Is this mount an EQ1 or EQ2? (Or something entirely different?)

[julianh72]

So … I bought a second-hand telescope on Gumtree. It’s a York SkyRover R90 90 mm short-tube refractor. There’s no technical specs with the so-called “Owner’s Manual”, which just covers unpacking and assembly of the scope and mount; York went out of business a few years back, and a Google search turns up almost no hits, but I would guess it’s probably basically similar (identical?) to the Orion 90 mm short-tube refractor (which they don’t seem to sell any more), for which the basic specs are: 90 mm (3.5") aperture; f Ratio = f/5.6; focal length = 500 mm, and which often seemed to ship with an EQ2 mount.

(By the way: Feel free to tell me I’ve wasted my money and bought a junk “Department Store” telescope :), but it actually seems to have quite decent optics, based on my first play last night – certainly good enough for a handy “grab and go” scope between opportunities to play with my Dad’s Meade 8” LX90. Oh yes - it came with the original sales receipt from 2002 – the whole kit cost $800!!!!)

Anyway …

What I would like to know is if the mount is an EQ1 or an EQ2, or something entirely different – and does it matter anyway?

I’m thinking of buying a motor drive for it, and I see that there are different model drives offered for EQ1 vs EQ2, but I’m not sure of how to tell the difference between the two mounts. Do they run at different speeds (for different worm gear ratios)? Does an EQ2 have a bigger shaft diameter than an EQ1? Does an EQ2 drive have more torque (for heavier loads) than an EQ1? Would an EQ2 drive fit onto an EQ1 mount, and turn it at the right speed? Is there any chance that this mount is non-standard, and I’m out of luck buying a suitable drive unit?

So – what are the defining characteristics of an EQ1 vs an EQ2?

Any assistance would be most welcome!

[astro744]

See http://skywatcher.com/downloads.php?cat=18 for links to mount and drive user manuals.

[julianh72]

astro774,

Thanks for the link - I found this myself while searching around, but I'm afraid I am none the wiser - while the "Instruction Manual for Telescopes With EQ1 & EQ2 Mount" http://skywatcher.com/downloads/Instruction_Manuals/GENERAL_EQ1and2.pdf (and the manuals for the EQ1 and EQ2 motor drives) give instructions for both mount types, I haven't been able to find out the definitive difference between the two models (e.g. shaft diameter, worm gear ratio, etc), so it doesn't actually answer my question, I'm afraid. :(

The only difference I could spot between the manuals for the EQ1 and EQ2 motor drives is that the EQ1 seems to clamp onto the main altitude axis pivot pin, while on the EQ2 it screws to the RA body. Is THIS perhaps the key difference? My mount appears to have a screw hole on each side of the RA body (I'll take a closer look tonight) - does this mean I have an EQ2, perhaps?

[astro744]

I'm not sure you have either EQ-1 or EQ-2 as your mount looks different from the pictures I found on Orion's web site. The RA setting circles look different.

Sorry I cannot be of any further assistance.


EQ-1

http://www.telescope.com/catalog/product.jsp?productId=9011&type=product

EQ-2

http://www.telescope.com/Orion-EQ-2-Equatorial-Telescope-Mount/p/9828.uts

[julianh72]

Thanks - I'm sure it's not a "genuine" Orion or SkyWatcher EQ1 or EQ2, but I thought it might be a "clone" of one or the other, in terms of dimensions, gear ratios, etc.

However, the more I look a close-up photos of genuine Orion / SkyWatcher mounts, I'm not so sure now. On the genuine Orion / SkyWatcher, the RA body always seems to be mounted above / offset from the main altitude pivot pin. On my mount, the axis of the RA body points right at the altitude pivot pin, rather than being offset.

Oh well ...

[OzStarGazer]

Maybe you can try a local telescope shop. They should be able to advise you.
Enjoy your new telescope!

[julianh72]

Thanks, OzStargazer - yes, I think a trip to my nearest telescope shop is called for.
(This would be the first time in a long time for me that an internet search / forum has failed to bring up a straight answer to a tecehnical query! :( )

I'm beginning to think it is more likely to be an EQ1 clone. I found an Orion instruction manual http://www.telescope.com/assets/product_files/instructions/29126_07-10.pdf that spells out that an EQ2 mount should already have a circular drive gear and clutch installed on the RA Drive Shaft. My mount doesn't have these, suggesting it is more lilkely to be an EQ1 or similar.

[cometcatcher]

I think this is something entirely different. I don't see any place where a motor drive can be attached. There's no main gear on the RA axis either.

[doppler]

I have seen motordrives for eq 1 and 2 mounts on the net that simply attach to the opposite side of the RA slow motion control shaft (looks like the shaft on your second pic sticks out a bit). Bintel have some fancier ones that might work on sale at the moment probably worth giving them a call.

Here is a video link that might give you some perspective http://www.youtube.com/watch?v=xlGF7PYLpYE

[julianh72]

Thanks everyone for your help. I can now see that my mount is NOT an EQ1 or EQ2 clone - it has projecting RA shafts onto which a drive could be mounted, but doesn't have a gear to suit an EQ2 drive, and it doesn't have a standard mounting point to take either of the standard drive units.

I'm sure I could bodgy something up to install an EQ1 drive, but there is a chance the drive speed could be all wrong as well. I don't want to spend $100 or more as an experiment, but I might grab a cheaper second-hand one if I see one on eBay or Gumtree. I might also see if I can build something from scratch using a stepper motor and an Arduino to control it.

Anyway - the telescope itself is working fine!

Thanks again!

[julianh72]

While hunting around on the internet to see if I could find a motor drive to fit my non-standard mount, I found that Astro Pete's in Brisbane is selling a small number of genuine Saxon EQ-2 mounts for $39. (Yes, that's the asking price for the EQ-2 mount AND the tripod.)
http://www.astropetes.com.au/mounts.html
(Apparently, they were pulling the EQ-2 mounts off some telescope kits to replace them with Alt-Az mounts, and now they are getting rid of the surplus EQ-2 mounts.)

I picked one up yesterday, and it worked a treat for my 90 mm short-tube refractor. It's quite a bit more sturdy and smooth to operate than the one that came with my telescope, but not as compact or portable. I'll probably use the EQ-2 mount as my main home mount, but pack the lighter one that came with the scope into the carry bag for weekend trips.

Anyway - it's an absolute bargain for $39!

Now to start the hunt for a suitable motor drive ...

[brian nordstrom]

:D Jullian , that's an un-believable price for one of these sweet little mounts .

I had one under a 102mm f5 SW frak and it worked a treat , held it very well . Easy grab and go set up .

Brian.