Go Back   IceInSpace > General Astronomy > Observational and Visual Astronomy > Observation Reports

Reply
 
Thread Tools Rate Thread
  #1  
Old 04-12-2018, 09:44 AM
ngcles's Avatar
ngcles
The Observologist

ngcles is offline
 
Join Date: Dec 2006
Location: Billimari, NSW Central West
Posts: 1,664
A couple of odd spiral galaxies -- NGC 908 & NGC 922.

Hi All,

I have recently been going through my log, reviewing observations I made some time ago with smaller telescopes and editing them up from highly encrypted notes to sensible prose. During that process (that will probably take a year) time I have made a little list of earmarked objects to go back and re-observe with the larger telescope because I saw something in the previous notes or from the POSS photo that made them stand out and be worthy of a re-visit. I re-visited two of them last night with Brontes -- a more ordinary spiral; NGC 922, and the remarkable, peculiar spiral galaxy NGC 922.

Attached see the image of Adam Block of NGC 908. The original is here:
http://www.caelumobservatory.com/obs/n908.html

Here are my notes from last night:

x260 19' TF,

NGC 908 Galaxy *
RA: 02h 23m 05.3s Dec: -21° 13' 59"
Mag: 10.8 (B) S.B.: 13.1 B-V: +0.65Size: 6.0'x2.6' Class: SA(s)c
P.A.: 75 Inclination: --- R.V.: +1701 Source: RC3 *

x260: This is a large and bright, low-ish S.B quite elongated spiral galaxy in about PA 75. Above it to the N by 4' is a small key-stone type asterism of magnitude 12 & 13 stars. Large oval halo 4.5' x 2' .
The oval end at the WSW end of the galaxy has generally slightly lower S.B than the ENE end . It seems weakly blotchy or curdled over most of the halo and the W end generally has a less distinct edge to it. Overall, it grows weakly in brightness to centre. The E oval end exhibits a curved, weak enhancement just inside the edge of the visible halo that follows the curve around the E extremity. This curved enhancement is just above -- to the N, of a magnitude 14.5 star just inside the halo, slightly S of the major axis. There is a very small, weakly brighter core zone that is only 10-20" diameter containing a faint stellar nucleus.

Then there was the rather odd spiral NGC 922. The attached image is by Hubble NASA/ESA. It shows a mangled asymmetric star-bursting spiral galaxy that is partly ring-form in nature. The real odditiy is that peculiarities like this are usually the result of recent, strong interaction with another galaxy -- but there's nothing apparent nearby to do that -- it seemingly sits alone in space. Here are my notes:

NGC 922 Galaxy *
RA: 02h 25m 04.3s Dec: -24° 47' 24"
Mag: 12.5 (B) S.B.: --- B-V: +0.33 Size: 2.0'x1.7' Class: SB(s)cd pec
P.A.: 13Inclination: --- R.V.: +3069 Source: RC3 *

x260: This is a somewhat unusual looking galaxy, found 2' S of a magnitude 13 star. No other stars immediately associated. The outline overall is round, probably about about 1.5-1.75' diameter. The small, faint, spot-type core is offset within the halo by about 10% toward the SE and seems to contain an occasional stellar flash. As to the outer halo. the boundary of the halo from about NE to S is quite hard-edged and drops suddenly to background compared to the NW to SW quadrant that fades much more gently to background. The W side of the halo generally has lower SB than the E -- A bit like a round galaxy with a bite taken out of the W side
Occasionally, you get the impression there is a weakly brighter "bar" within the halo that runs from about geometric centre, through the offset core/nucleus and out into the brighter rim in about PA 90.

Best,

L.
Attached Thumbnails
Click for full-size image (n908mishler.jpg)
106.6 KB39 views
Click for full-size image (800px-Hubble_view_of_NGC_922.jpg)
133.8 KB41 views
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

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

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 11:22 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement
Testar
Advertisement