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#1 yock1960



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Posted 15 January 2013 - 08:58 PM

A busy evening last night!

The dovetail adapter that I ordered for the C8 that I've decided to buy (Super C8+, I think), came last night. So I got it de-forked and mounted on my SQ-G. Got it balanced and put it out to cool down, then waited to see if it would clear.

It did and here is the only image that I dare show (SSAG). I don't have a focus mask yet and trying to figure out focus without one, at long focal length, is not something I'm accustomed to. I also am going to have to re-figure out my settings, as the banding is back in a major way!

I took some video with the SPC900, but they are worse. I must not have had the focus as good as when I did this one. Hopefully I'll get another opportunity soon and hopefully the focus mask will get here sooner rather than later, along with a nice big dew heater strip! I was amazed (probably shouldn't have been) at how fast it frosted up. In hindsight, I think it was frosting up before I realized it, because I kept having to tweak the gain up just before I quit.

I have a ton of stuff to learn with this new scope! I also have to overcome my collimation phobia! I never could figure it out on a Newtonian, but this seems much simpler, albeit I've only done a coarse adjustment so far. I don't think that this is a 'Halley Era' dud, but I don't know enough to say so unequivocally yet.

I think I will be able to make some decent images with it.


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#2 ToxMan



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Posted 18 January 2013 - 07:14 AM

Yah, those diagonal bands have to be frustrating, Steve. But, looks like you have a moon shadow on Jupiter.

As far as collimation phobias go, you will get over it. Good rule is to start collimation by loosening a collimation screw rather than tightening and observe the change to the airy disk.

Right now, it makes sense to collimate on Aldebaran and move over to Jupiter. Knowing which screw to turn is fun to figure out because the optics (mirror reverse, etc) flips image.

But, I take notice of the shadow or outline of my hand and arm as I reach over the corrector plate of the SCT to adjust the screws. I can see which side of the airy disc my shadow enters the image on the display and that tells me which of the 3 screws I'm adjusting are going to move in what direction.

When you tighten or loosen a screw, the changes you make are fractional...like a 16th of a full turn is a big adjustment. Tiny turns. You can't break anything. But, I have fouled up collimation pretty well a couple times. On the Celestron Fastar compatible SCT's, you can remove the secondary all together. One time, I think it was the second time I tried collimation, it was so fouled up, I had to take out my secondary to see how far out of adjustment I was.

There are various collimation aids. Someone sells "knobs" to replace collimation screws. I'm not a fan. And, prefer allen head set screws. I think it is a finer touch and control.

#3 yock1960



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Posted 20 January 2013 - 05:59 PM

Hi Toxman,

The banding is actually horizontal, I didn't align the camera to make Jupiter's bands horizontal. I don't think it's related to gain either. I wonder if the SSAG is progressive scan and it's just not as noticeable on the smaller scope?

Collimation is going to be an adventure. I've been trying on stars and think I made it worse. Today I did it during the day on some power line insulator reflections. It's going to be cloudy for a while now...we'll see.


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