Buying second hand reflectors

[Arashhenry]

Hi. I have been offered a skywatcher 200p dobsonian scope for £165. I understand this is a good price? I would like to know how I can check the quality of the used optics and mirror before committing to buy. I am tempted to pay extra for a new one for the peace of mind and the warrentee. Is there much I can do to check these things whilst in the persons house during the day time?

Thank you for your help.

[PeterCPC]

You could make sure that the mirror is clean and not scratched. The same for the secondary and the EPs. Also check that the tube is not "dinged" and free of rust. Why not ask to look at something in the distance (NOT THE SUN) like a far off telegraph pole and see if it focuses ok and is clear. Make sure all adjuster knobs move ok.

Peter

[damnut]

Godd advice above, new they are c£280, so as long as the optics are ok its a decent deal.

[astrofox]

Dont forget to check the colimation knobs are all correct and no odd bolt has been substituted. Newts are pretty robust instruments and can easily be stripped down to their constituant parts. Collimation may be off but that usually happens to all newts but they are easily tweeked back.

[scarp15]

As above, check the mirrors are clean and that the mechanics are all in good working order i.e. the mount and that the focuser is operating smoothly. As is more often the case with optical equipment such as telescopes, It is most likely that it has been looked after well. Skywatcher reassuringly usually have good figured mirrors and coatings and as mentioned, dobsonians are quite robust to an extent. The savings on new means that you can begin to budget for other required items, mixing new and second hand is the way to achieve what you need, as buying the scope can be often be considered to become the less costly part.