ASTRO: Another Arp 273

The large galaxy is UGC 1810, the other spiral UGC 1813. They are
located about 330 million light years away at the southeast corner of
Andromeda. It's obvious that UGC 1810 is highly distorted. One arm
looks more like Saturn's F ring than a spiral arm and seems to make a
complete ring about the galaxy. It's hard to tell if NGC 1813 is
distorted. It looks greatly distorted to me as the arms are almost
straight but that is seen in other barred spirals. But it has faint a
faint arm that curls back and runs along the bar while the ends of the
bar, if it is a bar, seem to end differently. The left one ends in a
faint blob while the right one seems to merge with the outer ring of UGC
1810. In any case they curve very differently, likely due to the near
collision. To appear so large at such a great distance these have to be
two very large spiral galaxies.

When galaxies pass by like this they trigger massive star formation. We
see it in the arms of the bigger galaxy UGC 1810, this is common, but it
is confined to the very core of UGC 1813. This is very unusual. Also
UGC 1810 is a LINER galaxy indicating it has a nearly starved black hole
at its core. So we know the near miss hasn't yet caused a feast for the
black hole by sending matter its way. Yet UGC 1813 seems to have a heck
of a lot of disturbance at its core to trigger so much star formation.
This all goes to show it is very hard to predict just what will happen
in a near miss like these two have encountered. Nor do we know what
long term changes it will trigger. I can't even find if the two are
gravitationally bound. If so they will merge in the future.

14" LX200R @ f/10, L=6x10' binned 1x1, RGB=2x10' binned 2x2,
STL-11000XM, Paramount ME Image scale = 0.5" per pixel rather than my
usual 1" per pixel.

Note that Stefan's FOV is somewhat larger than mine.

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".

Nice image Rick. What magnitude are these?

Joe


"Rick Johnson" wrote in message
ster.com...
The large galaxy is UGC 1810, the other spiral UGC 1813. They are
located about 330 million light years away at the southeast corner of
Andromeda. It's obvious that UGC 1810 is highly distorted. One arm
looks more like Saturn's F ring than a spiral arm and seems to make a
complete ring about the galaxy. It's hard to tell if NGC 1813 is
distorted. It looks greatly distorted to me as the arms are almost
straight but that is seen in other barred spirals. But it has faint a
faint arm that curls back and runs along the bar while the ends of the
bar, if it is a bar, seem to end differently. The left one ends in a
faint blob while the right one seems to merge with the outer ring of UGC
1810. In any case they curve very differently, likely due to the near
collision. To appear so large at such a great distance these have to be
two very large spiral galaxies.

When galaxies pass by like this they trigger massive star formation. We
see it in the arms of the bigger galaxy UGC 1810, this is common, but it
is confined to the very core of UGC 1813. This is very unusual. Also
UGC 1810 is a LINER galaxy indicating it has a nearly starved black hole
at its core. So we know the near miss hasn't yet caused a feast for the
black hole by sending matter its way. Yet UGC 1813 seems to have a heck
of a lot of disturbance at its core to trigger so much star formation.
This all goes to show it is very hard to predict just what will happen
in a near miss like these two have encountered. Nor do we know what
long term changes it will trigger. I can't even find if the two are
gravitationally bound. If so they will merge in the future.

14" LX200R @ f/10, L=6x10' binned 1x1, RGB=2x10' binned 2x2,
STL-11000XM, Paramount ME Image scale = 0.5" per pixel rather than my
usual 1" per pixel.

Note that Stefan's FOV is somewhat larger than mine.

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".



----------------------------------------------------------------------------
----

J McBride wrote:
Nice image Rick. What magnitude are these?

Joe


Galaxy magnitudes can be highly misleading as to ability to see
visually. I've not tried these so don't know if my 14" can show them or
not. NED lists 1810 at 13.42 and 1813 at 15.08. Rather bright for what
I see in the data though the cores of both are very bright compared to
the rest of the galaxy making processing "interesting" to show detail in
the core yet bring out the fainter outer parts. How much that star seen
atop 1810 is included in the estimate I don't know but would bet it had
an effect making it appear brighter than it really is. The faint ones
around the pair go down below 21nd magnitude. Some must be fainter as
they just don't register in the astrometry program when I try to click
on them.

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".

Rick,

funny that we have posted these at the same time. This sure is an
interesting pair. Looks more impressive at your 1x1 binning scale, I should
have imaged with the focal reducer nearer to the camera to get a larger
scale (seeing would have been good enough to support a larger scale).

