|
Well finally I have made a start (probably much to most people saying about time) with the scope.
Last night I set out doing two things, getting the scope focused and doing a pointing run.
After mounting the scope on Thursday I had thought that one 2" extension (supplied with the telescope) would be enough to gain focus. Wrong; after 4 attempts I discovered that to focus the STL11 I had to have 3x1" extensions and 1x2" extensions. The telescope only comes with enough extensions to focus the telescope with an eyepiece; so bear this in mind when buying the scope. The beauty of all this though is that this leaves plenty of room for back focus and putting an AO on the STL and a rotator.
Another observation is that the focus does move a little over the course of a night but as much as I had supposed. Especially when you consider that the scope has an ali tube. I left the focus deliberately to see how much focus shift would occur.
With getting the scope focused I set about doing the Tpoint run. After several frustrating hours and a phone call to Mark (Wysi) (thanks for being the check list mate) I discovered that the guide cable I had put on the STL was in fact not the right one. I was getting elongated stars even after 2 seconds and all travelling in RA. After finding the Do'h problem the acquistion of points began. Only to find that I could not plate solve. I went over all the issues I had sorted in previous runs and finally thought that the focal length must not be right. This was in fact the answer. Retailers are saying the telescope is a 12" f8 telescope. That should make the focal length as being 2438mm. In point of fact it is most likely around 2400mm. Using 2400mm in AAG Tpoint mapper solved everytime so long as the exposure was long enough. Retailers should state the focal length as this would help with working out image scale and help with plate solving.
Once I got the run underway all seemed to go well, especially once I set the exposure length from 5 seconds to 10 seconds. Plate solving was reasonably fast (2-4 seconds) but solving each time in all regions of the sky.
I managed to get a run of 74 points done and pointing to around 12.2" before cloud and another problem reared its head. The PME mount alarm keep stopping the mount, so I will need to address this issue (see other thread).
I did take an image, but only managed a 120 second shot near running man which was out of focus and not guided, so it is a little blurred and with tiny donuts in the stars. Suffice to say I think so far this telescope is going to be a winner (time will tell though).
Another observation was that despite suspecting that the entire assembly at the rear was flexing this did not seem to be the case. Collimation did not shift according to the position in the sky. To be definitive though I will need to complete several images in several parts of the sky. I have replaced the focusor though as I think despite it looking a little beefy, it does have flexure problems. The Feather Touch as an expensive addition but worth the month everytime.
The optics at this stage look to be sharp and what we have come to expect from this budget buy RC. I am planning to examine all the sub exposures I gather in the coming tests and give a comprehensive report on what I see. Flexure is my main concern with the OTA.
So that is where I am at present. Come the Christmas break I hope to have the review written and an image to present for all to see. So far so good.
|