Wednesday, January 22, 2014

Trying out the TOA-645 Super Reducer

While I am trying to figure out if and what's wrong with my image acquisition, I wanted to try the Super Reducer for the TOA-130 scope.

One of the main advantages of this reducer over others is that it has the exact same backfocus of the .67 field flattener. I.e. I don't need different adapters. I exchanged the field flattener with the reducer. The only other thing I had to do was to rotate the OAG as it was pointing sidewards now.

When taking the first images I noticed (of course) that the scope was completely out of focus. I had to move the focuser in a lot (from 7500 to 1000). But then the autofocusing routing of SGPro worked flawlessly.

Next I connected PHD and tried to use it with the same calibration parameters. It resulted in the same accuracy of <0.4 pixels - which means 0.4" accuracy!

Finally, I had to enter the different pixel scale in SGPro to get plate solving to work.

My first try was a 20 min exposure of the Rosetta Nebula:

and compare it with subframes that I took for my first light picture:

First you notice the larger field-of-view. Let's compare details:
Dust lane without reducer:

Dust lane with reducer:

The difference in SNR is so evident - great!

Now, let's look into the corner if the image is flat:
 
 

Hmmmm, that doesn't look flat at all! But wasn't the reducer supposed to have the same backfocus? Asked on the UncensoredTAKGroup...