Stefan

"Rick Johnson" schrieb im Newsbeitrag
ster.com...
The large galaxy is UGC 1810, the other spiral UGC 1813. They are
located about 330 million light years away at the southeast corner of
Andromeda. It's obvious that UGC 1810 is highly distorted. One arm
looks more like Saturn's F ring than a spiral arm and seems to make a
complete ring about the galaxy. It's hard to tell if NGC 1813 is
distorted. It looks greatly distorted to me as the arms are almost
straight but that is seen in other barred spirals. But it has faint a
faint arm that curls back and runs along the bar while the ends of the
bar, if it is a bar, seem to end differently. The left one ends in a
faint blob while the right one seems to merge with the outer ring of UGC
1810. In any case they curve very differently, likely due to the near
collision. To appear so large at such a great distance these have to be
two very large spiral galaxies.

When galaxies pass by like this they trigger massive star formation. We
see it in the arms of the bigger galaxy UGC 1810, this is common, but it
is confined to the very core of UGC 1813. This is very unusual. Also
UGC 1810 is a LINER galaxy indicating it has a nearly starved black hole
at its core. So we know the near miss hasn't yet caused a feast for the
black hole by sending matter its way. Yet UGC 1813 seems to have a heck
of a lot of disturbance at its core to trigger so much star formation.
This all goes to show it is very hard to predict just what will happen
in a near miss like these two have encountered. Nor do we know what
long term changes it will trigger. I can't even find if the two are
gravitationally bound. If so they will merge in the future.

14" LX200R @ f/10, L=6x10' binned 1x1, RGB=2x10' binned 2x2,
STL-11000XM, Paramount ME Image scale = 0.5" per pixel rather than my
usual 1" per pixel.

Note that Stefan's FOV is somewhat larger than mine.

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".

Wonderful Rick and Stefan,

i am very interested by ARP objects. It is about 1 week that i am reading
the book "The Arp Atlas of Peculiar Galaxies A Chronicle and Observer's
Guide" and i like it too much. Now i see your images, that are wonderful.

I want to try somehow, using my C9,25 and H9C. Maybe in binning 2x2.
Using the FLT110 f7 , would be too difficult i think. just for ARP/Messier
objects.
What do you think ??

Thanks for sharing

Fabio




E-mail :



Website : http://www.fabioh2o.it





"Rick Johnson" ha scritto nel messaggio
ster.com...
The large galaxy is UGC 1810, the other spiral UGC 1813. They are
located about 330 million light years away at the southeast corner of
Andromeda. It's obvious that UGC 1810 is highly distorted. One arm
looks more like Saturn's F ring than a spiral arm and seems to make a
complete ring about the galaxy. It's hard to tell if NGC 1813 is
distorted. It looks greatly distorted to me as the arms are almost
straight but that is seen in other barred spirals. But it has faint a
faint arm that curls back and runs along the bar while the ends of the
bar, if it is a bar, seem to end differently. The left one ends in a
faint blob while the right one seems to merge with the outer ring of UGC
1810. In any case they curve very differently, likely due to the near
collision. To appear so large at such a great distance these have to be
two very large spiral galaxies.

When galaxies pass by like this they trigger massive star formation. We
see it in the arms of the bigger galaxy UGC 1810, this is common, but it
is confined to the very core of UGC 1813. This is very unusual. Also
UGC 1810 is a LINER galaxy indicating it has a nearly starved black hole
at its core. So we know the near miss hasn't yet caused a feast for the
black hole by sending matter its way. Yet UGC 1813 seems to have a heck
of a lot of disturbance at its core to trigger so much star formation.
This all goes to show it is very hard to predict just what will happen
in a near miss like these two have encountered. Nor do we know what
long term changes it will trigger. I can't even find if the two are
gravitationally bound. If so they will merge in the future.

14" LX200R @ f/10, L=6x10' binned 1x1, RGB=2x10' binned 2x2,
STL-11000XM, Paramount ME Image scale = 0.5" per pixel rather than my
usual 1" per pixel.

Note that Stefan's FOV is somewhat larger than mine.

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".

Fabio, I think you would be better of using the C9.25 with a focal reducer.
Aperture counts if you want to image small galaxies. I you use a reducer I
would not use binning.

Stefan

"Fabio" schrieb im Newsbeitrag
. ..
Wonderful Rick and Stefan,

i am very interested by ARP objects. It is about 1 week that i am reading
the book "The Arp Atlas of Peculiar Galaxies A Chronicle and Observer's
Guide" and i like it too much. Now i see your images, that are wonderful.

