Is it possible to go both wide and deep with an amateur telescope only 106mm/4” in aperture?
To answer this question, I would like to present the
nebulae surrounding R Coronae Australis (R CrA).
Located within the small and faint constellation Corona Australis (CrA, Southern Crown), a magical dust cloud graciously sweeps through this scene, harbouring numerous star forming regions. Visible are the magnificent blue reflection nebulae (NGC6726, NGC6727 and IC4812) produced from young, hot stars reflected by the clouds of surrounding cosmic dust. It’s estimated that the nebulae is around 420 light-years distant. Near the two blue reflection nebulae is a small yellowish arc (NGC6729) which marks the location of the erratic variable star R Coronae Australis. This star is accreting interstellar matter and would appear to be the source of two tiny red patches indicating active stellar creation. The grand globular star cluster (NGC6723) is seen below and left of the nebulae. It resides nearly 30,000 light-years away, well beyond the Corona Australis dust cloud.
Info and processing on the image;
Total exposure time: 3 hours (Luminance:75min, R:35min, G:35min, B:35min). The image is a LLRGB composite and processed similar to my other recent post of NGC6188 Wide Field (see post for info) – so I won’t repeat myself. The only exception, I did no deconvolution/sharpening on this image as I wanted to maximise nebulosity. This signifies the quality of the data captured. I did however use a couple of PS layers to manage highlights ensuring critical/detailed information didn’t get white clipped. Certain not an easy object to process as it has a vast dynamic range – really stretched the data hard to bring out the sweeping cosmic dust cloud.
So how wide and deep?
I feel this image comes close to showing the theoretical limit in resolution for the FSQ and STL11k combination. In its native configuration (530mm F/5), the FSQ-106ED has a documented resolution limit of 1.09”and a limiting magnitude limit of 11.9. I certainly wasn’t expecting such resolution and depth from a 3.52 arcsec/pixel scale. To demonstrate the resolution/depth achieved, I present an annotated version of the image highlighting a few background objects (with a 1:1 scaling ratio - 100%) from this scene.
Annotated Image
Thanks for looking. I hope you enjoy. All comments welcome.
