Sunday, October 3, 2010

8 inch refractor telescope in Singapore

A video is worth a thousand photos:

Due to recent feedback about the Toa Payoh Starparty Report, I will do a quick summary followed by a full report to satisfy two different types of readers.


Last Saturday evening, three telescopes pointed at Jupiter at Jurong West - 8 inch achromatic refractor, 6 inch apochromatic refractor and 8 inch catadioptric. Best view of Jupiter came from the 6", followed by the 8" SCT and followed very closely by the 8" refractor (very personal opinion). True potential of the 8" refractor could not be experienced due to light pollution, lack of clear skies and lack of time to pimp it - the telescope was delivered only a few hours earlier.

Full Report:

I met James during my second Punggai trip (Johor, Malaysia). He brought a Celestron C14 telescope along during that trip and we had some nice views through it though the skies were not completely clear. So I was quite excited when he informed me his new toy, an 8 inch achromatic refractor telescope, will be arriving in Singapore soon. We decided to conduct a mini first light star party on Saturday. Richard came with his 6 inch refractor (yellow submarine) and I brought my Celestron C8 along. I do not need to bring my alt-azimuth mount along as I will using James's CG5 tracking mount. Later in the evening, Mr Au, Carole, Jin Peng, Mooey, Junming and Mr Oo join us to observe through the telescopes.

I packed my C8 in my backpack and took a direct public bus to the venue. While on the bus, I managed to checked my emails, tweet about the event, invite more people to join the session and check the latest updates on the weather maps. All in the comfort of an air-conditioned bus. I have been using my android phone for a few months now but I am still amazed by what affordable technology can do today - especially for conducting or co-ordinating sidewalk sessions where the weather and people's schedule are so unpredictable.

From the earlier pictures posted by James in singastro, I do not have a sense of scale how big the telescope is. When I finally saw it with my own eyes with the telescope lying on the floor with James sitting beside it, that's when it hit me how massive this monster is! Fortunately, the lift is big enough to accomodate the telescope vertically, else we can't imagine carrying it down so many flight of stairs without breaking our backs - it weighs 21 kg!

We chose a grassy patch on a slope to deploy the telescopes. That was a good location to observe Jupiter for the rest of the night. As you can see from the video it took three person to mount the telescope. They have to be careful not to bang the tube into the mount and at the same time not to fall down the slope while executing the 360 degree turn!

It was quite impressive to see Richard load his 6" alone. You can now understand why it is rare to see 8" refractor telescopes. A difference of just 2 inches in lens diameter can make such a huge difference in total weight and bulk. As far as I know, I believe this 8" is the biggest achromatic refractor telescope in Singapore. If you know of anyone who has a bigger achromatic/apochromatic refractor, please inform me so that I can try to persuade the owner to do sidewalk astronomy with it! :)

We are very happy Mr Au found time to join us in this observation session. Mr Au is the recipient of the Lifetime Achievement Award in 2008 for his effort in promoting astronomy in Singapore for many many years. I remember meeting him for the first time in 2003 during Mars Watch. Seven years later, he is still so full of energy and his passion for astronomy is very contagious. I brought my videocam mainly to film the 8" telescope but I am very glad I can also get to film Mr Au and subsequently upload this video for all to see. This is my small tribute to his contributions and also to encourage other much more younger and stronger bodies to help promote astronomy in Singapore.

Back to the main star of the event. The telescope is manufactured by ISTA Optical. It is front heavy as the main lens is located there. The holes at the front end makes it easy to grip it. But at the same time, they allow stray light to hit the lens which will affect contrast of objects viewed through the eyepieces. We pointed the scope at Jupiter and everyone had a good look. Jupiter looked really bright. There were some chromatic aberration which is expected from all achromatic telescope but it is not obvious enough to bother me.

I was glad Richard brought his 6" apochromatic telescope along. I missed two opportunities to look this highly rated telescope. First was during the Bedok Reservoir Jupiter event (I was at Jalan Kayu event) and second was the Toa Payoh Starparty event (the queue was way too long, I was busying manning my scope and Richard had to leave early). So finally, I got my "revenge" for these lost opportunities. Through this telescope, I had the best view of Jupiter I have seen so far. The contrast was simply amazing. Jupiter cloud bands was well defined and the shadow transit looked really dark on Jupiter. Moreover, the eye relief for his eyepieces is really good. It was so comfortable to look at Jupiter. The view should be even more mind-blowing if Richard add a binoviewer to this scope in the future.

