15" ZOC dob : DIY Project

rlow · Post by **rlow** » Tue Jun 28, 2011 10:34 pm

Yes that conversation actually took place and captured on camera! Quoted with permission.

Post by **Airconvent** » Tue Jun 28, 2011 10:49 pm

yeah...not the first time. The public sometimes can't believe how clear it is especially the moon. I remember at one session, one girl commented the image of the moon "must have been projected from a film inside somewhere"!
Great event rlow! [smilie=cute.gif]

I bet that flash photo killed whatever dark adapted eye that is left!

Bergkamp_ · Post by **Bergkamp_** » Tue Jun 28, 2011 11:58 pm

Hope will have the chance to look thru it =)

rlow · Post by **rlow** » Wed Jun 29, 2011 8:30 am

Well...you won't get dark adapted eyes at the well-lit Science Centre. And you don't need dark adapted eyes to observe Saturn. Furthermore you won't have dark adapted eyes after looking at Saturn 563x through a 15 inch scope (:

For anyone who wants to look through this scope, there will be opportunities... at Science Centre on some Fridays and at Sedili Besar on moon-free weekends. You can PM me for specific details.

orly_andico · Post by **orly_andico** » Wed Jun 29, 2011 9:18 am

is the EQ platform commercial? i don't think anybody makes EQ platforms for this low a latitude..

jimmyleong · Post by **jimmyleong** » Wed Jun 29, 2011 12:32 pm

this is a big telescope... will see if i have the opportunity to view, when you are at science centre...

rlow · Post by **rlow** » Wed Jun 29, 2011 1:33 pm

Yes the Roundtable Eq. Platform was ordered from USA and specifically custom-built for 1 degree North. Very convenient for public viewing. Unfortunately Roundtable is no longer in business.

rlow · Post by **rlow** » Wed Jun 29, 2011 1:53 pm

Here's another view of the dob, taken at 2nd Light on 25 June 2011 at Sedili Besar. In this case the Eq.Platform is not necessary and I could even view at zenith without that small stool (if I tip-toed). It has smooth motions on both axis, almost like the Obssession, so hand-tracking at 400-500x is relatively easy.

Star images are tight and pin-point, and images are in high contrast. Surprisingly, even when I set the collimation slightly off, images are still very sharp for this f/4.5 optics even at a high power of 343x. This was in contrast to my 11" f/5 dob, where this slight mis-alignment is easily detectable in a reduced sharpness in the image. Also the 15" f/4.5 optics is usable without a Paracorr, whereas my 11" f/5 dob didn't fare as well. Of course it is better corrected at the edge once the Paracorr is in place.

Robin Lee · Post by **Robin Lee** » Wed Jun 29, 2011 2:08 pm

Awesome！ Looking forward to see it at Sedili.

cloud_cover · Post by **cloud_cover** » Wed Jun 29, 2011 2:15 pm

Ah, the ubiquitous IKEA plastic stool

Bring me out to Sedili *grin*