GSO 16 inch Dob Quality and Problems

[anthony.tony]

Hello there does anybody have any info on the quality and any problems with the GSO16 inch Dobs. Tony

[CoombellKid]

Have a read here.... it's the same scope re-badged

http://www.iceinspace.com.au/forum/s...ad.php?t=34571

regards,CS

[Blue Skies (Jacquie)]

I've had the occasion to use one recently and was amazed/unhappy at the size of the rockerbox and the weight. I look after a club-owned 17.5" that has a smaller footprint than the GSO 16s! And the 17.5" is easier to transport - you need a big boot to fit the GSO rockerbox in.

I didn't notice any of the upper cage movement using only the three struts but then I was concentrating on just what was needed to get it working that night I tried it. The optics were fine. Was easy to collimate although there was a bit of slop in the focuser. Balance could be an issue but there is a way to adjust it, but not at night! It looked a bit fiddly. The GSO scopes in my experience have always been difficult to balance without modification.

There are no shrouds available for them yet, either.

[tnott]

They are simplistically scaled up old-fashioned designs of the smaller dobs, constructed of cheap particle board. So they are heavy, bulky, have flexure issues and move less smoothly than the more expensive or good home-built truss dobs. Any small problems the smaller dobs might have are greatly compounded when you go up in aperture.

The flexure and movement issues can be fixed to a certain extent though. There are some good articles about on this site and others.

Optics are generally OK, so you can always plonk them in a different structure at a later date.

Some of the hardware (focuser etc) can be a little"cheap" but better than they used to be.

Fairly good value for money overall.

[PhilW]

Also: thermal mass. There's too much material in the structure; the cells are not well ventilated; the mirrors are really thick.

They are a lot of bang for the buck though.

[Starkler (Geoff)]

Originally Posted by PhilW

Also: thermal mass. There's too much material in the structure; the cells are not well ventilated; the mirrors are really thick.
.

This becomes significant at larger sizes. I recall some months ago I was at MPAS with my 15"er with a number of other large dobs present.

At around midnight all scopes were turned to saturn and mine was the only scope out the lot giving a good image in what was good seeing.

The reason being that my cooling fan had been running all night working to keep my 1.6" thick mirror near ambient temp. The 16" lightbridge with its 2" thick mirror without fan going presented a boiling blob of an image.

[Ian Robinson]

Originally Posted by tnott

They are simplistically scaled up old-fashioned designs of the smaller dobs, constructed of cheap particle board. So they are heavy, bulky, have flexure issues and move less smoothly than the more expensive or good home-built truss dobs. Any small problems the smaller dobs might have are greatly compounded when you go up in aperture.

The flexure and movement issues can be fixed to a certain extent though. There are some good articles about on this site and others.

Optics are generally OK, so you can always plonk them in a different structure at a later date.

Some of the hardware (focuser etc) can be a little"cheap" but better than they used to be.

Fairly good value for money overall.

You know what happens to particle board when it gets wet , or is left damp for extended periods .... is not pretty ....

[Satchmo]

Originally Posted by Ian Robinson

You know what happens to particle board when it gets wet , or is left damp for extended periods .... is not pretty ....

They don't call it Weetbix for nothing

[Ian Robinson]

Originally Posted by Satchmo

They don't call it Weetbix for nothing

Yes ....

I can't believe reputable telescope builder companies are still using the rubbish in dobs....