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Mounting a refractor to a tripod

Started by NGC88888, 08/14/2002 10:05PM
Posted 08/14/2002 10:05PM Opening Post
I am looking at the Astroview 120ST as a travel scope - the OTA weighs 8.5 lbs and is pretty short at f/5. I have seen posts where people have these hooked to a Bogen tripod, but I called Orion tech support and they told me:

a. There is no 1/4-20 mounting bracket on the Astroview 120 OTA.

b. Even if there was, it is too heavy for such a tripod.

Does anyone have experience with this? Or, am I being too ambitious with aperature? There is an Astroview 100mm f/6 that is lighter and does have the 1/4-20 bracket - maybe I will just go with this.

PS Just got my 80mm 2" plossl from SurplusShed - that is some piece of work. Eye relief is somewhere around 3 feet! Well not really but it is long. Will take it out tonight to try to compute AFOV but it looks pretty small.
Posted 08/15/2002 01:35AM #1
I have a 5lb refractor (about 6 or 7 with diagonal, eyepiece) that I have mounted on a pan head on occaision, but it is not an ideal combination. There are plenty of midsize tripods that will handle the 10+ lb. weight of the 120ST with accessories weight but very few heads of reasonable size that will. I would recommend a balanced alt - azimuth head for ease of use and stability, they can even be made fairly easily if you are handy with shop tools. I would give a conservative estimate that the ST90 is the largest scope I would mount on a reasonably sized tripod head. Anything larger and you might as well go will a real alt-azimuth (balanced) mount. Keep in mind that I am picky about vibration, etc.
That 80mm plossl is a way longer focal length than you would need unless you plan to use it with an F 12 or longer scope. At F5 I would stay at or below 35mm and at F6 42mm or below. Also, if there is much light pollution in your area, I would go for 32 to 25mm for an F5, 37 to 30mm for an F6 scope. My advice - send the 80mm back to Surplus Shed for a 31.9mm (same price and much more pleasing apparent field of view).

Joplin