That Azimuth thing

[davehunt]

My Skyliner 200 Dob has arrived,and I am spinning with ethereal delight....not so the azimuth base,which definitely needs tweaking. Ideas please!

That apart,even on a poor night I had a nice view of Saturn and managed to find M81,82.I learned a bit about nudging with my little Celestron-the EQ mount was so lousy that pulling the scope around was the only way to follow Saturn.The Dob is a veritable wonder after that experience-but could be better.

I know this scope is built down to a price,but I cannot for the life of me understand why there are tools provided for assembling the base-five of them,most of which even the least ardent of DIYers are likely to have around the place- but NONE to collimate the thing! How idiotic.Bob's Knobs will benefit from this oversight.

Nothing can detract from the overall value for money of this beast,all the same-not even the sticky az. For an ageing novice,it is a revelation.

[Rottweiler]

Is it motorised in any way? You can always mesh the gears together better, I found the capheads holding the motor in place to be too small, the motor was able to move around a bit, I fixed this with washers.

One of the Chinese favourites is to use the cheapest grease available, no matter what, this can be cleaned off and replaced with top quality lithium grease.

In general look where it appears to be weak, put bigger washers under the bolts, tightien things here and there, use a little discretion and process of elimination and you will find where the worst points are.

[davehunt]

Not motorised-I am a nudger.

[scogyrd]

I've fitted a lazy susan bearing and done the fixed bolt mod to mine and it made a world of difference.

Sky-Watcher SkyLiner 200 Dobsonian Telescope

Orion XT10 Dobsonian Azimuth Bearing Lazy Susan modification

I do think you need to do them both though. If you just fit the lazy susan you might find the base too wobbly without the fixed bolt and, if your base was anything like mine, the fixed bolt mod might not improve things that much. My base seemed to suffer from a flatspot before, even though I kept checking it with a spirit level and it appeared to be flat..

[twotter]

The base is basically the same as flat packed furniture, and every single item I've ever bought has included the basic tools to assemble it. Not everyone has allen keys, screwdrivers etc... so I'm glad Skywatcher included them. You could try taking yours apart to see if the teflon pads are badly scuffed or the main bolt is too tight?

As for including a collimating tool...how far do they go? There are enough different options to put together a package to choose from. Some people like a simple cap, others a cheshire, and others prefer the various lasers.

Far better to do a deal when buying the telescope. That way you might get a demon deal, and, the collimating tool you want.

[davehunt]

I meant the tools to slacken the mirrors,actually.But thank you for your kind advice.I have a Cheshire e/p.

[Ad Astra]

Hi Dave,

After reading your replies, I'm no longer sure what is wrong!

If the problem is with the azimuth (horizontal base rotation), you can cut an extra washer cut from a plastic milk carton and put it between the two plates on the base to take some of the weight off the teflon pads (make it at least 2" wide!). It may take more than one, and trial and error is the only way to test this. Making sure you haven't over tightened the center bolt is also a must. If it isn't too tight, try the plastic washers idea.

If it is the collimation of the primary mirror, these often have two knobs at each of 3 positions. One is a "locking" knob, the other adjusts the position of the mirror. You must release the lock before the mirror will move at all - failing to do so can be problematic, even disasterous (mirror damage) with some mirror cell designs.

If you post a photo, I could probably be more focused with my advice.

I hope that helps,

Dan

[davehunt]

Hi Dan,

I think I was so overwhelmed with the view of Saturn through my 8" Dob(the first object to be seen through it) I lost my usually quite articulate powers of expression-so much so, I got snapped at,and quite misunderstood....(heard that before?)

Saturn,of course,rushed across my viewfinder,and my inexperienced hands struggled with the nudging-partly because the az was "sticky".I have come across some solutions to what is apparently a not unusual problem with these beauties,and will doubtless sort it.

Then I expressed what was(I thought) a reasonable grievance that whilst Skywatcher provided very basic tools that everyone gets in flatpacks,there was no suitable tools to aid collimation-meaning,tools to adjust the mirrors,not a collimation e/p, which I have and which I used successfully. I should have just said how wonderful the scope was-and it is-and that I think it is worth every penny,without trying to work through the convoluted thinking that provides you with tools in plenty except the ones you really need.Nuff said. And I have collimated it perfectly,thanks.Good to hear from you again.

[Ad Astra]

Hi Dan,

I think I was so overwhelmed with the view of Saturn through my 8" Dob(the first object to be seen through it) I lost my usually quite articulate powers of expression-so much so, I got snapped at,and quite misunderstood....(heard that before?)

Saturn render me speechless and inarticulate? Oh yeah.... only every time I see it!

Glad to help!

Dan