How precious are clear night skies in Singapore?

CCD vs Film? Lots of time vs no patience? Alright, this is your place to discuss all the astrophotography what's and what's not. You can discuss about techniques, accessories, cameras, whatever....just make sure you also post some nice photos here too!
Post Reply
hhzhang
Posts: 730
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

How precious are clear night skies in Singapore?

Post by hhzhang »

I had never been so interested in (somewhat obsessed with) clear night skies. When I started taking long exposure pictures of the stars in late Jan this year and then enjoyed a stretch of nice nights in Feb till March, I did not know that, over the following months from April to now in August, clear nights were so scarce.

I wish it will get better in September and Oct. How much is the likelihood?

I knew the year-end season will be quite wet -- does it mean we do not expect clear night skies then?
rifleman175
Posts: 81
Joined: Wed Aug 22, 2018 5:16 pm
Favourite scope: Skywatcher Esprit 100ED

Re: How precious are clear night skies in Singapore?

Post by rifleman175 »

For the climate of Singapore you can refer to this excellent introduction:

http://www.weather.gov.sg/climate-climate-of-singapore/

It does depend on the time of year as the monsoon winds reverse, the inter-tropical convergence zone (ITCZ) migrate north and south of Singapore. In addition you need to factor in the effects of ENSO cycles, or El Nino/La Nina on the climate of Singapore year to year.

Looking at the long-term climatological record, the drier periods are usually from Feb to May, and then Aug to Oct. The more ideal periods will be February and March, as it is the time of year when drier air from Asia is directly overhead Singapore, pushing the equatorial rainband south of the Equator, plus you'll get some cooler nights as well! Sometimes even during the height of the winter monsoon from Dec to Jan, there can be a streak of calm nights after monsoon surges with excellent seeing.

After the northeast monsoon season ends in late March, there is an increased chance of convective storms in afternoons, but there is usually a high pressure system dominating the equatorial region. As such, you can expect about 5-10 clear nights per month, but the duration is shorter with more low clouds rolling in.

Then comes the summer Monsoon season from June to Sep, which is the season of early morning storms called Sumatra Squalls that can occur on about 5 days a month. In my experience the later half of the summer Monsoon season is typically drier with more clear nights, although subject to variations.

Finally as the summer Monsoon transitions into the winter monsoon from Oct, there is a general increase in the rain nights with occasional monsoon surges occuring on average 2 times a month in Dec and Jan. You can look forward to a few clear nights if lucky after Monsoon surges, otherwise the skies are usually overcast even for non-rainy days.

Apart from the monthly variations, there is a quasi regular biweekly oscillation in rainfall anomalies known as the Madden Julien Oscillation (MJO) that typically brings two weeks of wetter conditions followed by two weeks of drier conditions to Singapore. However, the MJO is highly variable within the year and sometimes has little to no activities at all. You may refer to the following site for more information:

https://www.cpc.ncep.noaa.gov/products/ ... /mjo.shtml

For year to year variations, look up on El Nino/La Nina updates. In a nutshell, El Nino brings drier and warmer conditions to Singapore and vice versa. The latest ENSO update is given here:

https://www.cpc.ncep.noaa.gov/products/ ... enso.shtml

The above is good for long term planning purposes, but if you need to decide whether or not to go out at 11 pm on a weekday for a session, I recommend downloading an app called "Windy", where you can see the real-time satellite images of the globe and zoom in on Singapore. You can judge by the animation the direction in which clouds are moving and then decide if you want to set up or call it a night.

Best of luck on your astrophotography journey!
hhzhang
Posts: 730
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

Re: How precious are clear night skies in Singapore?

Post by hhzhang »

rifleman175 wrote: Sat Aug 15, 2020 2:44 pm For the climate of Singapore you can refer to this excellent introduction:

http://www.weather.gov.sg/climate-climate-of-singapore/

It does depend on the time of year as the monsoon winds reverse, the inter-tropical convergence zone (ITCZ) migrate north and south of Singapore. In addition you need to factor in the effects of ENSO cycles, or El Nino/La Nina on the climate of Singapore year to year.

Looking at the long-term climatological record, the drier periods are usually from Feb to May, and then Aug to Oct. The more ideal periods will be February and March, as it is the time of year when drier air from Asia is directly overhead Singapore, pushing the equatorial rainband south of the Equator, plus you'll get some cooler nights as well! Sometimes even during the height of the winter monsoon from Dec to Jan, there can be a streak of calm nights after monsoon surges with excellent seeing.

After the northeast monsoon season ends in late March, there is an increased chance of convective storms in afternoons, but there is usually a high pressure system dominating the equatorial region. As such, you can expect about 5-10 clear nights per month, but the duration is shorter with more low clouds rolling in.

Then comes the summer Monsoon season from June to Sep, which is the season of early morning storms called Sumatra Squalls that can occur on about 5 days a month. In my experience the later half of the summer Monsoon season is typically drier with more clear nights, although subject to variations.

Finally as the summer Monsoon transitions into the winter monsoon from Oct, there is a general increase in the rain nights with occasional monsoon surges occuring on average 2 times a month in Dec and Jan. You can look forward to a few clear nights if lucky after Monsoon surges, otherwise the skies are usually overcast even for non-rainy days.

Apart from the monthly variations, there is a quasi regular biweekly oscillation in rainfall anomalies known as the Madden Julien Oscillation (MJO) that typically brings two weeks of wetter conditions followed by two weeks of drier conditions to Singapore. However, the MJO is highly variable within the year and sometimes has little to no activities at all. You may refer to the following site for more information:

https://www.cpc.ncep.noaa.gov/products/ ... /mjo.shtml

For year to year variations, look up on El Nino/La Nina updates. In a nutshell, El Nino brings drier and warmer conditions to Singapore and vice versa. The latest ENSO update is given here:

https://www.cpc.ncep.noaa.gov/products/ ... enso.shtml

The above is good for long term planning purposes, but if you need to decide whether or not to go out at 11 pm on a weekday for a session, I recommend downloading an app called "Windy", where you can see the real-time satellite images of the globe and zoom in on Singapore. You can judge by the animation the direction in which clouds are moving and then decide if you want to set up or call it a night.

Best of luck on your astrophotography journey!
Super informative! Thanks a million.. Yes I have been using Windy for a while.
Post Reply