Scratches on Megrez 90

[ReZ]

Hi folks

I do AP and I want to buy a used Apo refrector. I have found this WO megrez 90 and it is a good deal, but it has some scratches on its front glass. the rest of the optic is in a good condition.
Do these scratches have any negative effect on AP? does it make any CA or coma or any kind of problems?

Regards, Rez

[Peter Drew]

Not easy to see which suggests that they would have little or no affect on the performance. If the price is low enough it would be a good deal.i

[JohnSadlerAstro]

I'm not a refractor expert, but if small amounts of finger marks on camera lenses don't really cause any issues, I wouldn't have thought that those tiny scratches would. 

As Pete says, if the scope is at reduced price, it shouldn't me too much to worry about. It's William Optics too-very good quality, I'm told!

P.S. The scratches might cause a bit of reflection--using a dew shield would go a long way to prevent that, though.

John

[timwetherell]

Bit hard to say because your phone camera lens appears to be a bit gunked up too  But if it's just the two little dings I would say the effect would be very small indeed. The main detriment they bring is to the resale value. Anyone buying it from you will want to bargain the price down so providing you do the same, it would probably be fine. Personally I'd rather have a good quality optic with a small scratch than a bad quality one in pristine condition!

[DaveS]

I have a Meg 90 like the one in the photo and can attest to the quality, but it's not for sale. In fact it will have to be prised out of my cold dead hands.

[ReZ]

Thank you guys for your Comments. i will probably buy it

[rl]

It might just be the flash and the photo but the lens seems to have been the victim of some aggressive cleaning that has left a lot of sleaks. If these don't come off this may drop the contrast a lot more than the tiny dings. Might be worth a gentle wipe with some Baader cleaning fluid and their lens cloth before passing over the brown envelope...It's probably all just cosmetic but you have to wonder how a lens gets those dings in the first place. 

RL

[timwetherell]

I wondered that too, but I think the streaks may just be grease on his phone camera lens because they occur on the lettering around the objective too. But yes, definitely something to check because if they are on the objective itself, as you say, that will have a detrimental effect on contrast

[Rob]

Hi There, don't worry you should be fine for AP. As said above, it will be down to over cleaning and not using a bulb blower to remove particles!.

I've said many times before - resist cleaning until you really, really have too. This is mostly when pollen build up gets bad.

I'd love a Meg 90.. been on my list for years!. enjoy it

Rob

[Rob]

16 hours ago, rl said:

Might be worth a gentle wipe with some Baader cleaning fluid and their lens cloth before passing over the brown envelope...It's probably all just cosmetic but you have to wonder how a lens gets those dings in the first place. 

RL

And yes.. agree with a very light touch.. no circles or rubbing

[ReZ]

many thanks guys

 

[DarkTraveller]

I can't help with your imaging question but noticed my own Megrez 90 is f/6.2 - 558mm.  I see a lot of pollen and dust on mine.

[John]

6 hours ago, DarkTraveller said:

I can't help with your imaging question but noticed my own Megrez 90 is f/6.2 - 558mm.  I see a lot of pollen and dust on mine.

My understanding is that all WO Megrez 90's were all F/6.2 scopes with a focal length of 558mm but the earlier ones had incorrect engravings on the objective ring. Yours is a later scope which corrected this engraving error.

 

[JohnSadlerAstro]

@ReZ Did you get the scope in the end?

John

[DarkTraveller]

I think I bought mine just about the time they discontinued the model. It was on sale or clearance at the time.