A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Others » Astro Pictures
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

ASTRO: Berkeley 58 and NGC 7790



 
 
Thread Tools Display Modes
  #1  
Old April 7th 14, 04:36 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
external usenet poster
 
Posts: 3,085
Default ASTRO: Berkeley 58 and NGC 7790

There is a line of open clusters in Cassiopeia that's far longer than my
field of view allows. Here I've picked up the two furthest east, NGC
7790 and Berkeley 58 (upper right to lower left). All may be closely
related. I imaged NGC 7790 and NGC 7788 back in 2011. The others
further north and west are still to be taken. Those are Frolov 1,
Harvard 21 and King 12. Only King 12 is really recognizable as a
cluster from the rich Milky Way background.

This rich background makes it hard to tell where a cluster ends. For
this reason I found sizes ranging from 4.5 to 7.5 minutes for NGC 7790
and 5 to 8 minutes for Berkeley 58. In fact I found little agreement on
much of anything to do with these clusters.

NGC 7790 was listed as being 9,600 light-years distant, reddened by .53
magnitudes and having an age of 56 million years by WEBDA. Another
paper (http://arxiv.org/abs/1211.6398) says it is 10,300 +/- 500
light-years distant and 50 to 100 million years old. Wikipedia says
10,800 light years distant with an age of 60 to 80 million years. Other
values can be found as well. Combine this with the various size
estimates and the cluster is 13 to 22 light-years across. It contains 3
well studied Cepheid variable stars and even with that there's little
agreement on this cluster,

Things are no better with Berkeley 58. WEBDA says it is 12,000 light
years distant, reddened by 0.55 magnitudes and 250 million years old.
But another paper
(http://mnras.oxfordjournals.org/cont...1/444.full.pdf) says it is
10,000 light-years away, reddened by .7 magnitudes and 100 million years
old. I found size values of 5 to 8 minutes of arc giving a size range
of 14 to 28 light-years depending on which size and distance you use.
It contains a single well studied Cepheid which doesn't appear to help
any more than the three in NGC 7790 to pin things down.

Also in the image is a ghost of a flat galaxy, 2MFGC 18005. It is
faintly visible as a somewhat red fuzzy streak west of Berkeley 58 and
below NGC 7790. I wouldn't have prepared an annotated image but this
galaxy is so difficult to spot I made one just for it. When I saw it on
my FITs stack I thought it an asteroid but then it was very faintly seen
full size on the individual frames showing it wasn't an asteroid (one
this high in declination is rare). While it appears flat enough to
qualify for the flat galaxy catalog it isn't listed there for some
reason. This is such an obstructed region they may not have searched
this area for flat galaxies. NED lists no other galaxy in this area but
for what appears to be a duplicate entry for this one with a slightly
different position with a 35 second of arc error circle that easily
includes 2MFGC 18005. The galaxy hosted a super nova back in 2007 which
is how I came to learn of it. I wanted to catch it but that never
happened. I can't recall why.

Weather limited my color data for this cluster. I can't say the color
data is as good as I'd have liked. Only the red frames were sort of
clean. Both blue frames were weak and hazy. Only one green frame was
usable and it was dimmed by clouds. I never had a night to retake the
data, besides this was my third try with the other two a total loss due
to weather.

14" LX200R @ f/10, L=4x10' RB=2x10' G=1x10', STL-11000XM, Paramount ME

Rick
--
Prefix is correct. Domain is arvig dot net

Attached Thumbnails
Click image for larger version

Name:	NGC7790L4X10RB2X10G1X10R.JPG
Views:	264
Size:	765.7 KB
ID:	5055  Click image for larger version

Name:	NGC7790L4X10RB2X10G1X10R-67.JPG
Views:	155
Size:	460.3 KB
ID:	5056  Click image for larger version

Name:	NGC7790L4X10RB2X10G1X10R-ID.JPG
Views:	161
Size:	443.9 KB
ID:	5057  
  #2  
Old April 8th 14, 09:19 PM posted to alt.binaries.pictures.astro
Stefan Lilge
external usenet poster
 
Posts: 2,269
Default ASTRO: Berkeley 58 and NGC 7790

Rick,

while these might not be the most spectacular clusters they are easily
recognizable among the dense starfield.

