REFLECTION NEBULAE - EEVA STYLE

[Mike JW]

To parallel the EEVA thread on Planetary Nebulae, this thread can be devoted to Reflection Nebulae.

To start the ball rolling here is an observation and notes from last night (19/09/20)

PARSAMYAN 21 - found in Aquila.

When this 'little comet' appeared on the screen - I had yet another one of those WOW moments. I get a real buzz out of seeing things with the EEVA technique that otherwise would be elusive. This reflection nebulae set amongst so many stars is wondrous as far I am concerned.

and so to the scientific detail.

Parsamyan Nebulae (also spelt Parsamian) are reflection nebulae. P. 21 belongs to class V - comet like nebulae. This is where the parent star is at one end of nebulosity (which can be in a ring shape). The parent star is young and sheds material but something causes the release of gas to be directional. In the case of P.21 the suggestion is there is a disc of stella material or a torus (doughnut) of material causing the directional shape. P.21 takes the form of an elongated tube which is closed at both ends. The star lies outside this tube. Light polarization studies reveal that the dust on the reflection nebulae is small grained but at the star end and also surrounding the star the polarisation changes direction suggesting that there is indeed a torus of stella material causing the direction flow - hence the comet.

Mike

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Marvin Jenkins]

Super interesting. I had no idea that this kind of object existed, at first glance I was wondering why you were posting a distant comet pic but talking about reflection nebula.

It has to be said that from your very detailed description it sure is one odd object. Thank you for the effort and the info, I will be following this thread with interest.

Marv

[Mike JW]

26/10/20 -  Hubble Variable Nebula - NGC 2261.

This reflection nebula is the gas and dust coming from R Monoceros. It is about 1 lyr across and varies in time.

http://adsabs.harvard.edu/full/1966AJ.....71..224J  provides some interesting reading.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Close ups below are different settings to try to tease out some more detail. Right hand image begins to show the longer tail that extends out at the top of the nebula. Pleased to pick up some of the darker (dusty?) regions.

Mike

 

[Mike JW]

As well as the Hubble Variable I took a peak at M 78. This reflection nebula is being illuminated be blue type stars embedded within the gas cloud.  This area contains several star forming regions which illuminate the area - about 4 lyrs across.

https://www.youtube.com/watch?v=M98udfgd7g4 - enjoy the link for a spot of awe and wonder.

Mike

 

 

[callump]

To continue a Variable Nebula theme, here is Hinds Nebula, NGC 1555, in Taurus. It is associated with the variable star T Tauri. 

I think that the VNe nebulae are generally dust and gas in the region where the star formed rather than being thrown off the star. The illuminating stars tend to be quite young stars. There are just a few known VNe, and a couple of these have currently disappeared - NcNeil's near M78 in 2018 (still not visible), and Gyulbudaghian's (associated with PV Cep). The areas are worth visiting from time to time in case they burst into life again. The BAA has a programme monitoring these, and there are interesting observations  over many years.

Last night was clearish, but not the best of skies. This was late on (for me, on a work week). 

I've changed to a Celestron focal reducer (f6.3), which seems to be better across the field compared to my old clone. Measured focal ratio is f/6.1.
Horrible dust bunny appeared though annoyingly in the middle of the field - will need to hunt that down over full moon.

Callum

 

[Mike JW]

Hind's is on my list to visit. Thanks for posting and the extra detail. I use the Celestron f6.3 reducer as it matched to the Celestron scopes.

As to Gyulbudaghain's Neb, I visited it with the 15" Dob earlier this year. See below.

Mike

[Mike JW]

Last night I decided to visit the Hinds Variable Nebula in Taurus. (NGC 1555, HH 155 or Sh2-238) is about 400 lyrs away and about 4lyrs across. In my image I have only picked up the bright central part. It is reflecting the light from T Tauri ( a variable star - bright orange, ranging from mag 8.5 to 13.5 ish). Apparently it is quite a young star at around 1 million years old. The reason it has the HH designation (Herbig Haro object) is because  infrared observations indicate there could be a very young star lurking in there. Jets of gas and matter from this young star would be colliding with the surrounding gas and dust producing bright shock waves. 

With such high humidity, thin cloud and Christmas lights it was difficult to get a shot with low noise so I have posted two shots but at slightly different settings. The right hand shot gives possible hints of more extensive detail (could be noise) and also a darker region toward the bright star on the right (sort of coincides with decent images?)

Mike

 

[callump]

NGC 2261 - Hubble's variable nebula. Last image from my session last night. Sky was quite poor by this stage, so background is very noisy.

[Mike JW]

Hi Callum, just been comparing my shot to yours from last night - look to be the same - no signs of variability but well worth revisiting just in case.

[Martin Meredith]

Here's a shot from 4 years ago to compare with. I do see some differences, especially on the 'left-hand' (in my picture) edge.

I must revisit this soon. Thanks for the visual reminder!

Martin 

Edited January 8, 2021 by Martin Meredith

[Mike JW]

Martin , you could be right re slight difference on left side - could you do a zoomed in image (just a little) as would help the comparison to my images.

