Collimating a William Optics Star 71

[ianaiken]

Well that worked well. It was on very tight. I need to do a star test ideally with a real sky.

[Pompey Monkey]

22 hours ago, Jonk said:

16 minutes ago, ianaiken said:

Well that worked well. It was on very tight. I need to do a star test ideally with a real sky.

 

[Pompey Monkey]

Jonk said what?

 

[Pompey Monkey]

18 minutes ago, ianaiken said:

Well that worked well. It was on very tight. I need to do a star test ideally with a real sky.

Hooray, I got to where I wanted to be!

Glad that worked, Ian. I didn't realise that you are a cyclist until I clicked through to your website, so I guess you actually used proper cone spanners?

[Jonk]

2 hours ago, Pompey Monkey said:

Jonk said what?

 

What did I say?!

Confused...

[Pompey Monkey]

47 minutes ago, Jonk said:

What did I say?!

Confused...

Jon, I couldn't get rid of your name in the quote, even though I was replying to Ian...

"<Name> said what?" is a bit of an internet joke in some circles. Sorry to confuse!

More relevantly, the cloud has just arrived in Portchester

[Jonk]

Ha, that'll teach ya! Always clear in Southsea, except when it's not.

So, you happy with the star 71 or are you still trying other things?

[Pompey Monkey]

1 hour ago, Jonk said:

Ha, that'll teach ya! Always clear in Southsea, except when it's not.

So, you happy with the star 71 or are you still trying other things?

I was feeling happier, but then I saw Gnomus' stars in his Markarian chain, taken with the same scope and same chip as me: 

Even though he's processed it more carefully to reduce the star bloat than my quick and dirty test, all of his stars are ROUND. Mine aren't

I'm not sure that I'll ever now sure that I'll never be satisfied with it, even though it still probably still out performs something like an ED 80 pro with reducer.

Unfortunately, I'm now very enamoured of the wide fov (approximately 3 by 2 degrees!). I should've saved up for a baby Q with a reducer....

Ain't hindsight a wonderful thing. lol.

[gnomus]

 

1 hour ago, Pompey Monkey said:

I was feeling happier, but then I saw Gnomus' stars in his Markarian chain, taken with the same scope and same chip as me: 

.......

I should've saved up for a baby Q with a reducer....

Ain't hindsight a wonderful thing. lol.

Thanks for the name-check Pompey.  I feel for you because I had terrible problems with the scope I had before the WO which was (you've guessed it) a Baby Q.  If you want to read my sorry tale (you'll probably need strong drink before starting) then it can be found here: https://stargazerslounge.com/topic/255860-ovoids-with-mesu-and-tak-fsq-85/?page=1  I returned my Baby Q and would be very wary of dipping my toe back into Takahashi waters.  I do not believe that I am the only person to have had Baby Q issues.  During my issue I spent some time looking at the corner of Baby Q images on Astrobin and such like.  On the other hand, I have used Olly's dual FSQ 106 rig and that was terrific.  

For balance, I should say that plenty of excellent imagers here swear by their Baby Qs and get fantastic results with them.  The issue for me is what happens when you get a duff one.  It seems to me that a top class retailer (such as FLO) is essential.  My first WO 71 had to go back to FLO because my stars were 10x worse than yours all over the field.   You call yours 'acorns': mine were badminton shuttlecocks.

[ianaiken]

22 hours ago, Pompey Monkey said:

Hooray, I got to where I wanted to be!

Glad that worked, Ian. I didn't realise that you are a cyclist until I clicked through to your website, so I guess you actually used proper cone spanners?

Yes, which is why I got excited when I saw your solution! Proper cone spanners with curved edges so it would have been hard to scratch the lens anyway. I tried a test with my dslr on afterwards but the star was really way too small to get any idea if it is better. It still looked a bit acorn shaped, which is a shame.

[Jonk]

Too many acorning lenses out there part of the reason for discontinuing it?

