Observation by Kevin Gurney: Sh2-91

Uploaded by

Kevin Gurney

Observer

Kevin Gurney

Observed

2022 Aug 06 - 23:24

Uploaded

2022 Aug 17 - 10:37

Objects

Sharpless 91

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Constellation

Cygnus

Field centre

RA: 19^h35^m
Dec: +30°09'
Position angle: -10°01'

Field size

2°31' × 1°26'

Equipment

William Optics Star71
Fornax 102
ZWO ASI1600MM pro
Baader narrowband filters
Atik EFW2
SX Lodestar X2
FLO OAG

Exposure

27x300s Ha, 24x300s OIII over two nights (6/7 August)

Location

Charente, France

Target name

Sh2-91

Title

Sh2-91

About this image

This was the Deep-Sky object of interest for August. I'ts part of a larger supernova remnant and the challenge was to image the whole structure which is around 4deg across. I tried this with a Canon 200mm lens and the ZWOASI1600m camera but I didn't have filters for this rig and the results were disappointing... you really need narrowband I think.

So I focussed on the designated part (Sh2-91) with the WO71 refractor. This object is hard to image! Its much fainter than the more well know Veil nebula. Good images in Astrobin have upwards of 12 (often > 30) hours of data... I didnt have the patience for this :) so my 4 hours 15mins of data are all I have. Captued in Voyager, Processed in PI. Ha in Red, OIII in Blue/Green

The other problem is the 'noise' supplied by the density of stars surrounding it. I used star masking and morphological reduction in PI, but these always lead (at least in my hands) to somewhat odd-looking stars. However, on balance I think this helps bring out the nebula...

The bright red stellar object in the field looks artefactual but it turns out to be Campbell's Hydrogen Star (HD184738, V1966 Cyg) which is also a small planetary nebula.

Files associated with this observation

LRGB2_proc1c_Xnview_FINAL_BAA.jpg (1.5 MB)

Like this image

David Davies, Jeremy Shears, Callum Potter, Alan Thomas, David Basey, Brad Thomas, Manolo_Rodriguez

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