Thoughts of an equipment addict - views on mount's scopes and vibration

[DaveGibbons]

Hi all, I've been meaning to put all this down for a while so here goes! I was just going to post my thoughts on mount stability and motor vibration issues but I realised I needed some scope history in there to give a full picture.

I hope you find some of this interesting and take pity on my sad addiction. Over the past 3 years I've had seven mounts and 13 scopes, some of you will have bought my old scopes (I want them ALL back ,well all except ONE).

I am almost 100% a visual observer although I will take the odd webcam image . In particular it's planatary lunar and double star observing I enjoy . Splitting close doubles at High magnification requires perfect collimation and a stable mount with no motor vibration. So in the beginning.......

An EQ5 with homemade legs and Tal 100r f9 achromatic refractor:-

This was my humble Eq5 mount after I had junked the useless pressed auminium legs . It had dual 6v drives and was perfect with the Ash fixed height tripod I made. The tal 100r was and still is the best 4" Achromat you could get. Optically it split doubles at theoretical limits and it was very well colour corrected. The Eq5 mount had no motor vibration whatsoever even at silly magnification it did have a somewhat variable tracking speed depending on new batteries or not! The tal focusser was not that good it would wander around a little and it could also only take 1.25" eyepieces . I no longer have this scope but do have the 25mm plossl and the tal 2x barlow(still the best budget barlow).

EQ5 and Orion Optics GX200 F6 Reflector

I don't have a picture of this set up . I made some shorter legs for the eq5 and Just about got away with it on the Eq5. It did have a few issues if a breeze got up due to the tube length and surface area but still kept motor vibration free at high mag although It was definitely on the limit for visual use with the eq5. As for the Orion Optics OTA, well it was just magnificent the best set of newt optics I have ever seen . I did manage to take a few webcam images through it and here is my best saturn webcam image from January 2004.

HEQ5 and Orion Optics GX200

I decided a heavier mount was needed for my gx200 and bought the first of my heq5's as a non working mount for £100! I ordered a new Circuit board from importers OVL It took 8 weeks and £60 but did the trick! It's now that I run into motor vibration issues with the Heq5 mount. Despite great care in balancing the OTA at high magnifications I cannot get rid of a approx 2 arcsecond fast vibration. This is no good if you are a close double star observer, so I completely strip the mount down re-grease and adjust all worms put back together and it's exactly the same! I have too switch the motor drive off if I want to split sub 2 arc second doubles or see finest detail on the planets. I still have my EQ5 mount so decide to buy a lighter OTA just for that .

EQ5 and OMC140 deluxe

I was so excited at getting my OMC140 Deluxe(1/7th wave hilux coatings) I paid £1,100 for it new. It looked superb on the EQ5

nice and compact I just could not wait for first light. First light was a big dissapointment! It was of the moon and the moon looked dull and just not crisp. I won't go into great detail on this other than say it went back to OO for the mirrors to be re-done

(Zygo report not worth a carrot) never happy when I got it back images always dim and not wel defined - My skywatcher 150 mak was optically far superior at a fraction of the cost. I know some people rave on the OMC140 but mine was Rubbish. I sold the scope at a £600 loss and was glad to see the back of it. I sold the HEQ5 mount due to the motor vibration to raise cash for something else that caught my eye!

EQ5 and AR5 5" Refractor and XT10 i Intelliscope.

I purchased the xt10i as I was looking for a bit more aperture and liked the sound of a push to with object locator. The optics were very good not far behind the gx200 with the added bonus of more aperture. The intelliscope gave flawless performance and with a 3 star alignment placed everything in the fov of a 25mm eyepiece. The AR5 OTA was a joy to use on my trusty EQ5 and optically every bit as good as my tal with just a tad more colour. Both scopes were let down by the focussers and I changed them for moonlite crayfords. It's the best upgrade you can do to any scope , absolute zero image shift and perfect collimation can be achieved , they are engineering works of art.

I wish I had stuck with this set up as it was probably the best mix for me but unfortunately I then had a ticking time bomb hit me, I had a small stroke! My aortic heart valve was about to pack and I had open heart surgery in 2005 to replace with a metal one. I was unable to work and had to sell everything to pay the bills. Astronomy was on the back burner for 6 months.

12" Revelation dob

It's 6 months after my op and I am nearly back to full fitness , back in work and up comes the chance of a 2nd hand 12" dob at a great price. *beep* the weight I thought , after a great time with the intelliscope I can't wait to try my new toy out. First light reveals the revelation to have average optics , virtually impossible to hold collimation due to the primary shifting around in the poorly designed undersprung mirror cell. It still gave great views on deepsky objects and overall was just worth the cash. It was to blooming heavy though as my sternum would protest every time I carried it outside.

I wan't another equatorial mount and scope to go with it so I decide to get another HEQ5 as maybe the first one I had was a lemon? I pick up a nearly new one from a great guy I know , but what OTA shall I stick on it? As I said before it's double stars planets and the moon for me so I go for the New Skywatcher pro f12 6 " Maksutov . After my experience with the OMC140 I hold my breath at first light with this set up- no need the optics completely blow me away! I can't believe the crispness resolution and sheer beauty of the false colour free images also this second HEQ5 has only a tiny amount of motor vibration perhaps 0.5 arc secs, still there but I can live with it for now. The only downside with the 150 mak is a large image shift when racking through focus . This is not a real problem for visual use but would be an absolute pain for imaging. Oh and cooldown from house to perfect thermal equilibrium is around 2.5 hours. This is one set up I don't have any images of so use your imagination.

