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arad85

Revelation 12" Dobsonian

126 posts in this topic

OK, so this is the first post in a series where I'll review the 12" Revelation. This post will deal with the "out of box experience" and I'll add more as I do observing/get more acquainted with the beast.

Building

OK, so to start with, the beast comes in two boxes - the main box containing the OTA and a second flatpack box containing the base. These things are relatively big - the OTA box is about 1.7m long, and weighs 24kg, but still, if you want a big dob, that's what you expect.

IMG_0576.jpg

Opening the boxes shows the innards. Firstly, the OTA. For something so large, I think it is lightly packed (I had to return one OTA as the plastic packing ties had been used as handles by the couriers and gone through the cardboard and bent the OTA!). In comparison to Celestron - where I've always had things in two cardboard boxes - it is liable to damage in transit.

IMG_0577.jpg

You can also see the accessories that come with the OTA in situ.

You get:

  • 30mm WA Revelation eyepiece
  • 9mm Revelation plossl
  • 35mm extension tube (needed to reach focus on some eyepieces)
  • 8x50 finderscope and bracket
  • battery cage for the fan in the base

These are shown here:

IMG_0584.jpg

The mount box contains the mount, all the screws as well as the accessory tray as well as some instructions on how to assemble from Telescope House. The instructions were adequate, but they were for an older version of the mount as there were some minor discrepancies between my mount build and that in the instructions.

IMG_0578.jpg

With a little careful thought (figuring out which weay is the bottom on the baseplate - it's actually with the screw insert at the bottom, I fixed the 3 stubby legs and had the whole mount built in about 20 minutes. Build quality is OK, but then this isn't a premium mount and it does rather look like it is from the Ikea Darth Vader collection.

IMG_0582.jpg

Still, it is functional. One point to note is to ensure you get the sides the right way around. You have when the felt on the rear of the cutout where the tensioners fit is towards the back of the box.

OK, so that's the box built. Now to the OTA. The OTA uses some hefty machined knobs to mount into the rocker box. These are attached to the side of the tube via allen bolts in a nifty sliding holder that allows you to alter the rotational point of the tube. Put the knobs higher, the tube becomes base heavy, lower and it becomes top heavy. Quite neat I thought (although I don't have any knowledge of the Skywatcher or Meade fittings which look different. Unfortunately, as these are fixed with allen bolts, you can't change the balance in the field to counteract different weight EPs. This is where the knobs fit:

IMG_0580.jpg

and here is an image of them fitted:

IMG_0588.jpg

What you can alter is the tension in the pivot. Screwing the two knurled knobs up increases the turning resistance, unscrewing them decreases the resistance.

Here is a picture of the competed tube on the mount.

IMG_0583.jpg.

Tube detail

I must say, that for the price, I'm very happy with the details of this OTA. Firstly, the round circle appeared centrally placed to as near as I could measure it and the mirror mount looks sturdy and has a fan to cool it. Additionally, the collimation/locking knobs seem of good quality (although I have been advised I may need to change the springs for some from Bobs Knobs (see: MLB12).

Here is a picture of the underside of the mirror showing both the knobs, 9 point mounting and fan:

IMG_0591.jpg

Another thing I am impressed with is the focuser. It is a dual speed Revelation and appears to be very smooth. Although I don't have any experience of the more expensive after-market crayfords, this one is an order of magnitude smoother than the rack and pinion one attached to my C80.

IMG_0581.jpg

That's it for now - as soon as I get it out on a night, I'll compare it alongside my C9.25 and post back some initial impressions. Bear in mind that this is not only my first review, but also the first proper view through a Newtonian (although I have another, it is in use by someone else and I've never looked through it ).

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A very detailed and entertaining read.

One thing I'm surprised about is how small the altitude bearings are. I thought the Meade LB ones were small but these are smaller.

The OTA looks very nice indeed. Looks a perfect size for the base and looks extremely well proportioned.

What's the azimuth bearing like? Is it a lazy susan type.

