Chasing Ghosts

[scarp15]

Since this was going to be an early morning session, there was no hurry to reach my dark sky location. Optimistically, I hoped to pursue two specific deep sky objects. Barnard's E constitutes a feature derived as part of a pair of dark nebulae embedded within the Milky Way star field in Aquila. The Little Veil, sh2-91 is a lesser known super nova remnant located in Cygnus. This would provide a last opportunity for this season, as the constellations shift increasingly towards the west.

Moonlight cast long shadows as I set up my 76mm refractor alongside my 14" dobsonian, gradually transforming into rustic orange, as it sank towards the horizon. Occasional meteors darted brightly and the Milky Way overhead began to reclaim its dominance in the sky, increasing in definition as the light from the moon faded. A gentle breeze prevailed and no issues with dew were encountered. 

I began the session in pursuit of less challenging subjects. Not all ghosts have to be difficult and Mirach' s Ghost NGC 404 in Andromeda was such, pleasingly revealed in fine composition close to its namesake star. The Pac man nebula  in Cassiopeia does indeed create just such an impression of resemblance. Auriga was up and a quick tour through the clusters ensured, such as M38, M36, NGC 1907 also the double cluster, Caroline's Rose and the Pleiades. The Andromeda group looked very fine in my 31mm Nagler. M57 and M27 were defined sharply, when finally I considered it dark enough to pursue larger nebulae in Cygnus.

Veil Nebula

Western and Eastern segments along with Pickering's Triangular Wisp were captivating abound by many other patches of nebulosity. The Eastern Veil in particular looked 3D particularly centred upon the knotted filaments forming NGC 6992. Within the vicinity IC 1318 was apparent, the North America dynamic and engaging and the Crescent still to my mind somewhere between a skull and a jellyfish.

Barnard's E

Circumstances were not really ideal, the moon had fully set, but Altair and Tarazed were situated at a fairly low elevation. Altair was blinking a little not a good sign. The two stars were centred comfortable in my 21mm nagler, 4.32' refractor field of view. Drifting across towards where the nebulae lay was a complete blank, nothing doing. Repeated attempts gained nothing, a complete contrast to two weeks earlier when at much higher elevation and under different circumstances, my 8" dob had encountered aspects of these nebulae within a dynamic and vibrant star filled area of sky.

The Little Veil

Sh2-91 is a significant distance in comparison with the Veil, some 2,500 light years, compared to 1,500 light years and formed as a super nova remnant 440,000 years ago. It shares similar characteristics, a wispy streak of dimly glowing filaments of nebulosity. It is fundamentally much harder to detect and the exact star field has to be accurate. I committed considerable time and concentration on this subject, going over and over the location checking with my finder and telrad, employing my 14" dobsonian, 21mm ethos and Lumicon OIII filter to the task. A little north of Albireo locate 12 Cygni and consult closely the star field pattern. Not unlike when I first pursued the Horse Head had I tried so hard to grasp subtle hints of nebulosity. I detected a faint streak and what I determined was a very faint trace of nebulosity which I could follow with some conviction, then would pause, go back and could not be clear anymore what I might have seen. Mental trickery perhaps or was I trying to see a 'ghost'. The concentration was intense and I felt that there were other faint nebula formations there - fascinating yet tiring. This is most certainly something that I need to go back to - next year.

To gain some respite I turned towards Cassiopeia and attempted to locate NGC 896 and the Heart and Soul nebula. Cloud had emerged and enveloped the view, so I turned to a prominently emerging Orion and was greeted by a staggeringly bright and expansive Orion Nebula, as though containing two bat like wings. The sky completely cleared again, yet at approaching 2.30am I had to pack, taking one final SQM reading 21.3. I arrived home, stepping out of the car could hear birds chirping, 'they are early' I thought, erm no I was late.

 

[John]

Lovely report Iain

I found the Little Veil similarly vexing - I might have detected something but then again I might not have ????

Amazing how compelling things that we can hardly see are !

 

[Mark at Beaufort]

Fantastic report Iain really enjoyed the read. So let us hope for a good Autumn and Winter session to bag some of these less well known areas of nebulosity.

[jetstream]

Congrats for viewing the Little Veil Iain!, there will be more to come, and it may grow in size for you... this object is a super test of, well, everything. Another one under your belt!!

