Arty Farty Jelly

[Peakedge]

First post of this winter season, never mind this year as like everyone else, have been frustrated with the constant cloud.
Anyway, one of my few sessions was the Jellyfish Neb and whilst processing I must have been drinking and started seeing shapes in the nebula. The attached is my interpretation, hence the name of the post!! I am reminded of an ethereal alien being (the nebula) staring into the depths of the cosmos. Told you I had been drinking! I wonder how many others can see this or am I the only one. If I am, think I'd better let her indoors empty the fridge of beer!

20 x 5 mins @ ISO 800
Processed in Pixinsight (my first attempt with the trial version, and I'm now a PI convert - I love it!)

Can't wait for your feedback, even if it is just to say to give up the beer!

David
 

[Stub Mandrel]

Perhaps it's a flying spaghetti monster?

Edit - on a serious point, you have nice detail but you seem to have the faint, angled 'brushstroke effect' on the sky background that I get (aligned from 11 o'clock to 5 O'clock). Any ideas what causes it?

[laudropb]

Very nice image. You don't have to give up the beer.

[Peakedge]

Neil

Perhaps it's a flying spaghetti monster?

Edit - on a serious point, you have nice detail but you seem to have the faint, angled 'brushstroke effect' on the sky background that I get (aligned from 11 o'clock to 5 O'clock). Any ideas what causes it?

 I have no idea what causes it. Perhaps its the relatively low amount of integration time for the picture and possible low SNR? I'd love to know too and possibly how to process it out, if anyone has any ideas? I used flats and bias in the processing but no darks since is from a DSLR.

An etherial spaghetti monster alien hybrid. I like it!!!!

David

[Peakedge]

Very nice image. You don't have to give up the beer.

Thank you and reassuring to know I dont have to empty the fridge!

David

[Bart]

I see it too. Does he have horns pointing downwards?

[wimvb]

Perhaps it's a flying spaghetti monster?

Edit - on a serious point, you have nice detail but you seem to have the faint, angled 'brushstroke effect' on the sky background that I get (aligned from 11 o'clock to 5 O'clock). Any ideas what causes it?

Neil

 I have no idea what causes it. Perhaps its the relatively low amount of integration time for the picture and possible low SNR? I'd love to know too and possibly how to process it out, if anyone has any ideas? I used flats and bias in the processing but no darks since is from a DSLR.

An etherial spaghetti monster alien hybrid. I like it!!!!

David

Nice image! I think the background brushstroke effect (or rainy effect) is caused by noise from the DSLR. I have it on multiple images. You can check if it is stacking related by using the Blink function in PI (All processes, blink). Use it on the raw light frames.

I got rid of it when I started dithering.

See this video for an explanation about DSLR noise and dithering.

https://www.youtube.com/watch?v=PZoCJBLAYEs

Good luck

[Peakedge]

I see it too. Does he have horns pointing downwards?

I hadn't thought of that but now you mention them, yes!!!

[Peakedge]

Nice image! I think the background brushstroke effect (or rainy effect) is caused by noise from the DSLR. I have it on multiple images. You can check if it is stacking related by using the Blink function in PI (All processes, blink). Use it on the raw light frames.

I got rid of it when I started dithering.

See this video for an explanation about DSLR noise and dithering.

https://www.youtube.com/watch?v=PZoCJBLAYEs

Good luck

I will certainly check using Blink, saw it for the first time whilst playing around with PI yesterday. However, I always dither between lights so wonder if it is more noise related due to the DSLR being quite warm. I thinks the temp recorded in the EXIF data was 16 deg C, +- 1 deg for each frame!

[Stephen Green]

 Nice image

Stephen

[ollypenrice]

You don't really have the field of view for this target, which is pretty big! (I believe alcohol diminshes peripheral vision but if you were giving your beer to your camera and scope then you are far more generous than I am...) 

So I'd go for a target you could catch in one or brace yourself for a marathon mosaic, maybe?

 lly

[wxsatuser]

Perhaps it's a flying spaghetti monster?

Edit - on a serious point, you have nice detail but you seem to have the faint, angled 'brushstroke effect' on the sky background that I get (aligned from 11 o'clock to 5 O'clock). Any ideas what causes it?

This is the infamous 'walking noise'.

Neil

 I have no idea what causes it. Perhaps its the relatively low amount of integration time for the picture and possible low SNR? I'd love to know too and possibly how to process it out, if anyone has any ideas? I used flats and bias in the processing but no darks since is from a DSLR.

An etherial spaghetti monster alien hybrid. I like it!!!!

David

More than likely, trying to stretch low signals brings it out more.

I think it's related to drift between each sub, you can see a similar effect on hot pixels.

You can check the drift in DSS, the dx dy columns should give an idea how much each

sub has moved.

[Peakedge]

You don't really have the field of view for this target, which is pretty big! (I believe alcohol diminshes peripheral vision but if you were giving your beer to your camera and scope then you are far more generous than I am...) 

So I'd go for a target you could catch in one or brace yourself for a marathon mosaic, maybe?

 lly

Olly

I would never waste beer on the camera and scope, even hate spilling it!

The picture is a crop from a much larger frame, and I realise I would struggle to fit this target in but it was my first night out for months and had to get something in I hadn't imaged before. I aspire to a mosaic and think it will be the old favourite of the area around the Horsehead and Flame nebulae. I tried the Flame nebula at the weekend and will be posting soon.

[Peakedge]

This is the infamous 'walking noise'.

More than likely, trying to stretch low signals brings it out more.

I think it's related to drift between each sub, you can see a similar effect on hot pixels.

You can check the drift in DSS, the dx dy columns should give an idea how much each

sub has moved.

The picture is quite a tight crop of the original frame to show the 'alien head' and so may bring out the noise more.

However, whilst stacking in PI, I did notice the dx dy columns and the values in them. Is this movement not due to dithering between subs or is it caused by poor polar alignment, for example. It just seems counterintuitive that movement between frames causes this issue when dithering is use to increase the SNR of a stacked image. I will happily take your advice on this because its another issue to learn and master!!

David

[wimvb]

I will certainly check using Blink, saw it for the first time whilst playing around with PI yesterday. However, I always dither between lights so wonder if it is more noise related due to the DSLR being quite warm. I thinks the temp recorded in the EXIF data was 16 deg C, +- 1 deg for each frame!

Good point. If you dither in a random or non-linear pattern, streaks caused by stacking shouldn't be there. And to be fair, I started dithering recently, so at about the same time the temperature dropped. I can't rule out that the lower noise I have is (in part) due to low temperature. If the weather plays along, I can check that next spring.

[Peakedge]

Good point. If you dither in a random or non-linear pattern, streaks caused by stacking shouldn't be there. And to be fair, I started dithering recently, so at about the same time the temperature dropped. I can't rule out that the lower noise I have is (in part) due to low temperature. If the weather plays along, I can check that next spring.

If you look at my latest post of the Flame Nebula with exactly the same set up and lights plan, I don't think the noise pattern you spotted was aparent though that could be my eyes! There were only 11 frames but the temperature was lower, around 2 deg C.

David