Collimation

[Geordiemac]

Hi

Looking for alittle advice on collimation, I have a Skywatcher 150PL which I have had for a week, I had the scope away at the weekend and managed to do alittle observing Friday ( Jupiter + 4 moons & the Moon), Saturday (Saturn) and Sunday (Juptier + moons), the OTA was took off the mount several times as we were caravaning and on days out I wanted the OTA in the van locked up, am I right in assuming my first purchase should be a collimator and if so would I also need to purchase a collimation cap, I ask because I would like to look into buying some new ep's, this is all totally new to me so any advice would be greatly appreciated.

I was fairly happy with the views I achieved but think over the course of the weekend the detail deteriated, I realise the conditions could be different but like I said the OTA was moved several times.

One other thing, I used the 10mm and 25mm ep's sometimes with the 2X Barlow and sometimes without unless I am mistaken each time I used the Barlow the views suffered in quality ? while observing the moon I have to admit I was alittle dissapointed can I be doing something wrong? I would have been using at most x240 mag and thought I would see more detail. Jupiter was fairly small and I could see the rings in the form of a disc, I have read people have viewed the cassini division, is this realistic with my scope?

I apologise for so many queries but want to learn to use my scope to its maximum enabling me to enjoy my nights viewing, no doubts I will have many questions over the coming months and look forward to the great advice I,m sure I will receive.

Cheers

George

[Stargazer_00]

I think the collimation is pretty solid so long as you dont throw it around. Use a star to do a star test with a really high power, highest you can get. 10mm in the barlow for instance.

If you defocus slowly you will see a set of concentric stars, equally spaced light and dark light and dark. If you notice a bias in the direction they circle then it's an indication your collimation might be out. Atmospheric conditions do ruin star tests a little so you cant read too much into them but they give a good indicator.

It's a good idea to get a cheshire collimator anyway though. avoid cheap lazers, they wont be accurate.

EDIT: just google 'how to do a star test in collimation' to get some graphics of what to expect. my description is a little lacklustre to be frank.

[Twiggles]

I have the 130m, the supplied barlow does affect image quality and I try to avoid it, otherwise teh supplied eyepieces aren't too bad for a starter set. My favourite is the 25mm as I love the wide views it provides particularly for clusters. As for collimation, others will know plenty more than me, but I opted for a collimation cap and a cheshire along with astrobabys excellent collimation guide (this is easy to find using a search engine of your choice!). Been surpirsed by how much atmospheric conditions can affect image quality myself, but hang in there!

[Moonshane]

For collimation, I bought one of these and it gets you close enough in all aspects to not worry http://www.firstlightoptics.com/collimation/rigel-aline-collimation-cap.html . cheap too. I use other tools but this will allow you to check it and make sure it's close/perfect.

Sounds like you were looking at Jupiter not Saturn. Rings and Cassini are Saturn. You will not mistake Saturn for anything else when you see it.

make sure the scope is cooled for about half an hour to an hour before observing if possible. more magnification makes the image bigger but probably fuzzier/dimmer too. the 10mm and barlow are possibly pushing the quality of the eyepiece too much. an 8mm eyepiece will give 150x which will provide a nice image and good magnification. planets are always going to be small. the moon is currently low too so atmosphere will play a part. it will get higher as the year goes on so there will be others chances.

[umadog]

Higher? It will get lower from now on, no?

[Moonshane]

well both really. for the next two months it goes slightly lower, for the rest of the year it gradually gets higher

http://astro.unl.edu/classaction/animations/lunarcycles/fullmoondec.html

[MadAlbert]

+1 for the collimation cap. You could get yourself a Cheshire but stay away from lasers until you're familiar with collimation.

[Geordiemac]

Oops sorry of course it is Saturn with the rings .... (blushing) and it was great to see it

as for the 8mm ep , would I benefit from buying a 16mm so I have ineffect double my eps (8mm with x2 Barlow) or would the 8mm alone be the better choice?

Thanks for the replies guys I appreciate it

George

[Hzadbhat]

Cheshire? Cap? A must in my opinion.

Was very happy with my scope, then collimated it, and was simply blown away.

The supplied ep's and barlow won't be all that good quality, but don't just throw them away. I upgraded my barlow the day i got the scope and did a comparison of the 2. The supplied one was like a bicycle, if you persist, you'll get there just after the 10th of whenever. The (slightly) upgraded one has caused an unnatural dust collection on the first.

Am buying a televue next month and expecting to get to my destination a day or 4 before I leave.

Read lots of eyepiece and barlow threads. Learn, research and save.

There's heaps of gear at good prices if you do a bit of research.

The top of the line gear ain't cheap, and at this stage, would not be recommended. (unless you have a spare few thousand quid).