27 May 2011 Observation besides Science Centre Observatory

[rlow]

Tomorrow Friday 27 May 2011, we will be having another observation session besides the Science Centre Observatory from 8pm to 10pm. Event is weather permitting, of course.

A curious thing happened at the Science Centre observation session last Friday 20 May 2011. Some people had highlighted to me that a particular scope was showing Saturn to be "bigger, brighter, better than the one upstairs". Interesting enough, this didn't come from amatuer astronomers but from more than half a dozen members of the public. This particular scope was less than half the size (only about 47% in area) of "the one upstairs" and yet the so-called "untrained eye" of the public was able to discern the difference. Unfortunately I did not managed to take a look at the one upstairs last Friday, so I hope to take a good look tomorrow to seek the truth in this strange phenomenon. Join us there if you are free, and curious....

[rcj]

the primary desparately needscleaning... the image for a 16" is dim. There was a visible layer of dust on the surface last seen many months back. the observation is not surprising.

[hommel]

Tomorrow Friday 27 May 2011, we will be having another observation session besides the Science Centre Observatory from 8pm to 10pm. Event is weather permitting, of course.

A curious thing happened at the Science Centre observation session last Friday 20 May 2011. Some people had highlighted to me that a particular scope was showing Saturn to be "bigger, brighter, better than the one upstairs". Interesting enough, this didn't come from amatuer astronomers but from more than half a dozen members of the public. This particular scope was less than half the size (only about 47% in area) of "the one upstairs" and yet the so-called "untrained eye" of the public was able to discern the difference. Unfortunately I did not managed to take a look at the one upstairs last Friday, so I hope to take a good look tomorrow to seek the truth in this strange phenomenon. Join us there if you are free, and curious....

i have on few occasions looked through the "upstairs" scope and most of the time it is out of focus for me, also the eyepiece is full of fingerprints from kids/adults trying to touch the eyepiece. So this may be one of the reasons. Not forgetting the mirror as far as I heard was clean once every few years

[rlow]

I can think of a few reasons (:

We know, so it falls within our expectation. It's the general public who were surprised.... nevertheless it's still an interesting observation.

[superiorstream]

Senting that giant back to Japan for servicing would be expensive,perhaps more cost feasible to buy a say HD or RC to replace it.By the way,it seems that there are lots of obs session this friday--at Elias primary School,TJC,Science centre,etc.Really pray the weather cooperate.

[shirox]

half a million can be spent on "CEO on par" people, why can't they spare some cash to maintain the items they bought.
I can only say that some level is not supporting. So don't don't who is not working.

[rlow]

Update: I just jogged at Chinese Garden...the sky is overcast, so it is not likely we get to see Saturn this evening

[superiorstream]

Well,we at TJC try our luck but clouds keep coming in;manage to give a talk in solar obs with personally shooted photo.Really no luck as 3 attempts so far ALL failed.Sign.

[rlow]

Last night, in spite of the clouds, Saturn was still somewhat visible, so we went ahead to set up our 11" dob besides the SSC Observatory. Again we pushed the magnification to 460x and Saturn was still sharp and steady, though slightly inferior to last week. Once again the public were somewhat surprised after they looked through this "piece of home-made furniture" (as one fellow said) and a few people commented that this was "better than the one upstairs".

So this time I went upstairs when the queue had lessened to about five persons. When I looked through the eyepiece, the first thing I noted was that the focus was off, reducing the optics to the equivalent of only 1/2 wave ptv, but no one in the queue ahead of me pointed this out. Of course I pointed this out and got permission for me to re-center Saturn and tweaked the focusing. Now in focus, Saturn was much sharper though contrast was not the best. I asked and found out that the eyepiece in use was the TV Plossl 21mm, giving a magnification of 247x. By sheer coincidence, I had a 20XW in my pocket so I asked to try using it. Contrast was significantly better.

I asked if we can try a higher magnification, and a 2x barlow was brought out. With the 21mm plossl and this barlow, we are now observing Saturn at 495x and the image held quite still at certain moments. Image was quite dim but sharp, just slightly soft, and there was quite a fair bit of light scattering but the image was bigger and details were more obvious compared to 247x.

So I went back to my dob. Later, the public who came down from upstairs and looked through the dob had different comment from the earlier group, now they said that Saturn (460x) in the dob is "same as upstairs".

[Airconvent]

Hi rlow
It looks like there is dust that did not affect its performance as much as the misalignment and wrong eyepieces used. I wonder if Albert is aware to assist the Science Centre to ensure the volunteers (whose efforts are appreciated) are briefed on how to maximise the experience.

Thanks for sharing. Any photos on the event?