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What's the azimuth bearing like? Is it a lazy susan type.
Two metal plates of about 8 inches diameter encapsulating a rollerball (there are about 20 rollerball bearings around the outside of the middle insert) lazy suzan circle. You tension it by screwing down on the knob at the centre of the base. Seems to work very well and is very smooth... :)

As to the altitude bearings, they may be small, but they are quite heavy and appear to be machined. They certainly fit very well into the cutouts. We'll have to wait until I try it in anger to see if the clutch mechanism in them is effective... For some scale, the knurled knobs are 7cm across...

I agree with you - well proportioned, and I quite like the black rocker box...

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Same set up as my Meade azimuth bearing.

7cm across the picures don't do the size justice.

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Nice report!! Things have really moved on since the last time bought a Chinese Dob...:)

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I really am chuffed to bits with this... Quality seems exceptional for the money. They obviously have understood how to make the bits that matter good... Time will tell if the optics are any good (but I was assured it's the SAME mirror that goes into a lightbridge...

Now if only they made a 16" :)

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A 9 point mirror cell, fan and a dual speed crayford is awesome!

Look forward to the first light mate, good luck.

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Looks good, Arad. 24kg OTA? Not as heavy as I thought it would be - about the same weight as my rucksack when I went off travelling earlier this year!

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For those that have asked about the azimuth bearing... here is a picture of it:

IMG_0592.jpg

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Looks good, Arad. 24kg OTA? Not as heavy as I thought it would be - about the same weight as my rucksack when I went off travelling earlier this year!

Ideal for when hiking to dark sky site then!!!:)

Nice to see the bearing setup on some less "agricultural" dobs than my Darkstar. I really must sort out the altitude bearing on mine for something neater (my wife is rather averse to the yellow slices of gas pipe stuck on the sides - you try telling her it's for looking through not looking at!) and tensionable (now I've attached a 2" focuser it just won't stay put when changing EPS).

Nice scope by the look of it - If I were you I'd do something about sealing the joints on the base, it looks like moisture could get in there.

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Nice scope by the look of it - If I were you I'd do something about sealing the joints on the base, it looks like moisture could get in there.
Good idea - will get the sealant gun out... :)

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Looks a brilliant scope and congratulations ! Did they centre spot the primary mirror for you ? I don't recall where I heard it, but I recall that it might be worth checking the position for the centre dot (i.e. that it really is central) because if not, then from that moment on, all your collimation will be out.

As I'm sure you appreciate, it's a fast system so you'll need to get accurate collimation to get the very best out of it.

Also, like the way the ALT bearings are adjustable - seems to be a very simple way to manage the balance of the system without weights.

Looking forward to first light and other info...

Steve

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Did they centre spot the primary mirror for you ?
Yup.. to within the limits of my steel rule and measuring accuracy - it was spot ( :) ) on :)

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I don't recall where I heard it, but I recall that it might be worth checking the position for the centre dot (i.e. that it really is central) because if not, then from that moment on, all your collimation will be out.

Steve

I read that thread it was about Meade LBs apparently some are so inaccurately placed they must have been thrown on the mirror from several yards away.

A simple thing that could be very frustrating if not accurate and unnoticed so worth checking on any brand.

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Great write up...

Me want one now .. ooh Xmas seams such a long way...

My 9 yr old daughters B'day's end of August... wonder if she'd like one :)

Guy.....

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I've just been to Telescopehouse in Kent and had a look at one of these. I must say i was impressed with the smoothness of movement in both directions. The OTA is not too heavy to lift off the base either, and of course it comes with that ultra smooth focuser. I am still in two minds as to which one I buy between the Skywatcher flexiwotsit 300p and the Revelation as they didnt have the Skywatcher on display.

Look forward to hearing of its first light outing........

Allan

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I bought a secondhand one of these and i still luv it!!!. Absolutely awesome!!!!! There is a post i wrote on here somewhere under the observing reports.

