Wednesday, May 4, 2016

A Perfect Night

Got out to Kumeu Observatory last night and was happy to see the conditions were much improved from the Monday night, I measured my focus star with a full width half maximum of 2.1! this is the best focus I've ever recorded with the C14 so it must have been pretty decent astronomical "seeing", hopefully after we refine the collimation we will be able to get even sharper images, with the conditions being so good I set about capturing a new pointing model and this time I isolated the south east portion of the sky thanks to advice from Grant Christie who dubbed this region the "zone of death", I was ecstatic to see all the pointing samples solve without issue, I had almost completed the entire model when I got my 1st fail it was up near the zenith in the east, the point was probably just a little too close to the dreaded "zone of death" so I aborted the slew and saved my model which at this stage was up to 209 pointing samples, I then converted the standard model into a "super" model and was pleased to see it only dropped one sample, it was the sample captured just before the fail, I was really happy to see that as when I attempted to turn the previous night's model into a "super" model it dropped 130 odd samples! so feeling like I've finally got over the hump in regards to capturing a robust pointing model I set about testing the new model.

I imaged targets in all areas of the sky including the "zone of death" and was really pleased to see that targets were either on the crosshairs or just a few arc seconds to either side of it, so I'm thinking we finally have a really decent pointing model to work with now, I'm also feeling much more confident about the whole T-Point process so if I need to capture a new model in the future it shouldn't be a problem, I've enabled the pro-track feature and it seems like the tracking has improved some what, in some parts of the sky you can easily get 200 second exposures without any noticeable drift.

All we need to do now is concentrate on getting the auto-guider working but this should just be a simple matter of sourcing the correct cable, we also need to replace all the filters in the SBIG as when we had the camera off when the mount was being repaired we noticed mold growing on them, thankfully there was no mold on the CCD sensor itself, the dome slave issues need to be resolved and the collimation of the C14 needs to be refined, after all this has been taken care of we should be ready to do some research grade astronomy.

Below are a couple images from the night, note that the calibration is not really effective anymore as all calibration files date back to Summer so I'll need to replace them with new calibration files soon ( I'm just waiting on the new filters to arrive )

Pointing and tracking test of the Sombrero Galaxy, the image is a 200 second exposure and is un-calibrated, weird stuff near the edges might be from the mold? I'm not sure. ^

Pointing test of the Southern Pinwheel Galaxy, this image is a median stack of 11 x 100 second exposures, the image was also calibrated. ^

Posted by Jonathan Green

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