Missing argo objects ?

[GrahamL]

Has anyone else experianced some ngc or messier objects
not showing up on a tour despite being well inside constellation and mag boundaries ?... make no mistake what does is dead centre in the eyepiece but others seem to be completely overlooked for some reason .?.. any thoughts much appreaciated as this has been frustrateing me for a while .

thanks :)

[gary]

Thanks for the post.

When assigning a magnitude limit filter whilst in MODE TOUR or MODE IDENTIFY,
it should be kept in mind that not all objects have assigned magnitudes.

For example, In some cases the association of a magnitude with a particular
object may make no particular sense, for example on very extended or
otherwise unusual objects with low surface brightness, so no magnitude
has been applied. On some NGC and IC objects, there may be no assigned
magnitude because no observed magnitude could be found. In some instances
we had to go and observe the objects ourselves and assign a magnitude.

In order to ensure every object you would like to observe in MODE IDENTIFY
or MODE TOUR appears, use the special magnitude selection of ANY.

Best Regards

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place, Mount Kuring-Gai
NSW. 2080. Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
sales@wildcard-innovations.com.au
http://www.wildcard-innovations.com.au

[Garyh]

I have had only one object that wasn`t on the list and it`s a IC 2169 as I was unable to put the 9 in the sequence?
Not sure what was going on there? Have read there are some duplicate objects that were removed in this catalog?
Gary

[gary]

Thanks for the post.

The Messier, NGC and IC catalogs are all "historical catalogs" and contain many
historical errors and puzzles for those who have come after to ponder. Some of
these have been resolved by various practitioners over time and some will for ever
remain a mystery. For example, some errors can be accounted for as a simple slip
of the quill pen, perhaps not entering a minus sign for a Dec. Other well meaning
practitioners who attempted to revise these historical catalogs unfortunately added
additional errors that others that followed would then have to correct.

When we compiled the catalogs we made every effort to use the best data
available to us and that often meant independently scrutinizing survey plates
or going out and trying to observe an object ourselves. For example, I spent
a good part of a year attempting to independently correct the NGC catalog.

IC 2169 is a duplicate object with IC 447 and the Argo Navis IC catalog was compiled
in such a way as to intentionally avoid duplicate entries appearing.

We like to keep the catalogs as correct as possible.

If an Argo Navis user ever comes across an error in a catalog, please let us
know by email along with a link to some supporting reference such as survey
data or images and we will investigate and correct it.

Best Regards

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place, Mount Kuring-Gai
NSW. 2080. Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
sales@wildcard-innovations.com.au
http://www.wildcard-innovations.com.au

[GrahamL]

Ok gary .. what you say is likely what I'm experianceing , last night
two objects I know and can find easily enough didn't show up .

Yes I do limit my mag to suit my sky around 12
ngc 2264 and 2261 , the first dosn't show up as an OC
but would it as a nebula?... the second does its variability mean it
also would not fit my selection criterea ?

M1 is also not showing up on a messier tour under my same mag 12
selection ?.


thanks for the input :)

[gary]

Thanks for the post.

NGC 2264, the Cone Nebula is a cluster with nebulosity and appears around a
5th mag star. It is reasonably large at around 20' across.
Currently the Argo Navis database does not assign it a visual magnitude and
hence for it to participate in a tour it would need to have the MAG setting set
as ANY. Quickly reviewing this particular one, I see we did not have a
magnitude estimate available from the source data used, but we should be able to
derive an estimate from alternative data sets. It probably has an integrated visual
magnitude of around 4.1. When in tour mode, it will appear if the object type
filter is set to either OPEN CLUSTER or BRIGHT NEBULA, but as noted the
key at present is that the MAG filter would need to be set to ANY.

There is a similar situation with Hubble's Variable Nebula NGC 2261 where a
mag estimate was not assigned and therefore one would need to currently
set the MAG as ANY to have it participate in a TOUR. A quick check does
not reveal a magnitude estimate in any of the source catalogs we used
but we'll investigate further and see if we can peg it down.

M1, also known as NGC 1952, does not currently have a magnitude estimate
assigned. As you are aware, it has quite a variation in its surface brightness.
I have added it to the list to review and it might end up with a magnitude assigned
of around 8.5.

Only as recently as the last few weeks we have been revising the entries for
some NGC objects so I will be sure to add them to the review list :thumbsup:

Thanks again for the post.

Best Regards

Gary Kopff
Wildcard Innovations Pty Ltd

[GrahamL]

Thanks for the input gary.

The MAG filter is something I have only started using more often fairly recently .. I did look at the magnitude of a couple of objects
previously (some a little obscure some not) that I know visually thinking I might have got something wrong .. I understand now that however well I can referance them the data I see regarding magnitude, and a lot of it is likely close , is still a little Arbitrary in regard to these historical catalouges ?

