sighting scope crisper than main 200p

[Motorhead]

Hi,

Have to say im pretty underwhelmed with the 200p...its never really in focus....ive used the allignment tool and it was ok...its a bit off but doesnt seem to want to line up fully...but reasonably close. If i look at something on the horizon the image is bigger but its kinda fuzzy compaired tp the sighting scope....The moon looks better through my bins!

[zhgutas]

Might be a dumb question, but have you checked the collimation?

Marius

[NGC 1502]

Hi, I would say that you probably have two issues, collimation & cooldown. Either will make your 200P give very poor views. You can check collimation on a defocused star at high power, you should get concentric rings when centred in field of view. Ed.

[mdstuart]

Hmm...Maek sure you are using a relatively low power eyepiece say a 20mm or 25mm. Try pointing the scope at Polaris, the Pole star. You should be able to get the star down to a point. Next to the main star is another much fainter star. The Pole star is a double star. Try that tonight and see how you get on.

Then try Saturn which is high up to the south early in the evening. You should make out the rings. They should be small but sharp.

Good luck.

Mark

[johninderby]

If your 200p is properly collimated then you should see a nice sharp image of Saturn with banding on the surface and also the shadow of the rings on the surface as well as the rings. An 8mm to 10mm eyepiece should work OK and perhaps a 5mm if the seeing is good.

Also what eyepieces have you been using?

John

[brantuk]

Apart from cool down and collimation - at the moment the seeing isn't so good (assuming you're in the UK). A clearer, crisper night will produce better results. The finder scope has a fixed focus setting so it doesn't change - the main scope will be affected by other factors however.

[ronin]

People use refractors because they produce (usually) sharper and crisper images then reflectors. Reflectors are used to gather more light as the design lends itself to this, a big mirror with just the single surface figured.

When light is not an issue, planetery observing and imaging, when multiple images are stacked, it tends to be refractors that are the better.

In simple terms one scope does not fit all aspects and each has its failings.

[Bizibilder]

People seem to have missed your comment that you are looking "on the horizon". The image will be awful! This is because you are looking through a very thick layer of atmosphere that is full of turbulance and heat haze - the image will be "boiling" all over the place! This is a constant problem with astronomy. Where possible try to observe at least 30° above the horizon if you can. You will still get atmospheric troubles but nowhere near as bad. This is what astronomers are always complaining about - "poor seeing". Also this is why we send telescopes into space!! (part of the reason, anyway!).

[RobH]

To add to Bizibilders comments.....also, the bigger the scope, the more affected it is by bad seeing.

Atmospheric convection cells in the UK are usually about 10 inches across, so the closer you get to that in aperture, the more you will find the view is affected. Scopes larger than 10 inches, although grabbing more light, will in general have their effective resolution limited by this.

Your finder (and bins) are low powered small aperture refractors....you're not asking much of them and they will be pretty sharp in even the worst conditions.

Your 200P should, if properly collimated and pointed at a target that is reasonably high up, give you excellent sharp views.

Rob.

[NGC 1502]

Post #8, a very good point, that I missed too, Ed.

[Llamanaut]

check collimation first and i concur with post #8 and #9

[Motorhead]

Again thankyou for the obviously well informed replies...when I say horizon I meant an object maybe 4 miles away.....

As for the collimation...theres something wierd...if I take out the eye piece I can see the circle for the center of the main mirror pretty much central...but when I put in the collimation tool the cross hair that it overlays is well off...kinda like the barrel that holds the eye piece is off?...but I would have thought that would have been factory set...Anyways I`ll try what has been suggested.

I know there is something amiss as my better half whos idea it was to get the scope came out with "That thing is rubbish...why did you buy it?"....Sheeesh you just cant win.

[Astro_Baby]

I agree - collimation and cool down are the likely culprits OR poor seeing conditions. Trust me on this I own a 200 and its generally superb BUT it can be affected by bad collimation and tube currents which can severely impair the views. A finder will always tend to be sharp because its so much smaller and so less critical. Think of it tis way - your computer screen is only 72dpi so an image can look quite good at pretty low resolution (thats your finder) your printer however can run at 300dp or above and when you rpint a screen image its sometimes a lot less good on paper because the printer is showing all the defects that were invisible on the screen (thats your scope).

[barkis]

We are in the summer months, and temperatures are fairly high during the day. Perhaps your Telescope resides indoors when not in used, therefore it too will be quite warm. When you do take it out to observe, the mirror will commence to cool down to match the outside temperature, which will also be gradually dropping. So, the scopes mirror will be playing catch up. Until it has cooled to ambient temperature, the mirrors optical figure will be constantly moving, and will present you will poor images.

Sorry for the long winded version of what has already been said .

Ron.

[Motorhead]

The scope lives out in the garage so its pretty much at ambient....there is no way it would see the rings on Saturn through the eye piece...just no way...when I look at Saturn its like a splodge of colours...like a filled in figure of 8....I will try and get the barrel that holds the eye pieces lined up as it looks like it can be adjusted.

[John]

I agree with the other posters that collimation is the most likely culprit here. It will be the secondary and main mirrors that need adjusting more than the tube that holds the eyepieces I think - this is normal maintenance for this type of scope but it sounds like yours is way off.

If you have, or have access to, a digital camera could you try taking a picture of the view down the focusser tube (with the eyepiece removed) ?. We might be better able to diagnose the problem and help you sort it if we could see what the view down the focusser tube looks like and whether the mirrors are more or less aligned or way off.

[johninderby]

As in previous posts collimation is the likely culprit.

Here's an image grabbed from StarryNights software that shows the sort of views of Saturn you should be getting with a 200p.

John

[pvaz]

I got a scope with the same optical configuration as the 200p. Made by the same main company (Synta).

It's amazing how seeing conditions affect the views. On a steady night I get a view of saturn as sharp as john's image, although smaller. On the next day, if seeing conditions are bad, it looks smudged and completely lacks details.

Weather play a big role on your observing sessions. Don't be too quick to judge the scope.