Orion UK 12''/F4 - I'm looking for advice

[astrolulu]

Dear colleagues, greetings from Poland! I would like to say hello with a question about the Orion UK 12 '' (F4) telescope. I noticed that there are a lot of entries on the forum about it, so maybe there will be someone who will advise me on its purchase. Well, I have the opportunity to buy a used, I think older model, which has clamp rings in green and olive green, resembling the color of Vixen mounts. The second characteristic feature is the traditional rack and pinion focuser. On this basis, I believe that it may be a dozen or so years old. 

My problem is the necessity to move the equipment over quite long distances, so on the one hand I am looking for an instrument with as large a diameter as possible, mainly for planetary and lunar photography, and on the other hand - a mobile one. This also applies to the mount. The EQ-6 definitely exceeds my lifting capacity, hence my first question. The owner weighed OTA and claims it weighs 12.6 kg without the finder. Do you think I will be able to put it on the Celestron CG-5 mount, which theoretically has a load capacity of 16 kg? Can this tube be relatively convenient to carry, so that it can be mounted and removed during each observation?

Second question - what is in your opinion the value of such a telescope, assuming that the optics is in good condition and the tube has only slight dents and traces on the paintwork? I'm not able to judge the seller's price offer because this model is rarely sold second-hand.

Thanks in advance

Lukasz

[astrolulu]

OTA looks like this one: https://www.cloudynights.com/gallery/image/1096-orion-uk-12/

[Stu]

8 minutes ago, astrolulu said:

Dear colleagues, greetings from Poland! I would like to say hello with a question about the Orion UK 12 '' (F4) telescope. I noticed that there are a lot of entries on the forum about it, so maybe there will be someone who will advise me on its purchase. Well, I have the opportunity to buy a used, I think older model, which has clamp rings in green and olive green, resembling the color of Vixen mounts. The second characteristic feature is the traditional rack and pinion focuser. On this basis, I believe that it may be a dozen or so years old. 

My problem is the necessity to move the equipment over quite long distances, so on the one hand I am looking for an instrument with as large a diameter as possible, mainly for planetary and lunar photography, and on the other hand - a mobile one. This also applies to the mount. The EQ-6 definitely exceeds my lifting capacity, hence my first question. The owner weighed OTA and claims it weighs 12.6 kg without the finder. Do you think I will be able to put it on the Celestron CG-5 mount, which theoretically has a load capacity of 16 kg? Can this tube be relatively convenient to carry, so that it can be mounted and removed during each observation?

Second question - what is in your opinion the value of such a telescope, assuming that the optics is in good condition and the tube has only slight dents and traces on the paintwork? I'm not able to judge the seller's price offer because this model is rarely sold second-hand.

Thanks in advance

Lukasz

Lukasz, do you have any photos of the scope? There can be big differences between the older scopes and newer ones, such as the rear cell which holds the primary mirror and the secondary support bands. I old scopes the rear cell collimation is very basic with poorer cooling and they have a solid bar holding the secondary rather than 4 thin vanes. All this will affect value.

[astrolulu]

Well - I hope the seller will forgive me for posting them without his permission - maybe I'll just delete them when the discussion is over ...

[iantaylor2uk]

I used to have one of these and I think it weighs closer to 14 kg. I used it on a Losmandy G11 which coped with the weight easily but it still was prone to the wind when guiding. You will have problems if you under mount it, especially if you plan on taking photographs with it.

[astrolulu]

Thanks, it's worth remembering that we are talking about planetary and lunar imaging. Image stability is not crucial to me. As long as the object remains in the frame, AutoStakkert! it deals with it somehow 🙂 At least I count on it - the question is whether not too optimistic ...

[NGC 1502]

Looking at the images that scope has the better quality ventilated primary mirror cell.  The OO 12” f4 optical tube fits across the back seat of most cars.  If I were buying that scope much would depend on how good the mirror coatings are, the pics look good….

[astrolulu]

And what price would you consider fair in such a case?

[NGC 1502]

15 hours ago, astrolulu said:

And what price would you consider fair in such a case?

 

Tough call.  First consideration is the condition of the mirror coatings.  Second question, how far away from you is the scope?  If it’s nearby and I could inspect and it’s all good and agree a price then take it home right away I’d pay £350-£450 for the optical tube only.

As it’s unlikely to be nearby then I’d proceed with more caution.  Do you trust the seller’s description?  How much hassle to obtain it?   Hard to say, it could be a bargain but take care.

[astrolulu]

Thanks. The seller is in Germany so only distance selling is possible. He would like to get 900 euros, which seems too high to me, considering that the telescope does not have a mirror quality certificate, has an old, rack and pinion focuser that probably requires replacement and of course, regardless of the condition of the mirrors, their optical efficiency after several years is correspondingly lower than in the new one instrument.

[iantaylor2uk]

My old Orion Optics 12" f/4 was recently on sale (as a dobsonian) on UK Astro Imaging for around £450. 900 euros is high, but on the other hand how often do scopes like this turn up second hand? Getting something like this sent through the post from Germany would be risky and you might be hit by import duty too.

[astrolulu]

Exactly. And here we are talking about the price for OTA only...

For now, I have withheld the decision because it also seems to me slightly above the reasonable risk limit - although the temptation to change from 8 to 12 inches is great.

And how do you rate the suitability of this model for lunar or planetary photography...?

[iantaylor2uk]

When I had the scope I didn't do any planetary viewing or imaging but the moon was good through the scope. I took some photos of the moon and of some DSOs which are on my blog (in 2021)

[astrolulu]

Thanks a lot. One of the questions I ask myself is whether F4 is a good parameter for a planetary-lunar telescope. Fortunately, it is not achromatic 🙂

[CraigT82]

13 minutes ago, astrolulu said:

Thanks a lot. One of the questions I ask myself is whether F4 is a good parameter for a planetary-lunar telescope. Fortunately, it is not achromatic 🙂

Yes it wouldn’t be my first choice for a planetary scope due to the small diffraction limited field size but with a good focuser and confident/accurate collimation it should produce good high resolution images. 

[astrolulu]

Well - we are easily seduced by stories about the quality of optics, which often remain valid in the case of visual observations, when even a small but excellent quality refractor can bring us to our knees when observing the Moon or Jupiter. But it is different with planetary and lunar photography - here the diameter rules and it cannot be deceived in any way. If I had decided to buy it, I would have hoped that the diameter would be more important than all the other parameters.

To obtain optimal parameters with my 2.4 pixel camera however, I would have to extend the focal length by about 3x with a Barlow lens. I wonder what impact this would have on the image quality ...