Longer FL truss/skeleton tube dobsonians

[25585]

Given that assembling a skeleton tube dob in the field requires collimation checking, what models of say F7 to 8 upwards, 8 to 10 inches aperture are available, which would not exceed an OTA vertical height of 72inches/6 feet?

I like Portaball scopes, do they come with shrouds, or can shrouds be bought separately for them?

 

[John]

The longest that I'm aware of in regular production is Orion Optics 10" F/6.3 but they would make something slower to special order I think.

My 12" dob is F/5.3 and, mounted, the top of the tube is at around 66 inches.

 

[Stu]

I've seen a few Orion Optics 8" f8 scope reviews on the web, such as here:

http://scopeviews.co.uk/OrionOptics200Dob.htm

Always fancied giving one a go.

I also had an 8" Portaball which did have a shroud though it was possibly an extra. Lovely optics, if anything I found it a little on the low side, I ended up observing on the floor for lower objects.

[John]

The aperture is smaller but this is an Orion Optics 6" F/11.3 dob:

http://www.ebay.co.uk/itm/Orion-optics-dobsonion-telescope-150mm-f11-3-ultra-grade-optics-/162652653439?hash=item25deda877f:g:sUIAAOSw8thZpxOD

 

[25585]

23 hours ago, John said:

The aperture is smaller but this is an Orion Optics 6" F/11.3 dob:

http://www.ebay.co.uk/itm/Orion-optics-dobsonion-telescope-150mm-f11-3-ultra-grade-optics-/162652653439?hash=item25deda877f:g:sUIAAOSw8thZpxOD

 

Same fl as a SCT! Neither that or f8 8 inch are made anymore.

 

On 28/09/2017 at 15:03, John said:

The aperture is smaller but this is an Orion Optics 6" F/11.3 dob:

http://www.ebay.co.uk/itm/Orion-optics-dobsonion-telescope-150mm-f11-3-ultra-grade-optics-/162652653439?hash=item25deda877f:g:sUIAAOSw8thZpxOD

 

Tempting for its rarity! How would it compete with a 4 inch refractor of same fl?