Willam Optics Star 71 5 element Apo Astrograph

[Robp]

1 hour ago, Droogie 2001 said:

Thanks. I realise some people will think that its my fault for mounting it on a low end mount (the AVX) but I know people with similar cost mount i.e. HEQ5 do seem to have had less issues in balancing...

I don't think its a problem with the Mount but more of a case that the scope is so small and light that adding a bigger camera to the rear causes it to be rear heavy. You have to offset this with a weight at the front.

I don't have this issue because my camera is relatively light and I have a finder guider mounted on top and slightly towards the front of the scope. I think this offsets the Camera weight at the back, by luck, perfectly.

Looking at your image, could you not mount the finder guider a little more forward to offset the weight?

[Droogie 2001]

Hi Rob,

I guess you are right. The finder guider was a joy to fit as well  If I remember correctly I think I was limited to how I could attach the Orion Guidescope to the small dovetail, but I will give this some consideration. I think the balancing issue can be resolved by adding a dovetail counter weight.

 

 

[Robp]

Adding the weight would do it ? 

What about some sort of strap weight that fitness fanatics wear around there wrists? 

This is how my scope is setup

 

[gnomus]

2 hours ago, Droogie 2001 said:

I wish I could send you a photo of my rig, but I have taken it off the mount for now - I have my SCT on for lunar & planetary work for the next week or so.  The counterweight system I bought was this one:

http://www.teleskop-express.de/shop/product_info.php/info/p750_Baader-1-kg-tube-balance-weight-for-3--prism-rails.html  I thought I'd got it from FLO, but they don't seem to have this in stock at present.  Nonetheless, the item you have linked to is virtually identical.  I got a second 1kg weight which simply screws into the bottom of the first weight.  It is attached flush with the edge of the Losmandy Plate (the left edge in your photo) .  I have taken the Star 71 off of the Vixen plate and attached it well forward on the Losmandy.  I have a 14" Losmandy plate  - the front of my lens hood is roughly flush with the front end of the Losmandy.  

I too have my focuser facing upwards (I also have a Lakeside Unit on it which makes things even bulkier).  My camera/filter wheel combo is also angled upwards so that I can get the telescope well forward.  I have an ST80 fixed to the top of the WO Star 71 as my guide scope.  It will likely be heavier than your finder guider.  But I note that that long extender on your finder guider has the effect of bringing it far back, such that it is almost over the camera.   Can you attach this further forward I wonder?

If you look at your photo you will see that virtually none of your weight is in front of the mounts centre of gravity.  I can see why you are having issues.  Take a look at PhotoGavs's picture of his set up and compare it with yours.  I think you need to get things well forward.  

[PhotoGav]

Droogie - you definitely need to get everything further forwards. A long vixen plate will help and turning the scope upside down will be essential, which will cause an issue with the finder... I can see why you are cursing things at the moment! Do you really need the finder as well as the guider? As with all of this astrophotography mullarkey, there is always a way, but much patience will be required to find it!

[Droogie 2001]

Thanks for all of the replies. I wont be able to move the OTA further up the plate unless I turn the scope upside down which may be on the cards. This is my gripe about the STAR 71, you can see from my picture that the focuser lock will collide with vixen plate as well will the focus dial itself. I also should not have to turn a scope upside especially when its designed as a Astrograph.
I have considered a different ADM dovetail but that's just going to result in the same issue. Maybe large OTA tube rings that lift it higher, though that sounds like another complete can of worms..

I think for balancing the Vixen counter weights are the way to go.

It is all very frustrating. The issues seem to require money to be thrown at it and whilst I am more than prepared to do so (and have done) there is no guarantee it will fix it. We as hobbyists don't really seem to have the option to take the kit to a shop and say sell me the exact stuff that will solve this! Especially if you have purchased kit from all different vendors. Anyway I need to sort the back focus out first. When that's sorted I will consider how to finally resolve the balancing issue.

 

[Davey-T]

I always mount the camera upside down, can't see it's a problem.

Dave

[Droogie 2001]

Do you mean the OTA or camera? Trying to work out how the camera being upside down would help?

[Davey-T]

2 minutes ago, Droogie 2001 said:

Do you mean the OTA or camera? Trying to work out how the camera being upside down would help?

Yes camera and focuser up 'tother way.

Dave

[Droogie 2001]

Thanks.

[gnomus]

I've asked before - what is 'upside down'?

The telescope produces an imaging circle.  Whatever way the camera is, it will be the other way up after a meridian flip.  

Having said all that, if you are not happy with the scope then maybe you should return it, or sell it on.  I had to do this with my Tak FSQ 85 which cost considerably more than the WO.  Incidentally, the FSQ also had to be moved well forwards to get this in balance.  I bought my counterweight when I had the FSQ - the scope I had before the WO 71.  With the FSQ I had to have the filter-wheel pointing 'upside down' to clear the Losmandy.

[gnomus]

Incidentally, I found a photo of the WO rig on my iPad.  The photo is not very good and I have no idea why I took it (indeed I can't remember taking it).  But I hope it shows you what you are looking for.   I don't think this is an overly heavy set up, and I am sure that my Celestron CGEM mount would have coped with it.     

[Droogie 2001]

Lovely setup Gnomus. I have no intention of selling the scope, to be honest I would imagine the same problems will apply to most setups. Don't get me wrong I am not adverse to mounting it upside down so please don't take offence (none is meant)  it just means that it will introduce yet more changes and configurations, the guide scope, the RDF (which I may be able to ditch). I may have no choice in this and I am certainly appreciate everyone's ideas to a solution. I am just trying to cover all possible options.