Mike

[Martin Meredith]

Sure, but this is zoomed in from the png (capture predates Jocular), so no interpolation:

[Mike JW]

Thanks Martin, subtle differences on the left side compared to my shot - more evidence of darker regions on your image. OK, must note we were using different scopes  and different overall time. 

Mike

[Bill S]

A bit late to the party again.

This is a shot from late October 2020.

It's pretty sensitive to the type and amount of stretch as shown in the two images with hyper stretch and asinh stretch.

So I suppose we need to be careful when making comparisons.

 

 

[Mike JW]

Hi Bill, your thoughts on type of stretch sent me back to the original for my image. I have just tried hyper, asinh and gamma and with careful adjustment I found that all three gave the same final result!!!!! 

Mike

[Martin Meredith]

Discuss! 🙂

 

See also Hubble image from 1999 I believe, which helps identify some of the above structures https://en.wikipedia.org/wiki/NGC_2261#/media/File:Hubble's_Variable_Nebula_-_NGC_2261.png

Plus two images from late 2016 and early 2018: https://britastro.org/sites/default/files/styles/xl_image/public/member_images/ngc2261comp.jpg?itok=wnSByP4S

Plus an animated gif demonstrating variability between 2013 and 2016: https://www.cloudynights.com/topic/528106-ngc-2261-hubbles-variable-nebula-ver2016/

check out post 7 in the last link re the high proper motion star

Edited January 9, 2021 by Martin Meredith
added Hubble link

[callump]

There are some nice animations on this facebook page https://www.facebook.com/HubblesVariableNebula

These have been created by Dr. John Lightfoot of ROE who wrote this interesting paper in 1989 http://adsabs.harvard.edu/full/1989MNRAS.239..665L

Dr. Lightfoot will be talking about Hubble's VN at the BAA deep sky section webinar on March 6 - will be open to all.

Callum

[Mike JW]

Martin - great idea to put them alongside and the links.

Callum - enjoyed the links.

Hard to pin point differences between our images but with Martin's image (the less zoomed in image) there does seem to be a brighter streak along the outside edge.

Mike

[Martin Meredith]

Here's a completely new one for me, found by accident last night as I was continuing my Berkeley collecting...

I've been playing around with automatic annotation, so the first surprise was finding not only Be 68 but also part of the larger and supremely unconvincing open cluster Majaess 50. (Note that the positions for many of the Berkeleys in the catalogue I'm using are somewhat 'off' --  I believe the Be cluster to be to the upper right of where it is indicated; but that's a matter for another thread).

However, this is the reflection nebular thread, and the odd smudge in the centre of Majaess 50 is indeed such an object. It isn't on my charts so I had to visit Aladin to find its designation: GN 04.41.8. There is only one reference to it in Simbad, namely Magakian's Merged Catalogue of Reflection Nebulae from 2003 but I read the GN refers to the Atlas of Galactic Nebulae published in 1985-1990 by Vehrenberg and Neckel. This latter book sounds like a wonderful thing to examine (I believe it was published in German and English).

 

The close-up suggests that the RN contains a range of tendrils emanating from its centre (I count at least 6). I've no idea if these are artefacts and so if anybody is in the vicinity of Perseus I would appreciate further observations!

(I also need to deal with the black stellar artefacts that are present on some of the subs ie not a stacking issue...)

cheers

Martin

 

Edited January 19, 2021 by Martin Meredith

[callump]

Hi Martin,

Coincidently I have Magakian 82 (GN 04.41.8) on my observing list, but not had a chance to observe it yet. I did some light research, and both the Magakian and Galactic Nebulae catalogues have a lot of interesting things to look at.  I noticed it when browsing my Interstellarum atlas, which notes it as Magakian 82. 

Cheers,
Callum

 

[CCD-Freak]

I am also late to the party.   This image was shot back in 2015 with an Atik-383L+ OSC and an 8" RC

 

John
CCD-Freak
WD5IKX

[Mike JW]

GN 04.41.8 - your shot Martin compares very favourably to DSO images in b/w. 

John - late comers to the party are always welcome - thanks for adding in your shot and in colour.

Mike

[CCD-Freak]

Thanks...My image is not EEVA by today's standards but in 2015 I had to shoot a short batch of images then stack them with Astro Art (V4 back then) to get the above image.  EEVA or EAA as it is called across the pond is much easier these days with very sensitive cameras and live stacking.  (^8

 

John
CCD-Freak
WD5IKX

[icpn]

Martin

   I have the physical Neckel and Vehrenberg Atlas and it is a 3 ring 3 folder printing. It was also scanned and digitised  and sold as a DVD. I know I have a copy in the Webb sales boxes but I would need to check the original source. to see if it is still available there. The orginal source was http://www.stellarum.de/

 

Owen

[Martin Meredith]

Here's a shot of Hubble's Variable Nebula from last night with decent seeing. I've not looked at it in colour before so wasn't sure if the brown edges and smoky blue interior were 'correct', but they do seem to concur with the Hubble shot  https://science.nasa.gov/ngc-2261-hubbles-variable-nebula

So: has it changed much in the past year? I still see the pair of 'blue streamers' that were present in my 2017 image (edit: blue in this shot, not in the 2017 monochrome version!)

This is a bin2 shot at unity gain

Martin

Edited January 27, 2022 by Martin Meredith