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Willam Optics Star 71 5 element Apo Astrograph


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I'm not sure I understand the point of getting a finder.  Why not just plate solve and let the software align the scope for you?

I only mention  this as I went through this whole process and found that as I am only interested in taking images and I assume that having  chosen the Star71 the same applies? 

Fire up Sequence Generator Pro or whatever  plate solving compatible software you use, tell it what you want to image and let it figure it out all on its own. 

Spend the money saved on an autofocuser  maybe :)

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Ok so I feel like a void has just opened up beneath me. Yes I only want to image with the Star 71. Not familiar with plate solving though Astrotortilla is a popular choice from what I have read. I have all of the ASCOM drivers installed so maybe an option. All I want is a simpler method of aligning my mount. May have to do some in depth research. Thanks.

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Ok so I feel like a void has just opened up beneath me. Yes I only want to image with the Star 71. Not familiar with plate solving though Astrotortilla is a popular choice from what I have read. I have all of the ASCOM drivers installed so maybe an option. All I want is a simpler method of aligning my mount. May have to do some in depth research. Thanks.

Go to http://mainsequencesoftware.com/  .. Try SGP..  They still have a free beta running so you'll get quite a few days free at the moment and the current beta is stable.

SGP includes plate solving and can use the same base as astrotortilla ... astrometry.net.  This can either be installed locally for  speed or just leave your PC/laptop to use the internet based version assuming your  PC has internet access whilst guiding.

When it comes to your alignment concerns etc ...this is how I use it :

(note: I use an old laptop running  windows, it sits in a plastic box sat outside underneath the telescope and then I use teamviewer to control the laptop whilst sat in the warm)

1) Pick pretty picture on astrobin.

2) Run the Mosaic Wizard in SGP, tell it to use web address of the pretty picture from (1) and tell SGP to create a batch job that centres the scope and takes the images.

3) Make sure the mount has its  alignment marks pretty much in line, turn on scope,   and tell it to do a quick align  (i.e. don't bother doing any alignment, just assume that the scope is  pointing at the pole  star).

4)  Focus the scope - I have  a lakeside focuser so I do this inside in the warm :) I also use an off-axis  guider so need  the  scope  to be  in reasonable focus before  guiding.

5) Make sure PHD2 is connected  and  running although no need to do its calibration .. SGP will automagically do that for  you.

6) Run the job in SGP created in (2).  It then takes an image  of the sky, works out where the scope is  pointing, slews the mount to where the pretty pic is , takes another image to check the mount got it right (iterate until it  does .. just occasionally it takes mine 2 goes to get within 50 pixels .. take the number of  images you have specified in (2).

7) Go to sleep / watch TV :) SGP includes the use of an alerting system called GoodNightSystem (GNS).  The mobile  phone software bit of GNS then  plays a hooting owl noise  if any errors occur (like if the clouds roll in and the guiding fails).

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Thanks for this Andy. I have a whole bunch of reading up to do... :embarassed: I did wonder how other people were aligning the scope especially as it does not come with a diagonal! (though I have this)

Reading Astrotortilla instructions but will definitely give SGP a look.

So before going further the Astrotorilla instructions keep referring to the camera as a CCD. I am correct in thinking that you can do all of this kit I have. An OTA - the Star 71 in this case, a DSLR, a guide camera, a guide scope and a ASCOM mount. Plus software such as PHD, Backyard EOS and a plate solver software.I understand there are many other options available but that's basically what I have. I do not have a imaging CCD such a ATIK?

Also does it just simply require the mount to be pointing to Polaris? There is no need to adjust Alt / Azi bolts or do a Polar alignment? I have a Celestron AVX which has ASPA and I don't have a polar scope,

If so that is crazy and feel like everything I knew about imaging has been crushed into ground... :eek:

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You will have to do polar alignment, the more accurate the better. If you have APT it includes DARV to drift align, though I use the drift tool in PHD2.

The plate solving will only correct for the GOTO accuracy, without accurate polar alignment you will get field rotation even with guiding. The field will rotate around the guide star, which may not even be in the field of view of your image.

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I am lucky in that I leave my mount outside so I rarely have to go through the polar alignment exercise.  If you do have to set up each time than somehow mark the position of the tripod legs to allow easy re-positioning next time.   If nothing else it's too damn cold out there in winter to be faffing with the setup.  

I did buy the celestron polar scope which within reason gets the alignment good enough for a small focal length 'frac I think.  I'm sure playing around at longer focal lengths would lead to more field rotation issues but with my ZS71+reducer I can't see any examples in my images.   

There is a slight design flaw with the AVX in that you WILL bang your forehead on the bolt when trying to look thru the polar scope.  Mind numbingly stupid design .. both literally and figuratively.

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Hi.

I have been using my Star 71 on a number of occasions now. I am really happy with the build quality and its a great little scope though initially I had quite a tough time mounting a guide scope onto a dovetail, I primarily did this to help with the balancing all of which is now working well.

Though the guide scope works well I am struggling at times to align the mount with an illuminated 12mm reticule eyepiece slotted within 50mm guide scope as the FOV is quite tight.