Both refractors have nice dual speed focuser. Till then, I have only manage to spend time with my Maskutov and SCT telescopes which involves moving the primary mirror with their default focuser. These superior refractor focuser is a real joy to use. Now I can fully understand why some SCT owners are willing to pay a premium to add such focuser to their telescope. It's very hard to go back to normal focusing once you have experienced dual speed focusing. For the more budget constrained telescope owners, there are other ways to "hack" the default focuser to improve focusing.

Mr Au and James helped me set up my C8 on the CG5 mount and showed my how to use the GOTO controller. It was my first full hands-on experience with an equatorial mount. I have always delayed learning how to use one since it looked complicated, less portable and more expensive then an alta-azimuth mount. After playing around with it for a few hours, I started to appreciate the benefits of a tracking mount - you see more details. When the object is stationary and centered in your field of view for relatively long period of time, it will be able to "send" more photons to your eyeball.

I got the best view of Jupiter from my C8 that night. I saw details inside Jupiter's northern equatorial belt. The cloud bands also looked more contrasty than before. The seeing for Jupiter that night was pretty good so we were quite fortunate. Now that the "too complicated" mindset of mine has been broken, I will be looking forward to the day I am able to afford an equatorial tracking mount. I have said it many times to many people before and I will say it many times more - nothing beats hands-on learning experience on telescopes during star parties. Don't you ever dare to buy your first telescope without attending one. :)

Towards the end of the session, I manage to take a look at the 8" through its 22mm eyepiece. The view was very wide and nice. Jupiter and its moons were framed nicely with pinpoint stars shining in the background. By then, Jupiter had risen so high up in the sky that we had to squat down to look through the eyepiece!

To fully realise the potential of this refractor (or any telescope for that matter), it needs a dark and clear sky. The views of Deep Sky Objects (DSOs) like galaxies and nebulas on this telescope will be truly astonishing.

Although one of the purpose for the event is to compare the views between the three telescopes, I think we are more interested to just having fun looking through each others setup and catch up with one another. If my memory serves me right, I don't recall see more details when observing Jupiter through the refractors compared to my scope but the contrast level in the 6" is definitely way higher.But the refractors are using premium grade accessories like 2 inch dielectric diagonals, dual speed focusers and very branded eyepieces. Whereas my C8 was using low-end third-party 1.25 inch diagonal, default focuser and entry-level plossl eyepieces. To make things worse for comparison purposes, I was too lazy to bring my DIY dew shield as I lost my tube rubber band during my last Punggai trip. There was a very bright sodium light shining at the observation area (can be seen in the video above the 8" telescope before it was lifted up from the floor). Ironically, if this very powerful source of light pollution is not there, my videos will turn out to be too dark and noisy.

Halfway through the event, Mrs James brought us delicious cold deserts. Yummy! Just in time for me after being "sun-baked" by the sodium light for a couple of hours.

James's friend came later in the evening with his Canon 7D to take some astrophotos. Unfortunately, there was battery leak issue his camera and we didn't manage to take any astrophotos. With Richard's help, we managed to mount the camera to his 6" telescope. We stacked two 2x barlows. It was quite fun to look at Jupiter through the camera's viewfinder.

Two passer-by came to look at Jupiter through our telescopes. For the 15 minutes they were there, you can see this permanent WOW look on their faces. Total state of shock for them.

We packed up shortly before midnight and were once again reminded of how massive the 8" is when we transported it back to base. :) Thanks to everyone who came for the event on such a short notice. Looking forward to see you guys again in future star parties.

I have done some videography work for my clients but this video is one of the most enjoyable one I have done to date. Had so much fun editing out the parts that are not meant for public consumption. Haha. :P

Two days after this event, I find my scratching my left knee profusely. This is how it looked like:

I wonder why just the left knee and where did I get this infection from. Then I realised I wore bermudas and was occasionally kneeling on my left knee on the grass patch while enjoying the views on my telescope. Applied Tiger Balm for a few days and the itch finally subsided. A very small price to pay for incredible views, the knowledge gained and the friendships made that evening.

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