation: Ursa Major (UMa)  ·  Contains:  NGC 3718  ·  NGC 3729
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NGC 3718 - Last-light for my Celestron 8SE OTA, Anthony Quintile
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NGC 3718 - Last-light for my Celestron 8SE OTA

Getting plate-solving status, please wait...
NGC 3718 - Last-light for my Celestron 8SE OTA, Anthony Quintile
Powered byPixInsight

NGC 3718 - Last-light for my Celestron 8SE OTA

Equipment

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Acquisition details

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Description

I ordered a new Celestron 9.25" SCT expecting arrival in August 2022 (!) and it ended up showing up in about week instead.

So that means this is the last image I'll be shooting with my 8SE OTA. This had been the "replacement" for the Super C8 I had as a kid when I got back into astronomy a little less than 40 years later in 2018, so a fond farewell to a classic platform, although the extra resolution and faster focal ratio will be welcome. (Yes, the 8" scopes are something like F/11 actually.)

I used only the best 13 hours of well over 20 hours as an experiment in quality over quantity for my subs.

The pixel scale is half the actual because I dithered and 2x drizzled.

Comments

Revisions

  • NGC 3718 - Last-light for my Celestron 8SE OTA, Anthony Quintile
    Original
  • NGC 3718 - Last-light for my Celestron 8SE OTA, Anthony Quintile
    B
  • NGC 3718 - Last-light for my Celestron 8SE OTA, Anthony Quintile
    C
  • NGC 3718 - Last-light for my Celestron 8SE OTA, Anthony Quintile
    D
  • NGC 3718 - Last-light for my Celestron 8SE OTA, Anthony Quintile
    E
  • NGC 3718 - Last-light for my Celestron 8SE OTA, Anthony Quintile
    F
  • NGC 3718 - Last-light for my Celestron 8SE OTA, Anthony Quintile
    G
  • NGC 3718 - Last-light for my Celestron 8SE OTA, Anthony Quintile
    H
  • Final
    NGC 3718 - Last-light for my Celestron 8SE OTA, Anthony Quintile
    I
  • NGC 3718 - Last-light for my Celestron 8SE OTA, Anthony Quintile
    J

B

Description: I should really wait until morning to post images. Lightened slightly since the image seemed too dark in the daylight.

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C

Description: Reprocessed and nearly full APS-C field.

I get some blue coma from either the scope or the corrector in the corners, and I had shot this object meaning to crop since it is so small. I could chase those tails in PS, but that's pretty tedious and this image isn't going to print or anything, so...

That said, there are a ton of interesting tiny galaxies and I wanted to do a version with those in the image as well.

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D

Description: I liked my reprocess for wide-field better, so I cropped to be my final "close-up".

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E

Title: Complete reintegration and reprocess from old data

Description: Once again, this image utilizes a lot more data, with total integration time being 22 hours 25 minutes - much more than the original ~13 hours, because I am defaulting to weighting rather than culling images.

This old setup (Nexstar 8SE with Starizona SCT Corrector II, I am currently using the IV which uses upgraded ED glass), of mine suffered from some severe chromatic aberration because I was using an older FR/CC with my SCT. I integrated using Separate RGB in WBPP and then combined them after integration. This helped with CA a bit.

I also used the Color Saturation tool and targeted the purple-blue star tails in the corners.

Because of the substantial tails on the stars, BlurX resulted in essentially a double-star effect on stars anywhere near the corners and edges. I did not use stars sharpened with BlurX and only reduced midtones on my stars to reduce the stars because of this. Better small tails than doubles.

Some of the stars are still a bit more pink than I'd prefer, but overall the widefield version of the image is pretty acceptable.

I also experimented with an extracted Luminance image to sharpen and work the contrast a bit. This is the first time I've done this. I did sharpen the RGB image some, but less. I need to research what I am doing with the separate Luminance a bit, but I can see where it can be helpful.

I did revert at the end to blending a darker Layer in Photoshop to increase the saturation and contrast in the galaxy cores, but only a little bit. Although I played with HDRMT and Local Histogram Equalization on the cores, I wasn't finding a result that I liked on these galaxies. They were mostly OK as they were with a bit of enhancement in Curves Transformation and a little of the above mentioned Photoshop technique.

One big goal with this image was to save all the little tiny galaxies and galaxy clusters as much as possible. I used a GAME Script generated mask to protect these before running StarXTerminator, which gave a pretty good result. Maybe I am mistaken but a lot of these deeper images have reddish clusters of what I assume to be distant galaxies, because they don't look round enough to be stars, and they aren't true red/pinkish like an H-alpha region. Either way, I saved some of those as if they were distant galaxy clusters, so maybe this is incorrect and silly.

Given the less-than-ideal nature of the data, (chromatic aberration-wise), I am pretty happy with this updated result. Be sure to also check out the un-cropped version of this image to see all the little galaxies!

Uploaded: ...

F

Title: UNCROPPED - Complete reintegration and reprocess from old data

Description: Full-field.

Spend a minute to check out the tiny galaxies!

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G

Description: Minor Histogram Transformation adjust to make the background more neutral/slightly less red.

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H

Description: Uncropped, minor Histogram Transformation adjust to make background more neutral/slightly less red.

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I

Description: Fixed pink halo around bright star in front of NGC 3729, slight Color Saturation increase, and minor Local Histogram Equalization to draw out details in the bright galaxy cores.

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J

Description: UNCROPPED - Fixed pink halo around bright star in front of NGC 3729, slight Color Saturation increase, and minor Local Histogram Equalization to draw out details in the bright galaxy cores.

Uploaded: ...

Sky plot

Sky plot

Histogram

NGC 3718 - Last-light for my Celestron 8SE OTA, Anthony Quintile