Did I read Olly say that he suspects the scope was too cheap (hence lower tolerances, qc etc)?

I think FLO also were weary when it was released, given its price.

Even expensive items can go wrong, but in terms of ratio, the higher priced things should have more of the better, than more of the worst.

I've seen a lot about the star 71 and the fact that there's a lot of poor ones about unfortunately.

Still waiting for the mk2 and will see whether I should get one.

If you can get it sorted I'm sure you'll be more than happy. I'll also be more confident in buying one knowing they can be sorted if poor.

[ianaiken]

1 hour ago, Jonk said:

Too many acorning lenses out there part of the reason for discontinuing it?

I didn't realise it was discontinued so soon.

[Pompey Monkey]

18 hours ago, gnomus said:

 

Thanks for the name-check Pompey.  I feel for you because I had terrible problems with the scope I had before the WO which was (you've guessed it) a Baby Q.  If you want to read my sorry tale (you'll probably need strong drink before starting) then it can be found here: https://stargazerslounge.com/topic/255860-ovoids-with-mesu-and-tak-fsq-85/?page=1  I returned my Baby Q and would be very wary of dipping my toe back into Takahashi waters.  I do not believe that I am the only person to have had Baby Q issues.  During my issue I spent some time looking at the corner of Baby Q images on Astrobin and such like.  On the other hand, I have used Olly's dual FSQ 106 rig and that was terrific.  

For balance, I should say that plenty of excellent imagers here swear by their Baby Qs and get fantastic results with them.  The issue for me is what happens when you get a duff one.  It seems to me that a top class retailer (such as FLO) is essential.  My first WO 71 had to go back to FLO because my stars were 10x worse than yours all over the field.   You call yours 'acorns': mine were badminton shuttlecocks.

Steve, Thanks for the heads up. I have just finished reading your thread and it is a tale of woe indeed.

I have given up on my Star 71 now as it is sapping all of the fun out of this hobby for me. I enjoy the technical challenges, yes, but not to the extent of trying to fix something that should just work out of the box.

Lessons I have learned about buying an imaging refractor:

1. Unless you have had first-hand experience with the 'scope and seller, do NOT buy second hand, buy new, so that a return/compensation can be made;

2. Buy new, using a credit card;

3. My Skywatcher 150 pds (with coma corrector) really is fantastic value for money. And I can collimate it myself.

3. Er... Buy new!

I'm going back to my Newt while I ponder my next move - less smoke, more mirrors

BTW, if anyone who's read this thread is feeling adventurous, or who thinks the stars are acceptable (they probably look better in a DSLR), keep an eye on the Classifieds...

 

[Jonk]

Send me a pm if you give up on it, I may be able to bring my stuff up to you to test one night?

[gnomus]

3 hours ago, Pompey Monkey said:

Steve, Thanks for the heads up. I have just finished reading your thread and it is a tale of woe indeed.

I have given up on my Star 71 now as it is sapping all of the fun out of this hobby for me. I enjoy the technical challenges, yes, but not to the extent of trying to fix something that should just work out of the box.

Lessons I have learned about buying an imaging refractor:

1. Unless you have had first-hand experience with the 'scope and seller, do NOT buy second hand, buy new, so that a return/compensation can be made;

2. Buy new, using a credit card;

3. My Skywatcher 150 pds (with coma corrector) really is fantastic value for money. And I can collimate it myself.

3. Er... Buy new!

I'm going back to my Newt while I ponder my next move - less smoke, more mirrors

BTW, if anyone who's read this thread is feeling adventurous, or who thinks the stars are acceptable (they probably look better in a DSLR), keep an eye on the Classifieds...

 

It is a geat pity. As you can see, I was spending all of my hobby time testing and that was no fun at all.   

I have bought some second hand stuff, including a rather expensive second hand scope (a Dob which I am really enjoying).  You do take a bit of a risk I suppose.  

