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Cave Astrola options, You pick

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#26 turk123

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Posted 23 August 2013 - 09:38 AM

Here is the patent paperwork for the Skymicro (public record).

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#27 tim53

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Posted 24 August 2013 - 08:34 AM

I have the Sky Micro Giant on the 12.5" Cave. I rebuilt it along with a 1 1/4" Sky Micro that I'm planning on using with one of my OC OTAs at some point. The Sky Micro on the OC Connoisseur is sweet! I love the adjustability of these focusers. They can be dialed in so smooth!

Here's the big one on the big Cave:

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#28 terraclarke

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Posted 24 August 2013 - 09:26 AM

Did Cave make sets of mirrors specifically for other scope manufacturers? If so, might it be possible to identify such a mirror in another scope?


They also re figured mirrors for individuals. When I could never get the parabola right on my 6" F4.5 I sent it off to Cave and they figured, aluminized, and coated it for me. They also sent me an 1/8 wave elliptical flat of the appropriate size for the mirror's F-Ratio.

#29 turk123

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Posted 24 August 2013 - 02:52 PM

I have the Sky Micro Giant on the 12.5" Cave. I rebuilt it along with a 1 1/4" Sky Micro that I'm planning on using with one of my OC OTAs at some point. The Sky Micro on the OC Connoisseur is sweet! I love the adjustability of these focusers. They can be dialed in so smooth!

Here's the big one on the big Cave:


Hi Tim

I have the same sky micro. It is not very smooth which makes me think it is out of round (dropped). Any ideas how to get it round again?

#30 tim53

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Posted 24 August 2013 - 03:28 PM

Ouch! I would think you'd want to put it in a lathe and measure for runout. Probably the drawtube is bent if anything is.

I've been known to straightn things with a rawhide mallet while rotating them slowly and watching a dial gauge. Not optimal, perhaps, but if it is bent it might be TG only thing to do, short of machining a replacement.

It would be neat if someone were to reproduce the sky micros, but I suspect the market isn't there for that.

Tim

#31 tim53

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Posted 24 August 2013 - 03:31 PM

iPhones are strange!

#32 Datapanic

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Posted 24 August 2013 - 04:21 PM

The pinion shaft on my Sky Micro Giant was a little bit bent causing uneven tension when focusing. I was able to straighten it out a little and tweak the bushings which improved it, but it still needs some more work. It is usable, and as Tim said, they can be dialed in very smoothly.

#33 amicus sidera

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Posted 25 August 2013 - 09:27 AM

Lots of great information on this thread!

Reading and learning... :gotpopcorn:

Fred

#34 apfever

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Posted 25 August 2013 - 03:17 PM

Well hijacked and my own fault. At least I remembered to get the Carle picture and get back here. I forget things. I was also busy this morning looking at an 8" F7 Newt that was bult in 1939. The mirror had the Clausing sticker dated 04-02-39. Oh, now I'm hijacking my own. Never mind this morning. :wron:

Here is a picture of the Carle photography helical focuser offered by Cave. This would include the original paper, and collimation cap and T ring adapter. The cap and adapter were optional and shown on the paper.

This is in great condition and everythiing works well. It is nicer than the lousy picture shows (or doesn't show - dark). Everything including the paper just needs a dusting or wipe.

The choice would be between this one or the 1.25" I showed in this string way back when. I'm beginning to wonder if I need to ask which you'd choose, but go ahead and why?

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#35 Datapanic

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Posted 25 August 2013 - 03:36 PM

The Carle focuser is photo-visual - obviously meaning that it has enough in/out focus travel for prime focus photography and visual. It is a pretty cool focuser and the helical focus method allows very fine focus plus will not roll out of focus if there's a lot of weight on it from a camera.

For only $23.50 ppd. - how can you go wrong!

But it is 1.25", I prefer the Novak 2" helical focuser myself. But I don't think it was resold by Cave.

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#36 apfever

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Posted 25 August 2013 - 03:43 PM

Here's the side by side, and my choice of finders which I found surprising.

Both have the same mechanical approach. Both are in equal condition. Both are the same magnification and aperture. EITHER one by itself would perform admirably. The side by side comparison shows definate differences.

1. The HOC is longer and will fit in either scope. The shorter AvA will not span the rings for the HOC.

2. The HOC has a noticable larger AFOV (aparent field of view). Since the powers are the same, the HOC has a noticable larger TFOV (true field).

3. The HOC has no ring of fire or blue hue. The view is uniform to the sharp field stop. The AvA has a nice sharp field stop, but a blue hue ring. The ring is minor but there.
Quickly moving from one finder to the next, it can be seen that the HOC has a truer whiter view. This is very subtle, but there.

4. The HOC has better resolution. Seriously. This was a day test on two rows of truss style high voltage interstate electrical towers. I have two runs of these, one row several miles away, and another further row about 10 miles out. I use these frequently for detail on the tower truss structure, suspended insulators, and tension lines. The HOC won with easy to see detail. Both were VERY good (I have experience using these towers), but the HOC won on the first comparison look through both finders at best focus. This did not take a back and forth scrutiny.

The HOC wins.

Now I have no intentions of opening any indeterminate bucket of worms from another subject so I'll meekly mention: HEY!! HOW ABOUT THEM THAR JAPANESE SYMBOL DOO DADS AND WHO MADE WHAT WHEN WHERE? AND DOCUMENTED CONFIRMED SOLID DESIGNATIONS AND AND ALL THAT, AND HOC? or not.

#37 tim53

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Posted 27 August 2013 - 11:59 AM

The Carle focuser is photo-visual - obviously meaning that it has enough in/out focus travel for prime focus photography and visual. It is a pretty cool focuser and the helical focus method allows very fine focus plus will not roll out of focus if there's a lot of weight on it from a camera.


Holy capeevy dust! Is that what the screw on the side of the base of the Carle is for?? I thought the outside was machined so you could clamp a camera adapter to it! I had no idea it moved!

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-Tim.

#38 Datapanic

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Posted 27 August 2013 - 07:16 PM

The Carle focuser is photo-visual - obviously meaning that it has enough in/out focus travel for prime focus photography and visual. It is a pretty cool focuser and the helical focus method allows very fine focus plus will not roll out of focus if there's a lot of weight on it from a camera.


Holy capeevy dust! Is that what the screw on the side of the base of the Carle is for?? I thought the outside was machined so you could clamp a camera adapter to it! I had no idea it moved!

-Tim.


I never had one before and it didn't occur to me that was how it worked either until I took it apart to paint it when I was overhauling the Cave 8" RFT. After that, it was one of those Aha! moments and the "Photo" part of Photo/Visual was realized. Originally, that tube part was stuck in there tight because of years of dust and dirt and didn't slide in or out easily at all.

I was really surprised that it was positioned just right to get prime focus with my DSLR - it was close as you can see from the picture. But it works. A Web Cam has no problem with it either.






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