Jump to content

sgl_imaging_challenge_2021_2.thumb.jpg.72789c04780d7659f5b63ea05534a956.jpg

Planetary nebulae, EEVA-style


Recommended Posts

Great haul of PNs. NGC 2392 is really special as is the Medusa, hanging there in space like a ghostly crescent.

I thought I'd visited NGC 2392 in colour but apparently not (blue with a touch of pink?). Here's a shot showing far less resolution than yours.This is a single sub, possibly too long at 30s; stacking didn't really help (produced a smoother result, but not what is needed here).

Its impressive how you can get great results with a 15" scope and relatively small sensor (by today's standards). What system are you using for tracking?

Martin

 

784184704_NGC239207Feb21_09_22_14.jpg.a96cc6a1c42d1bb5f914e8e8a60cbb47.jpg

  • Like 1
Link to post
Share on other sites
  • Replies 92
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

I'm starting this thread to encourage posting of short-exposure images of planetary nebulae. Apart from the obvious suspects, M27, M57 etc, I generally haven't had a lot of success (and have ther

From the same session, this is NGC 6445, a mag 13.2 PN, also in Sagittarius, this time with a surface brightness of 22.0. This 'wide' field shot shows the object, just over half an arc-minute in

Thanks Chris for that link.  Here's most of the rest that I observed over 2 nights this week. They consist of 8 of the 11 NGC PNs in Aquila (turns out I didn't manage to get 2 of them in the fram

Posted Images

I could not resist having a look at my colour (LRGB) Jocular snapshot of NGC 2392. Tried out the various stretch options. With faint distant galaxies I usually settle on hyper but this object is a lot brighter (only 5 second subs). Anyway, I settled on either gamma or log. Log is the one below. Brings out a bit of detail. Mike JW's in mono with the bigger scope and more pixels shows more though. Always good to see different shots and compare.

99034991_NGC239207Feb21_22_34_16.png.e56f9dd5d601b878b475fce9d00a9bc5.png

  • Like 5
Link to post
Share on other sites
  • 2 weeks later...

Last night (16/02/21)  I took a look at three more PNs in Gemini. They are rarely visited and I struggled to find out any information on them, so if anyone finds out something about them please add it into the thread.

First up K3-71 - a very distant PN lost in a lovely star field. Lost being the operative word - if it wasn't for Jocular plate solving the subs I would have had to spent ages checking to see if the star field matched - probably impossible.  It is there in the wide field shot but you have to know where to look. Just above centre and tiny.

 

593784472_K3-7117Feb21_07_26_30.thumb.png.e79d7f4ac78329593a25f7c10f1f4260.png
1492130174_K3-7117Feb21_07_27_00.png.ad7bfcbbd7c09156462f57866879211b.png

 

The close up below shows hints of detail - is it bi-polar?, dark line through it.

1265553172_K3-7117Feb21_07_27_48.png.07c94772192ff2b1986b9dfa02da5b98.png

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NeVe 6 was easy to pick up in a crowded star field.  I saw somewhere the comment  'probably a PN'.  Latest data suggests it is a H11 region and not  a PN.

595348417_NeVe617Feb21_08_21_46.thumb.png.75272222283eeea3dec5ba89ceeede13.png322255478_NeVe617Feb21_08_23_05.png.b0c6af7d1527ef4ee6ecf29fda3eddfb.png

 

J 900 - at first I could not spot it until I realised it was  the rather bloated star. I guess the give away is, for its size it lacks diffraction spikes. Colour might pick it up easier?

https://www.nasa.gov/mission_pages/hubble/science/j900.html  - worth a look

965033340_J90017Feb21_08_33_15.png.99e828ed112ce11f8a421004341b60ba.png93799275_J90017Feb21_08_33_42.png.224719ad03128e667cf3a46fe356c11c.png

Edited by Mike JW
  • Like 2
Link to post
Share on other sites

Really interesting to see what these look like with your 15". I imagine they are very rarely observed, as you say. I've tended not to add the more obscurely-named PNs to my observing list but maybe I should. I've tried a few Ms and Ks in the past without a lot of joy. I'll definitely check out J 900 in colour next time I'm out. NeVe 6 doesn't look like a PN. I've seen at least one Arp that looks similar to that fuzzy nest.

