20 replies to this topic

[j.gardavsky]

Hello friends of the very large nebulae along the Galactic equator!

 

It has been the MDW Sky Survey project, which has attracted my attention towards the very large SNR touching the Rosette Nebula in Monoceros,

https://www.mdwskysu...c4-093f6cc54912

 

The first observations have been through the binoculars with the nebular filters in March and April 2021, and now, I have decided to complete the area north and north-east off the Rosette Nebula with my 6” F/5 achro.

 

The documentary sketch shows the area between the Rosette Nebula, and the bright stars 13 and 14Mon, and 16 and 17Mon:

 

 

This area is dominated by a very large SNR G205.5+0.5

 

https://www.mrao.cam...G205.5 0.5.html

 

Following anticlockwise the SNR western arc from the Rosette Nebula towards 13 and 14Mon, several condensations in the western arc became resolved.

Some of them have the Lynds catalog numbers:
LBN 941:  06h29m 05°55‘, 18’x8‘  SW condensation
LBN 932:  06h29m +07°00‘, 55’x10‘  W condensation
LBN 930:  06h31m +07°, 20‘  NW condensation

 

These condensations, visible through the H-Beta 5.5nm filter, are the brightest parts of the difficult to resolve SNR filaments.

 

The southern arc of this SNR,
LBN 952:  06h38m +05°30’, 200’x90’
passes between the Cr 107 and Cr 106 open clusters, to finally turn towards north.

 

The eastern arc seems to pass by, or to touch the VMT 10, visible through the OIII filters,

VMT 10  (LBN 947) Nebula: 06h42m +06°40’, 60’x10’

 

And finally, the expected northern arc merges with the very large and bright nebular complex surrounding the X-Mas Tree nebula.

 

This SNR reminds me of the SNRs in Orion, which have lost most of the high kinetic energy affordable for the collisional ionization of oxygen, and therefore, what has been left are mostly the HII emissions.

 

Planetary nebula PN-G206.2+00.6  06h41m30 +06°16‘30“, size 26’

 

This one is a recently discovered (2021) large planetary nebula, in a close proximity to the VMT 10,
https://www.utkarshm...s-constellation
named by its discoverers the “Bubblegum Nebula”.

 

Its expected position is found in a triangle of bright stars.

Due to the proximity of the VMT 10 and of the eastern SNR arc, this PN can be easily overseen.

It took me some time to see the annular form through the OIII filters, and the faint diffuse glow inside the disk and outside towards NW through the H-Beta filter.

Once having seen it, and keeping in memory its appearance, I am sure to find it again.

I am also tempted to regard this nebula as a nice bi-color planetary.

 

SNR  G206.9+2.3

 

This small SNR has been already on my list,
https://www.mrao.cam...G206.9 2.3.html

 

Its position has been expected to be about 1° to the east of the eastern arc of the large SNR G205.5+0.5

 

At least, something of this SNR became visible with certainty through the OIII filters.

The level of difficulty is comparable to that of SNR G82.2+5.3, I have been observing in 2021.

 

The technical details of this observing session are listed in the documentary sketch.
The visibility of these deep sky objects is challenged by the molecular clouds, and hence the ultra narrow nebular filters, and eyepieces delivering maximum contrast become helpful.

 

Thank you for reading,
and clear skies,
JG

 

 

 

 

[PEterW]

Great report

Peter

[Raul Leon]

Excellent narrative and sketch J.G.! Would love to see that one day myself. 

[SNH]

Massively impressive accomplishments, Jiri. While I have deep respect for those who push the limits of large telescopes, it's people like you who do so much with sub-10" telescopes that I reserve my highest respect. Right now I'm working my way through van den Bergh's reflection nebulae catalog and Sharpless' emission nebulae catalog with my 5.1-inch and 10-inch. Doing so is teaching me how to observe objects that are extremely diffuse. I do hope to follow in your footsteps one day though in going after LBN and the like.

 

While impressive, this ESO image even struggles to show all that you saw!

Scott

[C.Hay]

Dear Jiri,

 

Thanks for your excellent presentation of this very interesting part of the sky - and your remarkable observations!

