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ASTRO: Arp 70



 
 
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  #1  
Old October 16th 11, 06:28 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
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Posts: 3,085
Default ASTRO: Arp 70

Arp 70, a pair of interacting galaxies, is in northeastern Pisces about
2 degrees due west of M33. It is about 460 million light-years from
earth. Arp put it in his category of spirals with small, high surface
brightness companions on arms. There does seem to be a very faint
stream of stars coming from the southern, cut-off arm over to the
companion galaxy. Though in Arp's image it is difficult to see. It's
easier to see a connection from the northern arm down to the companion
in Arp's image. There does appear to be a broad band of stars running
from the main spiral to the companion coming from the entire western
side of the galaxy and going beyond the companion a little ways, if a
few million light-years can be considered a "little ways".

The main galaxy is UGC 934. It has other designations such as PGC 5085.
NED classes it as S? The companion is LEDA 212740 among other
designations. NED makes no attempt to classify it. While it appears to
be related to UGC 934 NED has no redshift or other distance data so this
is possibly an illusion though most see it as a true interacting companion

NED has no redshift data on any galaxies in the field except UGC 934.
Only a dozen or so other galaxies are even identified, all from the
2MASS survey of IR galaxies. The Sloan SR8 Survey has been released but
not included as yet. The Sloan image of Arp 70 from this data release
comes the closest to my colors of any I've seen so far. Stars are far
different however. Arp 70 must not have much IR or UV emission for this
to happen.

There is one asteroid in the image. It is (255475) 2005 YN165 at an
estimated magnitude of 19.7. To find it look near the top of the image
directly above Arp 70 to the right of the brightest blue star in the
frame and a fainter one. The trail goes up at a rather steep angle and
yes the asteroid was moving upward in retrograde motion when this was taken.

The stars in Arp's image are rather elongated. I've seen this when he
was capturing two Arp's on one film plate and was pushing the limits of
the Winn Corrector that corrects for coma and flattens the field. But
there's no other Arp's in the area. The nearest is over 2 degrees to
the north, far beyond the field of the 200". Maybe there was something
else that interested him but didn't make the catalog. BTW, his exposure
was 30 minutes on 103a-D emulsion for this one. 103a-D is most
sensitive to yellow-green light. I used 40 minutes for the luminance
data with a telescope that gathers only 0.5% the photons of the 200"
Palomar telescope. Yes, CCD's are more sensitive than film--a lot more
sensitive.

Arp's image:
http://ned.ipac.caltech.edu/level5/A...big_arp70.jpeg

Attached are my full size image, a cropped image enlarged to 0.67" per
pixel and the Sloan Survey image at the same 0.67 image scale.

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

Rick
--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

Attached Thumbnails
Click image for larger version

Name:	ARP70L4X10RGB2X10.JPG
Views:	327
Size:	261.9 KB
ID:	3770  Click image for larger version

Name:	ARP70L4X10RGB2X10CROP150.JPG
Views:	155
Size:	104.4 KB
ID:	3771  Click image for larger version

Name:	SDSS_ARP70.jpg
Views:	175
Size:	67.4 KB
ID:	3772  
  #2  
Old October 17th 11, 08:06 PM posted to alt.binaries.pictures.astro
Stefan Lilge
external usenet poster
 
Posts: 2,269
Default ASTRO: Arp 70

Great image Rick.
This galaxy apparently got a good stretch.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
.com...
Arp 70, a pair of interacting galaxies, is in northeastern Pisces about
2 degrees due west of M33. It is about 460 million light-years from
earth. Arp put it in his category of spirals with small, high surface
brightness companions on arms. There does seem to be a very faint
stream of stars coming from the southern, cut-off arm over to the
companion galaxy. Though in Arp's image it is difficult to see. It's
easier to see a connection from the northern arm down to the companion
in Arp's image. There does appear to be a broad band of stars running
from the main spiral to the companion coming from the entire western
side of the galaxy and going beyond the companion a little ways, if a
few million light-years can be considered a "little ways".

The main galaxy is UGC 934. It has other designations such as PGC 5085.
NED classes it as S? The companion is LEDA 212740 among other
designations. NED makes no attempt to classify it. While it appears to
be related to UGC 934 NED has no redshift or other distance data so this
is possibly an illusion though most see it as a true interacting companion

NED has no redshift data on any galaxies in the field except UGC 934.
Only a dozen or so other galaxies are even identified, all from the
2MASS survey of IR galaxies. The Sloan SR8 Survey has been released but
not included as yet. The Sloan image of Arp 70 from this data release
comes the closest to my colors of any I've seen so far. Stars are far
different however. Arp 70 must not have much IR or UV emission for this
to happen.

There is one asteroid in the image. It is (255475) 2005 YN165 at an
estimated magnitude of 19.7. To find it look near the top of the image
directly above Arp 70 to the right of the brightest blue star in the
frame and a fainter one. The trail goes up at a rather steep angle and
yes the asteroid was moving upward in retrograde motion when this was
taken.

The stars in Arp's image are rather elongated. I've seen this when he
was capturing two Arp's on one film plate and was pushing the limits of
the Winn Corrector that corrects for coma and flattens the field. But
there's no other Arp's in the area. The nearest is over 2 degrees to
the north, far beyond the field of the 200". Maybe there was something
else that interested him but didn't make the catalog. BTW, his exposure
was 30 minutes on 103a-D emulsion for this one. 103a-D is most
sensitive to yellow-green light. I used 40 minutes for the luminance
data with a telescope that gathers only 0.5% the photons of the 200"
Palomar telescope. Yes, CCD's are more sensitive than film--a lot more
sensitive.

Arp's image:
http://ned.ipac.caltech.edu/level5/A...big_arp70.jpeg

Attached are my full size image, a cropped image enlarged to 0.67" per
pixel and the Sloan Survey image at the same 0.67 image scale.

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

Rick
--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".



 




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