Hi Folks "A beautiful ruby star of the ninth magnitude surrounded by a crown..." is the way Father Secchi described the magnificent galactic cluster NGC 6520...
I think it's fair to say that in recent years, there has been a developing trend in amateur astronomy of giving surface more weight than integrated magnitude...
Although I have not re-visited the cluster in detail recently, I am pretty sure the red 'central star' is not an HD star, but is instead CD-27 12315 = CPD-27...
Brian Skiff
bas@...
Apr 2, 2006 1:57 am
17744
Hi Brian, Dave transposed numbers. I believe the star he is proposing is HD 316951, which is spectral type A, V = 8.9. Doesn't change the point you are...
I use Guide8 software and I notice a flaw when Guide accesses the Tycho-2 dataset - the central star of NGC 6520 (GSC 6850-3214 = CoD-27 12315 = CPD-27 6027)...
Mati Morel
morel@...
Apr 2, 2006 10:00 am
17746
Hi Bill, your thoughts about a useful numerical scale for estimating the visibility of extended objects remind me of a little known catalogue compiled by the ...
Arndt, Thanks for your input. It's a very interesting scale, but I find it heavily slanted toward the bright end. The scales levels #10-12, for me, describe...
Bill, Stephen Saber's post in the same discussion to which you allude contains an interesting calculator that works a little better than IM+SB-30. You know...
... This is one of many SIMBAD corrections pending, which I think I've sent them three times: once from working over the Blanco & Munch list (yielding the...
Brian Skiff
bas@...
Apr 2, 2006 10:41 pm
17750
has anyone an amateur image of the local group galaxy PGC 29194 (antlia dwarf)?,the only images I have seen on Google and other sites are from large...
I am resending this post, which I sent nearly 24 hrs ago. Does not appear to have reached the amastro list server, nor bounced. Lost in cyberspace? My...
Mati Morel
morel@...
Apr 3, 2006 3:18 am
17752
Is this catalogue available electronically ? Owen ... Owen Brazell Editor Webb DSO www.webbsociety.freeserve.co.uk owen@......
Hi Dave, ... In his paper (actually a published letter to Richard Carrington) Secchi wrote: "A perfectly dark spot of the shape of a pear, about 4' large. This...
Steinicke-Streifeneder
Steinicke-Streifenede...
Apr 3, 2006 7:01 am
17754
Owen, I'm afraid it's not available online yet. But it would probably be no more than a few hours' time to hack in all the data if it is of some value. Just ...
I think they could be of some interest as a single observers set of notes, much like Steve Gottliebs are. Perhaps just scan them. That would be easier. Owen ...
... Yes, I think that's pretty indisputable. No matter how high the surface brightness, you're not going to see a mag-15 galaxy through a 100mm telescope....
... Oh yes, I was going to say this in my previous post but forgot. Brian Rachford developed a very interesting approach to galaxy visibility by using the...
... and ... integrated ... galaxies. ... Hi Tony, Yes, a lot of qualification. I think of the lists as "Best Case Scenario" rankings. Assuming the object is...
I rummaged around in our archive for the Hagen "zone catalogues". They appear to be parts of volume X (i.e. 10) of the Specola Astronomica Vaticana, and...
Brian Skiff
bas@...
Apr 4, 2006 12:03 am
17760
Some reference is made to Hagen's work in Harold Corwin's Historical Perspective on the NGC/IC Project at http://www.ngcic.org/history.htm) \, but I've never...
... My note on the General Catalogue was sent before reading Brian's, but I believe I also photocopied the Zone Catalogues. I'll check to see if there is more...
There was extensive discussion in the 1920s and 30s within an IAU commission on "nebulae" about the idea of preparing essentially an revision/update of the...
Brian Skiff
bas@...
Apr 4, 2006 3:13 am
17763
Howdy all; Well, I am going to mention this again and you folks can tell me when to stop. When we were putting together the Saguaro Astronomy Club deep sky...
I am mostly an observer of galaxies and it seems like we had a similar discussion about galaxy visibility several months ago when I first joined the Amastro,...
Hagen's "Zone catalogue" contains about the same amount of information as the "General catalogue", at least concerning the NGC objects. What has been condensed...
Some general, if limited, conclusions you could draw from Blackwell's work on contrast visibility might add perspective. A darker background will help the eye...
Dear Arndt,Tom, Brian,Paul, & group, After a spectacular total eclipse in Turkey during which it was absolutely possible to make out solar prominences with the...
A apparent nova has been found by H. Nishimura in Japan. It was reported as mag 10.5 from T-Max films on Apr 2.8 UT. Confirming images and astrometry was done...
Brian Skiff
bas@...
Apr 5, 2006 5:03 am
17769
Steve, I've added a column to my Excel file that calculates the surface brightness minus magnitude for the 573 galaxies in my database. I've uploaded the file...
Another possibility in trying to quantify this business is using the value in the RC3 called "mean effective surface brightness", flagged m'_e in the...
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