 

You note on the recently discovered planetary nebula PN-G206.2+00.6  "I am also tempted to regard this nebula as a nice bi-color planetary." I like your concept of bi-color observation. What you mean is, if I understand correctly, that you are using ultra-narrow emission-line filters to see substantially different impressions of one and the same object in the OIII and H-Beta lines.

 

On that theme, you're now evidently using 5nm and even 3nm OIII filters, and complementing them with Baader's 5.5nm H-Beta filter. We had choices for ultra-narrow OIII filters in the past, but not for H-Beta, so this new 5.5nm filter really is something of a game-changer in visual H-Beta observation. I can't contribute observations in the depth you are presenting - my sky is just not good enough - but I can say that under my sky, too, the 5.5nm H-Beta filter is making objects visually accessible to me that were previously out of range.

 

CS, Christopher

Edited by C.Hay, 29 March 2022 - 09:04 AM.

[j.gardavsky]

Hello Christopher,

 

and thank you very much for your kind words!

 

The ultra narrow passband filters are the game changer not only in imaging the nebulae, but for the visual, as well, and even for the small aperture telescopes, like my 6" F/5 achro.

 

And it have been your observing reports, why I have decided to add a pair of the Baader H-Beta 5.5nm CMOS-optimized filters to my arsenal.

Towards the end of 2021, these filters have been already sold out at Baader's, and so I have purchased them from Telekop Service.

 

More observing reports will follow in due time,

Jiri

[Dave Mitsky]

I just came across your report and am extremely impressed with your observations!

[j.gardavsky]

Hello Dave,

 

and thank you very much for your kind words, highly appreciated!

 

Best regards,

Jiri

[Erik68]

My observation from this winter. I detected LBN 941(top) and a portion of the loop (right),in the direction LBN 952.At the time,I didn't know there was a loop,I would definitely try to observe more.

 

Rosette Nebula

Refractor 152/760
25x+Lumicon Olll 3rd gen.
NELM 6.5mag.
transparency - excellent

 

 

[j.gardavsky]

Hello all,

 

regarding the planetary nebula candidate PaRasMoMi-1 (G206.2+00.6),

see also the confirmation with the much deeper resolving sketch in https://www.cloudyni...1-pn-g-2062006/

 

Best regards,

Jiri

[C.Hay]

Dear Jiri,

 

I had the opportunity to use a handheld night vision device over the past days, fitted with an H-alpha filter over the lens. It delivers a power of 2x and 21° FOV. So it is a kind of eye booster similar to 2x54 binoculars, but with additional massive boosting of the non-visually-accessible H-alpha signal, which correlates with a factor of ca. 3 with the pure-glass-accessible H-beta signal.

 

I used it to examine the region of your drawing. Here is my sketch, produced under a NELM 5.0 sky:

 

There are lots of surprises with such a device. One is how bright such objects are in H-alpha which I always thought of as being OIII objects, notably the Rosette Nebula. Another is the immediate visibility of small nebulae the existence of which I was not aware, in this case Sh 2-280 and Sh 2-284 south of the Rosette.

 

The most delightful thing, however, was, firstly, to see the Cone Nebula complex billowing over 3° large, with its southwestern extension almost reaching 13 Mon. And, secondly, to see quite clearly the southern fringe of SNR G205.6+0.5 merging with the Cone complex to the north and almost reaching the Rosette.

 

The arc of SNR G205.6+0.5 appears thickest in the southeast. I presume this impression is attributable to VMT 10. VMT 10 is mapped in the Interstellarum Deep Sky Atlas as an OIII object, but the image in the MDW survey suggests it has strongish H-alpha emission. Perhaps PN-G206.2+00.6 is also contributing to this impression. I couldn't resolve VMT 10 or PN-G206.2+00.6. I suppose this can not be expected at a magnification of only 2x.

 

I hesitated before reporting this observation as I am not quite sure whether using a night-vision device in H-alpha qualifies as "visual" observing at all. One is looking at an image on a screen. At least in this handheld application one is pointing the device directly towards the object. This makes it feel much like handheld binocular observation.

 

However one defines night-vision-device observing, it does provide an interesting complement to "pure-glass true visual" endeavours. My hope is that I can use it to scout areas to find out which objects or parts of them may be accessible with pure glass. In the present case, the nebulous tongue reaching from the Cone towards 13 Mon suggests itself as a true-visual 5.5nm H-beta project.

