Posts Made By: Bill Byrd

[COLOR="Purple"]Not bad Joe!! I'm impressed with the images I've seen from the Orion 80EDs. Must be a nice scope for wide field imaging.
Bill[/COLOR]

[COLOR="Purple"]Well, I got three pieces (two ends + middle, inner splice piece) cut today in preparartion for gluing (with 90 minute, high strength epoxy) up a trial run 7' 3" pole. But....7' truss poles are VERY L O N G !! Even if gluing works like a charm, I'm not sure I can transport 7' truss poles on a regular basis in my little scope hauler without resorting to using the roof rack, which would have to be installed each time I wanted to go observe.

Sooo...back to an idea I had for a much smaller scope: two piece poles. The pic shows the parts that went into the prototype, which was 1" OD....much smaller than the 1.25", thicker walled tubes I have to work with for the 18.75" scope.

I ended up selling the mirror for the smaller scope so I never finished a working scope with the two piece poles.

Anyone have experience making two piece poles and if so, how was it done??
Bill[/COLOR]

[COLOR="Purple"]Very nice Filippo!
Wonderful job considering the light pollution you have in Rome!!
Bill[/COLOR]

[COLOR="Purple"]I'm in lust....even though I'm more of a wide field kinda guy. Man, it just barely clears the dome.
Bill[/COLOR]

[COLOR="Purple"]WOW! Jim B at Starsplitter confirms that the composite alt bearings weigh 3 pounds. That's pretty incredible since most of the Aluminum alt bearings out there seem to weigh between 10 and 18 pounds. With my aging/aching back, saving that much weight on the mirror box justifies the extra cost for some composite bearings.

No one has any experience with these bearings?? Either on a Starsplitter scope or some other?
Bill[/COLOR]

[COLOR="Purple"]Hi Mike![/COLOR]

> Unless I miss it, what is your Focal length and
> also what size secondary do you intend to use?

[COLOR="Purple"]Focal length is just under 2500mm; f/5.22. Not exactly a super "fast" mirror. I'm looking at using a 3.1" secondary.[/COLOR]

> So……. If you’re going to use the 3.1 your clear
> could be 20” with no additional light loss. Also
> understand that if you use a 3.1 and a 20” clear
> aperture you’re able to push the secondary out
> further in the light cone resulting in less
> vignetting. The thickness of your focuser board
> can also help in this case.

[COLOR="Purple"]I like 20", if I'm not losing too much on the front end, so to speak. Understood about the secondary being further out.[/COLOR]

[COLOR="Purple"]One wrinkle: I might try to "fold" the light path back down a little bit to end up with a shorter EP height. Even with the 3.1" secondary, I don't think I'll be limiting illuminated FOV. [/COLOR]

> Point I trying to make is if you’re going to
> undersize your secondary it makes little since to
> run a full clear aperture unless you intend to
> change to the larger secondary down the road.

[COLOR="Purple"]At 3.1" for an f/5.22 focal ratio, I don't think I'm undersizing the secondary...thus probably never going to "upsize" it.[/COLOR]

> Also do you know the quality of the mirror? If it > has edge defect you’re better off masking the edge
> anyway.

[COLOR="Purple"]It's good to the very edge. WooHoo!! 8)

Thanks for your insight! Any thoughts now that I've thrown out some more details?
Bill[/COLOR]

[COLOR="Purple"]Here's the tube ends with hardware installed.[/COLOR]

[COLOR="Purple"]Looks good Floyd!
I did something similar for my Astro Master and it really is nice to have it always near and in the same spot when observing.
Bill[/COLOR]

[COLOR="Purple"]I got a new wallpaper picture for my computer!!

Great pic Tom!
Bill[/COLOR]

[COLOR="Purple"]Hi David!
I have one of the 8" SN OTAs and it is a very nice performer for wide field viewing. I also have a wondeful 10" f/6 dob. The 10" gives better views but has a smaller field of view. I've never been much of a planetary observer so maybe someone else will answer about planetary use of the SN.

I use a Paracorr with the SN and stars are good almost to the very edge of the field of view. Without the PC, edge stars are still not great, even though the SN with the corrector is definitely better than a plain newt at f/4. Better eyepieces, like Naglers, are probably a good thing too with the fast light cone of the f/4 (f/4.6 with PC) optics.

For cool down, I do two things. First, I removed the Kydex in the mirror cell so I can blow a fan directly on the back of the mirror while I set up. Second, I usually use only low power with the scope so tube currents aren't very noticable.

My only issue with the 8" SN is that the secondary mirror is VERY oversized to allow for film astrophotography. I'm strictly a visual observer so the big secondary is a bit of overkill and adds a lot of obstruction. I just got a 6" SN OTA with a smaller secondary and I'm going to try to swap the smaller secondary over to the 8" OTA to improve contrast and light through put.

Like any scope, the SNs are trade offs depending on the type of viewing you do. I love DSOs and wide field sweeping of the MW so I like the SNs. For the DSOs, I have a bigger scopes. Soooo....when I get out to really dark skies, I take two scopes most of the time.

Sorry to ramble! Let me know if you have any other questions.
Bill[/COLOR]