Re: [guide-user] Find LDN Dark Nebulas

Bill Gray Jan 5, 2015

Hi all,

Truth to tell, I don't know why there wasn't a "Go to LDN" right from
Guide 1.0...

For the nonce, I've provided this :

which contains the data file and .tdf required for display and "go to"
capability. UnZIP this in your Guide folder, use Go To... Go To .TDF,
select "Lynd's Dark Nebulae", and enter the LDN number.

Now, there's a possible problem here, which is that "LDN number"
appears to be ambiguous. There are _three_ possible numbers for an
LDN object.

There is a number assigned by the original author, Beverly Lynds,
"when the updated catalogue was created. The significance of this number
is unknown. Also, it is not a unique number throughout this version of
the catalogue." Which suggests to me it's probably not the one to use.

There is a "Running Number in this version of the Catalogue".

And finally, there is a "Catalogue number from original published
version (ApJS 7, 1)". That's the one with which I am currently going.
I'm not sure which is really in use. If it turns out I picked the
wrong one, we'll just change (in ldn.tdf) the line

text 1 4

to read

text 51 4

for the "Running Number in this version", or to

text 56 4

for the "Number that B. Lynds assigned when the updated catalogue
was created".

And I may puzzle this one out myself shortly. But I thought I'd
best post what I had here, before any of you invested too much time
on it.

-- Bill

On 01/05/2015 12:22 PM, 'Anthony J. Kroes' akroes@... [guide-user] wrote:
> Konstantin and Pierre,
> Not natively there isn't that I am aware of, but you can create a 'user
> dataset' for them if you don't mind doing a little work - the instructions
> are on the Project Pluto website. I did this for all the globulars in M33
> (over 200) and it worked great. Someone here may already have done that for
> the LDN's and might be willing to share.
> Your only alternative is to look them up the old fashioned way, by RA/Dec,
> or by alternate name if you know it (i.e. LDN 1531 is Barnard 18). That's
> the way I did a bunch recently for a list of Dark Nebula I was working on
> observing. Please let me know if you come up with a dataset!
> Tony.
> From: []
> Sent: Monday, January 05, 2015 5:17 AM
> To:
> Subject: [guide-user] Find LDN Dark Nebulas
> Hi,
> is there a possibility to find the LDN Nebulas if you know the number?
> Konstantin
> Konstantin v. Poschinger
> Hammerichstr. 5
> 22605 Hamburg
> 040/8805747
> 0171 1983476