I am considering a longer focal length refractor.  A few scopes have caught my eye, but the Tak experience has had an impact.  I am keen to buy only from retailers from whom I have had good (or even reasonable) service and in whom I have confidence.  That rules out 2 major players (so far)!  

 

 

[ollypenrice]

Frustrating, isn't it, that great optics are not given the mechanical infrastructure in which to work properly.

Interesting to note the significant difference in 'fit and finish' between the inside of a WO and the outside.

Olly

 

[Pompey Monkey]

26 minutes ago, gnomus said:

It is a geat pity. As you can see, I was spending all of my hobby time testing and that was no fun at all.   

I have bought some second hand stuff, including a rather expensive second hand scope (a Dob which I am really enjoying).  You do take a bit of a risk I suppose.  

I am considering a longer focal length refractor.  A few scopes have caught my eye, but the Tak experience has had an impact.  I am keen to buy only from retailers from whom I have had good (or even reasonable) service and in whom I have confidence.  That rules out 2 major players (so far)!  

 

 

I have a lovely 10" revelation dob that I, too, bought second hand - nothing wrong with it at all.

With my light pollution (both local and general) imaging is the way to go. I have spent literally hours pouring over the handful of satisfactory images that I've produced in the last year and I find that absorbing and enjoyable in a way that even the romanticism of having original photons hitting my retina can't match. I want to make more and I want to see how deep I can go from my sub-urban environment. You know that there are 16th magnitude galaxies on that 36 minute luminance stack of the region around Capella? That's nuts! It means with four hours I'll get to the 17th magnitude and eventually down to the 18th if I can accrue 15 hours combined exposure plus.

Unfortunately imaging requires good optics to do it justice and I cannot afford to spend £2.5k on a new BabyQ, especially if I end up going round in the same circles. On the other hand, I've also had direct experience of Olly's Tak and it's a wondrous device, so I'm sure that good ones exist aplenty.

I'm not giving up, but I think I'll go back to my trusty 150 pds for a while and hone my capturing and processing skills.

[Pompey Monkey]

5 minutes ago, ollypenrice said:

Frustrating, isn't it, that great optics are not given the mechanical infrastructure in which to work properly.

Interesting to note the significant difference in 'fit and finish' between the inside of a WO and the outside.

Olly

 

I made up the OTA for a 6" Newt when I was a kid (from bought optics) and the draw-tube was guided in the focuser by exactly the same method: Teflon strips. To give credit where credit is due, the focuser does have a nice action and will progress nice and smoothly towards the critical point when coaxed to do so.

The WO looks sexy, so it sells. The innards are rather less honest. A bit like our politicians

Have you ever had a Tak focuser apart Olly? I suppose you've had no need...

[ollypenrice]

Just now, Pompey Monkey said:

I made up the OTA for a 6" Newt when I was a kid (from bought optics) and the draw-tube was guided in the focuser by exactly the same method: Teflon strips. To give credit where credit is due, the focuser does have a nice action and will progress nice and smoothly towards the critical point when coaxed to do so.

The WO looks sexy, so it sells. The innards are rather less honest. A bit like our politicians

Have you ever had a Tak focuser apart Olly? I suppose you've had no need...

No, I never have but there are lots of pictures on the net.

Olly

[Owmuchonomy]

It is very frustrating isn't it.  I eventually got the well known manufacturer (not WO) of my EDT 102mm to take it back and fix it.  When it was returned to me it was so bad it showed CA on the stars!  When I queried what QA/QC the manufacturer had applied I was greeted with stony silence.  Fortunately my local retailer was magnificent and sorted out a complete refund for me even though it was well out of warranty.  I then picked up a used 130 PDS for 1/15th of the price of the triplet and immediately got much better results and I haven even fettled it yet.

