dwarfvision - Double Stacking the Rosette

PROCESSING: Double Stacking the Rosette

Explore my unique approach to astrophotography processing, where "double stacking" takes on a new meaning. In this feature, I dive into a workflow centered around the Dwarf 3 Smart Telescope's raw stacks, using not individual .fits frames, but rather two complete raw stacks generated directly by the scope itself – One capture in AZ mode with sharp stars, and one EQ capture with better nebula detail. This innovative method bypasses traditional deep-sky stacking software, instead leveraging Photoshop and Lightroom to expertly blend these two Dwarf 3 outputs. Join us as we uncover the step-by-step process, from capture and noise reduction to sophisticated color manipulation, demonstrating how to achieve stunning Rosette Nebula images through this distinctive "double stacking" technique.

Capture Details

AZ capture (fainter details, sharper stars)

EQ capture (brighter details, softer stars)

To capture the Rosette Nebula, I undertook two separate sessions, each exceeding 2.5 hours, using my Dwarf 3 scope. Both employed a duo-band filter and consisted of 30-second exposures at a gain of 60 with 4X binning, deliberately avoiding any in-camera AI enhancements. The first raw stack capture at left was captured in AZ mode, resulting in a sharp capture of the stars but the nebulosity was faint. The second capture, which was acquired in EQ mode, unfortunately exhibited slightly more bloated stars, potentially due to a less-than-ideal focus or minor cloud interruptions during the session. Still, the nebula's details were much brighter and the color was more accurate.

To create the best final image, I intend to stack the two together in Photoshop, ultimately selecting the image exhibiting the most pleasing stars for the final composite.

DeNoise In Gigapixel 8

Both astrophotos were processed using Topaz Labs Gigapixel 8 to prepare for stacking and enhance image quality. As depicted in the settings screenshot, I selected the "Low resolution v2" AI model for noise reduction to address potential issues and refine details. Within this model, specific parameters were applied: Sharpening was set to 38, Denoising to a more aggressive 85, and "Fix compression" was dialed to 20. The images were upscaled by 1.30x, resulting in an output size of 5000 x 2827 pixels at 92 dpi. This Gigapixel 8 pass aimed to reduce noise and refine details before the subsequent stacking and final compositing stages.

Denoising in G8 - or your own fav. Denoiser

Stars Isolation and reduction in Photoshop

Color range selection

Reducing star size & Brightness

Curves Adjustment Layer for Star Emphasis:

Moving into Photoshop on the sharper AZ mode capture, my first step was to prepare the stars for isolation. I created a separate "Curves" adjustment layer by duplicating the background layer. Using this layer, I manipulated the curve to specifically brighten the stars while subtly reducing the overall prominence of the nebula. This adjustment helped make the stars more distinct and straightforward to select in the following steps.

Color Range Star Selection: To specifically target the stars on the curved layer, I then employed the "Color Range" selection tool. I carefully adjusted the "Fuzziness" and "Range" sliders within the "Color Range" dialog to select primarily the brighter stellar elements and their immediate surroundings.

Expanding and Feathering the Selection: To ensure I captured the subtle glow and halos extending beyond the core of each star, I expanded this initial "Color Range" selection by 5 pixels. Following expansion, I applied a "feather" of 5 pixels to the selection edges to create a smooth, graduated transition. This feathering prevents harsh or artificial boundaries when manipulating later star selections.

Reducing Star Size and brightness: With the star selection active on the curved layer, I utilized the "Minimum" filter. As shown in the screenshot, I set the "Radius" to 2.0 pixels and ensured "Preserve Roundness" was checked. Applying the "Minimum" filter with these settings effectively reduced the size of the selected stars, helping to refine their appearance in the final image.

Deleting fuzzy stars

Eliminating poor star images

For the EQ mode capture with less desirable stars, my goal was not minimization. Like the AZ image, I used a "Curves" layer and "Color Range" to select the stars, expanding and feathering the selection. However, I removed the selected stars from this image instead of minimizing. This allows the EQ capture to contribute nebula detail to the final composite, without its bloated stars.

Aligning the shots

To align the two captures in Photoshop, I first increased the canvas size to accommodate any potential shifts during alignment. I filled the expanded area with a black background for visual clarity. I then placed the star-removed EQ capture (with star "holes") as the top layer, positioning it directly above the sharper AZ mode capture.

I inverted the top "holes" layer to aid in precise alignment and reduced its opacity to 50%. This allowed me to visually compare the star holes to the stars in the underlying AZ layer. Using the Transform tool.

I performed a rough alignment by centering the images and rotating the top layer until the star holes coincided roughly with the stars beneath. After confirming the rough alignment and hitting return to apply the transformation.

