I have just bought my first telescope on Friday night from AstroPetes, a 10" sky watcher dob. He didn't have any collimators that night but I thought I'd still give it shot.
The only thing I thought worth trying to look at by the time I got home and set it up, was Saturn. Well it was pretty much a blurry ball, not real fuzzy, just not in focus and no real detail. Played around with focusing and the 25mm and 10mm ep's.
I put it down to collimation. Went out and bought an Orion Lasermate Deluxe 2 collimator, set about collimation. It was off a bit, so tweaked away until I thought it was all good. Went to view Saturn again that night and it was pretty much the same. Not really any different.
Tonight the moon is out and thought it'd be much easier to view. Same problem as with Saturn. Just blurry, no detail whatsoever.
In all, I've probably played around with collimation around a dozen times, each time I thought it was pretty much spot on, maybe out by a fraction or so. Every time same deal, blurry moon. The only time I have seen any detail is when I 'piggybacked' a 10mm EP on top of the 25mm that came with it. Also had the 'moon cover' on and off too.
Maybe my collimation IS off, but thought that I'd still be able to see some detail even if it was out a bit?! Or perhaps I've played with something that I shouldn't of..
I'll give Pete a call tomorrow, see what his thoughts are. Probably won't get a chance to take it back till Friday or Saturday so he can have a look/play to figure out where I'm going wrong..
Collimation shouldn't affect views of Saturn, unless something is really bad, could be smoke haze, winter means lots of wood fires burning, have you looked at eta carinae, omega centauri?, eta carinae should be easy to see, gee i've done heaps of observing with a badly collimated scope, blurry blob doesn't sound right for Saturn.
I haven't tried looking at anything other than Saturn and the Moon. Saturn wasn't very blurry, it's hard to describe. Certainly wasn't a clear view, I assume that the rigs should be prominent with a 10" dob? could not make out any rings.. I am more concerned that the Moon was blurry/fuzzy.
It is possible that it wasn't Saturn I was looking at, but I'm doubtful. Checked Stellarium and Google sky maps many times over.
I'll get back outside tonight and look for eta carinae and omega centauri.
I agree with Joe, collimation should not have the effect you have described.
It sounds like something else.
There have been a number of similar instances of this reported recently and they have turned out to be a result of having the 1.25 inch eyepiece adaptor attached to the 2" eyepiece adaptor, then an eyepiece.
Please check that you do not have both attached, as the 1.25 will fit into the 2" and look like it is supposed to be that way.
Then, stick with the 25mm eyepiece and move the focus in and out all the way until you achieve focus on your object.
A quick way to check you collimation is to point to a bright star, and defocus and you should get nice concentric airy rings.
However, with the amount of moisture in the air, there mat be some atmospheric disturbance which may prevent it looking perfect.
Damien
Collimation will have to be way off for it to start affecting focus that badly.
Most likely culprit is the old ol' Skywatcher adapter issue. This has come up so many times that when I saw your post I thought "Bet it's a SW dob" and guess what?
I don't have a SW but from what I understand they come with 2 adapters, one for 2" and one for 1.25". I think people have put the 1.25" one in the 2" one and this puts the EP out of range to focus. (SW users correct me if I am wrong here)
Try some other arrangement with the adapters to get the correct focus.
Thanks guys! That's the problem, I did indeed have the extra adapter in. I did think maybe that both shouldn't be in there, but thought that the 1.25" wouldn't fit without the 2", don't know why I didn't try though.
Ahh, so damn happy now. Knew it was user error, and not a faulty product. I'll be outside for the rest of the night now!
Thanks to that problem, I think I've mastered collimation..
Glad thats the solution. Do not why SW insist on doing it that way. The way GSO it is the focuser natively takes 2" EPs and you use an adapter for the 1.25" That also means you can use other adapters such as TV high hats if needed.
Re: Collimation. Glad you seem to have the hang of it. Just one quick question. Are you only using the laser? If so be aware that a laser is really only useful for the final tweaking (IMHO). Try to get a Cheshire or similar to do you collimation correctly. If found if I used the cheshire every month or 2 and then used the Laser as a tweaking check each night that worked OK in my 12".
Also, and this is something I keep repeating in these forums, don't stress too much about collimation. Try a little experiment sometime. Set up your scope collimated as well as you can and have a look at a few stars. Then deliberately throw it out a bit. I will bet you will struggle to see much difference unless you really throw it a long way out. I know as I have done this!
Good collimation helps, but it should never become so important taht it takes away observing time.
I'm not sure why they don't add a basic manual, with a problem solving section. Would save a lot of headache for beginners.
I am only using a laser, will definitely look into the Cheshire collimator. Before tonight, I thought that collimation was essential. It's good to know that it doesn't have to be spot on for a good view.
