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Atlas for planetary nebula

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#26 The Ardent

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Posted 22 November 2020 - 12:39 PM

If Kent Wallace can do it, why can’t I?

What exactly would you find helpful? If the atlas listed only objects visible in YOUR telescope? There's only so much they can realistically be expected to do on a printed atlas to help you out. Generally speaking, with these fainter objects you're going to want to research to know what to expect before you make an attempt anyway.



#27 Mick Christopher

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Posted 22 November 2020 - 01:38 PM

The Astronomical League (AL) observing program for planetary nebulae is not an entry-level effort, thus basic paper atlas references are insufficient to locate all of the 110 objects (and 4 challenge objects).

<...snip...>

I think the IDSA is the one for me then. I just ordered it off Amazon so I’m looking forward seeing what it shows. Thanks for the tip!



#28 Mick Christopher

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Posted 22 November 2020 - 01:50 PM

Pease 1 is one of those objects that requires very high power and superb seeing, and even then, it's nearly impossible.
In comparison, IC4617, the galaxy in the edge of M13 is a cinch.

I’ve was able to observe Pease 1 several times over this last summer/fall with my 12”. That being said: even under bortle 2 skies and with the OIII filter it was still barely noticeable. But I’m not complaining, it amazes me one can even see it.

Edited by Mick Christopher, 22 November 2020 - 06:05 PM.


#29 catalogman

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Posted 22 November 2020 - 03:31 PM

Is there a preferred atlas that lists most of the planetary nebulas in the AL observing program? I have the Cambridge and Tirion atlas’s but they don’t show all that many.
Thanks!

 

Finder charts were in the *printed* version of the ESO-Strasbourg catalogue and in Kohoutek's updated version:
 

https://cdsarc.unist...p/IV/24/images/
 

The .ps charts are easy to open in Linux (cf. att.), harder in other operating systems.

-- catalogman

Attached Thumbnails

  • chart_sample.jpg


#30 catalogman

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Posted 22 November 2020 - 03:34 PM

<snip>

 

I did a quick search on SIMBAD for PN's with a declination > -37 and it returned more than 8 thousand objects! Unfortunately, not all data is available for the objects, such as diameter.

 

<snip>

 

Unfortunately, most of them are stellar, extremely faint objects (m > 20) in other galaxies.

 

-- catalogman



#31 Starman1

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Posted 22 November 2020 - 04:00 PM

99% of amateurs using a scope <20” who live in populated areas, which is likely 99.9999% of all amateur observers.

So plotting an 18-19th magnitude PN with the same symbol as the brightest ones isn’t exactly helpful.
 

I use a 12.5", and I can't tell you how many times I have seen 3 or four faint galaxies at a spot where Uranometria shows only 1.

Yet, there are some galaxies in areas where I can see none.

So the selection criteria miss being perfectly suited to a particular telescope, whether it's an 8" or a 20".

I think that the selection criteria revolve around what data is digitally available rather that what is or isn't visible in a particular size of scope.

For an atlas to be usable over a period of time, you would hope that the atlas goes deeper than you can see.

You might get a larger scope, you might start observing in darker skies, your observing skills might improve.

Don't forget that an atlas may be for a wide range of observer circumstances.


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#32 Starman1

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Posted 22 November 2020 - 04:16 PM

What exactly would you find helpful?  If the atlas listed only objects visible in YOUR telescope?  There's only so much they can realistically be expected to do on a printed atlas to help you out.  Generally speaking, with these fainter objects you're going to want to research to know what to expect before you make an attempt anyway.  

Such, then, is the value of a computerized atlas--you can set the limits at whatever you want, both for stars and DSOs.

And you can print a few pages, at any scale you want, for your night's observing program, mark all over them, and reprint them again.

 

I like to print charts with a scale of about 1° per page so I catch all the little DSOs in the field, especially important for galaxy clusters and Hickson groups.

