Follow-up on previous equipment questions, and a new one ...

[Jay Freeman]

A couple of weeks ago I posted two questions about equipment here. I thought a follow-up on one might be useful, and I have an additional question ...


The follow-up: I was asking about a lightweight undriven altazimuth mount capable of supporting a C-8 or an Astro-Physics 110GTX, and someone suggested the Desert Sky units. I then asked about them in the Cloudy Nights "Mounts" forum, and got only one response -- they seem to be scarce. Since then I have sent two emails to Desert Sky's publicly posted email address, asking about lead times and availability, and making it clear that I was a serious prospect as a customer.

So far, I have no response from Desert Sky. I know that it is what might be described as "vacation season", but I suspect they are out of business, and that might be useful for you folks to know.


The other question I asked was about the 'Apertura AD16 Truss Dobsonian 16" Telescope'. I am a little leery about buying one, because of issues with the friction mechanism -- the instrument does not make proper use of Teflon. It is also a bit heavy, I suspect mostly because of the likely use of particle board in the structure. I can fix both of those things but it would take some work. So I am considering a couple of other instruments in this class, and I wondered ...

Do any of you have any experience with the Obsession 15-inch Ultra-Compact truss-type Dobson-mounted Newtonian? Or for that matter, with any of the Obsession Ultra-Compacts? I have seen reports that some of those are a bit flimsy, but if I were to buy an Obsession I would prefer to stay away from the "Classic" models, on grounds of weight and of eyepiece height. (I am looking not to upsize from my C-14, but to find something of comparable capability that is quicker to set up and easier to use for deep-sky work, e.g. with a PiFinder or whatever.)


Thanks for all previous comments, and for any new ones you may have.


-- Jay Reynolds Freeman, Deep-Sky Weasel
---------------------
Jay_Reynol...@mac.com
http://JayReynoldsFreeman.com (personal web site)

[Steven R.]

I've recently acquired the UC15. It isn't as pretty as some other scopes, but I find it well-designed and executed and the optical quality is excellent. I limited myself to the 15 instead of the 18 because I don't want to use a step stool while observing. The broken down scope takes up similar space in my CR-V cargo area as my previous 8" SCT with its tripod.

The main challenge with an Obsession is dialing in the balance, because its motion is biased towards low friction. When well balanced the motion is very smooth and easy to nudge tiny amounts, with no large stiction to break past.

In terms of flimsiness, I sometimes need to touch up the collimation over the course of a night of observing. And at last week's GSSP the daytime wind nearly knocked the covered scope over, so I laid it down pointed into the wind. That night I found the collimation was further out than usual, so something flexed during that near trauma. I also found that I sometimes needed to adjust focusing after a large slew, which was peculiar to that session so maybe one of the truss tubes attachments got loosened.

I love my UC15!

Cheers,

-Steven

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[Ted Baltz]

I've had a UC15 for almost a year now.  It really is very compact - it fits in my VW Golf hatchback, with 2 large Pelican cases of assorted gear, the wheelbarrow handles, etc., with room for a front seat passenger!

The balance is a bit finicky, but with a 9x50 finder, Telrad, Paracorr, and a 2" eyepiece it's pretty close to balanced with no extra weights.

Is it flimsy?  It's a bit susceptible to vibration but I don't find it too problematic.  I've been experimenting with various vibration damping approaches.

The optics really are pretty good.  With (rare) good seeing six blocks from downtown Mountain View, I have had nights where views of planets kept getting better at least to 500X.  I've observed with it at Henry Coe and Lake San Antonio.

Setup takes less than 30 minutes from opening the (car or garage) - this includes leveling the base to 0.2 degrees or better, collimation, and aligning the telrad and finder - again I'm aiming for 0.2 degree which is supposedly the tolerance of my cheap digital level.

I have used more expensive telescopes but I'm quite happy with this one.

-Ted

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[Arvind K]

Jay, for alt az mount, consider supermount.kr products.

A bit about super mount: 

It's a small outfit from S. Korea but I've done business with him over the years. Due to time zone differences his response to emails are delayed by a day but he is a reliable and trustworthy. His products are imo top notch. The caveat is the price. Both list price and shipping charges from Korea.

My purchases from him so far have been imaging oriented (heavy-duty tripods and custom accessories), but I'm considering their alt az mount as I'm gradually picking up visual observing.

[Paul Alsing]

I own one of these...

Stellarvue M002

... and it will hold up to 25lbs. A C-8 OTA is about 13 lbs , so this should be a good match. There are also optional accessories...

Stellarvue Mounts

It works just fine with my Explore Scientific 152mm David H Levy Comet Hunter Telescope, very sturdy with smooth motion.

\Paul Alsing