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150mm PST mod

Posted: Wed Oct 18, 2017 10:16 pm
by bart1805
I was lucky and found a relatively cheap used Skywatcher 150mm F8. So started this weekend with rebuilding the Skywatcher in a 150mm PST mod. Thanks to Paul I will be using the Baader Glasspath 1,25x to get to F10.
The 150mm Skywatcher is 200 grams heavier than the Bresser 127 I use at the moment, The Bresser is build like a tank and has got a good focusser. The focusser of the SW is terrible. Here is what I have done until now:

1) Forgot to take a picture of how it originally looked. But here is a picture I borrowed from the shop where I bought it (without the EQ6 by the way):

ImageDSC_0035-e1502976598634 by bart moors, on Flickr

2) Measured the distance form the focussing point to the focusser by using a bit of duct tape, some paper and a sliding stay for a window. It was about 15 cm.

Image20171014_132044_resized_1 by bart moors, on Flickr

Because it is a 150 mm F8 in the end the etalon has to be positioned at minus 16. So with a focusser that is a bit shorter then the original one there is no need to cut a piece of the tube. Lucky me!

3) Took everything apart, sanded everything. And spray painted the tube white. Removed all the paint of the dew cap and sprayed the dew cap with clear varnish.

Image20171014_152705_resized_1 by bart moors, on Flickr

Image20171015_094929_resized_1 by bart moors, on Flickr

4) It smelled terrible for a couple of days...

Image20171015_230936_resized by bart moors, on Flickr

5) The Bresser had a really nice handle to carry the scope. For this one I made one myself. A couple of pieces of wood and two dovetails. And the solsearcher has been mounted allready.

Image20171017_103025_resized_2 by bart moors, on Flickr

Thanks for reading, to be continued!
Bart.

Re: 150mm PST mod

Posted: Thu Oct 19, 2017 5:33 am
by Carbon60
Coming along nicely, Bart.

Stu.

Re: 150mm PST mod

Posted: Thu Oct 19, 2017 3:11 pm
by bart1805
Thanks Stu!

Some images of today.
The classical comparison between the original lens of the PST and the one of the donorscope:

Image20171019_155532_resized by bart moors, on Flickr

The SW for white light:

Image20171019_153018_resized by bart moors, on Flickr

And with the front mounted D-Erf and etalon train:

Image20171019_152732_resized by bart moors, on Flickr

No need to change the etalon train (here in doublestack), still waiting for the glass path:

Image20171019_152743_resized by bart moors, on Flickr

And the two brothers next to each other:

Image20171019_110830_resized_1 by bart moors, on Flickr

Thanks for watching!
Bart.