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OK.. On the advice of Steve from FLO, I ordered some primary springs for this scope. In the following two pictures you see the spring that comes with the scope on the left, Bobs spring on the right. Cost £10.60 for 3 springs delivered. CLEARLY a much heavier duty spring that should help hold collimation - once I've got it back again :)

IMG_0926_edited-1.jpg

IMG_0927_edited-1.jpg

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PS. I still haven't had a serious first light with this yet. When I do, I'll post a review vs the C9.25 using the same eyepieces.

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That is a very good write up and some nice information. I like seeing what packaging everything comes in it means my dreams can include me unpacking it as well (ahhh if only I could sell the first born...I think the missus would notice)

Neil C

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Anyone want to buy a nice 17 acre farm in East Lancs.? Uninterupted sky, plenty of room for an observatory.........

Then I could fork out for a huge dobber too..............

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Anyone want to buy a nice 17 acre farm in East Lancs.? Uninterupted sky, plenty of room for an observatory.........

This should really be posted in the For Sale section but I'll let it slide just this once....:)

1 person likes this

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OK... I finally got to give this a proper outing and compared it with the C9.25. Set the two 'scopes up side by side tonight - they had both been out nearly 2 hours before observing started. First thing to do was check collimation. The C9.25 required a small tweak whilst the dob didn't need anything as I'd collimated it earlier with the barlowed laser method (although I did check it with a star test). I think I was lucky tonight as even with a little light pollution from street lights, I was able to see the milky way clearly through cygnus and pick out easily the Andromeda galaxy and double cluster with the naked eye. So, with everything collimated (and the C9.25 aligned) the first target was:

M13. Here the dob seemed to show more detail and was able to resolve stars to the core more easily. The SCT was murkier looking by comparison and there wasn't as much "pop" to the image I was seeing. Both 'scopes gave a good view, but the dob was definitely better.

M57Again, the dob seemed to show a brighter image, although both 'scopes had enough detail to be able to see the ring, the darker centre and a hint of something lighter again right at the centre.

double double well I would have compared the view had I known where the double double was - the C9.25 pointed directly at it, I pointed the dob at delta 1 and 2 lyra (having just checked now I'm indoors...oops :) ). Anyway, the dob showed the lovely colour of delta 1.

Jupiter. By now jupiter was appearing over a neighbours house. Both 'scopes gave an excellent view of Jupiter although again, I think the dob edged it - not quite on scale as the C9.25 is longer focal length but more detail seemed apparent on the dob. I think I saw the GRS through the dob when I returned to it later in the night.

M81 and M82. With the longer length lenses, I was able to get both of these in the viewport of the dob at the same time. Lovely views - the brightness of the galaxies hinted at their shape. In the C9.25, both galaxies were there but again, the darker images just meant they didn't stand out as well.

double cluster (NGC 884/869). I spent quite a bit of time on this - partly as it was the first time I'd seen it, but also as it seemed a good test of resolving stars. Although the C9.25 was a tad darker again, I couldn't see any stars that were in one of the 'scopes but not the other.

Other objects seen tonight included Neptune (just) and Uranus and M103 (may have been more - this is typed up from memory, not notes). All consistently showed a brighter and "better" image than the C9.25.

On a use basis, the dob is far easier to set up, and star hopping is relatively easy if you have enough stars visible and a star map. The C9.25 (on a CG5-GT) is noisy and slow to set up by comparison and requires star aligning - although the targets are tracked once this is done. Personally, I find nudging the dob to be reasonably simple and I'm getting used to it.

I think my conclusion is that as a visual 'scope, the 12" is really rather good. I don't have experience of higher grade mirrors to know how that affects the view, but I'm more than happy with this 'scope. If I had to choose between the C9.25 and dob for visual - the quick setup and better views of the dob would win every time.

Any questions, please ask.... Apologies if this appears garbled - I'm almost asleep typing here....

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Aperture isn't everything but it sure beats whatever comes second :)

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