But, there is no way I would use an atlas with 41,253 pages to cover the sky (the number of square degrees in the sky).

So printing a page here and there makes a lot more sense.

 

If I wanted, I could print a series of 26 maps to cover the sky, or 80, or 400, or whatever.  That makes a computer atlas suited for use by a 4" or a 32" depending on what parameters are selected.

And it is why we are probably seeing the very last of the printed atlases.  The SkyGX would have been the ultimate printed atlas, but the author couldn't find a printer for the 6-volume atlas, so I think

if Uranometria 2000.0 becomes available again soon, it is likely to remain the ultimate printed atlas.  I doubt it will even be updated to Uranometria 2025.0

At this point, there really is no need.


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#33 catalogman

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Posted 23 November 2020 - 07:17 AM

<snip>

 

What bothers me is that there are so many galaxies that are in visual reach that are not plotted while others that are not are.

It makes me wonder where the list came from.

 

In catalogues of galaxies the magnitudes are almost always photographic (B),
so of course the atlas won't agree with visual estimates.

 

With planetaries, the discrepancy between catalogue and visual magnitudes is

even greater because the discrete wavelengths of the planetary are recorded

by film that doesn't have the same color response as the eye. 

 

-- catalogman



#34 catalogman

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Posted 23 November 2020 - 07:20 AM

<snip>

 

The other problem with Uranometria though is that it uses the PK designation for all non-NGC, non-IC planetaries, while the actual AL list refers to those objects by generally anything BUT their PK number, so you'll need to cross-reference them somewhere as well.  

 

 

<snip>

So plotting an 18-19th magnitude PN with the same symbol as the brightest ones isn’t exactly helpful.
 

 

Both problems are solved in Cartes du Ciel:

 

When you build a catalogue, include both names (PK and other) in the search index.

 

Also, printed charts and screenshots display brighter objects with larger fonts:

 

https://www.cloudyni...ses/?p=10632214

 

-- catalogman



#35 Starman1

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Posted 23 November 2020 - 01:09 PM

In catalogues of galaxies the magnitudes are almost always photographic (B),
so of course the atlas won't agree with visual estimates.

 

With planetaries, the discrepancy between catalogue and visual magnitudes is

even greater because the discrete wavelengths of the planetary are recorded

by film that doesn't have the same color response as the eye. 

 

-- catalogman

Yes, I know, but ostensibly Uranometria 2000.0 was supposed to be an observer's atlas--well, maybe I'm wrong about that.

Your comment about planetaries is definitely apropos--I remember logging some planetaries with an 8" scope in the mag.16.5 range when galaxies of mag.14.5 were at the limit.

It was both a demonstration of the difference between surface brightness and total integrated magnitude and the difference between a photographically-derived magnitude and a visual one.


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#36 catalogman

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Posted 23 November 2020 - 06:50 PM

The classic Webb Society Deep Sky Observer's Handbook, Vol. 2 had a section on revising the photographic mags

of planetaries.

 

Also see "In Pursuit of Planetaries", by Jack B. Marling (S&T, Jun. 1986), p. 631.

 

There are more corrected mags on an archive of Doug Snyder's classic site:

 

https://web.archive..../SEC_data00.htm

 

which includes the database on all 1,143 PN's in the Strasbourg-ESO Catalogue (SEC):

 

https://web.archive....ntro.html#Files

 

This should help the OP identify the brightest planetaries.

 

-- catalogman



#37 SNH

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Posted 23 November 2020 - 09:35 PM

It's not a required program for Master Observer.  It's just one of the ones I picked (because I like PNs), and the only really hard one.  There are definitely harder ones (like the Galaxy Groups & Clusters program, which I'm working now).  

 

Not sure what you mean by "confirmed" but I'm pretty confident I saw all of them.  Pease 1 I used a friend's 25" rather than my 16" that I used for the rest though.  You must have pristine skies if you did it in a 10".  

