joining the GS Dob club!

[janoskiss]

Hi everyone!

My GS 8" Dob from Andrews has arrived! :jump2::clap::jump2:

I haven't opened the boxes yet, but they must have sent me the wrong thing because there is not a cloud in the sky within 800km of Melbourne! :)

[[1ponders]]

Careful Janos. Don't jinx yourself, or you may become unpopular in Melbourne.:D:P Congratularions. Enjoy.

[ving]

the clouds seem to be parting here too... but thye will come back! i know it!
i am just not that lucky :/

congrats :)

[Striker]

*******s.......the same cloud has been over my place since last week......

Enjoy your Dob Janoskiss....until it rains in about 2 hours...sorry

[ving]

now now tony!
be nice :P

[BLiTZWiNG]

The reason there are no clouds is because my scope hasn't arrived yet :(

[iceman]

Nice one, i'm sure you'll love it.. notch up another happy 8" dob owner, courtesy of these forums :D

Look forward to reading your first light reports!

[Rodstar]

Congrats Janos! You must be thrilled!

You'll have to give us a field report after your first session. Have you got an itinerary in mind? I'm thinking when my scope finally arrives that I'll work through one constellation at a time. I have picked up a pretty good text by Patrick Moore which has a double page for each constellation, with a sky map and description of the main features. Orion is so well placed in the evening sky at the moment that it'll be my first target, starting with M42!

Rodstar

[gaa_ian]

welcome to the club Janos:cool:
Good choise as a first target in M42
We had a good look with a new 2" EP in the LX90 the other night under Vgood seeing, was like seeing it for the first time again :astron:

[jackenau]

Welcome Janos

Take your time, there is so much to see. A dob is a good scope to start with.

Ken M

[ballaratdragons]

Come on Janos,

You've had long enough to assemble your scope and use it.
It's been 9.5 hours since you got it.

Tell us how it went!!!


HURRY UP!!!!!!!!

(wait until you see the sky when the Moon has gone - Wow)

[janoskiss]

The scope is great. Saturn looks amazing. I haven't left the back yard in hours except to rotate eyepieces (dew!). I'm just in for a moment to check something in kstars (starchart/desktop planetarium software). Tell you more later. Going now, Jupiter's waiting.

[janoskiss]

A thin cloud cover has moved in, but I got a good look at Jupiter before that. (The heavens are telling me to go to bed, but I'm too excited!)

There is a lot of things I like about the scope and a few I don't.

I'm impressed with the everything on the OTA. All looks well made. And that finder is a beaut. (Dewed up in 5 minutes though and stayed that way for the rest of the night! :lol: ) The spring loaded finder mount is awesome too!

Collimation was a long way off, which was quite obvious when looking at Saturn. Still looked great to me though. At transit, I was astonished with the amount of detail I could see.

With Jupiter I could no longer tolerate the blurry edges, so I got out the laser collimator I ordered with the scope and got to work. It was pretty easy. (I practiced on my cheap 4.5" first) Wow! What a difference! The detail and crisp edges on that huge planet! And how clear are those four little moons! Thoroughly impressed! Now, I can't wait to see Saturn with the collimated optics!

The laser collimator is great; it's a "return beam" type so there is a window where you can see the reflected beam hitting a target the centre of which is the laser source. Makes adjusting the primary is a piece of cake. $79 well spent! Must say that without the collimator I would be somewhat disappointed with the scope.

Dew was a big problem. But I expected it to be, so I left half my EP collection inside. (I've got 7 ploessls. The three that came with the cheap Dick Smith scope are as good as the GS ones!) I swapped the two sets 4 or 5 times. That's OK at home, but I don't know what I'm gonna do when I travel to darker skies out of Melbourne.

The alt-az motion needs some work. The altitude axis is a little stiff (too much tension in the springs I think) and the azimuth is more than a little stiff for tracking the sky. I'll read up on the mods for the mount.

The free 10x32 binos are surprisingly good too (but mag of 10x is a bit too high).

Really gotta go to bed now!
Good night!

PS:
Sorry, but you can't take credit for this one! :P I ordered the scope before finding these forums. :)

[iceman]

Well, shhh don't tell anyone :P

You can't blame the scope for the collimation being out. It's inherant in the newtonian design and you have to expect collimation to be out when you receive a scope that has travelled from Taiwan to Sydney to Victoria.

Some people say you should check collimation every time you're out under the stars, especially if you've travelled with it. I don't do this, but some people do.

It's quite possible that someone new to astronomy who buys a newt of any kind could be disappointed because collimation is out and they don't even know what collimation means.. It's up to us and these forums to make sure we try to educate new owners of newts what collimation is, how important it is, and of course how to adjust and fix it.