[Pompey Monkey]

2 minutes ago, Owmuchonomy said:

It is very frustrating isn't it.  I eventually got the well known manufacturer (not WO) of my EDT 102mm to take it back and fix it.  When it was returned to me it was so bad it showed CA on the stars!  When I queried what QA/QC the manufacturer had applied I was greeted with stony silence.  Fortunately my local retailer was magnificent and sorted out a complete refund for me even though it was well out of warranty.  I then picked up a used 130 PDS for 1/15th of the price of the triplet and immediately got much better results and I haven even fettled it yet.

I have a 150 pds and a 130 pds for <cough> "spares". Both were purchased from Astroboot for just over a ton each. Mint both of them. The 130 is still in it's box in the loft. The 150: I've chopped 15 mm of the primary end of the OTA to avoid the draw tube diffraction problem, I've added the third screw to the eyepiece holder and I've tightened the Crayford so it doesn't slip. All three fettlings were well worth the effort. The only issue now is that one of the spider arms is either twisted or slightly non-colinear with the its opposite, so I get double diffraction spikes on bright stars.

At least I know how to try to fix it!

[Owmuchonomy]

My 130 PD-S suffers from the 'pacman' star bite.  So I need to shorten the draw tube OR get the MPCC further into the said tube than I can now.  Other than that it is pretty good to go.  I could flock it etc., but maybe in the summer whenever it appears.  Like you, it cost me a ton.

[ianaiken]

8 hours ago, Pompey Monkey said:

Steve, Thanks for the heads up. I have just finished reading your thread and it is a tale of woe indeed.

I have given up on my Star 71 now as it is sapping all of the fun out of this hobby for me. I enjoy the technical challenges, yes, but not to the extent of trying to fix something that should just work out of the box.

It's a pity. I feel the same way I seem to be obsessing about trying to fix it when really it should have been replaced then ultimately just returned.... I've had it too long now though. I've still not tested it on a real sky since I've been testing it with an artificial star so maybe it might be OK. But, it's got me thinking into replacing it.

[ianaiken]

Well after loosening both the primary cell and also the built in flattener I can say the star shapes are massively improved that they are no longer acorn. I collimated using CCD Inspector but after slewing noticed there was some tilt due to the draw-tube being a bit loose so I need to address this. Problem is to get it collimated it appears that the two brass screws need to be set in a specific place, which is not tight enough to hold the draw-tube steady. I guess I need to investigate the focuser to see if I can adjust from that side (or if anyone has any other ideas).

The other thing is that I'm using a lakeside focuser and I have measured that there is backlash. So when SGP was running it's auto focus routine it was travelling in OK but when it travelled out it wasn't moving to the correct place resulting in slightly out of focus stars. I think I have the backlash resolved now too. It would be better if I could put something on it like a Baader SteelTrack, the new diamond as that is solid.

[Pompey Monkey]

30 minutes ago, ianaiken said:

Well after loosening both the primary cell and also the built in flattener I can say the star shapes are massively improved that they are no longer acorn. I collimated using CCD Inspector but after slewing noticed there was some tilt due to the draw-tube being a bit loose so I need to address this. Problem is to get it collimated it appears that the two brass screws need to be set in a specific place, which is not tight enough to hold the draw-tube steady. I guess I need to investigate the focuser to see if I can adjust from that side (or if anyone has any other ideas).

The other thing is that I'm using a lakeside focuser and I have measured that there is backlash. So when SGP was running it's auto focus routine it was travelling in OK but when it travelled out it wasn't moving to the correct place resulting in slightly out of focus stars. I think I have the backlash resolved now too. It would be better if I could put something on it like a Baader SteelTrack, the new diamond as that is solid.

The screw holes just forward of the finder bracket positions could be used for nylon guide screws that push on the draw tube. Be warned that the grub screws already fitted are too short for this and could well end up inside the tube (at least on my version!). I got some 10 mm M5 (yes, M5!) nylon grub screws that seemed to do the trick, holding the draw tube very steady indeed from everybody's favorite online auction site.

Using this method will, however, reduce the focuser travel to approximately 25 mm...

How much did you loosen the flattener screws by? did you have problems with the glue?