Saturday 12 September 2009

Getting back in the saddle

On the 12th, I had a clear night, and decided to get out the rig and run some tests. First off, getting out the rig was tricky, but with a lot of care (having a bad back really doesn't help), in pieces, I was able to get it all outside and setup. An Obsy really would make this much easier, but I don't have room... never mind.

I checked the level and this was spot on without adjustment, then powered up and polar aligned, amazingly I'd plonked it down so there was only a very minor adjustment on the Azimuth adjusters to get alignment. A check on focus, and a tweak on both the guidescope and imaging scope (although I'd added the TC to the imaging side to get 1200mm and really push the guiding) and good to balance. Started trying to balance the mount, and then my troubles began.. First off trying to get my head around what needed to be moved where with the dual mount bar. Gotta say, balancing with the scopes piggy backed was a lot easier. It did my head in for a while till I discovered that a) I needed to add the second countweight... (not more damn weight)... and I had to re adjust the C80ED tube rings. Being a bright spark, it occurred to me that putting the tube rings as far apart as possible was a really good idea, being more secure etc etc. Until that is, you find that you can't actually shift the OTA and camera far enough forward to get balanced... So in the dark, I dismounted the C80ED with camera and 2x TC still attached (I didn't want to adjust anything around the focus again), grabbed some tools and a camping lantern, and set about moving one of the tube rings along the OTA and dovetail and locking it back in place. I've gotta say this is not the worlds easiest DIY job in the dark (thankfully it wasn't cold to go with it).

Once the rings had been adjusted, allowing more play in the scope position, I was finally able to balance everything out. Phew. So I went for the N star align on EQMOD. Another problem... I couln't get CDC to tell the mount to slew. I tried for about 10 minutes, the mount would move quite happily to my control inputs from both EQMOD and the gamepad, but not from selecting a star in CDC. Till I found I was using the wrong option and instead of telling the mount to goto the star I was telling CDC to centre the star in the view... blast it. Anyway, having finally solved that one, the N Star align was easy. I then slewed around to NGC457 (The Owl Cluster) and set PHD running. After a few minutes, the green box and guiding appeared. I set the camera off on a run of 7.5 minute subs @ ISO800. Then just to finish, as I was testing, set one 20 minute sub running. When that was finished, I grabbed some flats (I forgot about the extent the TC made to the exposure times... ) and cleared up.

Anyway, the guiding worked a treat, even with the TC making 1200mm. Here's the single 20 minute sub. The green tint is from the EOS CLS Clip filter, this really works well on killing the LP around here, much more effective than the Skywatcher LPR filter. This image has had no processing done on it.



And here's the combined results.



I'm happy now that everything is working as it should, and as equally as important, I can also remember how to set it all up and make it work.

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