How to Estimate Limiting Magnitude in Singapore?

[Fuzzball]

Hi guys

Just curious.

what do you estimate is the limiting magnitude of the skies in Singapore? From my own observation, I think its around mag 3.

There has been some differing opinion even in this forum of what magnitude can be seen from sg skies (the disparity can be from mag 2 to mag 4.5).

This I think is due to the place different folks observe in Singapore.

Therefore the next question I would like to ask what are some of the darkest spots in Singapore (mainland) that you folks have observe at ?

Thanks for your opinions!

[ggodetucsamoht]

Lck cemetery.....total darkness, no street light provided you want to share obs with 'them'.

I use to obs at neotiew area, some where near the farm resort. Pretty dark, can easily dinstinctgish Sagittarius but it might not be safe to obs there alone or even 2... should go there in a group. Snakes can be seen crawling since it is forest area beside...

[Mariner]

Darkest place I ever got while in Singapore was the 100meter rifle range on Pulau Tekong. During our BMT night shoot, I looked up and saw the full glory of the Milky Way. Kenna scolded by my PS for holding up the detail....

[Fuzzball]

Thanks Mariner and ggodetucsamoht for your response..

I would think that LCK cemetery may not be too ideal as a site as I don't want "brothers" to follow me back after a session! and Tekong will be unaccessible for observation...

To be more specific, if you are to observe, what will be a ideal accessible dark spot for you albeit the urban environment? what magnitude do you think that site will be?

Thanks, guys for your feedback!

[Gary]

Hi Fuzzball,

You can investigate areas like Marina Barrage and Bishan Park (near Big Lawn I) if you do not wish to go to the darker coastal areas. You can explore public rooftop gardens too.

I have seen mag 4.65 (star in Canis Major) near zenith on a rare clear night at light-polluted area outside Toa Payoh Public Library. My point is, the clarity of the sky and the ability to react quickly to it may be more important than obsessing about the absolute darkest area in Singapore and only go there for stargazing. Over time, you will get to use your equipment more and see/enjoy more as a result.

Base on your equipment list, I assume you are mainly a visual person. If you do not have personal transport, lugging and setting up a C11 outdoors regularly takes quite a bit of motivation, especially on a clear night on a working weekday. Transporting them to a place that can potentially see slightly dimmer stars (e.g. mag 0.5 more) may not be enough motivation for you in the long run.

If you truly yearn for dark skies and getting the max value out of your astro investment, find a good stargazing spot overseas (e.g Johor) and try to go up once a month to get your stargazing fix. Then you will be less demanding of only going to the best dark spot in Singapore when you are in Singapore.

[weixing]

Hi,
The sky in Tampines can be quite good:
1) The dimmest star I had seen naked eye in Tampines should be Zeta Sagittae which is rated as mag 5.01.
2) I also see the faint milky way using 42mm bino quite a few times.
3) The hint of the spiral arm of M31 using my 6" SCT (see it this year).

Hopefully, after the tampines town hub construction (beside my obs site), the sky can be back to normal.

Have a nice day.

[mymoon]

Hi

If you have an Iphone 4S and 5 install the free version of Apps Dark Sky Meter or for a bit of money you can get the full version.

It will give you the night sky brightness for your area in Magnitude per square arc-second. You have to convert to Visual Limiting Magnitude converters freely available on the internet.

Then there is a dedicated SQM meter which at the press of a button give you the same measurement .

If you have a DSLR you can do your own measurement as shown here


I live at the Red/White Bortle Scale of 8/9 and the measured SQM is 16.7

How I wish we live in the area where just outside our house we can see view like this at SQM 21.7

cheers

[Fuzzball]

Gary, I definitely like coastal areas like Labrador and East coast. etc. Just not places like LCK cemetery! I do agree with you that clarity and being able to set up quickly is more important then having absolute dark skies. That is also the reason why I intend to set up my CPC11 on my balcony in the future (moving house to the east soon:). Currently, I observe on the top floor of a multi-storey carpark. I do have personal transport and what I do is to drive up to the top floor of the carpark which is usually empty and observe there. ( not ideal due to ambient light though..but I make do). Therefore set up is still not too much of a hassle.

btw, seeing 4.65 mag from Toa Payoh Central is a amazing! I never thought that can be done in a light polluted area..

Wei Xing, I must try out tampines one day..5.01 mag from Tampines..again that is amazing. is it from the usual spot you observe next to the mosque area?

Mymoon, Thanks for the suggestion of dark sky meter, I have it previously installed already. I did a check on the sky condition where I stay and it indicated 16.5 SQM which is quite similar to your area. But it was not a very exact test when I did it as there were stray lights intruding and I did the test at my hdb block.

I read somewhere that to get a accurate reading. You have to fully cover the the phone during the first take(under a jacket or something). This will ensure when you take the sky reading on the second take it will be accurate.

I may try it again.

Again, thanks for all the feedback and advise, it has been really helpful!

[weixing]

Hi,

Wei Xing, I must try out tampines one day..5.01 mag from Tampines..again that is amazing. is it from the usual spot you observe next to the mosque area?

Yes, but currently the construction of the town hub is on-going just behind the obs site... so

Anyway, since you drive, Changi beach should be a better location if you can find a site with minimum local pollution.

Have a nice day.

[Fuzzball]

Hi Wei Xing, thanks for the suggestion on changi beach. Will try the place out.