How Many Galaxies can we see in Singapore?

zackae · Post by **zackae** » Sun Aug 05, 2007 4:34 pm

Just actually how many distinct galaxies are we able to see in out light polluted skies? By galaxies i'm referring to those that are as bold as the M31, Andromeda Galaxy. And to side track a little, what is the lowest magnitude of light we can see in Singapore in average weather?

Just wondering if We can see the Canis Major Dwarf galaxy or the Sagittarius Dwarf Elliptical galaxy on clear nights.

Sam Lee · Post by **Sam Lee** » Sun Aug 05, 2007 5:44 pm

M31 Andromeda Galaxy is an easy target in the upcoming skies , probably 1-2 more months when pegasus is up.
M104 Sombrero Galaxy in Corvus is also a nice target.
If i remember correctly, Centaurius A is also similar to Sombrero in shapes and brightness levels.
Some other elusive ones are M51 (Whirlpool G) in Ursa Major.

Canis Major Dwarf and Sagittarius dwarf galaxy are both merge together with our Milky way. So it depends on your interpretation of 'see' .

Regards,
Sam

zackae · Post by **zackae** » Sun Aug 05, 2007 10:03 pm

Thanks for enlightneing my Sam. What about the Triangulum galaxy? The magnitude i saw on wiki is around 10+- and some clusters are actually of that magnitude i saw yesterday.

I would really look forward into seeing the M51.

Since the 2 dwarfs are like seen through the milky way i guess maybe they are only visible in very dark and clear skies after thorough searching.

I saw the sombrero galaxy on wiki as well as on the forums and that would definitely be an interesting target. Hope i can actually witness the obvious bulge in the center.

Sam Lee · Post by **Sam Lee** » Mon Aug 06, 2007 12:33 am

I dont remember M33 Triangulum being so dim..Maybe we can try it out in one of these observations. Dont expect much though , i suspect it will be a fuzzy spot in SG skies as well.

Regards,
Sam

Post by **weixing** » Mon Aug 06, 2007 1:27 am

Hi,
Galaxy is very difficult to observe in Singapore due to light pollution even through a telescope... just don't expect to see galaxy in detail.

Also, please note that galaxy is an extended object and like most extended object, the apparent magnitude is usually given as an integrated value. For example, M31 is listed as around magnitude 3.4 and this means that M31 will be as bright as a magnitude 3.4 star if all the light from M31 is compress to a point. So, the actual surface brightness of M31 is a lot lower due to it size... around magnitude 13.6. This mean that if the galaxy is large, it'll be very difficult to see in Singapore even the listed magnitude is very bright. Anyway, in Singapore, you basically only see the core of M31.

I would really look forward into seeing the M51.

I think you'll be very disappointed if you see this object in Singapore... Through my 8" scope in the Tampines site, you can only see the two core as two very small blur patch of very dim light (hardly visible)... which is the 2 core of the object.

What about the Triangulum galaxy? The magnitude i saw on wiki is around 10+- and some clusters are actually of that magnitude i saw yesterday.

M33 (Triangulum galaxy) is listed at around magnitude 5.7, but the surface brightness is around magnitude 14.2 due to it's size. Also, most cluster is easier to see than galaxy, because cluster will be resolved into individual star at higher magnification.

Anyway, don't have too high expectation especially in Singapore... just go out relax and enjoy the fresh air under the stars... with right expectation, luck and experience, you'll be surprise on what you can see.

Have a nice day.

vhuang168 · Post by **vhuang168** » Mon Aug 06, 2007 10:56 am

Basically what Weixing said.

Galaxies are really hard to observe in detail from light polluted skies. Even from my relatively mildly polluted skies, I can make out M51 and companion plus some of the bridge thru averted vision thru my C14 only.

M33 was surprisingly nice with some details in the core.

Vincent

rlow · Post by **rlow** » Mon Aug 06, 2007 2:11 pm

Just actually how many distinct galaxies are we able to see in out light polluted skies? By galaxies i'm referring to those that are as bold as the M31, Andromeda Galaxy.

Strictly speaking, based on your criteria, the answer will be only one other galaxy besides M31, and that would be the Milky Way Galaxy or more specifically, usually the M24 Star Cloud and its surrounding.

Whether you can see a particular galaxy in Singapore or not depends a lot on
(1) the location (eg, the outskirts of Singapore are least affected by light pollution),
(2) the weather (especially the sky transparency) and also
(3) the scope aperture (for the bigger scope, the galaxy can appear brighter, more resolved and can be pushed to a higher magnification).

rlow · Post by **rlow** » Mon Aug 06, 2007 2:42 pm

Broadly speaking, there are many galaxies that are visible using standard binocular (about +/- 100 galaxies) and scopes (many more galaxies, depending on size of scope) in Singapore under clear skies. It would not necessarily be bold and distinct like M31, as most are just visible as smudges of light seen best with averted vision.

zackae · Post by **zackae** » Mon Aug 06, 2007 4:21 pm

Wow thanks that really gave me a lot of insight. Now i am able the expect what to see when i look at the sky. However some pictures that the members of the SingAstro took are really amazing. The way you can even see the spiral arms will not be possible from what you guys just said.

It could be digitally enhanced, however, the rings would appear to have a lack of detail if it was edited.