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Old 29-04-2018, 12:40 AM
Placidus (Mike and Trish)
Narrowing the band

Placidus is offline
 
Join Date: Mar 2011
Location: Euchareena, NSW
Posts: 3,719
NGC 3293 in HaRGB

Greatly inspired by Mike Sidonio's version, thrilled to notice that our brand new replacement generator (with remote start/stop) had just arrived from Melbourne, but aware of the full moon, we thought we'd do something very bright to celebrate.

Hydrogen alpha 1x1 hour (mapped to red), and RGB 15x60 sec each. Each pixel is the brighter of the H-alpha and the RGB images.

Original image here

There is a great deal of fine wispy detail in the H-alpha. We are guessing that the very orange star in the cluster is a red giant nearing the end of its days.

In the RGB-only image, we noticed some very faint blue reflection nebulosity which is not visible in the combined image. We have pushed the attached RGB-only thumb to bring it out. In previous work, an OIII filter shows it is reflection nebulosity rather than OIII, which is extremely sparse in this field.

Edit: We've just noticed the reflection nebulosity is quite clear in Mike Sidonio's HaRGB image, so we just need more hours and a more thoughtful way of combining the Ha with the RGB.

Further edit: Here we've increased the blue channel, but using the luminance as a mask, so the reflection nebulosity is brighter, but the H-alpha and the stars are unchanged.

Best,
Mike and Trish
Attached Thumbnails
Click for full-size image (Gem Cluster Ha 1hr RGB 15 min each thumb.jpg)
170.8 KB91 views
Click for full-size image (Gem cluster pushed to show reflection nebulosity Thumb.jpg)
191.4 KB112 views
Click for full-size image (Enhanced reflection nebulosity thumb.jpg)
163.1 KB65 views

Last edited by Placidus; 29-04-2018 at 10:55 AM.
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