(OPEN CLUSTER or BRIGHT NEBULA) with regard to ngc 2264 you have
nailed exactly what I did , in that ok your not showing up as a OC
so you must be a NEBULA , referance some more info still
get (no more objects )...haha.


I did think of mailing you on this but thought maybe others
using the argos intuitive controls could stumble into a similar
situation ..

regards graham

[gary]

There are several considerations with regards visual magnitudes.

For extended objects, the concept of magnitude itself can become a little
nebulous. For example, many extended objects such as some galaxies can
have what appear to be reasonably bright integrated magnitudes but their
overall surface brightness can be quite low.

Historically, many of the definitive observations of objects have been performed
by professional astronomers by way of various surveys. Many of these surveys
were conducted using glass emulsion plates and filters that had a different
frequency response compared to the human eye. As a result, many of the
visual magnitudes for objects are often synthesized estimates, using
inputs such as the magnitudes from the red and the blue plates combined with
corrections for the size of the object, the type of the object and so on. However,
wherever possible, a visual magnitude taken from direct visual observation is
used when available.



Just to clarify it, Argo Navis will present you with NGC 2264 either if you
have searched for a NEBULA or an OPEN CLUSTER.
However, Argo Navis has the concept of a special magnitude selection called ANY.
Since NGC 2264 currently has not been assigned a magnitude, unless one uses
a MAG selection of ANY, then NGC 2264 will not appear in a tour.

Best Regards

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place, Mount Kuring-Gai
NSW. 2080. Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
sales@wildcard-innovations.com.au
http://www.wildcard-innovations.com.au

[Starkler]

I did once happen to stumble across a planetary nebula quite by accident and I hoped that mode-identify might tell me what it was.

Nope! Checked mag limits werent filtering the results and try again. Nope!

I made a note of its RA and Dec in case I could later claim to name my discovery Starkler-1, but alas a gentleman called Fleming had beaten me to it and named it Fleming-1 (PK 290+7.1).

Now this appears in a miscellaneous catalogue of the argo navis but it appears to not be picked up in tour or identify modes.

[gary]

Hi Geoff,

Thanks again for the post.

Fleming 1 is another example of an object for which a magnitude has not been
assigned.

When using MODE IDENTIFY or MODE TOUR the MAG setting must be
set to the special keyword ANY for FLEMING 1 to appear.

In other words, if the MAG filter is set to a numerical value, then FLEMING 1
will not appear. the MAG setting must be set to ANY.

A quick check here shows FLEMING 1 appears in both MODE IDENTIFY
and MODE TOUR if and only if the MAG is set to ANY. Other nearby
planetaries in the tour include HENIZE 2-63, ESO 216-02, HENIZE 2-64,
and HENIZE 2-55.

Also keep in mind that when using MODE IDENTIFY, there are two modes
of operation, namely, continual "search" mode and "GUIDE" mode.
When in continual search mode, the name of the object that nearest matches
the filtering criteria will appear in the top line and the word FOUND will
appear in the bottom. During this continual search mode, the entire database
is scanned for the best match in real time. If a new object should come closer
to where the scope is pointing, either because the scope was moved or because
the Earth's rotation brought it closer to where the scope was pointing, the name
of the object will change to show that this new object is now the closest.
GUIDE mode is entered by either pressing ENTER or spinning the dial in either
direction by one click. The word GUIDE will appear in the bottom line of the
display and the guide angles to the object will be shown. When in GUIDE mode,
the unit "locks on" to that object and the continual search of the database is
halted. If the user exits GUIDE mode, either by spinning the dial by one click
or by pressing EXIT, the unit will once again enter continual search mode.

Also be sure to set the object type to PLANETARY N and not accidentally set
it to PLANET. Fleming 1 appears if the object type is set to PLANETARY N or
NON STELLAR.

For example, if one aligns the unit and then performs MODE TOUR,
FIND PLANETARY N, FAINTEST MAG ANY, IN CENTAURUS, then the
object FLEMING 1 definitely appears in MODE TOUR. Likewise, if one aligns the
unit and then moves the scope to the approx RA/Dec of FLEMING 1 and then
performs a similar search in MODE IDENTIFY, it definitely does appear. :thumbsup:

Best Regards

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place, Mount Kuring-Gai
NSW. 2080. Australia
Phone +61-2-9457-9049
Phone +61-2-9457-9593
sales@wildcard-innovations.com.au
http://www.wildcard-innovations.com.au

[Starkler]

Thanks Gary. I knew it wouldnt take long for you to respond. :thumbsup:
It was maybe two years I stumbled onto this. Shall test for sure at next opportunity.



I'll forgive you.
Geoff:lol:

[gary]

Apologies with the name mix-up! Thanks Geoff! :)

Best regards

Gary