I am still new to CCD's and despite taking nearly a year on planning what I wanted from the CCD (as well as the OTA) it seems that the obvious concerns such as balancing and indeed just mounting the kit were overlooked by me. My in experience really I guess...

[gnomus]

3 minutes ago, Droogie 2001 said:

Lovely setup Gnomus. I have no intention of selling the scope, to be honest I would imagine the same problems will apply to most setups. Don't get me wrong I am not adverse to mounting it upside down so please don't take offence (none is meant)  it just means that it will introduce yet more changes and configurations, the guide scope, the RDF (which I may be able to ditch). I may have no choice in this and I am certainly appreciate everyone's ideas to a solution. I am just trying to cover all possible options.

I am still new to CCD's and despite taking nearly a year on planning what I wanted from the CCD (as well as the OTA) it seems that the obvious concerns such as balancing and indeed just mounting the kit were overlooked by me. My in experience really I guess...

Thanks.  I wasn't taking any offence - I am sorry if it came across that way.  I'm trying to be helpful.  I think these 'electronic' communications because they are brief and informal are often prone to misinterpretation.  (Or perhaps I am just a curmudgeon).  I do sympathise with you - because I have been through all of this.  A Canon weighs a lot less than these CCD thingamajigs and I don't think that scopes are necessarily designed with CCD imaging in mind.  I've had to have loads of extra 'bits' to get things working as they should.

I would certainly stick with the Star 71 if I were you, because, if you have a good copy, I think it produces cracking images (plenty of which I have seen on SGL).  If you do decide to sell it - be careful you don't lose any fingers - because several people will be biting your hand off for it!!!!  

[Droogie 2001]

Thanks. I think it was me just being a bit sensitive  As you say this whole experience is tiresome but I will get there. Thanks to advice from this thread.

[gnomus]

You may well not need the RDF.  Have you looked into the murky world of 'plate solving' yet????   

[Droogie 2001]

Yes. Least said the better.

I have got it working Astro Art but struggled with SGP. Though have just got a new trial of SGP and that is my next target to crack!

[gnomus]

Good luck!!  I use SGP and like it a lot.  

[AndyUK]

(I also thought of mentioning an OAG, but decided I'd probably better not... )

[gnomus]

1 minute ago, AndyUK said:

(I also thought of mentioning an OAG, but decided I'd probably better not... )

I would like to fit an OAG to my set up (to 'simplify' - LOL) but have the opposite issue to Droogie - I will not be able to get the focus tube forward enough if I do that.  

[AndyUK]

That's a shame ...  But it would be a possible option for Droogie - It would add 26mm, and with the Moravian, that would give 55mm (leaving 11.4mm to pull out on the focuser, which, in theory, would be great).

However, the Moravian OAG platform has a part that juts out, and it also has one of the 3 guide scope attachment thumbscrews forward facing - I suspect that at least one or the other would get in the way and you'd need a 10mm M48 spacer to avoid them  (although I guess the forward facing screw could be replaced with a grub screw).

(Why is it never easy...?!)

[ollypenrice]

What we did on one of the robotic scopes I host was insert a length of square section steel between the scope and the dovetail. This just involved drilling four holes. So the length of square section steel is bolted to the dovetail bar and the scope rings are bolted to the opposite side of the square section steel. This gives room for motor focusers, lock screws, whatever, underneath the scope because it is now raised up a little and it can be moved further fore and aft as balance dictates. I agree there is no right way up for a scope but sometimes both top and bottom of the focuser become crowded.

Olly

[PhotoGav]

Sorry to go slightly off topic here, but I have to ask:

Gnomus - what was wrong with the FSQ 85? You're not the first person I've heard who has 'got rid of' a babyQ. I lusted after one, but ended up spending less on the Star 71. I still wonder if I would rather have an FSQ85, so please give me some ammo to stop those expensive thoughts! Also, what size obsy do you have - looks great.

 

[gnomus]

Easy things first: the observatory is around 13' x 9'.  There is a ~ 9 x 9 'observatory' and a ~ 9 x 4 warm room.  Built by Home Observatory, UK whom I would heartily recommend.

FSQ85:  You are right - I am not the first person to have returned an FSQ 85 - ask around.  Take some paracetamol and strong liquor before reading this, if you really must: https://stargazerslounge.com/topic/255860-ovoids-with-mesu-and-tak-fsq-85/?page=1

As a counter to my problems, there will be plenty of folks here who are perfectly happy with their FSQ 85s and who do not experience the issues I have experienced.  I 'lusted after' an FSQ 85 and was disappointed with the experience. I am, by contrast, very happy with my WO Star 71 and I am getting round stars into all corners.  I should say that my first WO Star 71 had something wrong with it and stars (corners and centre) looked like badminton shuttlecocks!!!  I have no idea what caused this.  I contacted the supplier - FLO - and I had a replacement WO Star 71 in my hands the following day, without any fuss or questions about my competence (or lack thereof).    

My experience has led me to conclude that the supplier may well be equally as important as manufacturer (maybe even more so).

I could not be persuaded back into the Tak fold (no matter what Olly (my spirit guide in all other matters astronomical) might say  ).   

[swag72]

6 minutes ago, gnomus said:

My experience has led me to conclude that the supplier may well be equally as important as manufacturer (maybe even more so).

 

I think that is a VERY relevant and important detail indeed   

A retailer that you can trust and who you know will deal with issues quickly and without issues is worth their weight in gold in my opinion. I'm not sure I would change my scope requirements for example based on the fact that I could not be best served by a retailer of choice.... but it is certainly a consideration.