@19. Jon Hanford : Thanks for that.

@15. Bill Gresho :

Now for the question. What is “high in the sky”? On the horizon toward the North or up at the zenith? Sorry. Serious question from a senile 70 year old.

Not *that* senile I think! Depends where you live (latitude esp.) and what time of night it is but usually I think “high in the sky” refers to being closer to zenith rather than more northerly. Sometimes o’ course its both!

(Sorry, meant to answer that last night and forgot. No need to apologise for asking questions – some of us here actually love answering them! [Raises hand.] )

Just now came back to check for responses. A belated, but hearty “thank you” is certainly in order.

I’m overwhelmed at how much has gone into studying these stars, and how difficult it’s been to accurately measure their movements and distances. I really thought it was a “simple” matter of parallax observation and red-shift determination. I should have known better. And now I do.

Again… thank you.

In addition to the material noted by MTU above, here’s a link to a 1998 study, again using Hipparchos data, that found Collinder 399 to be a chance alignment of stars and not a bound cluster: http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1998A%26A…340..402B&db_key=AST

Clearly these stars are at very different distances and as Brian A. Skiff of Lowell Observatory noted :

By comparing pairs of stars on the list [Hipparcos catalogue - ed.], you can see that there is no pair with similar parallaxes and motions, much less a full cluster. For instance, stars 3 & 8 [HD 182620 an A2 V Sirian & HD 182972 an A1 V Sirian - ed.] have very similar parallax distances, and the uncertainties overlap considerably. However, comparison of the proper motions shows them to be moving in very nearly opposite directions on the sky. Thus though they could be near each other, their motions through space are different.”

Source : Page 67, “Brocchi’s Cluster Revealed” article by B.A. Skiff in ‘Sky & Telescope’ magazine, January 1998.

Info from the table incl. there added too btw. Good article by on the non-cluster-ness of Brocchi’s Cluster / Collinder 399 / the Coathanger if folks can find a copy somewhere.

BTW. Red giant Anser (or shall we call it the goose star!) the lucida or brightest star in the constellation seems to be a member of the Arcturus stream, a group of stars with high proper motion and metal-poor properties thought to be the remnants of a small galaxy consumed by the Milky Way – Arcturus of course being the brightest example of that group in our skies! (Wiki-link to source in my name here.)

http://stars.astro.illinois.edu/sow/cthng-t.html

&

http://stars.astro.illinois.edu/sow/vul-t.html

Which give the Kaler’s ‘Stars’ links to the Coathanger asterism and Vulpecula constellation more broadly including photographic findercharts.

Wikipedia page for 4 Vulpeculae is here :

http://en.wikipedia.org/wiki/4_Vulpeculae

Noting it is an orange giant star about 235 ly distant whilst 7 Vul is a B5 blue dwarf star located 760 ly away and 3 Vul is a B6 type blue giant star located 400 light years away as noted on their respective wiki-entries and the wiki- list of stars in Vulpecula which is linked to my name here.

I presume the other un-Flamsteed numbered stars of the Coathanger / Brocchi’s Cluster / Collinder 399 would have other star catalogue designations – SAO / HD / HIP (etc ..) numbers but not sure what they are or their types and distances.

@14. Curt – From that wikipedia entry :

The group was considered to be a cluster for most of the 20th century. Looking at a variety of criteria, however, a study in 1970 concluded that only 6 of the brightest stars formed an actual cluster. Several independent studies since 1998 have now determined that this object is not a true cluster at all, but rather just a chance alignment of stars. These recent studies have generally based their findings on improved measurements of parallax and proper motion provided by the Hipparcos satellite which were first published in 1997.

The BA might perhaps have been using an older source thus explaining that uncertainty.

Jim Kaler’s excellent ‘Stars’ website also has a great entry on this asterism noting that three of its stars have Flamsteed numbers – specifically 7, 5 & 4 Vulpeculae.

From a former kid astronomy buff — like 55 years ago. Walked the barrel, grinding and polishing, “constructing” a six inch Newtonian.

Now for the question. What is “high in the sky”? On the horizon toward the North or up at the zenith? Sorry. Serious question from a senile 70 year old.

Why is it that we don’t know for certain? Am I mistaken? … (likely so)… But I thought we could determine movement and distance of stars. Someone please enlighten me.

Thanks!