My gear costs somewhere in the 4 figure area. Never added it all up because then I’d have to give an honest answer when asked by my family.

I bought a lot of it on the used market which helped a lot with the total price. I started with just the sirius mount, 6” newtonian, and my moms DSLR, but I’ve been slowly upgrading it over the last 5 years.

So despite doing astrophotography for over 5 years I've never gotten an image of M31 that I've completely liked until now. My last real attempt at it was in 2019, and looking back has some obvious noise reduction and color gradient issues (tbf I shot it from downtown Athens, GA). I recently visited my future in laws, who happen to live in the middle of nowhere, so I brought along my telescope to take some deep space pics. I also incorporated some hydrogen-alpha data from a while ago to help boost the Hii regions (the red splotches) in the galaxies a bit. At first I wasn't sure about the addition of the Ha data, so I ended up processing this image twice from scratch, one with Ha and one without. There were parts of each that I liked and disliked, so I blended the two finished pics together, and was very pleased with the results, which is the final image you see above. also here's a starless version for the hell of it. Captured on November 17th, 2022, from a Bortle 4 zone (Ha data was captured in October 2020 from a Bortle 6 zone)

Places where I host my other images:

Instagram | Flickr

Equipment:

• TPO 6" F/4 Imaging Newtonian

• Orion Sirius EQ-G

• ZWO ASI1600MM-Pro

• Skywatcher Quattro Coma Corrector

• ZWO EFW 8x1.25"/31mm

• Astronomik LRGB+CLS Filters- 31mm

• Astrodon 31mm Ha 5nm, Oiii 3nm, Sii 5nm

• Agena 50mm Deluxe Straight-Through Guide Scope

• ZWO ASI-290mc for guiding

• Moonlite Autofocuser

Acquisition: 11 hours 14 minutes (Camera at Unity Gain(Ha) and half unity (LRGB), -15°C)

• L- 46x120"

• R- 20x120"

• G- 18x120"

• B- 18x120"

• Ha -47x300" x 2 panels

• Darks- 30

• Flats- 30 per filter

Capture Software:

• Captured using N.I.N.A. and PHD2 for guiding and dithering.

PixInsight Processing:

• BatchPreProcessing

• SubframeSelector

• StarAlignment

• Blink

• ImageIntegration

• DrizzleIntegration (2x, Var β=1.5)

Linear:

• DynamicCrop

• automaticBackgroundExtraction

• EZ Decon

• NoiseXTerminator

• ArcsinhStrecth + HistogramTransformation to bring nonlinear

RGB Linear:

• Channelcombination to combine monochrome images into RGB image

• PhotometricColorCalibration

• SCNR green

• HSV Repair

Adding Ha:

> I followed this tutorial which had great results on some prior HaLRGB galaxy pics:

> http://www.arciereceleste.it/tutorial-pixinsight/cat-tutorial-eng/85-enhance-galaxy-ha-eng

• PixelMath to make Clean Ha. This effectively isolates just the Ha regions from the red continuum spectrum

> Ha-Q * (Red-med (Red))

> Q=0.15

• PixelMath to combine Clean Ha

• PixelMath to add Ha to RGB image ($T)

> R= $T+B*(Ha_Clean - med(Ha_Clean))

> G= $T

> B= $T+B*0.2*(Ha_Clean - med(Ha_Clean))

> B=1

Nonlinear Processing:

• PixelMath to add original RGB image into the gaps from the old Ha data

• Slight SCNR

• ArcsinhStretch + HistogramTransformations to stretch nonlinear

> The RGB image without Ha was processed almost identically as above, minus the Ha addition steps. while nonlinear they were processed pretty similarly, so I'm just going to list out the general steps as they broadly apply to both images:

Nonlinear:

• LRGBCombination with stretched luminance

• Shitloads of CurveTransformations to adjust lightness, saturation, contrast, hues, etc.

