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The Soap Bubble with Night Vision

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#1 Gavster

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Posted 24 August 2019 - 11:42 AM

Back in May I had a fun night vision observing session with my C11 which I wrote up here:

https://www.cloudyni...d-night-vision/

In the replies to that post Cnoct asked me whether I had viewed/taken a pic of the Soap Bubble. I’d never heard of this object and did a bit of research to find out that it was only recently discovered in 2007/8 by CNer Dave Jurasevich. It seems it is a rather faint object.

Anyway I was intrigued by it and so was Ray (GeezerGazer). Ray challenged me 😀 to see if I could see/take a phone pic of it with my night vision equipment. It was obvious that it would need dark skies, aperture and a fast scope to have a chance of success.

 

This weekend events came together and I had my 16 inch f4 dob at a darkish site with good clear skies forecast so I thought I would make an attempt.

I decided that my system to try this would be my harder gen 3 monocular, coupled with a 55mm plossl and a narrow chroma ha filter. I was also using a Televue paracorr which increases the scope f ratio to 4.6. My 55mm plossl would reduce the speed down to a relatively fast f2.2

The skies weren’t quite as dark as previously (I measured sqm 20.7) and the half moon came up around 11.30pm so there were some obstacles but at 12.45am I managed to get this image with my huawei phone with 50 iso and 25 second exposure.

Checking this apod link which Ray kindly supplied to me together with detailed star hop to get to the Soap Bubble I realised I just (and I mean just!) managed to capture the Soap Bubble on my image (I couldn’t see it live visually).

https://apod.nasa.go...d/ap151204.html

Its a bit of a hunt to find it in the image (the apod link does help) but it’s right and up of centre...(Ray and Moshen have both agreed it is visible). I may have another go tomorrow when the moon is further out of the way.

Attached Thumbnails

  • CA15CA7F-A551-44E8-9D72-CFE08030C917.jpeg


#2 Jeff Morgan

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Posted 24 August 2019 - 12:28 PM

An interesting challenge!

 

I went back through my old images to see if it could be found. Unfortunately, the image through my 16" scope was centered on the Crescent and the Soap Bubble falls outside the field.

 

I did find an exposure through the Epsilon e180. It has the correct field, and I can (with averted imagination) make out a partial wisp of the Bubble. Maybe. A bigger scope (and better image) is called for.

 

Attached is a screen shot I took and marked up with star-hopping arrows which may be helpful for field orientation.

 

I definitely want to give this a shot next week!

Attached Thumbnails

  • Soap Bubble Field.001.jpg

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#3 Mike Lockwood

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Posted 24 August 2019 - 03:58 PM

I decided that my system to try this would be my harder gen 3 monocular, coupled with a 55mm plossl and a narrow chroma ha filter. I was also using a Televue paracorr which increases the scope f ratio to 4.6. My 55mm plossl would reduce the speed down to a relatively fast f2.2

This is incorrect - eyepieces do not change the f/# of a system.

 

They decrease magnification, and this makes images brighter for devices that behave like cameras/film/CCDs.



#4 Gavster

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Posted 24 August 2019 - 04:12 PM

This is incorrect - eyepieces do not change the f/# of a system.

 

They decrease magnification, and this makes images brighter for devices that behave like cameras/film/CCDs.

I was referring to the impact on the nv views of using a 55mm plossl afocally which is broadly equivalent to using a faster scope, ie effectively like a speed increase.


Edited by Gavster, 25 August 2019 - 01:53 AM.


#5 Gavster

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Posted 24 August 2019 - 04:39 PM

Ray helpfully provided this image that has a green circle when the soap bubble position is which should make spotting it on my original image somewhat easier (it is faint I admit!)

 

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  • DF64924B-70FB-4AEA-BF24-F1A06BE47F5C.jpeg


#6 Jeff Morgan

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Posted 30 August 2019 - 08:05 PM

I made a run at this two nights ago. 16" f/7 Newtonian, afocal with the 55 Plossl. Can't remember the filter, probably 12nm. No luck visually.

 

Photographically I think it is there with close inspection (and perhaps a little averted imagination lol.gif ). Attached is a crop.

 

Look at the brightest star slightly left of center of the crop. The Soap Bubble is a very thin (just a couple of pixels) line to the left of the star. If you get to the next bright(ish) star, you went too far. The Bubble seems to split the distance between those two stars nearly in half.

 

The Bubble curves down and to the left. I can trace it faintly from the 1 o'clock to roughly the 7 o'clock position. Maybe a little further, but the definition is even worse. The APOD image shows that as the brightest portion, but it is near the edge of the exposure (I was not quite on target with framing).

 

A tough one! The exposure was ISO 8448 (max), 1/3 second. Don't know what else I can do. When Apple releases an iPhone with longer exposure capability I will have to try again.

 

Edit: Looking at the original image, my aim was off more than I thought. The bubble is outside the 50% zone. Given the dodgy edge performance of the Plossl, maybe an exact centering can yield the image.

Attached Thumbnails

  • IMG_2392 (3).jpg

Edited by Jeff Morgan, 30 August 2019 - 08:08 PM.



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