Globular Clusters

Razsky · Post by **Razsky** » Sat May 24, 2008 12:10 am

Hi!

Sky was clear yesterday so i went for a little obs session. Was wondering if we are able to see any globular clusters in sg?

Meaning will we be able to make out the stars and such inside it?

Was looking around for Omega Centauri yesterday. I don't know if i got the position right but what i saw was a fuzzy hazy like thingy. Around the same size as the moon i guess. Looked very much like a nebula but it is a lot clearer and distinct, even though it was full moon.

Is this what to be expected when observing globular clusters in sg?

Do you guys have any recommendations for objects that i can observe? Mainly around the crux/centaurs/scorpio area.

Btw, i was using a R130sf (5.1",650mm) with a 20mm eye piece. Magnification around 32x.

Thanks!
[smilie=cheer.gif]

Kai Long

JJLoke · Post by **JJLoke** » Sat May 24, 2008 12:18 am

u will need a bigger scope to resolve the densely packed globular star clusters, mostly 8 inch and above.

small sized scopes will produce 'furball' when viewing globular cluster

the Crux in Centaurus, jus beside Mimosa the star, there is this K Crux cluster

to the right of Acrux is Carina Nebula and Wishing Well Cluster NGC3532 (nicest in my opinion) in Carina constellation

Scorpio u will see globular clusters like M4, M62. open clusters NGC6231, M6 Butterfly Cluster, M7 (visible through naked eye in clear sky)

alot other nebula and clusters in saggitarius

*based on my observations with my small 3" scope*

Razsky · Post by **Razsky** » Sat May 24, 2008 12:20 am

Another thing, i managed to observe Jupiter for the 1st time yesterday. [smilie=admire2.gif]

I was able to make out at least 4 moons and 2 belts easily which was surprisingly clear. But there was no Red Spot. I remember hearing somewhere that the storm had already died now and thus we may not be able to see it clearly now.

Is that true?

Or was it simply tat it was at the back of the planet at that time? I remember seeing one of Remus's pic showing the planet rotating. If that is the case, do you guys know of any ways to determine the visibility of the red spot on certain times?

Or is my scope incapable of showing that? The highest magnification i can go now is around 213x. 6.1mm eyepiece on 2x barlow.

Thanks
[smilie=cheer.gif]

Kai Long

Canopus Lim · Post by **Canopus Lim** » Sat May 24, 2008 6:14 am

Hi,

Sky and Telescope website has very good animation of planets. It allows telling the names of the satellites and other details including the GRS timing.

http://www.skyandtelescope.com/observin ... ts/planets

GRS is not that easily observable..don't expect it to be red as it is more pale in colour. Jupiter is a nice planet and I actually prefer it to Saturn. It is nice to see the shadow transits and eclipses of the satellites. The timings can also be found in the Sky and Telelescope link.

In Singapore, to observe DSOs and Planets well...the bigger the aperture the better as larger aperture allows observing at higher magnification. Also, a tip to observe is to observe at higher magnifications. Once you located the object at lower magnification, try to use higher magnifications (about 2mm exit pupil and less) to observe. It gives much better results than lower magnifications. As higher magnification (smaller exit pupil) will reduce the background brightness (due to light pollution) and enhance the visibility of stars (Globs, star clusters..etc); contrast of stars will improve. However, refrain from using magnifications whereby the exit pupil is 0.5 or less as eye defects (eg. floaters) can easily be seen. I use 2mm exit pupil and less to observe in Singapore all the time..

To calculate exit pupil size, (EFFL of eyepiece)/( F# of telescope). EFFL is the focal length of the eyepiece you are using.

starfinder · Post by **starfinder** » Sat May 24, 2008 7:06 am

Hi Razsky,

To add to the above postings, from Singapore's urban setting, only the brightest globular clusters (e.g. Omega Centauri in Centaurus, M22 in Sagittarius, M4 in Scorpius, M13 in Hercules) can be seen moderately well through optical aid. My experience is that from Singapore, the amount of moisture in the air in a particular night makes a lot of difference to how well a particular globular cluster can be seen. Only in about one night in ten here would you be able to see these well.