Platesolving comes into its own for PNs. Browsing through some of my captures over the summer it has been interesting to see where some of them actually are (or missed in at least 2 cases).

Martin

 

Link to post
Share on other sites

I spoke with Mike about these. NeVe6 is an HII region not a PN. J900 may not be well known in some circles but it has been well known amongst visual PN observers for a long time. It even made the Webb Soc Deep SKy Observers Handbook  Vol 2 in 1978, along with J320 in Orion. It seems a shame that so much literature is ignored just because it is not  on the internet now. People need to look back at older references..

Link to post
Share on other sites
  • 2 weeks later...
Posted (edited)

Here are a couple of many PNs I observed last night as part of a 4 hour session, making up for lost time. Both were discovered by William Herschel and, although I didn't realise it at the time, both are distinguished by astrophysically-interesting central stars.

First, the blue-green gaseous glow of NGC 1501 in Camelopardalis, which has a complex filamentary envelope in 3D that is well seen on the Hubble image. One can just about make out a few strands in my image. The easily visible central star is mag 14.3 CH Cam, an extremely rapidly-pulsating ZZ-type variable (not looked up what the ZZ means yet) with an amplitude of 0.1 mag in around 20 minutes, so is something that is worth observing over an hour or so. The PN itself is less than an arcminute across.

WH discovered NGC 1501 in 1787.

1824148845_NGC150104Mar21_18_19_17.jpg.1549d624ea49dde3b9fb7d9a8d938cd2.jpg

152160417_Screenshot2021-03-04at18_33_17.png.0c5f000ffdfb72c89af11321f3939634.png

 

The second Herschelian PN of the night is NGC 2440 in Puppis. In contrast to NGC 1501, which has a healthy (for Northern observers at least) declination of over 60 degrees, this one is at around -18 degrees but just about clear of the murk for me.

 

1731362329_NGC244004Mar21_18_35_59.jpg.3f7f4906f5563f5dcc6d748182a8c6eb.jpg

 

362985449_Screenshot2021-03-04at18_36_44.png.51069e534b7c80cce05d49c70518cb30.png

Its central star is regarded as one of the hottest known white dwarfs. The central star is not visible here, at magnitude 17.7, being buried in the central pair of lobes.

WH discovered NGC 2440 on this very day, 4th March, in 1790. 

I must say that when I started this thread I was not sure whether EEVA and PNs were a good match, but I am now totally won over. My standard approach these days is a minute each in LRGB in 15s subs and this works well for many PNs -- except for most of the Abell PNs I've looked at! 

cheers

Martin

 

Edited by Martin Meredith
  • Like 3
Link to post
Share on other sites

Hi Martin,

I have just checked my records for the big Dob - I never got around to viewing 1501 visually, so good to see it and in colour. I have just had a look at what ZZ means -'non radially pulsating' - which I think means one part of the star is expanding whilst another part is not (or contracting) - need to read some more.

2240 - too low for a worthwhile view for me. https://esahubble.org/images/opo9935e/ - great image and some more detail

Mike

Link to post
Share on other sites

Hello Martin

A great couple of snapshots there. Beautiful and interesting objects. The central stars are fascinating. I had not heard about pulsating white dwarf stars before. More to follow up.

Good to hear your standard approach for getting reasonable observations for many PNs.

Bill

Link to post
Share on other sites

Thanks Mike and Bill. I was fortunate to have another lengthy session last night during which I observed 7 PNs which I need to sort through (since 3 of them are Abells one can predict a few failures to see much although Abell 21 is glorious). One of them was Jonckheere 900 (J900) that Mike posted a while ago. Here it is in colour -- distinctly greenish and slightly oval (I am always concerned about tracking when I see this shape).

771082007_J90005Mar21_09_51_40.jpg.de2c92115bae01c65ca95f80ee14bb8f.jpg

 

  • Like 4
Link to post
Share on other sites
Posted (edited)

Here's one that I found near impossible to see last night: Abell 33 in Hydra, discovered by George Abell in 1955. The labelled blue marker is in the centre of the PN and the near circular boundary just about intersects the bright star (mag 7.2 HD 83535).