In the AL's Guide to the Planetary Nebula Observing Program, it's written that they "...will allow negative observations in the completion of the advanced program." So I was just checked to see if had completed it without logging any negative observations. It's funny how 96% of all them are visible with a 130mm reflector while it really does take a 9-10" to see the hardest ones. As to my skies, I almost never get an SQM-L reading fainter than 21.4...

 

Scott
 



#38 SNH

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Posted 23 November 2020 - 09:58 PM

I'm using Megastar and there are hundreds in there. Of course, unless you have precision tracking, which I don't, when you get to those stellar ones, like down below 20 to 10 arc seconds, it's like looking for a needle in a haystack. And, I don't care if that's a cliche. I've found some smaller, but geez, when you're talking 2 arcseconds? Come on now. That's an exercise in frustration unless you have mechanically accurate tracking. With a Dob that just gets you in the ballpark, unless you have images of all the fields of view and filters you can flash in front of the eyepiece, or a wheel, or whatever other technique you use, it's better to look for size rather than magnitude for a lot of them. I may have some of you that don't agree and that's fine but I've spent a lot of time out there and still do when I DO get out and it can be an exercise in frustration without precision tracking. Then again, who says a challenge isn't such a bad thing? With Megastar, I can print the starfield down to less than 1 degree, so that helps. It still isn't easy though. It sometimes depends on how many other bright stars are surrounding it comparatively. All part of the fun!

Look at it this way. In our beloved Milky Way, there are less than 200 globular clusters, 500 planetary nebulae, 300 bright nebulae, and 200 dark nebulae visible with a 10-inch telescope (except for the globular cluster number, all are my estimations). Ignoring open clusters, you can quickly see you are basically "stuck" with viewing galaxies as the majority of your objects if you primarily view DSO's like myself. So cutting the number of PNe in a 10-inch from less than 500 to less than 150 doesn't make a lot of sense if you want a little diversity.

 

I agree that chasing down "stellar" PNe is work (and takes a lot of paper since I usually have to print of a 30arc DSS image of the area), but remember that there really aren't all that many visible in our Galaxy considering how brief they last! So I will continue to chase down all PNe visible from my location, but to keep it enjoyable, I'm going from brightest to faintest. So far, I've found over 100 that are visible with only 2-inch of aperture (50mm) and published my results in my 100+ Planetary Nebula with Small Telescopes & Binoculars eGuide. So stay hopefully and keep plucking away at them!!

 

Scott
 


Edited by SNH, 23 November 2020 - 10:00 PM.

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#39 KidOrion

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Posted 23 November 2020 - 11:08 PM

I agree that chasing down "stellar" PNe is work (and takes a lot of paper since I usually have to print of a 30arc DSS image of the area)

 

This. This is the way.


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#40 kt4hx

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Posted 23 November 2020 - 11:11 PM

https://www.etsy.com...-steven-j-hynes

Over 2000 planetaries here.

Alas, the book is no longer in print.  You will have to really hunt to find an affordable copy.

I was quite lucky in that regard. I found mine on Amazon about three to four years ago being sold by the friends of some library in Kentucky. It was the one from their local library and had never been checked out. It was pristine other than the library stamp on the top of the closed pages. I was fortunate to get mine for $30 plus shipping. An excellent book and I feel blessed to have it on my shelf as one of my many Will-Bell books.


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#41 KidOrion

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Posted 29 November 2020 - 02:07 PM

I was quite lucky in that regard. I found mine on Amazon about three to four years ago being sold by the friends of some library in Kentucky. It was the one from their local library and had never been checked out. It was pristine other than the library stamp on the top of the closed pages. I was fortunate to get mine for $30 plus shipping. An excellent book and I feel blessed to have it on my shelf as one of my many Will-Bell books.

I was even luckier--I got it through the Astronomy Book Club, but it was an accident, because I lost the card you were supposed to send in to prevent getting books you don't want.

 

Granted, I was 12 or 13 at the time, but still.


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