Sh2-171 – Resolution Perception Test (Alex Woronow)

Sh2-171 – Resolution Perception Test

Sh2-171 – Resolution Perception Test

OTA:______RH-305 (12” f/3.5)

Camera:___SBIG STX-16803

Observatory: Deep Sky West

EXPOSURES:

B: 12 x 300 sec

G: 11 x 300

R: 8 x 300

Ha: x 1200 sec

OIII: x 1200

SII: x 1200

Total exposure 27.6 hours

Image Width: 1d 47”

Processed by Alex Woronow, 2021 (data from 2018) using PixInsight, Topaz, Photolemur, SWT

The opening image blinks a grayscale and a color rendering of Sh2-171. In addition, the stand-alone grayscale image serves as the luminosity channel in the color image. The idea is to illustrate how color affects human perception of detail resolution (and to present my processing of Sh2-171, of course).

Once you’ve visually digested the blinking images, I hope you will examine one or both of the individual images (B and C) more deeply. (They are higher-fidelity.) Your comments and opinions, and observations about this comparison would be appreciated. My leaning is to eschew color images in favor of grayscale renditions when Ha dominates the color image to the extent of making a rather monotone anyway.

Some additional information:

1. The luminosity is not from L-filter images but the extraction of the L-emission line from the Ha and R filter data. Therefore, the structures shown in these images are those in the Ha emissions without a red “background” signal.

2. The OIII and SII emission-lines' structures are extremely weak relative to the Ha signal and would have added little to the pseudo-L structures show in the grayscale image. However, the OIII does add to the broad (low frequency) color patterns in the color image.

3. Obviously, I have added stars to the color image, but not the grayscale image. Consider that in your image comparisons as you will!

Thanks for looking and commenting…

Alex

Final
Original
B
D

B

Description: Ha line extracted from Ha stack and R images. These data serve as the L channel in image D

Uploaded: ...

D

Description: SHORGB with image B data serving as the L channel

Uploaded: ...

Members of Deep Sky West

	Distinct awarded users	Total awarded images
Image of the day
Top picks
Top pick nominations

	Image of the day	Top pick	Top pick nominations	Total submitted
Deep sky
Solar system
Extremely wide field
Star trails
Northern lights
Noctilucent clouds
Landscape

	Image of the day	Top pick	Top pick nominations	Total submitted
Backyard
Traveller
Own remote observatory
Amateur hosting facility
Public amaeteur data
Professional, scientific grade data
Mix of multiple sources
Other
Unknown

Submitted The date and time when you submitted this image for IOTD/TP consideration.	...
Views by Submitters (available since September 19th, 2023) Every image is assigned to 50% of available Submitters. In the event that at least 80% of them don't view the image before its time in the IOTD/TP process expires, it's assigned to the other 50% of Submitters and the process begins anew.
Promotions by Submitters When 3 distinct Submitters promote the image, it moves on to the next stage of the process: evaluation for Top Pick status. This requirement, in addition to anonymization of images and distribution to only a subset of them, prevents biases and ensures that the best images are selected.
Promotions by Reviewers When 3 distinct Reviewers promote the image, it moves on to the next stage of the process: evaluation for IOTD status.
Early dismissal Staff members have a lot of images to inspect on a daily basis, and they can dismiss images if they believe they don't meet the requirements for IOTD/TP selection. If an image is dismissed 5 times, it's removed from the process. This streamlines the process and ensures that any bias present in promotions could be overruled by other staff members.

Status	Basic failed
Started	...
Astrometry.net job	4575751
PixInsight job	n/a
PixInsight queue size	n/a
PixInsight stage	n/a

Image Index:

Contribution Index (beta):