Just to be clear, collimation is essential, just that perfect collimation is not. My personal philosophy is I would rather see beginners out using a slightly imperfectly collimated scope than wasting time trying to get it perfect.
A good reference I have found is here. http://www.astro-baby.com/collimatio...on%20guide.htm
I can vouch that perfect collimation isn't critical. my 10" GSO dob arrived today from Andrews, I bought a Cheshire with it just to be on the safe side. (Havnt used it yet)
After putting it all together and everything, took it outside for a test run, even travelling from Sydney to the gold coast stars are pinpoint (even thou I only used the 40/20/15mm eps I had alread), but the views were 100 times better then my old 4.5" reflector.
I did defocus to see how bad it was out of collimation and by the website it looks like it's only tube currents .. even after a few hours. defocused, stars looked more like this \\|// ... with the star under the | ...(if that makes sense) . in focus the stars look pinpoint and the brighter ones look like the ones in photos, with the + radiating from them, with a circular halo around them. (is that normal?)
or is that pinched optics? the closest thing on that website which looks like what I see is tube turbulance...
or is it astigmatism?! only bright stars show the + but its not a blob, its more like stars in pictures , but defocused it doesn't look like that (from the website).
(now I'm worried)
thanks, for any advice, and sorry for hijacking this thread..
matt
i should add it was B cen/Agena I was testing on. all the other stars, even in the jewel box look perfect ...like in the books, with 50 or so stars. maybe I shouldn't worry
Just to be clear, collimation is essential, just that perfect collimation is not. My personal philosophy is I would rather see beginners out using a slightly imperfectly collimated scope than wasting time trying to get it perfect.
I agree with Malcolm. It's an art that I have not yet perfected, tho it seems that as long as it is nearly right it doesn't detract from a good viewing session. In my experience anyway...
Thanks guys! That's the problem, I did indeed have the extra adapter in. I did think maybe that both shouldn't be in there, but thought that the 1.25" wouldn't fit without the 2", don't know why I didn't try though.
Any chance of a photo or two posted, with & without so I can see this adapter? You described perfectly issue I've had & now I'm wondering?
I did defocus to see how bad it was out of collimation and by the website it looks like it's only tube currents .. even after a few hours. defocused, stars looked more like this \\|// ... with the star under the | ...(if that makes sense)
When you use the defocus method to check collimation you need to use a high magnification eyepiece on a bright star to see the "airy discs" properly(I use a 6mm on my 8" f6 newt to check collimation)
When you use the defocus method to check collimation you need to use a high magnification eyepiece on a bright star to see the "airy discs" properly(I use a 6mm on my 8" f6 newt to check collimation)
Rick
thanks Rick, ill try it next smoke with a 6mm and see what happens (scope is out). those attempts were with longer length eps.
maybe I'm missing something but when I defocus on Agena (at 208x), I begin to see the spider vanes, either way I go from focus. maybe I need to collimate and in focus the star is like my previous description, not a round ball, but more like a ball with a whole lot of spikes. tonight seeing isn't the best, got a bit of wind around but I don't think it'd affect it that much.
but they look ok when using lower powers, like Saturn is crisp at times, between gusts of wind. I will experiement in the coming nights.
With a 10" scope you might need to find a star that is not as bright . If the secondary spikes are centered on the star image I would think that the collimation is ok.
With a 10" scope you might need to find a star that is not as bright . If the secondary spikes are centered on the star image I would think that the collimation is ok.
its hard to explian Rick, I tried to take a pic without success. I will try on a fainter star tomorra night. I've packed up because I already have a cold
even when I put the scope out (around 5pm) I noticed the spider vanes and secondary in view while looking in the eyepiece. noticable at a distance ... just a blur close up. I'm assuming that shouldn't happen? (or does it because the skies aren't dark enough to mask that apparition)?
let ya know how it goes, and thanks.
hey rick,
I tried the star n Her in Hercules, with the TMB 6mm I get an image cross between the 2 I've posted. I think I will have an attempt at collimation tomorrow.
the secondary vanes are pretty much centered on what I'm looking at when defocused a fair bit.
conditions have been clear but it has been windy lately so maybe it could be atmospheric turbulance. Saturn still wavers between crisp and blurryish with the Cassini division just visable .. but its nothing to write home about.
thanks for everyone's help. Doug, I don't think I'm going to repaint the secondary vanes, if anything I'll practice on my old scope first .. but I'm always scared to pull things apart.
thanks again
matt
ps. like earlier the fiery lines protude like \\l// off the star and the rings around it when defocused.
pps. I uploaded a pic of the butterfly cluster, I took with my phone afocally just earlier tonight (at 83x)... its not the best, with vibration and movement taken into account, the stars appear ok?(minus the movement when I pressed the shutter)
