Revelation 10" f5 Dobsonian (first impressions)

[FLO]

Hi all,

The following is something I recently posted on one of the Yahoo astro

groups; its more of a first impression than a review:

I took the 10" f5 Revelation (GSO/Hardin) Dobsonian out last night

for 'first light' at a local Perseids star-meet. I didn't see much of

the meteor shower as I was making the most of the new scope but,

judging from all the cries of 'wow' there must have been some impressive

streaks across the sky and occasionally, they came in threes and

fours.

Compared to my 4" Mak' the amount of extra detail visible in the

Dob' is incredible. The Double Cluster, a favourite of mine seen

thru a Meade series 5000 28mm SWA was breathtaking and the M13

globular thru a Meade series 5000 14mm UWA was a totally different

object with stars resolved right to the centre. The Andromeda

galaxy (low in the sky) was an easy target; its two smaller companion

galaxies M110 and M32 were also visible. The Alberio double was clear

and bright with contrasting colours (I feel sure a mild neutral density

would have improved the colour difference) and the Ring and Dumbbell

Nebulas were also easy targets.

With the Ring Nebula, I pushed the magnification to around 200x with

a Meade series 5000 6.7mm UWA and the image held together nicely; I

feel sure it can take more but collimation was straight `out of the box'

so i didn't push it further. The azimuth needle bearings weren't as smooth

at this magnification; they seemed to get caught in 'divots'. This caused

the image to shift slightly to the left or right in the eyepiece. I am

surprised 'Sky at Night' magazine missed this in their review of the

Revelation 12" ?!

What particularly pleased me was how quick and easy it was to set up

and how convenient it was to relocate it to other parts of the garden

for better views of new objects rising. No need to re-level or re-align.

The silky smooth Crayford focuser deserves special mention ...

although the focus bar did arrive a little bent (nothing that effected its

performance).

All things considered, I am very pleased

Regards, Steve.

[russ]

Nice mini review Steve. I'm surprised Sky at Night mag missed out that problem with centering the object. Does the Revelation use the roller bearings for the base?

Those Crayfords are silky smooth, soooo soo much better than the standard fare Rack & pinion.

And yes i can imagine the difference in deepsky views between the 10" dob and 4" Mak are huge.

Russ

[GazOC]

Nice mini review Steve. I'm surprised Sky at Night mag missed out that problem with centering the object.

It may not be too bad, the Ring is pretty near zenith, never on easy spot for a dob. You end up stuttering around in circles!!!

[FLO]

Does the Revelation use the roller bearings for the base?

Russ

Hi Russ,

Yes, both the 10" and 12" Revelations use bearings for the base - I'm not sure about the 8".  Several users in the states (where it was sold as Hardin DSH with the same GSO optics) have removed the bearings and converted it to the more standard arrangemant with the base running on Teflon pads, or similar, and several thin home-made washers (from plastic milk cartons!) fitted around the central bolt.  I might give it a try   

Steve.

[russ]

Hi Steve,

I use to have the Orion USA XT10. It used the the usual arrangement of teflon pads for movement of the base. But it was silky smooth, actually it was silky smooth in both axis. The only down side to the scope was the focuser which was rubbish. I remember the user groups used to mention the homemade washers back then. Everyone swore by them.

It's funny, they make quite a big thing of the roller bearings and i must admit it looked quite a good idea too.

How about the cooling fan at the rear...does it help much with cooling the scope down?

Regards

Russ

[GazOC]

I had a XT8 as my first scope, great scope, but the base was showing signs of weathering by the end!

[russ]

I had a XT8 as my first scope, great scope, but the base was showing signs of weathering by the end!

I had the first base changed because moisture got in somewhere and then the base ballooned up splitting the wood. Typical Orion USA aftersales though.....totally ACE. They sent over a new base from the states in 5 days.

The actual OTA was awesome and should have done what you did Gaz and stick it on the EQ6.

Russ

[OXO]

Great Review Stevenet04,

Cant get over how cheap they are for what you get.

James

[FLO]

How about the cooling fan at the rear...does it help much with cooling the scope down? 

Regards

Russ

I wasn't able to test that Russ as the scope had already come to temperature in the back of the van.  The fan appears to be a standard PC fan with a batt holder on the end of a lead and a power switch.

Steve.

[GazOC]

I havn't bothered putting mine on yet Steve, maybe in a couple of months when the winter starts to bite. Theres not really any point at the moment unless you store your scope in the airing cupboard!

[OXO]

One thing about those fan's that concerns me is if it will cool the entire Mirror evenly i have a feeling it will just be the centre of the Mirror and can see it causing problem's with the telescopes thermal current etc etc? just a cautionary note i hope i am wrong.

James