Mirror life of Skywatcher.

[John]

Out of interest then , how much is a re coating of a primary . Obviously I'm assuming size = more money.

For an 8" mirror it seems to range in the UK between £80 and £100 including shipping and around £120 - £150 for a 12" mirror.

[barkis]

Mirror with no coating at all will still give results, not as bright certainly, but they still produce.

Most mirrors, even newly coated ones can  have pin holes, nothing at all to worry about, their affect on performance is zilch.

Even dirty surfaces will perform, even if the images are degraded a little. However, if a dirty mirror is badly cleaned, that can and will

make it worse than if you'd left it alone.

Ron.

[rory]

For an 8" mirror it seems to range in the UK between £80 and £100 including shipping and around £120 - £150 for a 12" mirror.

Not as much as I suspected at least .

[Beulah]

Thanks for that Ron, your expert advice is reassuring. 

[rory]

ok, I visited the seller today and happy to say all looked fine.  it has chrome knobs for collimating the primary ,not alen key screws which confirms its an older design .

 it has I believe a R&P focuser , im not sure when skywatcher  changed to Crayford focusers.

 the mirror looks in good order and the dob base shows no swelling from damp ect.

all in all im happy with the deal.

looking forward to many cloudy nights now tinkering and modifying .

 appy days ...nights

[Avocette]

Good news! Did you get a couple of Super Plossls with it?

[rory]

Good news! Did you get a couple of Super Plossls with it?

Actually no, a 20mm Skywatcher ler and bog standard Barlow . No caps on them but tidy and clean all the same . Also no lens cap for the finder scope.

The base was a little stiff . I took apart to see at some stage some kind of grease was used in attempt to lubricate and add smoothness. I cleaned it all off and put it back together and simply didn't tighten the centre nut and bolt too much . Now much better .

Even managed a 20 minute test last night and had a peep at m31 .

It seems well collimated , stars were pin sharp.

I also found it lighter to lift than expected , didn't feel much different to the 8" smaller brother to me .

[Avocette]

I also found it lighter to lift than expected , didn't feel much different to the 8" smaller brother to me .

I've had both side by side to compare in the past and decided that the 200p wasn't really any more convenient from the weight and bulk point of view. But I added Bob's Knobs to the 200p so I couldn't stand the OTA on its mirror end on carpet like I can with the (older) 250px. I'm keeping the 250px in the garage at the moment and it's quite possible to carry assembled (lift higher and keep close to your chest), but normally I separate the OTA from the mount for transport in and out of the house (and up and down stairs to the storage place). In use I always put the mount on a water butt stand with levelling feet as shown in this posting http://stargazerslounge.com/topic/205732-my-sw-skyliner-200p-additions-and-modifications/