I inverted the top layer to its original state and reset the opacity to 100%. Finally, zooming in closely, I meticulously made fine, pixel-by-pixel adjustments to the top layer's position until all the intricate details within the Rosette Nebula were perfectly aligned between the two captures.

Inverting and changing the opacity of the EQ stack to align it with the AZ stack

Perfecting the composite for Lightroom

With the aligned layers in place, I blended them harmoniously. First, I set the top layer's blending mode (the star-removed EQ capture) to "Lighten." This blending mode ensures that only the brighter pixels from the top layer (primarily nebula detail) will be visible. This allows the sharper stars from the AZ capture to show through from the layer below. To refine the color balance, particularly addressing a slight green cast in the AZ capture (bottom layer).

I utilized the "Channel Mixer" adjustment on the top layer. As shown in the screenshot above, I set the "Output Channel" to "Red" and then adjusted the "Source Channels" to "Red: +120%" and "Green: +39%." This adjustment helped shift the slightly greener tones of the AZ capture closer to the redder hue of the EQ capture, creating a more consistent color palette across the composite. Finally, to achieve the optimal balance of light and dark details and refine the overall contrast, I independently applied "Levels" adjustments to both layers.

By carefully manipulating the input and output levels in each layer's "Levels" dialog, I fine-tuned the brightness and contrast until the nebula details from the top layer and the star sharpness from the bottom layer were seamlessly integrated. This resulted in a well-balanced and visually appealing composite image.

Lightroom ready composite

Astrobin Inspiration

Colorful high contrast VS single palette with faint details.

With a Lightroom-ready, double-stacked image of the Rosette Nebula now achieved – boasting enhanced detail and pleasingly reduced stars – I turned my attention to the final aesthetic direction.

Seeking inspiration for color palette choices, I explored Astrobin, a valuable resource for astrophotographers.

I was particularly drawn to two distinct approaches: the vibrant, "rainbow-hued" renditions that showcase a broad spectrum of colors, and the deeply immersive, single-toned orange/red palettes that emphasize the faintest details in nebulosity.

Contemplating these contrasting styles, I considered which color direction would best convey the beauty and character of my Rosette Nebula capture.

My conclusion: Both!

Lightroom 1: Warm, faint details.

For my first pass in Lightroom, I aimed to maximize faint detail within a cohesive color palette, leaning towards a richly saturated orange-red aesthetic.

As shown in the settings panel, I started by engaging several Auto adjustments: Auto Exposure (-0.84), Auto Contrast, Auto Highlights (-100), Auto Shadows (+100), Auto Whites (-78), and Auto Blacks (+23).

These automated settings provided a foundation for balanced tonality and detail retrieval. I refined the tonal range using a Curve adjustment (as depicted), to fine-tune contrast and shadow/highlight.

Refine Saturation was boosted to +100 to enhance the nebula's presence, targeting subtle color information and bringing it forward. In the Color section, I opted for a Custom White Balance, setting the Temp to +27 and Tint to +37, nudging the overall color towards warmer tones.

Warm palette version in Lightroom

To manage color intensity after these adjustments, I dialed back both Auto Vibrancy (-84) and Auto Saturation (-11). Finally, the partially visible Color Mixer panel is tuned to emphasize the orange and red hues characteristic of a single-palette, deep-depth rendition of the Rosette Nebula.

Lightroom 2: Multi-hued vibrancy

"Cool" palette in Lightroom

In contrast to the single-palette approach, this second Lightroom adjustment set aimed to create a more vibrant, multi-hued rendition of the Rosette Nebula.

While many of the Auto adjustments are similarly engaged – Auto Exposure (-1.04), Auto Contrast, Auto Highlights (-100), Auto Shadows (+100), Auto Whites (-100), and Auto Blacks (+93) – the color treatment diverges significantly:

The Curve adjustment remains in place, to provide consistent tonal balancing. Saturation is still maximized at +100.

The key difference lies in the Color section. Here, the Custom White Balance takes on a colder hue character, with Temp set to a negative value of -53 and the Tint to -37. This shift towards cooler temperatures is crucial for introducing the blues and purples that characterize a rainbow-hued palette.

Auto Vibrance is increased substantially to +89, to boost the intensity of these diverse colors. Auto Saturation remains at a lower value of +6, to prevent overall color from becoming too overwhelming. The partially visible Color Mixer panel is aimed at selective color adjustments to enhance the interplay of different hues across the nebula, rather than emphasizing a single color range.

Final Adjustments: Photoshop

For the final touches in Photoshop, I imported the warm and multi-hued variations, previously adjusted in Lightroom, as full-sized TIFF files.

