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Orion UK VX12 300 mm f/4 Dobsonian

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#1 NeutronStar79

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Posted 18 June 2019 - 02:16 AM

Hello everyone,

 

This is my second or third post in the last month or two in an attempt to solve the quest of what 12 inch Dobson to get to upgrade my trusted 8 inch. I've changed my mind so many times: custom made truss, then Orion SkyQuest 12XXg12, GoTo, manual, and then back again where I started.

 

The one thing that is not negotiable for me is that the scope must fit in an average car to be transported to a dark site. At the same time, I don't want to have to spend 20 minutes at the end of an observing session, in the cold, disassembling a scope in a dozen different parts. By the time I'm done observing I usually just wanna get home fast!

 

Anyway, today I found out that Orion Optics UK manufactures an 12 inch F/4 Dob with what looks like a pretty small base and weighs under 30 kg. The optics apparently are 1/8 lambda p/v wave with test report and 97% reflectivity. Here it is: https://www.teleskop...1-8-Lambda.html

 

The more I think about it, the more it seems to me this could be an ideal solution for me: I can fit it in my car, it's very quick and simple to put together, it's fairly light for a 12 inch, it packs a 12 inch aperture, and has premium optics.

 

The downsides I've identified are: at F/4 it requires a Paracorr, but to me it's a fair trade off for it's portability; collimation is more critical than on a classic F/5, and certainly much more than in my current F/6 tube.

 

I was hoping I could get some insight from people who've had fast reflectors on whether - with the right eyepieces - a 12 inch F/4 would perform well on planets and Moon and whether there are other downsides that I'm not considering. Is it a good idea to get this fast scope instead of a truss structure F/5?

 

Thanks in advance and clear skies to all!



#2 25585

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Posted 18 June 2019 - 05:28 AM

To keep to a solid tube is worth the collimation hassle of a faster mirror. F4 will be a great wide field scope! 

 

Paracorr 2 is worth having, as is a good collimation toolkit.  



#3 tmaestro

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Posted 18 June 2019 - 08:04 AM

Here you go, https://agenaastro.c...lector-ota.html ... it's a 12" GSO imaging newt with rings for $820.  Dennis at http://www.dobstuff.com will make you a sweet dobsonian base for it, and you'll be well ahead of that $2000+ kit from Orion UK.



#4 Jon Isaacs

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Posted 18 June 2019 - 10:09 AM

I was hoping I could get some insight from people who've had fast reflectors on whether - with the right eyepieces - a 12 inch F/4 would perform well on planets and Moon and whether there are other downsides that I'm not considering. Is it a good idea to get this fast scope instead of a truss structure F/5?

 

Thanks in advance and clear skies to all!

 

I have owned my 12.5 inch F/4.06 Discovery Dob for close to 20 years.  It started out a tube dob, it's been a truss Dob for something like 11 years.  With the right eyepieces, with a Paracorr, it is an excellent performer.  But for general purpose use, I would recommend an F/5 Truss.  A decent truss doesn't take long to disassemble and takes up much less room in the car.  Collimation will be less tricky and you can get by without the most expensive eyepieces.

 

5036961-Jstar in back of escort cn.jpg

 

As far as Orion UK..  A local astronomer purchased a 6 inch F/5 from them.  When it arrived, he brought it over because of collimation issues.  It turned out that the spider was improperly installed and it was not possible to position the secondary.  Last time I heard, his attempts to contact them were not successful.  I have read other similar stories from people in other countries.  

 

Jon



#5 SeattleScott

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Posted 18 June 2019 - 11:35 AM

My 10 VX holds collimation well. Realize that, at least years ago when I got mine, OO did their optical tests in red wavelength which is more forgiving. So in say Green, my 1/8th-1/9th PV mirror is probably more like 1/7th. Still a very good performer, but I feel like you have to take most manufacturers optical tests with a grain of salt. OO is better than mass produced, but they aren’t ZOC. Also, I have heard that shortly after I bought mine, their master optician left, and optical quality suffered. This is PURELY rumor, and even if true, I would like to think the issue has been addressed by now. But something to consider. They have never had a great reputation for customer service, and even their reputation for optical quality seems to be on the decline. But I can say I am happy with mine. Never needed service so I cannot speak to that.

In general with OO you have mostly satisfied customers who are happy to get something better than GSO for much less than Teeters. The light aluminum tube and high reflectivity coatings are nice, they have proper springs that can actually support the mirror, etc. But there is a segment who are unhappy and vocal because they paid a premium over GSO, but theirs had issues and OO didn’t do a good job of addressing them.

Scott
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#6 NeutronStar79

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Posted 18 June 2019 - 06:53 PM

Thank you all for your answers!
There are indeed mixed reports about OO. And I get Jon's point that it might be just easier to go with a classic F/5 for general purpose.
I'm Italian and ordering mirrors from the US adds a big cost for me. I'm looking for some European opticians to get a quality mirror made for me. I'll get an F/5 mirror and get a good truss structure. In the end it does seem like the best compromise.
I have also just purchased a Denkmeier binotronn supersystem which works fine with my F/6, but it might be difficult to focus it with an F/4.
Thanks again
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