Orion Optics UK VX200 modifications (or astronomy on a shoestring).

[ukskies]

As some of you may remember last year I bought a cheap used Orion Optics VX200L off ABS as a project scope as I was going to make it into a Dob. 

The mirror was covered in a thin layer of dust so I carefully washed it but many particles have become ingrained. As I bought it with a view to possibly re-figuring the mirror myself however I wasn't too worried. The secondary spider was an odd twin circle arrangement and I was undecided what to do with it and the mirror cell was badly assembled so the mirror did not sit centrally in the tube. All these little issues added up to a decision to shelve it until time would allow. It has since remained stored, stripped in my garage and been forgotten until two weeks ago when I decided I should really do something with it.

I was thinking that my new Tak DF could do with a companion and that an 8" Newt might just make a good one.

Also I have more recently picked up a mint 2004 Vixen Sphinx SXW mount with Starbook 1 from the original owner and an Orion Optics three legged pier (thank you Cliff if you are reading this), perfect for the newt and into the bargain it came with an I-polar adaptor and the I-polar scope and one very large counterweight. 

I took another look at the primary, quite a few marks are visible and it offends the perfectionist in me however it is still highly reflective and I've no doubt usable, the secondary mirror is fine and usable as is the finder. Why don't I simply rebuild it and use it a few times to at least assess if I actually want to own an 8" Newt? 🤔

The primary cell has to be re manufactured but then I would have a very usable scope! This then, 2 weeks ago is where this story begins:

Hopefully in a few weeks time a first light report will be where this story concludes. Watch this space for the filling....

P.S

Mods if this is in the wrong forum my apologies and please move it.

Edited March 15 by ukskies

[ukskies]

I had hoped to update this thread a little sooner but life had other plans.

The mirror cell had 2 issues that I felt needed resolving. 

1. It hadn't been built square causing the mirror to not sit centrally in the tube.

2. the screws for adjusting collimation were close to the centre of the mirror making them very sensitive.

First jobs then were to square things up and move the collimation screws to nearer the edge of the tube. the tube is an open ended affair so there was nothing to hamper access to the screws.

[ukskies]

1. the open ended tube arrangement.

2.The primary on first inspection.

3. The original date stickers.

4. The cell showing mirror supports (more later) and you can also see the misaligned assembly just about.

5. The bottom of the cell showing the position of the collimation screws.

[ukskies]

The arms of the two top and bottom parts of the cell were not lined up and this caused a twist in the cell which put the mirror off centre in the tube.

I decided to strip the cell, align these outer arms and then re-drill and tap for the collimation bolts out on the arms for more mechanical advantage thus making them less sensitive.

[ukskies]

1. Another pic of the misaligned arms. In this pic it doesn't look anywhere near as bad as it was tbh.

2. The two halves of the cell aligned properly and taped in place then pilot drilled with a vertical pillar drill. These holes were then drilled out to the correct size for the 6mm tap and then the thread was tapped into them.

3. The 6mm bolts threaded through the top half of the cell (looking from underneath). I countersunk the bolt heads and used countersunk bolts to keep the heads flush with the top of the cell.

4. The springs fitted over the bolts prior to re-assembling the cell halves.

5. The re-assembled cell ready for the primary. WE actually this didn't happen as I decided I might as well improve the 3 point mirror support screw arrangement.