sKYWSATCHER -BK180MAKSP

[stevemelzack]

I am thinking of buying a Skywatcher Skymax 180 PRO OTA Black Diamond.
Does anyone know if this is a good telescope?
I already own a 10 inch orion optics reflector but fed up with trying to collimate

Thanks
Steve

[Arthur]

Hi Steve - It is the nature of scopes that the faster they are the more they need collimating. A telescope with (say) and f/5 focal ratio will have a much tighter/smaller sweet spot than an f/8 - if you put it in photography terms, the faster the scope the wider the aperture the shallower the depth of field. That means your mirror needs to be better aligned to take advantage of the smaller dof. If a lessening of time spent on collimating is your target then yes, a slow scope will be better - but all Newtonians will need collimating over the course of a session. You will find that the more you observe, the more critical you will become... but also the easier the collimation will come as well.

Not sure if the above is any help - might explain *why* you have to collimate so much - but in essence, a fast scope is more sensitive to collimation errors than a slower one. Given that as a rule you can take it from there, but also remember that as you move away from the fast scopes, you will need a better mount to hold the longer ratio scopes steady. A Mak will need a reasonably solid platform as they do tend to be much slower (in the order of f/13 - f/15), that means more magnification, harder target location and less contrast as well. Nothing for nothing!


Arthur

[adt175]

I am thinking of buying a Skywatcher Skymax 180 PRO OTA Black Diamond.
Does anyone know if this is a good telescope?
I already own a 10 inch orion optics reflector but fed up with trying to collimate

Thanks
Steve

Steve
I owned one of these a while back, the optics are good and collimation was fine straight out the box. The focuser is ok but could benefit from an SCT crayford to really eliminate image shift. It is quite heavy and has a pretty long cool down, but that's no difference to any other MCT.
My one issue with the scope was the supplied dovetail. It's held on with a couple of very short screws which are towards the centre of the tube and are held in place by nuts inside the tube. There was therefore quite a lot of flex and vibration. It could be fixed with either a longer dovetail or rings. But the problem is the nuts inside  - you'd have to open the tube to get at them.
So it's an ok scope that could be improved. There's been plenty of them around on the second hand market - the gold version is identical to the BD and I've seen them going for less than £400.
Andy