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Return to a bigger telescope : but am i pushing things too far ?


Bino-viewer
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Hi guys.

I've recently taken ownership of a new scope, an Orion optics CT10 250mm F4.8 1200mm short tube reflector OTA.

Well, not actually new. 

It belonged to an imager from Leicester, who had very sadly, passed away after an illness.

I answered his sons advertisement on UKABS and drove over to Leicester to take a look.

The scope had been purchased new From OO in 2016 approx and housed in an observatory.

 

The seller was in the process of clearing his fathers house (a sad task, as i know only too well myself)

and the scope was one of the last items left. A deal was reached (a bargain price) and i assured the seller who knew nothing about astronomy

that the scope would be put to good use and well looked after.

 

For a while i had been thinking about the possibility of mounting a Newtonian on my alt-az mount.

Possibly a crazy idea, and i'd actually discounted a 10" tube as i thought it would be too big and heavy and

was actually waiting for an 8" model to come up for sale.

 

The scope i was looking for never transpired, and when this 10" cropped up i thought i'd try it out.

Back in 1995 i purchased my first ever serious telescope : an OO 250 Europa Newtonian.

Despite it being sold with a cheap German EQ mount, (no OO Dob mounts back then !) it provided me with some fine views, and i can

distinctly remember the perihelic 2003 Mars apparition, and viewing Comet Hyakutake around that time. I was hooked !

 

So fast forward 20 years and i'm on my 4th Orion optics scope.

When i brought it home i had a proper look at it close up. It was in excellent condition, but as it had been sitting unused for most of the year or more,

it had become a little dusty and dirty. The focuser is a Moonlite CR2, and seemed okay, but was a little tarnished.

I decide to take it over to Orion Optics (a 45 min drive away for me to Newcastle-under-lyme near Stoke-on-Trent) and have it serviced.

I know John there quite well, and it was nice to have a chat with him. I arranged to have the scope stripped down and serviced, the optics 

cleaned and polished and recollimated, and while i was there, i ordered a set of custom CNC tube rings for my 105mm refractor.

 

A few weeks later i returned and picked up an absolutely pristine telescope ; it looked as good as new.

Other than the non standard Moonlite focuser the scope is a standard high spec CT Newtonian.

This range of solid tube Newtonians have a rigid carbon fibre tube, and 'Ultra 1/10 Pv wave' optics as standard.

CNC low profile tube rings and a very nice 300mm dovetail were also included. The scope had also been fully flocked the the previous owner.

 

Here, things take a bit of a downward turn.

I tried mounting the scope on my DM6 alt-az mount, which was on my smaller Berlebach Uni 18 tripod.

Straight away, i knew it was a no-go. The tube was way too heavy (too much mass at 14Kg) and was in real danger of tipping over.

I took it down at left it at that.

Reluctantly i decided that i'd have to sell it, as i didn't really want to go down the OO Dob mount route, nor consider an EQ mount like an EQ6.

I figured i wouldn't have to take too big a hit on it if i sold it, so put it up for sale.

I had a bit of interest, but no firm offers.

I had one chap come down from Sheffield to look at it, and it was at this point that i mounted it up again, but since the week before sold my BB Uni 18

tripod ! , this time i'd mount it on the BB Planet / DM6 combo.

Hay presto, its a different setup all together. The Planet tripod is so much more stable.

 

My potential buyer decided against purchasing it, as it was a bit too big for his needs, so i withdrew it from sale, and decided to keep it

and try it out with the Planet and give it a proper go.

Set up in the garden the other day i was pretty convinced it would be a viable observing tool. As long as its not too windy............!!!

 

But am i pushing my mount too far ?  A 10" alt-az mounted solid tube is not your usual grab and go.

I'm planning on lowering the centre of gravity of the tripod by about 3 or 4cm by raising the shelf, and thus widening and lowering 

the footprint of the tripod. I did this with the old Uni 18 with some success when mounting my bigger refractor.