I want to try somehow, using my C9,25 and H9C. Maybe in binning 2x2.
Using the FLT110 f7 , would be too difficult i think. just for ARP/Messier
objects.
What do you think ??

Thanks for sharing

Fabio




E-mail :



Website : http://www.fabioh2o.it





"Rick Johnson" ha scritto nel messaggio
ster.com...
The large galaxy is UGC 1810, the other spiral UGC 1813. They are
located about 330 million light years away at the southeast corner of
Andromeda. It's obvious that UGC 1810 is highly distorted. One arm
looks more like Saturn's F ring than a spiral arm and seems to make a
complete ring about the galaxy. It's hard to tell if NGC 1813 is
distorted. It looks greatly distorted to me as the arms are almost
straight but that is seen in other barred spirals. But it has faint a
faint arm that curls back and runs along the bar while the ends of the
bar, if it is a bar, seem to end differently. The left one ends in a
faint blob while the right one seems to merge with the outer ring of UGC
1810. In any case they curve very differently, likely due to the near
collision. To appear so large at such a great distance these have to be
two very large spiral galaxies.

When galaxies pass by like this they trigger massive star formation. We
see it in the arms of the bigger galaxy UGC 1810, this is common, but it
is confined to the very core of UGC 1813. This is very unusual. Also
UGC 1810 is a LINER galaxy indicating it has a nearly starved black hole
at its core. So we know the near miss hasn't yet caused a feast for the
black hole by sending matter its way. Yet UGC 1813 seems to have a heck
of a lot of disturbance at its core to trigger so much star formation.
This all goes to show it is very hard to predict just what will happen
in a near miss like these two have encountered. Nor do we know what
long term changes it will trigger. I can't even find if the two are
gravitationally bound. If so they will merge in the future.

14" LX200R @ f/10, L=6x10' binned 1x1, RGB=2x10' binned 2x2,
STL-11000XM, Paramount ME Image scale = 0.5" per pixel rather than my
usual 1" per pixel.

Note that Stefan's FOV is somewhat larger than mine.

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".

Great minds think alike it seems, and procrastinate alike as well it
appears. Least I had this one on my hard drive for a couple months
before I got around to working on it then it sat another month before it
worked its way to the top of my posting pile.

It is rare I get a night I can work at 0.5" per pixel (1x1 binning). It
never happens in winter. This time of the year seeing is so bad I
often have to go to 1.5" and even that is blurry. I've got way too many
of those on the hard drive hoping for better seeing so I can redo the
Lum part. Doesn't hurt color so much.

Last night it "only" hit -34C but froze the filter wheel. I had to go
out and give it a heat treatment to thaw it. Then all was fine. Next I
came in to find I couldn't reach focus. As the temp drops the focal
point moves back and the focuser had reached max (I keep the mirror
locked). So again had to go out and unlock the mirror, run the external
focuser in (it's slow so that took 3 minutes on the "in" button), then
came the "fun" part. Since the laptop's screen dies at such temps and
does so almost instantly I had to then move the mirror to the right spot
to match where I'd put the 3" Crawford focuser. That took about 5 trips
back into the house to take another test shot then run out and try
again. Finally got it working in time to get some data before the moon
rose. At least I'm now set for the rest of winter with the focuser but
once moisture starts freezing the filter wheel I'll likely have to thaw
it out nearly every night or take the camera off and bring it in the
house to dry out but that first soaks it as it hits the warm air in the
house. So it is often easier to deal with the frozen wheel when it
happens. I have heat tape somewhere I got for the camera to warm it
when not in use. That worked last year to keep things dry and working.
I'd turn it off a couple hours before using to let it cool down. But
can't find where I stored it for summer! Thought I just left it in the
observatory but obviously didn't.

Rick


Stefan Lilge wrote:

Rick,

funny that we have posted these at the same time. This sure is an
interesting pair. Looks more impressive at your 1x1 binning scale, I should
have imaged with the focal reducer nearer to the camera to get a larger
scale (seeing would have been good enough to support a larger scale).

Stefan

"Rick Johnson" schrieb im Newsbeitrag
ster.com...

