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A frustrating night. NGC 7662 and M76


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Last night (2020-09-17) was not too bad a sky for me (SQM 20.3), but it was a rather frustrating session. Telescope alignment problems meant I had to re-do that mid-session. Some software problems. And then leaving the filter wheel on Blue for the last couple of objects.

First up here though, is NGC 7662 - the blue snowball planetary nebula - in fact it was really too bright! I tried this LRGB composite, which has a tinge of blue...
C11 on G11, f/6.3, ZWO ASI174MM mini
LRGB 2x30s each. 
Siril + Affinity Photo

ngc7662_20200917_800.jpg.b9f77ec073dbc647b2bb4a9df0e21760.jpg

M76 - this is just the Luminance frame - same equipment as above, 10 x 30s exposures. I tried a quick LRGB but the background noise was too horrible to make the image worth sharing. There is a star at the centre of the nebula, but I am not 100% sure if this is the central star, which is quoted at mag. 16.6.

 

m76_20200917_L_800.jpg.135fb0bd493f79d1e0de27cd3111f63c.jpg

 

Forecast for tonight is promising, so I hope I might be able to revisit last night list.

Callum

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1 hour ago, callump said:

Last night (2020-09-17) was not too bad a sky for me (SQM 20.3), but it was a rather frustrating session. Telescope alignment problems meant I had to re-do that mid-session. Some software problems. And then leaving the filter wheel on Blue for the last couple of objects.

First up here though, is NGC 7662 - the blue snowball planetary nebula - in fact it was really too bright! I tried this LRGB composite, which has a tinge of blue...
C11 on G11, f/6.3, ZWO ASI174MM mini
LRGB 2x30s each. 
Siril + Affinity Photo

ngc7662_20200917_800.jpg.b9f77ec073dbc647b2bb4a9df0e21760.jpg

M76 - this is just the Luminance frame - same equipment as above, 10 x 30s exposures. I tried a quick LRGB but the background noise was too horrible to make the image worth sharing. There is a star at the centre of the nebula, but I am not 100% sure if this is the central star, which is quoted at mag. 16.6.

 

m76_20200917_L_800.jpg.135fb0bd493f79d1e0de27cd3111f63c.jpg

 

Forecast for tonight is promising, so I hope I might be able to revisit last night list.

Callum

If it’s in the centre then I am taking it as the central star😁In all seriousness it looks to be about as bright as the least bright stars in the background. Is there a way you could identify any of the background stars to compare 16.6 mag?

Marv

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Hi Callum

Some of the planetary nebulae need very short exposures with our sensors. I visited this one recently (will post it in the PN thread at some point when I've found time to read up on it...) with 5s exposures and then found I needed to view it with almost no stretch.  I was quite surprised by the appearance: the lower-case 'omega' nebula! Orientated to match yours, this is 1m 20s total (4 x 5 seconds in each of LRGB).

1031994830_Screenshot2020-09-18at21_02_14.png.c4fc9df477a1411404bb75e526cdad94.png

 

BTW This is my overstretched version. Although LRGB is meant to separate luminosity and chromaticity, in practice I find that stretching the L washes out the colour and I suspect that is why you are only getting a tinge of blue.

1774108787_Screenshot2020-09-18at21_14_37.png.a9bb4f36db7a29ebc3c2ebc2fe947a25.png

cheers

Martin

 

Edited by Martin Meredith
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4 hours ago, callump said:

Last night (2020-09-17) was not too bad a sky for me (SQM 20.3), but it was a rather frustrating session. Telescope alignment problems meant I had to re-do that mid-session. Some software problems. And then leaving the filter wheel on Blue for the last couple of objects.

First up here though, is NGC 7662 - the blue snowball planetary nebula - in fact it was really too bright! I tried this LRGB composite, which has a tinge of blue...
C11 on G11, f/6.3, ZWO ASI174MM mini
LRGB 2x30s each. 
Siril + Affinity Photo

ngc7662_20200917_800.jpg.b9f77ec073dbc647b2bb4a9df0e21760.jpg

This is your pic processed using Topaz DeNoiseAI to give you an idea of options.

ngc7662_20200917_800.jpg.b9f77ec073dbc647b2bb4a9df0e21760-DeNoiseAI-low-light-new.jpg.fe903bf47ea084e0c4ea03123ace2de0.jpg

Edited by Monty
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