The DM-6 is rated to take up to 40 lbs and with a big eyepiece i'm looking at about 32 lbs here, but that 40 lb limit is generally 

geared towards something like a 6" refractor or 12" SCT type scope.

 

The DM-6 saddle has two blocks that lock up against a Losmandy type rail.

Theres evidence that theres some strain on these blocks that are holding such a big tube in place, but the saddle plate

is well built and i think it will be okay as long as i'm careful setting up and balance everything well.

 

Any sort of wind blowing will make observing with this set-up a dangerous proposition, and if thats the case, the scope will have to stay in.

But theres been plenty of times up at Belper when its been like that and even observing with a refractor has been difficult when upping the magnification.

The goal though is for me to return to bigger aperture and take in those low power, rich field views at a dark sky, and utilise my DSC computer on the DM-6

to track down those fainter Messiers and NGC's.

 

Enough of me rambling : heres a few pictures of the scope in action.

Thanks for reading 🙂

 

IMG_3135IMG_3139IMG_3136IMG_3140IMG_3138IMG_3181IMG_3183IMG_3182IMG_3184

 

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That is a lot of very nice scope Rob.

With all that weight hanging off the side I think I would be tempted to hang a large weight in the centre of the tripod to keep it firmly planted on the floor.

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Thanks, thats an idea and i have a kettle bell somewhere that i could use.

The BB tripods have floorspikes and i'm planning on lowering it a bit as well.

You are right though : its alot of weight hanging off the side

 

I've been very impressed with the Planet tripod though ; its so much more stable than the Uni 18.

Perhaps a better option for this scope would have been a Losmandy FHD heavy duty tripod but i'd be looking at

triple the price i paid for the Planet and lose that oh so useful shelf.

 

Heres a picture of the saddle plate on the DM-6 showing some strain on the blocks that press against the dovetail.

I may drop an email to Tom at Discmounts and see what he thinks. The are other saddle options i could consider though.

 

IMG_3191IMG_3190IMG_3188

 

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I also have the small issue that i can't get eyepieces to focus.

The scope was set up for imaging and has maximum infocus to cater for cameras , filter wheels etc.

 

It wasn't really a surprise my 2" eyepiece wouldn't focus. Not even close.

I put a 1.7x gpc into the bino and tried that, and although fairly close (about a cm away) that was a no go as well.

 

I have a couple of options here : most Moonlite focusers come with both a 1 inch and 1/2 inch riser block.

This one only came with the 1/2 inch fitted, so i could perhaps advertise for a spare riser block and see if anyone responds ?

Option B is a new focuser (with both blocks) and purchase it with a 60, or 70mm drawtube. The standard length is 50mm

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24 minutes ago, Ibbo said:

Looks very nice.

 

What it really needs is a camera hanging off the focuser. 🤣🤣

 

You'll be telling me i need an observatory next.....!! Bortle 7 skys and all !  😀

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22 minutes ago, Bino-viewer said:

 

You'll be telling me i need an observatory next.....!! Bortle 7 skys and all !  😀

Camera with filters can cut through the garbage somewhat.

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It’s a good looking scope but the strain on the saddle block bolts 

looks a problem. I would think about a stronger saddle of the likes of Rowan.  It would look good on their AZ100.  I tried to get a moonlite for my refractor and they are only selling them with motorised focusers now which is disappointing.

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I have heard that both Moonlite (and Starlight Instruments - Feathertouch) in the US have had some production issues

of late with staffing issues and supply problems etc. Hopefully things will return to some sort of normality though.

 

It seems odd though that Moonlite are only catering for imagers though.....?

Did you speak with FLO about it ??

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Nice purchase rob , I’d definitely consider picking up a used zwo1600mm and a Ha filter shame to waste its potential on visual 😂🤣😂

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Nice scope Rob

I woukd be tempted to knock up a countrteight bar to stabilise everything. Even though your mount is sturdy it is inherantly unstable with all that weight on one side. So countetweighting it wouls steady it up.

 

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