Webcam and fuzzies - why can't I see them?

[teh_orph]

Hello guys,

First of all (before someone suggests it!) I don't have a DSLR because

- they cost money

- I'll need to mod my telescope, in order to bring it to focus

- I live on top of a tube line so there are frequent vibrations (long exposures may be a no-no)

- I want to see how far I can go with a webcam.

The camera I'm using is a PS3 Eyetoy. I've modified it to have a nosepiece and I've got some custom software to pull frames off in raw mode. I have full control of the shutter speed, exposure, sharpening etc. I can photograph the moon and planets and stars ok. I can even image the Orion nebula too! (work in progress)

But many fuzzies elude me - I think it could be my location as I have super light pollution...

Anyway, I've been trying to shoot parts of the Veil and Cocoon nebulas yet I can't see a thing! Here's an anim of Stellarium, overlayed with my shot and then an off-the-web pic of the Cocoon nebula all aligned with each other.

In my picture I have captured stars down to mag 13.6 (the one under the Stellarium text "Cocoon nebula" is 13.20 and I've just snapped that. Yet the nebula itself is supposed to be mag 7.2. Surely I would have been able to capture some of it?? It should be 300x brighter than the dimmest star in my image!

My picture was taken from 15 mins worth of five-second exposures, two mins of darks, all stacked in AviStack. Skywatcher 130p (f/5). I used a IR cut filter for this image - using IR pass or UHC brought nothing out either.

I think it doesn't help that I couldn't see it visually either (even with a UHC filter) but I was hoping that photographing it would bring out...something!

What am I doing wrong??

Cheers!

EDIT: here's the veil too, shot with IR cut, IR pass, UHC. Note the UFO shape around HIP 102468 in all my pics - is that nebulosity? Bright star is 52 Cyg btw.

[Capricorn]

Magnitude is the light coming off the object.

The star is small and is Mag 13.? but that light is from a small and therefore intensish point.

The veil is also 13.? but extended, so the magnitude is off of the whole area that it covers. Each small section is therefore very very very dim.

A surface of say 1cm sq if transmitting 100 watts would be damn hot, a wall of 10 sq mtr transmitting 100 watts would just be a little warm.

By the way those pictures are difficult as hell to follow, may look fancy but not easy to study.

[Doc]

The bigger the area the dimmer the surface brightness and your 5 second subs are not really long enough to bring out any detail with the equipment you are using.

And I agree those pics are pretty hard to study.

[brantuk]

They do bring a certain mania into an otherwise sedate sort of hobby don't they lol

[teh_orph]

Yeah sorry about the trippy anims - yesterday was not a good day at work! Here's a side-by-side comparison.

Left is Veil (I've captures stars to mag 15 in this image) right is Cocoon (mag 13.5 ish).

But ah, I didn't realise that the quoted magnitude was a sum of the brightness over an object's entire area - I thought that was the average brightness of any point of it! Which would explain why I can't see it, as the area of some of these is these is huge!

[teh_orph]

Hello, so any feedback on these pics? In the pics from the internet the nebulas are very bright and are of (vaguely) comparable brightness to the stars in the shot. Surely I should be able to get a minor amount of nebula?

[riklaunim]

The exposures must be longer, gain lower. And you need to stack a lot of frames, substract darks to make it better. And if something is H-a nebula - will be hard to get in the webcam style without H-a filter.

On images nebula may be bright. But that image could have 30 min exposure time

[ollypenrice]

For those of us sitting down and laying seige th the Veil Nebula for 13 hours at dark sites your frustraton is not surprising...

Olly

[teh_orph]

Haha, yes I may have to blame the London factor...I noticed whilst laying in bed last night that even at midnight I could still see clear definition around each cloud in the sky! The sky is just a bit too bright I suppose (esp as I can't see it visually).

I just found it odd that even with many many short exposures and darks, I could easily bring out dim stars yet no hint of nebula. I've got some pics I'll upload later that show I can easily capture definition in the core of the Orion nebula, yet that's only a few exposures brighter! Ah well

[Shibby]

teh_orph,

I imaged the cocoon nebula back in August (see here). I used 30 x 2 minute exposures and the nebula was only *just* visible after several stretches of the curves. 30 x 2 minute is considered quite short for a nebula such as this.

Also, 7.2 probably refers to the associated star cluster, not the nebulosity itself (designated Sh 2-125 - don't know what magnitude, anyone?)