The large galaxy is UGC 1810, the other spiral UGC 1813. They are
located about 330 million light years away at the southeast corner of
Andromeda. It's obvious that UGC 1810 is highly distorted. One arm
looks more like Saturn's F ring than a spiral arm and seems to make a
complete ring about the galaxy. It's hard to tell if NGC 1813 is
distorted. It looks greatly distorted to me as the arms are almost
straight but that is seen in other barred spirals. But it has faint a
faint arm that curls back and runs along the bar while the ends of the
bar, if it is a bar, seem to end differently. The left one ends in a
faint blob while the right one seems to merge with the outer ring of UGC
1810. In any case they curve very differently, likely due to the near
collision. To appear so large at such a great distance these have to be
two very large spiral galaxies.

When galaxies pass by like this they trigger massive star formation. We
see it in the arms of the bigger galaxy UGC 1810, this is common, but it
is confined to the very core of UGC 1813. This is very unusual. Also
UGC 1810 is a LINER galaxy indicating it has a nearly starved black hole
at its core. So we know the near miss hasn't yet caused a feast for the
black hole by sending matter its way. Yet UGC 1813 seems to have a heck
of a lot of disturbance at its core to trigger so much star formation.
This all goes to show it is very hard to predict just what will happen
in a near miss like these two have encountered. Nor do we know what
long term changes it will trigger. I can't even find if the two are
gravitationally bound. If so they will merge in the future.

14" LX200R @ f/10, L=6x10' binned 1x1, RGB=2x10' binned 2x2,
STL-11000XM, Paramount ME Image scale = 0.5" per pixel rather than my
usual 1" per pixel.

Note that Stefan's FOV is somewhat larger than mine.

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".

I can see it will be a several year project to image all Arp's I can see
from my location. I have trouble in winter below the celestial equator
with only a rather narrow window that works below it due to ice crystals
over the lake and many of those between 0 and -15 degrees (my southern
limit due to seeing and ice) is small letting many escape my photon
detector.

Which scope to use depends on which Arp you are imaging. Most are very
small, well under a minute of arc across so you will want as large an
image scale as your seeing can support. I used 0.5" per pixel for this
one though that's rarely allowed by my seeing. 1.0" per pixel is more
common for my location. Others are large like Arp 26 = M 101. There
are quite a few Messier objects in the list. I still have Arp 134=M49
and Arp 168=M32 to go. The latter got past me this year so will try
again next.

A few URL's I use a lot a
http://arpgalaxy.com/arpord.html
Shows Arps in order and thus by Arp's classification
http://arpgalaxy.com/arplist.html
Arps in R.A. order. Useful for planning a night's imaging run.
http://nedwww.ipac.caltech.edu/level..._contents.html
Palomar photos of all Arp's in an easy to use interface. Most are taken
with the 200" though large ones are from the POSS plates.

There's an amateur in France (I think that's it), can't recall his URL
as it is in a different computer, that has almost completed the list.
Google should turn it up. He's using an 8" SCT with compressor so image
scale can be very small but they are there.

It's a fun project.

Rick


Fabio wrote:

Wonderful Rick and Stefan,

i am very interested by ARP objects. It is about 1 week that i am
reading the book "The Arp Atlas of Peculiar Galaxies A Chronicle and
Observer's Guide" and i like it too much. Now i see your images, that
are wonderful.

I want to try somehow, using my C9,25 and H9C. Maybe in binning 2x2.
Using the FLT110 f7 , would be too difficult i think. just for
ARP/Messier objects.
What do you think ??

Thanks for sharing

Fabio




E-mail :



Website : http://www.fabioh2o.it





"Rick Johnson" ha scritto nel messaggio
ster.com...

The large galaxy is UGC 1810, the other spiral UGC 1813. They are
located about 330 million light years away at the southeast corner of
Andromeda. It's obvious that UGC 1810 is highly distorted. One arm
looks more like Saturn's F ring than a spiral arm and seems to make a
complete ring about the galaxy. It's hard to tell if NGC 1813 is
distorted. It looks greatly distorted to me as the arms are almost
straight but that is seen in other barred spirals. But it has faint a
faint arm that curls back and runs along the bar while the ends of the
bar, if it is a bar, seem to end differently. The left one ends in a
faint blob while the right one seems to merge with the outer ring of UGC
1810. In any case they curve very differently, likely due to the near
collision. To appear so large at such a great distance these have to be
two very large spiral galaxies.

