200p and the 200px (skyliner dobsonian)

[tomlines]

hi guys

purchasing the skywatcher skyliner 200 auto dobsonian

got a great deal

455 with a power cable and scope cover

can any one shed any light on what the difference is between the p and the px version of this scope?

im pretty sure these are being discontinued as we speak so im ordering mine now as there guna faze out the autos for the go-to's

big price difference!!

any one help at all?

just wanna ake sure theres no big difference im missing out on

thanks guys

[RikM]

I am not aware there is a PX version of the Skyliner 200. The 250 is a PX which I believe is down to the Pyrex glass used for the primary. Something to do with lower thermal expansion so better performance with faster cooldown times. I don't think it makes a jot of difference. All the SkyWatcher Newts I have used from 130, 150, 200, 250 and 300 have been very good performers and great value for money.

[bombassa]

There IS a 200 pyrex version. The difference seems to be about 50 euros.

I have no idea if there is a practical (and noticeable) difference.

[j45on]

The blurb in the catalogue reads

" primary mirror made of low thermal expansion pyrex glass resulting in substantially shorter cooling times "

I suppose it comes down to where you are going to store the scope

My catalogue only lists a 250px though ?

[swamp thing]

Pyrex differs to plate glass in its reaction to temperature change.

However TBH in smaller sizes the difference would barely be worth worrying about.

There should be no difference in optical quality.

Regards Steve

[bombassa]

J45on: Skywatcher Skyliner-200PX / 200/1200mm Pyrex Dobson

Steve: Thanks for your info. How small is small in your opinion? 8" I guess? How about the 10"?

Regards

[LukeSkywatcher]

I was reading something here recently about pyrex glass being used in scopes. I couldnt quite get my head around it. I suppose it makes sense.

[swamp thing]

J45on: Skywatcher Skyliner-200PX / 200/1200mm Pyrex Dobson

Steve: Thanks for your info. How small is small in your opinion? 8" I guess? How about the 10"?

Regards

Sorry! Yeah I'm referring to an 8" as a smaller mirror. A 10" is sort of medium to my kind of thinking, but even that I wouldn't worry about.

Although Pyrex reacts to temperature change three times less than plate glass, the plate glass stabilises three times quicker. So it's much of the same.

Regards Steve

[bombassa]

Sorry! Yeah I'm referring to an 8" as a smaller mirror. A 10" is sort of medium to my kind of thinking, but even that I wouldn't worry about.

Although Pyrex reacts to temperature change three times less than plate glass, the plate glass stabilises three times quicker. So it's much of the same.

Regards Steve

Thanks again.

Regards,