Stefan


"Rick Johnson" schrieb im Newsbeitrag
...

There is a line of open clusters in Cassiopeia that's far longer than my
field of view allows. Here I've picked up the two furthest east, NGC
7790 and Berkeley 58 (upper right to lower left). All may be closely
related. I imaged NGC 7790 and NGC 7788 back in 2011. The others
further north and west are still to be taken. Those are Frolov 1,
Harvard 21 and King 12. Only King 12 is really recognizable as a
cluster from the rich Milky Way background.

This rich background makes it hard to tell where a cluster ends. For
this reason I found sizes ranging from 4.5 to 7.5 minutes for NGC 7790
and 5 to 8 minutes for Berkeley 58. In fact I found little agreement on
much of anything to do with these clusters.

NGC 7790 was listed as being 9,600 light-years distant, reddened by .53
magnitudes and having an age of 56 million years by WEBDA. Another
paper (http://arxiv.org/abs/1211.6398) says it is 10,300 +/- 500
light-years distant and 50 to 100 million years old. Wikipedia says
10,800 light years distant with an age of 60 to 80 million years. Other
values can be found as well. Combine this with the various size
estimates and the cluster is 13 to 22 light-years across. It contains 3
well studied Cepheid variable stars and even with that there's little
agreement on this cluster,

Things are no better with Berkeley 58. WEBDA says it is 12,000 light
years distant, reddened by 0.55 magnitudes and 250 million years old.
But another paper
(http://mnras.oxfordjournals.org/cont...1/444.full.pdf) says it is
10,000 light-years away, reddened by .7 magnitudes and 100 million years
old. I found size values of 5 to 8 minutes of arc giving a size range
of 14 to 28 light-years depending on which size and distance you use.
It contains a single well studied Cepheid which doesn't appear to help
any more than the three in NGC 7790 to pin things down.

Also in the image is a ghost of a flat galaxy, 2MFGC 18005. It is
faintly visible as a somewhat red fuzzy streak west of Berkeley 58 and
below NGC 7790. I wouldn't have prepared an annotated image but this
galaxy is so difficult to spot I made one just for it. When I saw it on
my FITs stack I thought it an asteroid but then it was very faintly seen
full size on the individual frames showing it wasn't an asteroid (one
this high in declination is rare). While it appears flat enough to
qualify for the flat galaxy catalog it isn't listed there for some
reason. This is such an obstructed region they may not have searched
this area for flat galaxies. NED lists no other galaxy in this area but
for what appears to be a duplicate entry for this one with a slightly
different position with a 35 second of arc error circle that easily
includes 2MFGC 18005. The galaxy hosted a super nova back in 2007 which
is how I came to learn of it. I wanted to catch it but that never
happened. I can't recall why.

Weather limited my color data for this cluster. I can't say the color
data is as good as I'd have liked. Only the red frames were sort of
clean. Both blue frames were weak and hazy. Only one green frame was
usable and it was dimmed by clouds. I never had a night to retake the
data, besides this was my third try with the other two a total loss due
to weather.

14" LX200R @ f/10, L=4x10' RB=2x10' G=1x10', STL-11000XM, Paramount ME

Rick
--
Prefix is correct. Domain is arvig dot net

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
ASTRO: Berkeley 65 Rick Johnson[_2_] Astro Pictures 0 January 16th 12 08:15 AM
ASTRO: NGC 7788 and 7790 Rick Johnson[_2_] Astro Pictures 1 November 8th 11 11:16 PM
ASTRO: NGC 7790/7788 Stefan Lilge Astro Pictures 3 December 29th 10 09:06 PM
Astro Talk at UC Berkeley Tomorrow? W. eWatson Astronomy Misc 1 May 12th 09 03:03 PM
What's up at Berkeley ... Anthony Ayiomamitis SETI 2 August 15th 05 10:37 PM


All times are GMT +1. The time now is 02:23 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.