• Extract L --> LRGBCombination for chrominance noise reduction

• color saturation to slightly desaturate the Ha regions

• More curves

• SCNR > Invert > SCNR > invert to remove some greens and magentas

• LocalHistogramEqualization

> Two rounds of this. one at size 16 for the finer 'feathery' details and one at size 500 for large scale structures

• even more curves

• NoiseXTerminator

• EZ Star Reduction

• noise generator to add noise back into star reduced areas

• guess what baby more curves

PixelMath to combine the two fully processed images 50:50

• Another round of EZ star reduction, NoiseXTerminator, and LRGBCombination chrominance noise reduction

• HEY DID YOU KNOW I LIKE USING THE CURVESTRANSFORMATION PROCESS?

• Resample to 60%

• Annotation

because even though there's some ionized gas floating around it's still pretty much a vacuum

the red is hydrogen gas, and the blue is oxygen. This image is false color, but the HOO palette I used is fairly close to true color, since the hydrogen-alpha emission is in the red part of the spectrum, and oxygen-iii is teal

I'll probably send it to the APOD folks at some point

Apparently it's called the crescent nebula because that's what it looks like through a visual telescope. I think it looks more like a scrotum ¯\_(ツ)_/¯

This is my third time shooting the Crescent Nebula! I had first shot it back in 2017 when I still used a DSLR for astrophotography. I still use the same scope, but eventually upgraded to a monochrome astro cam, and this was my first target using Hydrogen alpha + Oxygen-iii narrowband filters in 2019. This year I decided to shoot it again, although I combined this years data with the data from 2019 since my setup then was identical to how it is now. I did have to heavily crop in on this image due to differing camera rotations, but I ended up with a higher signal to noise ratio overall by combining the data. I also made a starless version of this pic which better shows off the faint nebulosity, including the Soap Bubble Nebula in the bottom left.

Captured over 5 nights in May 2019 (Bortle 7) and 4 nights in May 2022 (Bortle 6)

Places where I host my other images:

Instagram | Flickr

Equipment:

• TPO 6" F/4 Imaging Newtonian

• Orion Sirius EQ-G

• ZWO ASI1600MM-Pro

• Skywatcher Quattro Coma Corrector

• ZWO EFW 8x1.25"/31mm

• Astronomik LRGB+CLS Filters- 31mm

• Astrodon 31mm Ha 5nm, Oiii 3nm, Sii 5nm

• Agena 50mm Deluxe Straight-Through Guide Scope

• ZWO ASI-120mc for guiding

• Moonlite Autofocuser

Acquisition: 26 hours 5 minutes (Camera at Unity Gain, -15°C)

• Ha - 61x360" + 88x300"

• Oiii - 54x360" + 87x300"

• Darks- 30

• Flats- 30 per filter

Capture Software:

• Captured using N.I.N.A. and PHD2 for guiding and dithering.

PixInsight Processing:

• BatchPreProcessing

• SubframeSelector

• StarAlignment

• Blink

• ImageIntegration

• DrizzleIntegration (2x, Var β=1.5)

• DynamicCrop

• DynamicBackgroundExtraction

• EZ Decon

• NoiseXTerminator

• STF applied via HT to bring each image nonlinear

Combining Channels:

> really like how the colors turned out on this, especially the slight gold/yellow in the nebula compared to the red in the background

• Pixelmath to make RGB image using ForaxX's HOO palette:

> R= Ha

> G= ((Oiii*Ha)^~(Oiii*Ha))*Ha + ~((Oiii*Ha)^~(Oiii*Ha))*Oiii

> B= Oiii

Nonlinear:

• LRGBCombination with extracted L as luminance, used for chrominance noise reduction

• Shitloads of CurveTransformations to adjust lightness, saturation, contrast, hues, etc. with various masks

• NoiseXTerminator

• More Curves

• EZ star reduction

• NoiseGenerator to add noise into reduced star areas

• Even more curves

• ColorSaturation to better bring out the Oiii regions

• More NoiseX

• Resample to 80%

• Annotation