A Terrible View

[jeremy1]

Hi Guys. Please be gentle with me as I'm new on the forum, but I have just upgraded from my old celestron 114 Newtonian to a Skywatcher 200p Newtonian and to be honest the view through the eye piece is terrible. Planets that I could see clearly in my old scope are all star point if you understand what I mean in the new scope and the legs of the star points have dark bands in them. The view is very off putting and I'm gutted after spending good money and getting a worse image. Do any of you have any suggestions as to whats wrong with my scope.

[Woody]

Hello Jeremy

I don't own a Newt but could it be the focus? If it is your first time with it it may be way out.

[jeremy1]

Either side of the focus point is just fuzzy or is there another better focal point further up the range so to speak ???

[richbyers]

have you took into consideration the weather and transparency of late? it may not be a fair comparison

[Woody]

There is only one focus point so if you are sure that you have it then there is another issue. I wonder if it is out of Collimation? I don't know much about such things but I am sure another more experienced member will sort you out in no time.

Cheers

Jeremy

[Tinker1947]

It may be the EP you are using may need a extension, it may need collimation, it will be something as simple as that, try focusing on a planet or the moon, remember to move the focusor very slowly its easy to skip the point of focus, if this fails move the focus tube out as far as it will go, then move the EP away from the focusor and see if this brings the object into focus, you can do this in day light on a far off object, if this fails collimation may be require, this is a handy skill to learn as it will need to be done from time to time...

[Tribal-Wolf]

Also make sure you haven't fitted both adapters to the focuser as this seems to be a common mistake lately.

It may well need collimating, my secondary mirror was a mile out on mine.

[jeremy1]

Hi Guys. I tried having a check to see if it needed Collimating by reading various posts that I had Google'd and looking through the empty focuser tube the secondary seemed circular and in the middle of the focuser tube. I then looked past this at the Primary and the circle marked on the Primary was a little low and to the left of central. I had to turn one adjustment screw about a turn and another about a half turn until everything seemed square and true, but as a begginer maybe I am doing something wrong. I thought that when viewing through a Newtonian scope at stars then you will get the spikes because the a star is just a fine point of light and the secondary mirror mounting legs are what causes the spikes but other bigger objects should be clear without the spikes.

[RikM]

I thought that when viewing through a Newtonian scope at stars then you will get the spikes because the a star is just a fine point of light and the secondary mirror mounting legs are what causes the spikes but other bigger objects should be clear without the spikes.

Unfortunately this is not the case. You will also see the diffraction spikes on planets unless the magnification is high enough to dim the view so they are not obvious. The 200P gathers a huge amount more light than a 114, so diffraction spikes will be more visible on bright objects. This is something that caught me out the first time I got the collimation right with my 150P. No spikes before yet spikes after and the expert helping me siad...ah yes..that shows you have got it right and it is working

If you are getting double spikes, like four spikes with a dark strip up the middle of each, then that suggests that your collimation is a bit out and your focus is not quite right either. The best bet would be to get a Cheshire eyepiece and adjust the collimation properly. This is especially important when you are wanting to see planetary detail.

Also the 200P mirror is a bigger chunk of glass than the 114 so you will need to give it time to cool before it it will perform to its best. Depending where you store it vs. where you put it to observe, you may need to give it 30 - 60min to stabilise before you will get good (or at least representative) high power views.

Finally the effects of seeing will be magnified in the larger scope. Since it can show so much more than your 114, you will also be able to see much more of the atmospheric muck and distortion.

When everything clicks into place, collimation, focus, cooling and seeing your 200P will blow your 114 out of the water.

[jeremy1]

Thanks Rik. I will have a look at collimating again today to check that everything is as good as it can be. and let you know how it looks tonight.... Skys permitting.

[rwilkey]

Hi, make sure you are using a low power ep to start with, you should not get any defraction spikes when in focus.

[jeremy1]

Yeah I'm using the 25mm eye piece for initial viewing but the spikes are still there and they are not small. They are massive virtually starting at the width of the object (lets say Venus) and taper out with dark lines on them. It makes the viewing an absolute pain.

[rwilkey]

Are you using the correct eyepiece holder, the 1.25" and is it secure?

[knobby]

As Chris (tribal wolf ) and Robin (R Wilkey) said, its pretty common to have the 2" and 1.5" ep holder fitted, you only need the one otherwise focus point cannot be achieved

http://stargazerslounge.com/attachme...zoom-focus.jpg

should look like this

[jeremy1]

Yeah I only have the one EP fitted. I have ordered a laser collimator so I will check that everything is as good as it can possibly be before going any further. As I have only had the new scope for 2 weeks now I am still getting to know it and maybe only maybe the couriers were a little rough in handling and things might need setting up first.

[RikM]

Yeah I only have the one EP fitted. I have ordered a laser collimator so I will check that everything is as good as it can possibly be before going any further. As I have only had the new scope for 2 weeks now I am still getting to know it and maybe only maybe the couriers were a little rough in handling and things might need setting up first.

Please make sure your laser is collimated otherwise you could well make things worse. It is so easy to use a laser and just assume everything is okay, when in a lot of cases the laser is itself out of collimation.

Make a little V-block and put the laser in it. Shine the laser dot onto a wall or something 10m away and turn the laser in the block. The laser dot should not move at all. It it makes a circle as you turn the device, it is out of collimation and you should adjust it before using it to check your scope.

[jeremy1]

Thanks Rik. Some useful advice there