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Sumerian travel scopes - feedback please

Helen

By Helen
in Discussions - Scopes / Whole setups

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Helen

Helen

Posted
Posted

I used to have a 12 Skywatcher flextube auto dob and I loved viewing with it.  But the size just wasn't manageable for me and so I sold it after a couple of years.  Anyone who has seen me loitering around the large dobs at star parties knows that I keep hankering after something big but manageable....

I saw Stu was selling the 16 Sumerian a couple of weeks ago.  I remember the one at SGL7 was lovely to look at as well as through and that got me thinking.  I didn't really think about going for it, but a couple of days ago it came up in conversation and Mike suggested I think about it for Christmas (and as a bit of reward for having just about survived an incredibly hard first term of my Masters in Astrophysics - the workload has been immense).  But I was too late  :sad:  Stu had another offer before me.

So, I started looking around.  As has been discussed Sumerian have just started only selling through dealers - TS seems to be the only one at the moment and they are only stocking the 12 inch travel Dob.  The Sumerian website does have what I assume in the remainder stock of 14 inch travel Dob being sold as 'private sales'.  Now a 14inch in a package small enough for easy storage and travel, and therefore relatively lightweight for me to handle would seem a brilliant concept.  The website suggested that the travel scopes were scope only, no mirror.

I contacted Michael to ask for details.  It turns out that a travel scope could be provided with an OO f4.5 1/6 PV Hilux mirror.

So, after that ramble :smile: a couple of questions please.  Does anyone have the travel configuration, and if so how do you find it? and secondly a question about mirrors - is the OO good, or should I consider just buying the structure and get a Nichol mirror (price similar).

I think I may go for encoders too :wink:

Many thanks

Helen

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jetstream

jetstream

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I would personally get the mirror at min 1/8 PV and a Strehl of over .9 with the scratch dig around 10-5 or better if possible. OOUK mirrors are VG, they do subtract the central obstruction area from their numbers that tends to inflate their Strehl ratio. I really do believe that a very smooth mirror increases contrast, sky considered. Rumor has it that Zygo tested mirrors over 1/10 PV are smoother than the lower specs mirrors to some extent.http://www.rfroyce.com/standards.htm

http://zambutomirrors.com/zambutoopticalcb.html

A lot of scopes now use very thin mirrors... requiring very good mirror cells... I would check to see how these light travel scopes perform under the stars at varying EP altitudes. A great thin mirror in a poor cell is, well...

Another thing to consider is the mechanical construction and reliability of these travel scopes, the trusses will be on and off repeatedly, cage too.

Will you have stray light to contend with? Some of these scopes have no real cage and rely soley on a baffle to help out.

I like some of Teeters features, his truss attachment look VG and his components are top tier. The older Obsession UC's may not have reviewed well, the new ones better possibly. How are Sumerians lower truss attachments?

I am excited to hear what you choose!

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estwing

estwing

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firstly let me say...scope parts may bend or break, but the mirror is where the money should be spent...listen to simonfromsussex ,Alan,Mapstar,swampthing, me and anyone else who's on this forum that has or has met John Nichol. Not only will you get first class customer service but you will also get a hand crafted mirror that will constantly give views that will take your breath away. Secondly what ep's will you be using? heavy naglers and ethoses don't sit well in travel scopes...there might be slight flex in your scope.

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scarp15

scarp15

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Perhaps consider an Orion Optics UK VX10 F4.8 with dobsonian mount and 1/8 - 1/10 PV mirror. Light, quite compact, quick and simple to set up / use, in my opinion would make a very good travel scope. Hilux, highly reflective coating, would likely perform equal to a 12" standard coated mirror. Very good all-rounder performance.

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John

John

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If you are buying Orion Optics optics then it seems sensible to me to go for their higher quality mirrors since that is their strength.

Their scopes are quite a bit lighter than the Skywatcher / Meade / Revelation equvilents but a solid tube 12" OTA is always going to be a bit of a beast.

I think if I ever go up in aperture it would have to be to one of these lightweight minimal type designs.

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estwing

estwing

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Perhaps consider an Orion Optics UK VX10 F4.8 with dobsonian mount and 1/8 - 1/10 PV mirror. Light, quite compact, quick and simple to set up / use, in my opinion would make a very good travel scope. Hilux, highly reflective coating, would likely perform equal to a 12" standard coated mirror. Very good all-rounder performance.

I have to disagree with the hi lux coatings...theres been a couple of issues with OO mirror coatings of a late....

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John

John

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I have to disagree with the hi lux coatings...theres been a couple of issues with OO mirror coatings of a late....

Are those isolated incidents or is the whole Hilux concept now open to doubt ?

I've had 2 Hiluxed scopes and they have both been fine.

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John

John

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me and simon have both had major issues John.

Sorry to hear that Calvin (and Simon) :embarrassed:

I guess I've been lucky with mine then. I guess if I was comissioning a scope from scratch (bad choice of word perhaps !) I'd approach others than OO given this uncertainty.

With my scopes being purchased used I guess previous owners resolved any issues, if there were any.

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jetstream

jetstream

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i know about the problems calv and simon had, but like you john and iain(scarp) i am amazed at my mirror and calv and steve will vouch for mine

Mines been though hel and back for 3 years, frosted, soaked, thawed, baked... no problems yet, which amazes me.

Are all the problems associated with non OOUK substrate?

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Helen

Helen

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Interesting discussion guys - thanks :-)

Thanks John - yes I had seen that, and it sums up what I'm looking for really, but with a slightly smaller package in the 14" (16" are no longer available).  The smaller package would work better for me anyway, as I'm a smaller package too :wink:

I know it is likely that I'll compromise stability a bit for portability, but I'm prepared to accept that.

The mirror is a trickier decision though.  Buying the scope complete, now, is attractive compared with putting in an order and waiting a few months and then assembling myself.

There is another option which is to go for a 12" instead and go for the TS higher quality mirror... http://www.teleskop-express.de/shop/product_info.php/language/en/info/p8402_Sumerian-Optics-Alkaid-12--f-5-Dobson-Teleskop---Quarzglasspiegel.html

Hmmm

I need to think some more (and now need to get back to yet another assignment to be in tomorrow  :wink:)

Helen

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alan potts

alan potts

Posted
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Helen,

I don't have a travel Dob by Michael but the Canopus 18 for me is transportable if I wanted it to be all parts are not that big if you have an estate and the heaviest part is about 18kg.

I only have one thing to say about mirrors and it is in total agreement with Calvin, this is where the money should be spent and keep it British with a Nichols mirror, not spoken to him but it would seem he is a very nice person and nothing seems too much trouble.

Alan.

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John

John

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Hmmm  I've been in touch with John Nichol and he's so busy that it would be 3-4 months wait for a mirror  :sad:

Helen

Thats sort of good news (he is justifiably popular) and bad news (there is just one of him) I suppose.

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DRT

DRT

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Sorry I'm not going to discuss that on here.That was between me and Orion Optics

Is that fair to OO, who are not here to defend themselves?

Perhaps you could put both sides of the story and let others judge for themselves?

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