 

CS, Christopher

Edited by C.Hay, 30 December 2022 - 06:16 PM.

[j.gardavsky]

Hello Christopher,

 

this is a very interesting, and really successful observation of the SNR G205.6+0.5, and possibly the very first time reported through the night vision device at the magnification as low as 2x.

 

Clear skies,

Jiri

[C.Hay]

Hello Jiri,

 

I'm glad you find the night vision device perspective interesting. As I wrote, I'm not sure whether it counts as visual observing and don't want to get on people's nerves with it. When it can be linked up to true visual observing like yours, though, and sketches are made with objects labelled and their relative visibilities discussed, I hope it can provide an interesting additional perspective. 

 

In the present instance, I found it hugely interesting to compare my sketch against your pure-glass drawing on the one hand and the MDW Survey image - https://www.mdwskysu...c4-093f6cc54912 - on the other.

 

Regards, Christopher

[j.gardavsky]

Hello Jiri,

 

I'm glad you find the night vision device perspective interesting. As I wrote, I'm not sure whether it counts as visual observing and don't want to get on people's nerves with it. When it can be linked up to true visual observing like yours, though, and sketches are made with objects labelled and their relative visibilities discussed, I hope it can provide an interesting additional perspective. 

 

In the present instance, I found it hugely interesting to compare my sketch against your pure-glass drawing on the one hand and the MDW Survey image - https://www.mdwskysu...c4-093f6cc54912 - on the other.

 

Regards, Christopher

Hello Christopher,

 

I am tempted to put the purely visual perception through a conventional eyepiece, together with the real time night vision perception, into one class.

No problem on my side.

 

And moreover, with an SII narrow passband filter separating the view from the H-alpha, this would give us a totally new visual experience, revealing structural details in the diffuse nebulae, not perceived through the H-beta and OIII filters.

 

Best regards,

Jiri

 

[C.Hay]

Dear Jiri,

Pursuing SII with the night vision device is a fascinating idea. I hadn't thought of it at all! I shrink from it in view of the new investment it will involve - but I can't resist. SII, here I come!

Best regards, Christopher

[j.gardavsky]

Dear Jiri,

Pursuing SII with the night vision device is a fascinating idea. I hadn't thought of it at all! I shrink from it in view of the new investment it will involve - but I can't resist. SII, here I come!

Best regards, Christopher

Can't wait on your first reports and sketches!

 

If my suggestion works, then it will be the paradigm change,
Jiri

[C.Hay]

Dear Jiri, in the meantime I've looked through the "An Emission-Line Survey of the Milky Way" (R. Parker et al., 1979) and can't find a single field in which the SII image reveals anything additional or really different to the H-alpha image. This is demotivating.

 

However, the FWHM widths in the 1979 survey are very wide: 50nm for SII and 75nm for H-alpha. Is there a more recent/narrow SII survey?

Can you name any objects in which SII is strong?

 

Regards, Christopher

[j.gardavsky]

Hello Christopher,

 

my guess, the SII might enhance visual contrast of some features, like The Wall in the North America Nebula, the rims of the Pelican Nebula, Elephant Trunk, etc.

Possibly, it won't work as good on the SNR and W-R nebulae, as the SHO captures reveal often not enough ionized SII.

 

Best regards,

Jiri

[PEterW]

I got a thin mount with a swappable filter drawer, but a filter wheel could also work too, to enable blinking of different filters on objects. Not sure how this might fit with the prime/afocal mounting of your NV unit?

Peter

[C.Hay]

Hi Peter, you have me thinking about a filter slide once more - an idea I shelved long ago for telescopes, where I prefer a wheel. I place the H-alpha filter in front of the objective, which has a front aperture of about 36mm. So 2-inch threaded filters with apertures of 45mm would work fine in a slide.

 

CS, Christopher 

[PEterW]

C-mount to M45 lens gives enough spacing for one of these (other similar products exist), though you need to play with adapters and thread converters!! https://www.altairas...on-2-2379-p.asp might be able to also put a 5position filter wheel as well (if the filters are not too thick).

Peter