Thursday, April 30, 2015

My very first autoguiding exercise

The Sky Adventurer has only single axis guiding, so it would require good polar alignment to guide successfully... of course, it's rather hard to do indoor.

Finding a bright enough star is not easy too... but I managed to get one.  The polar alignment was rather off despite the target star stayed in the field for quite long, and that indicates not too bad polar alignment.  However, it did drift away slowly and PHD guiding was complaining.

Cloud moved in before I could try EQ Align to fine tune the polar alignment.

Now at least I know that my ASI 130mc and the ST4 port of my Sky Adventurer works, I will need a better night to try the whole thing again.

A small DEC motor was on order, together with some electronics, and I will try to make my Sky Adventurer with dual axis motor/guiding.  Not very confident, but why not have a try?


For dual axis guiding, the guide scope and the imaging scope  should be on the same side of the L adapter, so the balancing side should carry something heavy as well... is that making the whole thing meaningless in that case?  The Sky Adventurer is wide field and portable!

I guess I will be taking a 200mm lens for my trip, so the polar scope should be enough and no need of guiding.  So, I will be bring a 50mm lens, a 200mm lens plus a 2x tele extender and that's all.  The 300mm f2.8 will be left at home.


To test the concept of using camera lenses as guide scope, I found that I have to insert a 2x barlows in order to reach focus with a camera lens.  It's good in the sense that, the guiding lens is always working at higher power!  Suppose I have two lenses, 200mm and 300mm respectively.  If I use the 200mm as imaging scope and the 300mm as guide scope, the guide scope will be working at 600mm due to the barlows.  Even if I swap their role, the 300mm as imaging scope and the 200mm as the guider, but then the guiding side will still have 400mm focal length!

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