I decide to sell the Dob as I am in love with my mak and can't really handle the weight. With the cash I buy a 6" f8 Skywatcher refractor to give me something that will cooldown faster and give a wider field of view than the mak. Plus I always wanted a 6" refractor.

HEQ5 6" Skywatcher f8 achromat refractor

I make some very sturdy wooden legs so I can use the refractor whilst seated on the zenith. I junk the standard focusser and fit a 2" rotatable william optics crayford focusser. This is a very good focusser but NOT as good as the Moonlite crayfords. When you rotate the focuser it does not hold perfect collimation - if you have a laser inserted it scribes a small circle. I eventually sell this and replace with a dual speed moonlite unit. Optically it's very good but does have a fair bit more false colour than the AR5 or Tal as you would expect at f8.

Heres the tripod and mount - it cost me £16 for the wood from B & Q well worth doing.

The refractor actually is more of a problem with the HEQ5 vibration issue as all the weight is much further away from the central mass of the mount and It bugs me so much I decide to upgrade the heq5 to the new Synscan goto . Fitting the new motors was a doddle and all issues with vibration dissapear!

It's now very quiet very accurate and completely vibration free.

I now I have a 6" refractor and 6" Maksutov along with an HEQ5 goto mount .

Heres where the scope junkie gets hold of me again! You see I spent alot of time reading scope reviews and forums on cloudy nights when recovering from my op and in the back of my mind a little voice is saying C9.25 C9.25....... It's a planet killer with magical optics right? I take a chance bite the bullet sell the 6" Mak and pick up a 4month old c9.25 with XLT coatings.

C9.25 On HEQ5 GOTO mount.

What a fantastic set optics this scope has. I fitted a set of bob's knobs and dew strap and dew shield

and was amazed at how it did live up to the reputation it had as an almost mythical optical colossus. It was dead easy to collimate had no mirror flop and the image shift through focus was non existant.

I don't have a photo of this set up cos what do you do when you have the perfect scope- sell it of course and get your next bigger and better fix , The c11 with XLT!

C11 XLT on HEQ5 goto mount

I purchased this for £1950 with CG5 goto mount (what a noisy beast!) Sold the mount for £500 so all in all the OTA cost me £1450. It does everything the c9.25 did just a little better . It did exhibit a small amount of mirror flop across the zenith and did not hold collimation quite as well , it also had slightly more image shift than the c9.25 still very good though. I purchased a 2" screw on sct dielectric diagonal and would advise any sct owner not to get this type, as when using a short focal length eyepiece say 6mm your head actually makes contact with the rear cell of the scope making viewing awkward. Buy an adapter so you can fit a normal push fit 2"diagonal it gives more clearance and in reality is easier to rotate than the screw in type (cheaper as well).

The real problem for me was that the heq5 GOTO was struggling to give accurate goto's with this 30lb OTA. It needed four counterweights and it was just not up to the job.

To be continued.........

[DaveGibbons]

Sorry guys, spent ages typing this out my computer crashed and I lost nearly all of it and can't be bothered to type again! another day maybe!

Cheers

Dave

[FLO]

C'mon Dave, you can't leave it there...

I say we start a petition!

[geppetto]

Yep agreed... get cracking on part 2 Dave

Seriously though, you bring up some interesting points in part one

so looking forward to more.

The weather looks carp for yet another week so your stuff will

give us something to chew over

[GordonCopestake]

I too am looking forward to part 2

I love to hear these stories of equipment acquisition and then the reasons for selling up.

[richard42]

yes come on dave!

i want to hear the bit where i bought your celestron 8" scope yesterday!

It is very, very nice BTW took it out last night for a quick gleg at the moon, will post afull review when i've had a proper look, thanks agin it is a great scope! 8)

[tom.yates]

Dave i think me and you are in the same boat mate as i to have had well.

OO 250, 16" DOB, TAL 100R, 12 OO F5.3, 7" AP STARFIRE, APM 130, 102 VIXEN REFRACTOR 90MM REFRACTOR, MN86 MAK NEWT, OMC 140, MEADE LX200 10" AND 12" 102 FLO REFRACTOR, , A 80MM REFRACTOR, AND MANY MORE SCOPES I FORGET, I have decided to stay with the scopes i have because you can go on and on buying and selling kit it becomes a obsession If i was to give any advise to people it would be be happy with what you have and enjoy the views as we don't get enough nights in this country to justify the expense of expensive kit sitting around doing nothing

[George]

Dave, I think the vibration could be a burr or 2 on the worm. The EQ6 I bought off you had the same problem you said to me, well I stripped down for a regrease last week and both DEC and RA worms had burrs on them, quick clean up with a oil stone soon got rid off them, not finished reassembly yet so I cannot say if the vibration has gone or not.

[DaveGibbons]

Guys, I've added a bit more history the rest will have to wait for tomorrow!

Dave

[richard42]

i'm sorry to hear you've had a rough time!

But you are a real top bloke, and it is really interesting to hear about all the scopes!

[barkis]

Dave,

sounds like you have had a roller coaster ride through the equipment jungle. I know the feeling too well. I have had some dogs in my time.

I reckon when you are spending reasonable sums of money, you should be allowed a months trial to try and judge its performance. Some dealers may offer that provision, but I don't know of any. I stand to be corrected of course.

There is no worse feeling than having the anticipated joy of a new instrument, shattered at first light. Of course you persevere, because no scope can be judged on one nights viewing. There are too many parameters affecting performance. But, when a dog is a dog, it cannot be denied.

Please carry on with your story, we are all intrigued I'm sure, and let it be a happy ending, we all want that.

Barkis.

[SteelRat]

Good read - part 2 please. Stay well Dave!