Ultra Compact Obsession Telescopes

[mert]

Hi

Anyone have experience with these scopes? I’m looking for a compact scope. I’m looking at the 18 or 22”. 

[joe aguiar]

Well I never had anything that big. I had 2 16 inches.

Obsession is supposed to be very good quality and more portable that most of the same size in a smaller package.

But they are very expensive.  Mine were mass produced kind but if u want quality and smallest package well u gotta pay for it. For me tho cant see me spending that much on a dob

But good luck on purchase 

Joejaguar 

[Timebandit]

8 minutes ago, joe aguiar said:

Well I never had anything that big. I had 2 16 inches.

 

Joejaguar 

 

 

A bino viewing 2 16 inch. Woow that is a big beast 😀

 

 

I think Stu had some type of compact Dob in a box ,if I remember correctly. I am sure he will be along and say , and give you some feed back

 

 

 

 

[mert]

20 minutes ago, joe aguiar said:

Well I never had anything that big. I had 2 16 inches.

Obsession is supposed to be very good quality and more portable that most of the same size in a smaller package.

But they are very expensive.  Mine were mass produced kind but if u want quality and smallest package well u gotta pay for it. For me tho cant see me spending that much on a dob

But good luck on purchase 

Joejaguar 

Thanks 

I will be looking at a second hand telescope. There’s been a few for sale in the UK and one is for sale at present. I heard the ultra compact models collimating can drift during sessions, looking for feedback on that. 

Edited January 28, 2020 by mert

[Ships and Stars]

8 hours ago, mert said:

Thanks 

I will be looking at a second hand telescope. There’s been a few for sale in the UK and one is for sale at present. I heard the ultra compact models collimating can drift during sessions, looking for feedback on that. 

I think it's fairly common for some shift in collimation when slewing up and down in altitude with large dobs. My 500p changes ever so slightly when I have the collimation laser in the focuser, but again, it's very minimal and not anywhere close to detectable through the eyepiece to me. Other 500p owners have noted a lot larger range of shift, but it turned out to be the large nut on the bottom that holds the primary in place or the injection material that is used in the base of the mirror around the centre nut. You'd have to see a Stargate mirror in person to see what I mean, it's a different type of retention system (as is the ribbed mirror support which reduces mass and lets the primary cools down very quickly, I don't bother with fans), but mine works brilliantly. I simply cranked the centre nut on mine hand tight and check it about twice a year. That's the 450/500p mounting system, not seen it on other dobs. Not sure what system obsession uses, maybe they use the standard strap that runs under the bottom of the mirror or holder tabs at 90 or 120deg intervals, but perhaps the ultralight dobs do it differently. 

Edited January 28, 2020 by Ships and Stars

[niallk]

I've a 15" Classic, so no direct experience of Obs UCs.  I have read up on them (many posts on CN), and mostly read comments re collimation shift in the 18" model, and that the 15" & 22" exhibited less of an issue.

The free DVD you can request from the website is worth getting, if you haven't already.

[mert]

I spoke to a guy selling a 18” UC on ABS, there was an issue with the alt motor not working properly. It many have been resolved by now.

[mert]

I picked up an 18” Obsession UC today. Good price and in VGC. Came with some Ethos eyepieces , mirrors recently recoated.  Once this bad weather clears it will be given a workout.

 

[niallk]

Congratulations!!!

[Piero]

Yup! Congrats!

[estwing]

Congratulations!....hope the skies are kind for you.

[jetstream]

18 hours ago, mert said:

I picked up an 18” Obsession UC today. Good price and in VGC. Came with some Ethos eyepieces , mirrors recently recoated.  Once this bad weather clears it will be given a workout.

 

Congrats!

The 18" f4ish scopes hit a sweet spot for portability vs aperture, offering bright DSO views IMHO.

[mert]

Thanks everyone . It’s a decent size and pretty easy to move around. Much easier to shift than my old 16” and the very large 22” I had. The optics are in excellent condition I made some minor adjustments to the ServoCat and Argo Navis.  Just need a nice low power eyepiece to complete the setup.

Edited February 10, 2020 by mert

[jetstream]

6 hours ago, mert said:

Just need a nice low power eyepiece to complete the setup.

A 20mm Lunt HDC would be high on my list for this scope as well as a Paracorr II. The Lunt uses the same (very close) setting as the 21E. There are many nights where a 20mm class eyepiece is the only one used in my f4.1 dob. Of course a 21E would be nice if you want to splash out.

[mert]

Thanks, the scope came with a Paracorr, but it may be the older version. That’s a very interesting alternative to the 21E, much cheaper and I found one in stock. I will order one. 

