William Optics Zenithstar ZS71 ED 2013

[ollypenrice]

Thats good to know i am a bit of a widefield freak 330mm is a nice number.

Alan

Thanks Olly

Me too. With an 8300 chip the reduced Baby Q is right in its comfort zone. It's the only painless sub F4 instrument of which I'm aware. (I have a very low optical pain threshold though!!!)

Olly

[sloz1664]

Just picked this up. Yep my Z71ED 2013 suffers from blue bloat. With its speed  f4.72 its ideal for NB. I now use a triplet for my RGB.

Thanks Olly for the Blue Bloat routine.

Steve

[gingergeek]

I still have my ZS71 & FR and I found it bloated in the blue so I bite the bullet and got a Tak BabyQ. However the less than intelligent placement of LED street lights by our unapproachable councils prevent me from doing RGB regularly but the one limited test I did do showed the Tak had the blue under control.

BTW - still got my first scope and camera which were a SW ED80 and modified cannon 1100d. The blue did bloat on the ED80 but not as bad as the ZS71.

[lensman57]

Hi Martin,

My ZS 71 does show a little blue too , nothing to get too concerned about though. I have also seen images taken with a Borg or Tak ( not the FSQ80 or the 100 ) that show a little blue and thses cost 5 6 times as much. In the final analysis the ZS71 has excellent build quality, a great focuser and it only cost less than £370.00. I have also got a WO Star 71 on back order from IK which I will use for a twin rig, Star 71 for RGB or OSC and the ZS 71 for Ha, well that is the plan.

Regards,

A.G

PS: I also have a Megrez 72 that I bought second hand and this one seems to have a lot better control of the blue.

[ollypenrice]

Certainly the Tak Sky 90 and FS60 doublets are far from perfect regarding the blue. Personally I wouldn't pay the asking price for either but the quadruplets are another matter. I still think the ED80 borders on the supernatural for the price.

Olly

[lensman57]

Certainly the Tak Sky 90 and FS60 doublets are far from perfect regarding the blue. Personally I wouldn't pay the asking price for either but the quadruplets are another matter. I still think the ED80 borders on the supernatural for the price.

Olly

I agree with you there Olly, my ED 80 ( the older blue  version ) certainly seems more corrected that it has any right to, perhaps the use of the FPL53 glass and the slow F7.5 has something to do with this and as a " jack of all trades scope "  it is certainly in a class of its own. The problem for me is that with its native 600mm of  FL, 510mm with the 0.85X FF/FR it is just not wide enough in particular for a beginner on a budget,  for widefield imaging unless it is coupled  with a DSLR ( cheap but not ideal ) or a large CCD which is expensive to say the least but it is a great scope none the less.

Regards,

A.G

[Earl]

The ED 80 is imo an odd beast, good optics, its not been pushed hard hence gives good colour correction, yet the focusers on these really does let them down, I do know some get them to work. but it should work fine out of the box like the glass does.

Due to the cost of a good focuser it adds around £300-400 especially if you wish to have remote focusing.

If they just sold the tube and cell allowing the user to add focuser and rings it would be great.

[ollypenrice]

There are some truly bad focusers out there and WO have been at the cutting edge of making them worse! However, they seem to have repented by going towards R and P. 

Olly

[sloz1664]

I must admit Olly the R&P focuser on the WO Z71 is very sturdy, pity the optics aren't on the same wavelength (wavelength, get it    )

Seriously, if the optics were of SW ED80 quality, which is a budget scope also, you would have a seriously good scope for the price.

Steve

[ronin]

The problem is that the WO is f/5.9 and the ED80 is f/7.5.

The glass properties are pushed more on the WO and so some performance is lost.

Apo triplets are not usually pushed to below f/6, so a doublet finds performing at that speed even more difficult.

If they made the ZS71 as an f/7 or f/7.5 scope I think it would be a very nice little item.