SW 300p secondary mirror size

[Captain Scarlet]

If anyone has one of these, the solid tube Sky-Watcher 305mm f/4.9 Newtonian as pictured below, could you perhaps kindly let me know what the size of the secondary is please? Minor axis.

My 300p is in Ireland and I’m not there until Christmas so I can’t measure it myself...

Thanks in advance...

Magnus

 

[Ben the Ignorant]

I have the GSO dob with very nearly the same specs, 300mm f/5, and the secondary size is 70mm. 

[lenscap]

SW don't show specs for the fixed-tube 12" Explorer any more but the 305/4.9 collapsible dob is listed with a 70mm secondary.

http://skywatcher.com/product/bk-dob-12-collapsible/

[Captain Scarlet]

Thanks both. I’ve seen SW’s current Dob specs at 70mm, but there’s nothing “out there” that definitively states the dimensions for their solid tube any more. But the GSO also at 70mm strengthens the case...

 

Edited November 10, 2019 by Captain Magenta

[Geoff Barnes]

7 hours ago, Captain Magenta said:

Thanks both. I’ve seen SW’s current Dob specs at 70mm, but there’s nothing “out there” that definitively states the dimensions for their solid tube any more. But the GSO also at 70mm strengthens the case...

 

Hi Magnus,

I've just been out and measured my SW 305mm F/4.9 Flextube Dob secondary and it is 70mm wide.

Not a solid tube I know, but the specs are identical to yours, so must surely be the same.

[Captain Scarlet]

5 hours ago, Geoff Barnes said:

Not a solid tube I know, but the specs are identical to yours, so must surely be the same.

Thanks. I’d be surprised if it were different from 70mm, would just be nice to have it confirmed by someone with the identical scope...

[johninderby]

Telesope Express gives these specs for the 300pds so I’d be surprised if your secondary is different.

Aperture:	12” - 305mm
Focal length:	1500 mm
Focal ratio:	f/4.9
Mirror:	Parabolic primary mirror - substrate is Pyrex
Secondary mirror:	Diameter 70 mm minor axis

Edited November 10, 2019 by johninderby