When galaxies pass by like this they trigger massive star formation. We
see it in the arms of the bigger galaxy UGC 1810, this is common, but it
is confined to the very core of UGC 1813. This is very unusual. Also
UGC 1810 is a LINER galaxy indicating it has a nearly starved black hole
at its core. So we know the near miss hasn't yet caused a feast for the
black hole by sending matter its way. Yet UGC 1813 seems to have a heck
of a lot of disturbance at its core to trigger so much star formation.
This all goes to show it is very hard to predict just what will happen
in a near miss like these two have encountered. Nor do we know what
long term changes it will trigger. I can't even find if the two are
gravitationally bound. If so they will merge in the future.

14" LX200R @ f/10, L=6x10' binned 1x1, RGB=2x10' binned 2x2,
STL-11000XM, Paramount ME Image scale = 0.5" per pixel rather than my
usual 1" per pixel.

Note that Stefan's FOV is somewhat larger than mine.

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".

Thank you Stefan and Rick, some night in the future i'll try some object...

Regards
Fabio

"Rick Johnson" ha scritto nel messaggio
ster.com...
I can see it will be a several year project to image all Arp's I can see
from my location. I have trouble in winter below the celestial equator
with only a rather narrow window that works below it due to ice crystals
over the lake and many of those between 0 and -15 degrees (my southern
limit due to seeing and ice) is small letting many escape my photon
detector.

Which scope to use depends on which Arp you are imaging. Most are very
small, well under a minute of arc across so you will want as large an
image scale as your seeing can support. I used 0.5" per pixel for this
one though that's rarely allowed by my seeing. 1.0" per pixel is more
common for my location. Others are large like Arp 26 = M 101. There are
quite a few Messier objects in the list. I still have Arp 134=M49 and Arp
168=M32 to go. The latter got past me this year so will try again next.

A few URL's I use a lot a
http://arpgalaxy.com/arpord.html
Shows Arps in order and thus by Arp's classification
http://arpgalaxy.com/arplist.html
Arps in R.A. order. Useful for planning a night's imaging run.
http://nedwww.ipac.caltech.edu/level..._contents.html
Palomar photos of all Arp's in an easy to use interface. Most are taken
with the 200" though large ones are from the POSS plates.

There's an amateur in France (I think that's it), can't recall his URL as
it is in a different computer, that has almost completed the list. Google
should turn it up. He's using an 8" SCT with compressor so image scale
can be very small but they are there.

It's a fun project.

Rick


Fabio wrote:

Wonderful Rick and Stefan,

i am very interested by ARP objects. It is about 1 week that i am
reading the book "The Arp Atlas of Peculiar Galaxies A Chronicle and
Observer's Guide" and i like it too much. Now i see your images, that
are wonderful.

I want to try somehow, using my C9,25 and H9C. Maybe in binning 2x2.
Using the FLT110 f7 , would be too difficult i think. just for
ARP/Messier objects.
What do you think ??

Thanks for sharing

Fabio




E-mail :



Website : http://www.fabioh2o.it





"Rick Johnson" ha scritto nel messaggio
ster.com...

The large galaxy is UGC 1810, the other spiral UGC 1813. They are
located about 330 million light years away at the southeast corner of
Andromeda. It's obvious that UGC 1810 is highly distorted. One arm
looks more like Saturn's F ring than a spiral arm and seems to make a
complete ring about the galaxy. It's hard to tell if NGC 1813 is
distorted. It looks greatly distorted to me as the arms are almost
straight but that is seen in other barred spirals. But it has faint a
faint arm that curls back and runs along the bar while the ends of the
bar, if it is a bar, seem to end differently. The left one ends in a
faint blob while the right one seems to merge with the outer ring of UGC
1810. In any case they curve very differently, likely due to the near
collision. To appear so large at such a great distance these have to be
two very large spiral galaxies.

When galaxies pass by like this they trigger massive star formation. We
see it in the arms of the bigger galaxy UGC 1810, this is common, but it
is confined to the very core of UGC 1813. This is very unusual. Also
UGC 1810 is a LINER galaxy indicating it has a nearly starved black hole
at its core. So we know the near miss hasn't yet caused a feast for the
black hole by sending matter its way. Yet UGC 1813 seems to have a heck
of a lot of disturbance at its core to trigger so much star formation.
This all goes to show it is very hard to predict just what will happen
in a near miss like these two have encountered. Nor do we know what
long term changes it will trigger. I can't even find if the two are
gravitationally bound. If so they will merge in the future.

14" LX200R @ f/10, L=6x10' binned 1x1, RGB=2x10' binned 2x2,
STL-11000XM, Paramount ME Image scale = 0.5" per pixel rather than my
usual 1" per pixel.

Note that Stefan's FOV is somewhat larger than mine.

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".