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The Big Newt

Stu

By Stu
in Discussions - Scopes / Whole setups

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Stu

Stu

Posted
Posted

I can't quite call myself a member of the Dob Mob, but I am getting there in terms of aperture and simple mount.

u6atesyr.jpg

I had a reasonable run with the scope last night, on the AYODigi and pedestal mount which was much better than the EQ6 tripod. Eyepiece height at the zenith was just in reach.

I also had the Telrad on 4" riser and 80mm RACI finder fitted and aligned so was actually able to find things!!

The mount works reasonably well, although I can see the merits of a dob for stability. There is flex in the rings still so the scope wobbles a bit when moving it and takes time to settle.

One thing which works surprisingly well is the motorized focuser. It's a little crude, but carries the weight of 2" eps no problem and it's much easier to obtain a sharp focus when you don't have to touch the scope. The added benefit was being able to keep one hand in my pocket and focus from there :-)

I was cloud dodging all evening, but still managed some lovely views. The moon looked fabulous, nuff said, but Jupiter was also amazing. More detail than I have seen since viewing through Shane's dob :-). GRS very prominent and plenty to see around it and in the belts.

Had a quick look round at other targets. The Double Cluster and M45 were lovely in the Vixen 42mm LVW, although the coma was showing up more in this eyepiece not surprisingly.

The 37 and Owl clusters also looked wonderful, the 37 in particular really looking like its nickname.

Finally of course, the supernova. Wonderfully bright and very obvious. M82 itself was a little faded because of the moon, but still very nice.

A relatively short, but successful second light. Collimation beckons then bring it on!!

Stu

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Stu

Stu

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Actually it's not too bad. The scope is around 19kg and the mount is easy to carry using the handle without the weights. I need to check how much they weigh to see whether I need both but I think I do.

Chris, I gave Sirius a go last night and it was a bit of a mess, flaring all over the place, but I did pick up a spec which I thought might be Sirius b. Having checked this morning it was in the right place but I am by no means certain about it. Need to sort my collimation and observe from a different place so it is not over the houses.

Stu

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Mike73

Mike73

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Great stuff Stu.

Gotta say it does look a beast of a scope. Have you got any plans on putting it on a dob base? I should imagine it would be a little easier to carry and set up.

Did you put a larger secondary in there? 

You need to get that beast out to some dark skies to really let it sing! :)

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Stu

Stu

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Great stuff Stu.

Gotta say it does look a beast of a scope. Have you got any plans on putting it on a dob base? I should imagine it would be a little easier to carry and set up.

Did you put a larger secondary in there?

You need to get that beast out to some dark skies to really let it sing! :)

Thanks Mike. Yes it is a bit of a beast, but the views are lovely!!

I will probably put it on a dob mount sooner or later. If I get one for the 12", then I hope that I could also use it for my 10" with some spacers (once I get that sorted finally!)

The hardest bit with the current setup is getting the scope mounted. Holding the scope in one hand and tightening the dovetail clamp with the other is slightly hair raising :-)

At the moment I still have the smaller secondary in there. I wasn't looking for it, but didn't see any vignetting with 17 ethos or 42LVW but it must be there I guess.

I'm planning on flocking it, and probably fitting a Protostar curved secondary support to give it the best performance I can. I've received a replacement part to fix the 4 vane spider properly so will sort the collimation after I've done that and it should be even better than it is currently.

Totally agree regarding dark skies. I've been doing some work on understanding surface brightness and the visibility of galaxies under poorer skies and even with a 12" scope the situation is pretty rubbish.

That said, still got a nice look at M81 and M82 last night. Without the moon they would have been much nicer.

Stu

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Naemeth

Naemeth

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Good to see your replacement is giving you great views :). Let us hope for a whole clear night - mind you they seem few and far between given our recent weather :(.

Less than a month to go until I'll get the funds to get the Mak mounted and to start observing and imaging with it :hello2:. 

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John

John

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Nice setup Stu  :smiley:

I used to have my OO 10" F/4.8 on a Giro-type mount like that. It put the eyepiece at a very nice height and made for comfornable observing.

I can't fault the dob mount that Shane made me for my OO 12" F/5.3 though. It's 18mm ply and really stable even at 400x plus despite only weighing around 10kg. With the OTA on board the whole scope is 26kg which is very light for a 12" dob. Quicker to setup than my old 10" arrangement too.

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Laurie61

Laurie61

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The hardest bit with the current setup is getting the scope mounted. Holding the scope in one hand and tightening the dovetail clamp with the other is slightly hair raising :-)

Stu

If I'm mounting mine on the cgem I fit the mounting bar/rings first then offer up the tube and close the rings. It makes it a bit easer  :smiley:    

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Stu

Stu

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If I'm mounting mine on the cgem I fit the mounting bar/rings first then offer up the tube and close the rings. It makes it a bit easer :smiley:

I'll give that a go. I'm sure some of the flex is from the fitting of the rings around the tube. They are securely held to the dovetail, and the clamp seems firm.

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John

John

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I'll give that a go. I'm sure some of the flex is from the fitting of the rings around the tube. They are securely held to the dovetail, and the clamp seems firm.

I found getting my 10" securely mounted to the Giro challenging as well. I ended up replacing the tube rings and adding a solid CNC machined dovetail bar to remove vibrations.

I have an ultra heavy duty Giro type mount that could carry my 12" F/5.3 OTA OK but I feel the dob mount is a more stable way to go with a tube of that size. 

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alan potts

alan potts

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I like the fact that you have gone for a very high quality mirror. The one thing that sort puts me off a bit is I would like something at 1/8th or 1/10th and that sort of optics are difficult to pick up here. I may well be wrong but I believe the likes of Sky Watcher and Meade are around 1/5th, the Orion Optics stuff here take forever to get.

Alan.

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Stu

Stu

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Thanks Alan

The things which attracted me were the mirror quality and f6 focal ratio. The central obstruction is 16.6% or about 2.8% by area so the contrast should be very good, and coma well controlled.

The tube length is a slight challenge but the results are worth it from what I've seen already.

Stu

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