Guided by color theory principles, I established the warm-toned image as the base layer, setting its opacity to 100%. Knowing that orange and blue tend to neutralize towards gray when combined, I strategically placed the multi-hued version as a layer above. By reducing the opacity of this blue-toned layer to approximately 25%, I achieved a rich, dark sky background.

Experimenting with opacity around 50% revealed that star colors shifted towards a more natural appearance, but to prioritize the warm nebula details and prevent them from being muted, I opted for the 25% opacity setting.

Balancing the hues using photoshop layer opacities

To refine the color balance in areas that appeared overly purple due to the layer combination, I utilized a soft, broad eraser brush with a reduced opacity and flow (both at 45%). With this tool, or using feathered selections, I gently erased or masked away these purple-toned areas in the middle nebula regions. I added another layer at the very top to enhance the rainbow hues within the nebula's core. This layer consisted of the multi-hued image from Lightroom, but this time, I applied a further Hue/Saturation adjustment to push the colors even more towards a bright blue. Finally, I used a lasso selection with feathering to isolate and mask only the innermost region of the nebula on this top layer, ensuring this intense blue color enhancement was focused where desired, mirroring Astrobin examples. The resulting composite beautifully merges the deep, dimensional feel of the warm, single-palette base with the vibrant rainbow hues at the heart of the Rosette Nebula, capturing the best aspects of both color approaches.

THE FINAL IMAGES

A brilliant rose in a vivid palette

A more antique rose in a subdued palette

Software links and costs:

Adobe Photoshop & Lightroom Photography Plan:

Subscription Model: Adobe products are primarily subscription-based. The "Photography Plan" is their most popular option for photographers and includes both Photoshop and Lightroom.
Pricing:
- Monthly plan: Around US$19.99/month. This usually requires an annual commitment.
- Annual plan, paid monthly: Also around US$19.99/month, billed annually.
- Annual plan, prepaid: Around US$119.88/year (a slight upfront saving).
What's Included:
- Photoshop: Industry-standard image editing software with advanced features.
- Lightroom (Lightroom CC): Cloud-based photo management and editing software, great for organization and workflow.
- Lightroom Classic: Desktop-focused photo management and editing software, favored by many professional photographers.
- 20GB of cloud storage (can be upgraded for an additional cost if needed).
- Adobe Portfolio: Website builder.
- Adobe Fonts: Access to a library of fonts.
Official Link: Adobe Photography Plan

Topaz Labs Gigapixel AI and DeNoise AI:

Perpetual License (One-time Purchase): Topaz Labs software is generally sold with a perpetual license, meaning you pay once and own the version you purchased indefinitely. They do offer upgrade paths to newer versions for an additional cost.
Pricing (Individual Products - approximate):
- Topaz Gigapixel AI: US$99.99
- Topaz DeNoise AI: US$79.99
Bundles: Topaz Labs often offers bundles where you can purchase multiple products at a discounted price. They frequently have sales and promotions as well. Check their website for current bundle offers. The "Photo AI" bundle might include both Gigapixel and DeNoise, or they might offer a "Utility" bundle or similar.
Official Links:
- Topaz Gigapixel AI: Topaz Gigapixel AI
- Topaz DeNoise AI: Topaz DeNoise AI
- Topaz Labs Website (for bundles and sales): Topaz Labs

Notes on free trials:

Free Trials: Both Adobe and Topaz Labs typically offer free software trials, so you can try them out before purchasing to see if they meet your needs. Please be sure to look for trial download links on their respective websites.
Student/Teacher Discounts: Adobe often has discounts for students and teachers. Check their Education section on their website.
Sales and Promotions: Keep an eye out for sales for both Adobe Creative Cloud subscriptions and Topaz Labs products, especially around holidays or special events.

Equipment: Dwarf 3 Smart Scope

DWARF 3 SMART SCOPE

DWARF 3

The Dwarf 3 smart telescope stands out as a remarkably accessible yet powerful tool for astrophotography. Despite its relatively inexpensive price point, its features empower users to capture fantastic images of celestial objects like the Rosette Nebula. Its "smart" functionalities, such as automated alignment and tracking, simplify the often complex process of astrophotography, making it user-friendly for beginners and experienced imagers alike. Yet, it's far from a toy; the Dwarf 3 is a full-featured instrument capable of long exposures, filter use, and precise control, creating detailed and stunning deep-sky images that rival those taken with much more costly setups. It truly demonstrates that exceptional astrophotography results are achievable without breaking the bank.

Get your DWARF 3 smart scope here!

Join the Dwarf Vision D3 Stargazing Community!

Get inspired by accessible astrophotography with the Dwarf 3! Subscribe to our newsletter on Substack and receive weekly doses of cosmic beauty, practical tips, and connection with fellow enthusiasts.

Subscribe to Dwarf Vision D3 on Substack Now!

Page updated

Google Sites

Report abuse