 

1853653783_Abell3305Mar21_18_22_40.jpg.dabb08fa58148667e750567fb25039f8.jpg

The PN might just be easier to see in this negative image -- at least, I can convince myself that it is there. I think some new stretch techniques are called for to enhance local contrast... The central star, obscured by the blue circle in the image above, is very clear at mag 15.5/15.8 depending on the source.

713724501_Screenshot2021-03-05at18_23_52.png.e179c8728f3980aa72c694419a884a0e.png

 

Abell 33 has a listed magnitude of 12.9 but a surface brightness of 24.8, which just goes to show that magnitude is nearly meaningless for these extended objects. In contrast, as a bonus, there is a mag 17.9 quasar marked at 10 o'clock in the upper image (though the marking is a little faint -- still working on the automatic annotation).  This is pretty distant with a redshift of 1.9 (>8.5 billion LYs). It doesn't look clearly detected in the upper image but is definitely very obvious in the monochrome zoom.

1542859156_Screenshot2021-03-05at18_40_35.png.d766f568e98c24e3316edf750b86f565.png

 

I completely failed to see Abell 18 in Monoceros, also discovered by Abell in 1955 (Abell was one of 4 discoverers of the objects that ended up in his catalogue). This has an even lower surface brightness of 25.9 and a listed magnitude of 17.0, so it was crazy to even look (except I didn't check beforehand). Even the central star is shining at a dazzling magnitude of 20.9...

Nor did I spot Abell 31 in Cancer (SB = 26.6) although I did see the central star (no much by way of compensation...)

Unfortunately I didn't have my Oiii filter in the wheel but I plan to revisit these at a later date with the filter.

Next: more Abells...

Edited by Martin Meredith
  • Like 2
Link to post
Share on other sites

Now to one that can be seen without narrowband filter: Abell 21 in Gemini. I've turned the saturation up on this one not only for the sake of the nebula itself but to better appreciate the very blue central star that looks like a hot pixel. All I can find on this is that it is mag 16.0 and type D0Z. 

34940136_Abell2105Mar21_19_28_57.jpg.8b0a488cdcb7b36db217477b22ae9757.jpg

I did happen to have an H-alpha in my filterwheel so I took a quick look using a L-H-alpha combination with the saturation turned up to a lurid level (must do something about those pink stars):

 

481611766_Abell2105Mar21_19_37_26.jpg.a2e6dec7db873725a89888a785e78464.jpg

 

  • Like 3
Link to post
Share on other sites

And here are the remaining 'blue period' PNs I looked at over these last two nights (relative scales not preserved). These are mainly 1 minutes (4 x 15s subs) in each of RGB and L. The faint outer wings of NGC 2371 are visible in the colour shot but more easily seen in the negative view. Thanks to Bill S's image above for motivating me to look at this strange object. I also find the delicate 'sliced lemon' structures of NGC 1514 and 2242 very appealing for some reason.  

950767630_Screenshot2021-03-05at20_13_19.png.69f1b962a485f300ce1713ed19dbd30f.png

  • Like 4
Link to post
Share on other sites

Martin - what a fine set of observations. I’ll be adding some of these to my lists for future observations and background reading. 
 

Some clear skies would help...

Link to post
Share on other sites

Thanks Martin for those fine planetary objects and your descriptive comments.

I add them also to my "planetary to do" observing list.

 

Link to post
Share on other sites
  • 3 weeks later...

IC 1747 in Cas is a small PN and easily missed in a crowded star field. (centre of the wide shot). Some folk call it the Holepunch Nebula - beats me as to why this name!.  The shot is with my 7" scope  and would be of more interest in colour , bigger scope and probably a small pixel camera.


1559487578_IC174725Mar21_06_40_21.thumb.png.128c1b6d2f10fbcadba9255540c4adea.png

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Close up indicates it may well be bi-polar.

2065423654_IC174725Mar21_06_40_44.png.f0972b2c5a26468c26c1c62f57bc2675.png

 

Mike

  • Like 2
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.