However, the views of globular clusters (esp Omega Centauri) from a dark sky location such as in rural Johor are tens of times better than from urban Singapore. A total transformation. And with large apertures of 8" or more, quite a lot of detail can be seen, including many individual stars in some of the globulars.

Regarding Jupiter, another website where you can check whether the Great Red Spot of Jupiter is visible at a certain point in time is here:
http://www.skyviewcafe.com/skyview.php
Look under the "Moon/GRS" tab once the Java applet is up and running. This also shows the positions of the main moons of Jupiter and Saturn.
From Singapore, the views of the Moon and bright planets (Jupiter, Saturn, Mercury, Mars, Venus) are not much affected by our light pollution.

ian0138 · Post by **ian0138** » Sat May 24, 2008 7:51 am

Hi, Razsky,
Which part of Yishun you stay in ? I also stay in Yishun. Maybe we can meet up for a quick obs one of these day

Yes, the sky was very clear last night, no problem resolving omega centauri even with the big big moon nearby (can say one of the best seeing in a long time in sg) but it was through my 10" dob.

5" scope might be a little challenging resolving globular cluster if you viewing from hdb heartland, but will be much easier if you are in darker site like LCK

wucheeyiun · Post by **wucheeyiun** » Sat May 24, 2008 9:45 am

Agree, last night seeing is fabulous....

it was stars studded ...

Post by **weixing** » Sat May 24, 2008 12:16 pm

Hi,

Was looking around for Omega Centauri yesterday. I don't know if i got the position right but what i saw was a fuzzy hazy like thingy.

I think you look at the right place... use your hand to block any stray light entering your eye while you observe. Give a long look and learn to use averted vision. After a while, omega centauri will look brighter and clearer.

M4 globular cluster is suppose to be quite bright, but it's actually quite difficult to observe in Singapore unless you are in the darkest area in Singapore and the weather was very good. To me, it look more like an open cluster and don't have the round look when seen through a scope in Singapore.

M22 globular cluster is quite bright and easily seen. It's slightly brighter and smaller than M4, but a lot easier to observe than M4.

Have a nice day.

Razsky · Post by **Razsky** » Sat May 24, 2008 2:23 pm

Hello all!

Thanks for all the replies. Appreciate it. [smilie=hell-yes.gif]

the Crux in Centaurus, jus beside Mimosa the star, there is this K Crux cluster

YES! Jewel Box right? It was very nice yesterday. So many colours could be spotted. Wishing well is my next target.

However, refrain from using magnifications whereby the exit pupil is 0.5 or less as eye defects (eg. floaters) can easily be seen.

What do you mean by floaters? Is it those things that seems to float around on the eye pieces? Looks almost like bacteria under the microscope. Always tot it was my eyes playing tricks on me.

Which part of Yishun you stay in ? I also stay in Yishun. Maybe we can meet up for a quick obs one of these day

I stay just beside the swimming pool! Blk 771. Where do you stay? Any more yishun-ers or kahtib-ers here?! I find it hard to find a dark place here. The obs site that i am using now is the grass field beside the stadium car park. Quite dark over there, expect for the nasty car park lights.

M22 globular cluster is quite bright and easily seen. It's slightly brighter and smaller than M4, but a lot easier to observe than M4.

Shall give it a try later tonight!

Kai Long [smilie=super.gif]

Canopus Lim · Post by **Canopus Lim** » Sun May 25, 2008 4:34 am

Yes those things that look like 'bacteria' floating around when you are using high magnifications...

M22 is a nice target too. It is one of my favourite Glob.

To see DSOs better... yup it will be good to go somewhere darker and away from stray light sources. If required, I do observe with a black T-shirt over my head to cover the eyepiece so that there will be no reflections off the eyepiece from light sources and better contrast. Doing such a thing can enable one to see about 1/2 magnitude more.

To see more detail, another tip that I always use, is to wear an eye patch (sort of like pirate) and observe. Eye patch can be bought from pharmacies. In this way I open both eyes and always see more details with 2 eyes open than one eye straining. Also, I can observe for hours without any strain...no strain means more details seen. I also prefer eyepieces that have shorter eye relief as I can use my eye patch and the eyepiece's rubber eye guard to effectively block off stray light reflecting off the eyepiece lens. I never found wearing glasses while observing near a light source good as reflections occurs frequently and are not easy to block off..and it can be very annoying.