It can be daunting at first, but with a little practise it gets easier.

Great to hear your first light report, sounds like you'll be in for some great times with your new toy! Well done!

[BLiTZWiNG]

What is collimation? I've heard of it... something about mirrors being out of alignment? How do you fix it?

I'm considering myself lucky janos mentioned this otherwise I may have been disappointed on my first viewing (it's obviously not coming today, the skies are clear...).

[janoskiss]

Not blaming the scope, but I am blaming the manufacturer, because collimation should be the last step in the assembly instructions!

[iceman]

Well that's where it depends who you buy from. Bintel have aussie written instructions that include how to collimate, as well as a general guide to observing etc.

Andrews don't have this.

Bintel say this is the reason they charge more, as they also take the scope out of the box, collimate it, centre spot the mirror (if it needs it), etc.

It really depends whether you think that service is worth the extra $150 or not. Some may, some may not.. that's a personal preference and will depend on your knowledge and budget.

[gaa_ian]

Janos
If your was anything like mine it did not come with instructions:confused:
Best thing to do is go to Orion scopes & print a copy of theirs for the XT-8, same thing:D

[rumples riot]

Blitzwing, collimation is when the mirrors of your scope are in perfect alignment. If one mirror is at a slight angle then the image will produce slightly blurry images. How you test for it is to centre your scope on a star and defocus it until you see rings forming in the image. Each ring should form a concentric circle with the smaller one. If this is not the case, then your scope is said to be out of collimation. So you will need to collimate it to get the best performance out of it. This seems daunting, but with time and checking everytime you take the scope out, the corrections will be smaller and smaller. Searching the web will produce lots of discussion on the procedure. Hope this helped.

[janoskiss]

The whole issue of paying more for service is a tricky one, because the ones who really need it don't see the point and those who do see the point don't really need it.

The scope did come with some assembly instructions; most of it in the form of illustrations only, but quite easy to understand. They just need to print them bigger (like two pages per A4 sheet, instead of four). :)

Thanks gaa_ian for the tip about getting the Orion XT8 instructions. Got it, looks good; lot of info on collimation.

[gaa_ian]

No problems Janos :)
You will find the Alt. tension problem can be fixed by putting a keychain ring of suitable strength on the end of the tension spring & attaching that to the attachment point on the base.
A cheap dewshield for the finderscope can be made with a section of postal roll, painted black with adhesive velcro dots inside to give a firm fit.
Lots of good info under Equipment discussions: What mods have you made.

[janoskiss]

gaa_ian,

I'm just studying the collimation instructions in the Orion XT8 user manual:



Do you know what this silver bottom is, and what it is for? (Yes, I know I have a laser collimator but I like to have multiple independent ways of checking things.)

[gaa_ian]

Hi Janos
I have read that you can use an old film canister with a hole drilled in the centre to collimate your scope.
I have not tried it my self, my fav. way of collimating my dob is to remove the eyepiece, find a brightly lit wall & centre the secondary mirror in the centre of the primary, using the clips that hold the primary in place as a guide.
Then adjust the secondary by seeing the reflection of my eye in the centre of the shadow cast on the primary by the secondary.
Sounds a bit weird I know, but try it and you will see how simple it is.
I have tested this with a laser collimator afterwards and have found it to be quite accurate, the final test is with a high powered eyepiece & a bright star to check for neat concentric circles.:astron:

[Starkler]

One needs to be very careful with laser collimators.

Unless the laser itself is collimated well , it will introduce errors and youll never get an accurate collimation.

Cheshire or barlowed laser technique is easier to get accurate results with.

[gaa_ian]

I agree starkler, I found that problem with my "Andrews" collimator, the IC board inside is not secured & even a small amount of overtightening of the "on" screw can muck up the lasers collimation.
In fact I hardly use mine becqause of this fault.
The housing the laser comes in is good quality, but the laser pencil inside is a $5 special :confuse3:

[janoskiss]

Yes, I'm aware of possible laser misalignment mucking things up, and the laser I got is not perfect either, because the spot on the return target moves a little when I rotate the laser in the focuser (and I also saw the keychain laser inside the thing, and needless to say was unimpressed). Still it's better than anything else I have for a very quick alignment. I wish I could loan it to BLiTZWiNG, so he wouldn't have to fiddle so much before getting some decent views. BTW. focuser cap has pinhole in centre, no need for film canister. :)

[RAJAH235]

Hi Guys,
Janos, DOBs make good drip catchers as well, when you run out of ordinary buckets. Just watch out, when on public/open nights, for those that think it's a rubbish bin tho!:eek:

[janoskiss]

Had a good chuckle at that one. Thanks. I'll make sure not to point it near zenith. Maybe the next mod will be a giant label: "TELESCOPE".