[domstar]

What a beautifully written report. 14 inches sounds wonderful.

[Stu]

Lovely combination of easier and threshold targets Iain, enjoyed that a lot  

[alanjgreen]

Great report scarp!

i have not seen either of those harder targets. I have never tried the little veil, but I will get it on my list for next year. Now I have its name (sh2-91), I have added it to my "summer" targets in sky safari. Thanks.

Alan

[scarp15]

17 hours ago, jetstream said:

Congrats for viewing the Little Veil Iain!, there will be more to come, and it may grow in size for you... this object is a super test of, well, everything. Another one under your belt!!

Thanks again everyone.

Gerry, you may have posted an account on this before, could you describe in a little detail in terms of what you have become able to determine / see of this object? For a brief encounter, I seemed to sense that I was following the profile, as a dim grey streak not too unlike aspects of a tightly compact and much narrower version of the California (therefore little contrast), it just seemed to 'snap into place' I remember thinking, yes that will be it, though I could not comprehend this with a repeated attempt. The nebulosity was certainly there, perhaps I just need to become more accustomed.

Quite as John remarked, extraordinary how these things, more invisible than visible keep our attention.    

[jetstream]

I think we all see these objects a bit differently, unlike galaxies where everyone describes them pretty much the same. You are seeing the "brightest" section I believe Iain, and the object will extend on either side of the primary guide star, very similar to the western Veil in a smallish scope. To me if you view the western Veil unfiltered in a refractor the view is similar, minus so many stars and adjusted for the FOV.

12 Cygni is not our friend..... this is a really delicate object IMHO that needs to be persuaded to allow direct vision and a narrow TFOV can help. After another 20 -30 times viewing the streak more will appear.

Iain, do you use an Astrozap dewshield or similar? Shine a light through your eyepiece in the focuser, and look off axis through the front of the scope- if you see light, a flat black tube extension is needed. Also, I painted the back tube cap flat black and use it on these objects- light will enter from the back on the VX's.

[scarp15]

That's useful info thanks Gerry and I can visualise your reference to the Western Veil as an example, as seen in smaller aperture and potentially unfiltered. It would be interesting to approach this observation with my 20mm plossl, the exit pupil 20 -21mm eyepiece (with or without the paracorr) is optimum for my 14" scope on these subjects. Actually I do not use a dew shield with this scope, which being bottom heavy would not upset the balance if I did, so some consideration there. I haven't tried that shine a light through technique, so also something to consider. I keep the rear dust cover on, fabric Astrozap quite black, the tube is fully flocked but there is always attention to detail, room for improvement. Would be good to return to this observation when Cygnus is due South and perhaps find a location more inclined to SQM 21.4 - 21.5. 

[FenlandPaul]

Great read, Iain - it shows how much more there is to tease out when you get to a dark site.  Always worth the effort!

Paul

[John]

19 hours ago, jetstream said:

.... light will enter from the back on the VX's.

Thats a good point Gerry - my OO 12" has a very open mirror cell design and I guess some dim light might seep into the tube down there. I think a bottom end tube cap is called for.

[jetstream]

5 hours ago, John said:

Thats a good point Gerry - my OO 12" has a very open mirror cell design and I guess some dim light might seep into the tube down there. I think a bottom end tube cap is called for.

Thanks John, with the help of Randy at Astrosystems I have begun to understand newts a bit and the stray light and baffling issues. There are two recommended paints that actually absorb the light- I use Krylon Camo flat black for everything including the inside of my cap. The inside of my focuser is done, all my adapters, the front and back tube rings, spider, secondary edge, mirror clips and the primary mirror bevel.

Two (and more) unsuspected "glaring" issues surfaced with the 200mm f3.8- the top of the anodized mirror clips and the primary mirror bevel- they were blowing light all over the place as was the bottom inside of the tube ring. Then there was the front of the scope...

I was surprised that I could see light (torch) through a hyperwide looking off axis through the front of the tube... contrast reducing stray light will enter here for sure. One of the inherent advantages of a refractor is the ability to easily control stray light through baffling etc.

edit: another issue was the bright stainless steel nuts inside the tube and glare off the brass threaded spider threads.

[mapstar]

Nice report and a few targets to chase when the skies allow.

Half the enjoyment for me is finding the object after trying and failing. That moment is priceless 

Hopefully the weather will allow us all a few more trips out this season.