NGC 891 - the silver sliver (Tom Gray)

NGC 891 - the silver sliver

NGC 891 is edge on to us, at least it was when the light departed some 30m LY ago. It is part of a super cluster in Andromeda. This 'silver sliver', some 100 thousand light-years across is bisected by a prominent dust lane with an HII emission core.

You can just about make out filaments of dust that extend hundreds of light-years above and below the center line. According to NASA the dust has likely been blown out of the disk by supernova explosions or intense star formation activity [https://apod.nasa.gov/apod/ap170112.html]. A number of fainter galaxies can also be seen in this frame, but have not been identified in the plate-solve.

Seeing and transparency were moderate, and deteriorated as the night wore on (and my taes were cald as the first frost of the year formed) so I only managed an hour of luminance frames. Tracking was reasonable, with an RMS 0.8", allowing 5 min subs.

Although only 7 frames made the 30% quality threshold in Envisage, I managed to align and stack all 13 uncombined frames in Nebulosity, suppressing some of the noise. I have processed rather aggressively in Startools to show off the dust filaments, but this is no substitute for more and better data! There is a horrible dust 'snake' at the bottom of the frame...I must get into the habit of taking flat frames.

One to pursue again in a dark sky to add colour, and at native f10 in my 2000mm SCT, to really show off this magnificent, galaxy - a silver sliver of the universe.

Original
B
C
Final
D

B

Description: Processed in Nebulosity 3 - I am not sure which is the better image? 'Much of muchness' to my untrained eye. As ever constructive criticism welcomed.

Uploaded: ...

C

Description: A cropped and enlarged version - a bit more detail, I hope without over-processing, but accentuates the noise. Startools does make everything very easy, but I am sure has many subtle nuances that I am missing. That said, I don't think anything can make up for a lack of data and poor SNR.

Uploaded: ...

D

Description: My final revision, processed in Startools. I have been more aggressive with wipe, contrast, and deconvolution, trying (rather unsuccessfully) to reduce ringing around bright stars. Isolation of NGC 891 using the ‘life module’, has helped to make the galaxy stand out, whilst suppressing background noise.

Uploaded: ...

Altair Astro 183 M/C Hypercams
UK Astro-Imaging
Schmidt-Cassegrain Telescope (SCT) Imagers

	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	Advanced success
Started	...
Astrometry.net job	3882589
PixInsight job	ASAP678RGEWX53D9A4BC7M5GFQW28R18
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	02h23m04s.57
RA (top/left)	02h21m07s.63
RA (top/right)	02h24m42s.40
RA (bottom/right)	02h25m02s.59
RA (bottom/left)	02h21m26s.56

Dec (center)	+42°21′24″.1
Dec (top/left)	+42°08′49″.7
Dec (top/right)	+42°03′59″.4
Dec (bottom/right)	+42°33′49″.5
Dec (bottom/left)	+42°38′42″.2

Image Index:

Contribution Index (beta):