[estwing]

On 10/02/2020 at 15:02, jetstream said:

Congrats!

The 18" f4ish scopes hit a sweet spot for portability vs aperture, offering bright DSO views IMHO.

Totally agree ...

I can lift my mirror box into any car....20" no chance!!!!

[estwing]

21 ethos,  paracorr 2 , 8mm ethos and a powermate...I could happily sell the rest 

21 is fantastic with the 18"..

But the 8mm....oh my.....I have to have a cold shower now!!!!

[mert]

I have the 8mm and 13mm Ethos 😀 

[estwing]

Then you have the tools for the rest of your observing life!

[mert]

Just need to replenish my filter case now . 🤭 

[mert]

On 11/02/2020 at 18:38, estwing said:

21 ethos,  paracorr 2 , 8mm ethos and a powermate...I could happily sell the rest 

21 is fantastic with the 18"..

But the 8mm....oh my.....I have to have a cold shower now!!!!

Hoping to get a long session tonight. All ready to go. 

[mert]

Had a pleasant session last night under decent skies with light cloud. I have decided to remove the Argo and Servo and upgrade to the Nexus equivalent. I feel the more advanced option and no need for a large battery will make transportation easier.  The scope is a dream to move and is very smooth. I just need to get it up north to a more permanent location and away from the light polluted skies in Edinburgh. 

Edited April 26, 2020 by mert

[Ships and Stars]

20 hours ago, mert said:

Had a pleasant session last night under decent skies with light cloud. I have decided to remove the Argo and Servo and upgrade to the Nexus equivalent. I feel the more advanced option and no need for a large battery will make transportation easier.  The scope is a dream to move and is very smooth. I just need to get it up north to a more permanent location and away from the light polluted skies in Edinburgh. 

Glad to hear it's up and running, as they say.

Also good to hear it's going to live under dark skies! These larger aperture scopes are amazing under dark skies. I'm 20.20-20.45 at home, pretty meh most of the time, and the difference with taking the 20" to my 21.85 site is worlds apart. Like doubling aperture and the sky background is so much darker with more contrast.

Are you thinking about selling the Argo/Servo? I wonder if it would fit my 300p flextube. Was thinking about adding a Nexus system to that. 

[mert]

On 27/04/2020 at 10:21, Ships and Stars said:

Glad to hear it's up and running, as they say.

Also good to hear it's going to live under dark skies! These larger aperture scopes are amazing under dark skies. I'm 20.20-20.45 at home, pretty meh most of the time, and the difference with taking the 20" to my 21.85 site is worlds apart. Like doubling aperture and the sky background is so much darker with more contrast.

Are you thinking about selling the Argo/Servo? I wonder if it would fit my 300p flextube. Was thinking about adding a Nexus system to that. 

When I strip the scope I will upload some images of the entire kit. You can have the kit, I have no need for it anymore. 
 

I had a place a Loch Rannoch for 6 years and Glencoe for a year.  I hope to move back eventually.
 

I received the following from Serge at Nexus.

 

In order to be able use Nexus DSC/Nexus/Nexus-II on your telescope you will need an encoder installation kit. Our encoder installation kit (with 10,000 steps encoders) for Obsession 18” UC is priced at US$280. Then you will need either Nexus DSC, Nexus-II or Nexus. The main difference between Nexus DSC and Nexus-II/Nexus is that Nexus DSC can be used standalone or with SkySafari while Nexus-II/Nexus requires SkySafari to operate.

Edited May 2, 2020 by mert

[Ships and Stars]

34 minutes ago, mert said:

When I strip the scope I will upload some images of the entire kit. You can have the kit, I have no need for it anymore. 
 

I had a place a Loch Rannoch for 6 years and Glencoe for a year.  I hope to move back eventually.

Oh wow! Excellent, thank you very much, please drop me a line when you're sorted, no rush of course. Loch Rannoch and Glencoe must have been amazing though harsh weather at times, I like those sorts of conditions though. The midgies are one thing I struggle with, get a bit of a reaction! Your scope will be tremendous under those skies as you are no doubt aware. My good spot is in the Cairngorms, but it will be late August at least before I'm taking the big dob back out to the countryside. I would love to be able to set it up somewhere near home on a farm or estate perhaps. Thanks as well for the info on the Nexus! Work has been quite slow so that would be on hold anyway. Hopefully things pick up soon and hope you find another place near Rannoch. A friend inherited a small family cottage near the Skye bridge, I always let them know how lucky they are!!