Therefore to make life simpler I am looking to add a WO red dot finder to the STAR 71 for the initial alignment process. Once completed I would use a quick release base (probably a Baader Universal Quick Release Finder Base) to remove the Red dot finder as there is no point having the extra redundant weight for imaging.

I have done some research and have been told that I need:

This Baader base:

http://www.firstlightoptics.com/finders/baader-universal-quick-release-finder-base.html

and

The WO Red dot finder

http://www.firstlightoptics.com/finders/william-optics-multi-reticule-finder.html

If so and this should be the easy bit, how and where do I mount it to the OTA?

I understand I can either mount it to the left or right of the OTA.

There are three possible holes.

One hole contain a small black plastic slotted lug? The other two are similar to what PC's cases can be sealed up with. They are allen key style but more a 'star' head to them if that makes sense?!

Which one would I need to use for the Baader base if this is the correct base?

I noticed on page three of this thread 'Buzz' has what appears to be two bases attached to the 'Star' headed holes?

I apologise if this all sounds basic but the refractor comes with no instructions at all. I have emailed WO twice and have yet to have a response. Its only with the kind assistance of another SGL forum member I have got as far as I have.

Whilst I appreciate I entering new territory with refractor a manual of sorts would have greatly helped!

I have included a picture of my current arrangement.

Many Thanks

For some reason the image is on its side?!

Do not touch the silver screws these are to adjust the pressure on the draw tube. The mounting hole for a finder is the one with the plastic grub screw.

A.G

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Thanks for that. :smiley:

WO finally came back to me last night and responded with the same details. I thought it was the correct hole just that there are images of people mounting kit off of those other holes.

Need to start consolidating details. i.e. Do I go Polar scope and then go down the plate solving etc. The polar scope clearly has issues with it being used in UK latitudes due to the bolts. The recent information that people have kindly offered has opened a whole set of new questions so I need to spend some time learning and understanding how to proceed.

Thanks again.

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  • 6 months later...

Last to the party. But I have the WO and recently bought the lakeside focuser. Having major issues removing the grubs screws. The first screw is fine, but I can't get any traction with the second and third holding in the temperature gauge knob. For those that have done it, how? Many thanks!

af3c034dd70b03cd0e5e7cb3db05daca.jpg54c6b0f91b81ebf6a751cd93f76c7af2.jpg

Sent from my iPhone using Tapatalk

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Last to the party. But I have the WO and recently bought the lakeside focuser. Having major issues removing the grubs screws. The first screw is fine, but I can't get any traction with the second and third holding in the temperature gauge knob. For those that have done it, how? Many thanks!

Sent from my iPhone using Tapatalk

That's a coincidence, I have just been in e-mail correspondence with Ian King about this scope and if I get one, I will definitely be getting a lakeside focuser to go with it (love this focuser attached to my Esprit 120ED).  I am going to be meeting Ian at IAS next Friday to discuss, so not much use for you at the moment, as I am sure you do not want to wait that long.  Hope you get it sorted soon and please post what you think of the scope,

Cheers,

DDS :)

Edited by davedownsouth
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Public service announcement for William Optics Star 71 focus knob removal.

Managed to get the temperature gauge off.  However, this is an FYI to anyone else having similar issues removing the focus knob i.e. grubs loosened but knob not coming off easy.

The knob was removed by holding the large knob on the fine adjustment side and 'working' the fast knob back and forth/ forward and back until it came off.  Note the grubs are loosened but still in the hole to avoid them catching in the barrel.  Took some effort and a little force.

The issue was that while i expected a single grub screw, turns out William Optics used THREE grubs screws on my scope.  One in the first hole and two grubs (on top of each other!) in the second hole.  Given the clearance around the knob in the barrel, it's pretty near impossible to loosen the bottom grub because the top screw cannot be taken out through the access hole or even moved out of the way of the hole.  If it's lose in the barrel when you move the focuser you also run the risk of it getting stuck.

Got there eventually, but not a pleasant surprise.  This is the only issue i've had with the scope, it's been magic until now.  Here's hoping it continues to perform going forward and my hiccup has not damaged the focuser (don't think it has).  This shouldn't put anyone off the scope - i was probably just 'lucky', just be aware in case you face a similar challenge.

Thanks,

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I don't recall having any particular difficulty when I removed mine - just checked my original post:

"-   you don't pull the knobs off! - they are held on by grubs crews. On the WO, (I don't know about the TS) you have to remove a grub screw on the baseplate to reveal a hole. You turn the knob until you see a second grub screw in the shaft of the knob. You completely remove this and the knob will slide off. If you just loosen it, the screw fouls the housing and the knob will not slide off."

Edited by buzz
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  • 4 weeks later...

Public service announcement for William Optics Star 71 focus knob removal.

Managed to get the temperature gauge off.  However, this is an FYI to anyone else having similar issues removing the focus knob i.e. grubs loosened but knob not coming off easy.

The knob was removed by holding the large knob on the fine adjustment side and 'working' the fast knob back and forth/ forward and back until it came off.  Note the grubs are loosened but still in the hole to avoid them catching in the barrel.  Took some effort and a little force.

The issue was that while i expected a single grub screw, turns out William Optics used THREE grubs screws on my scope.  One in the first hole and two grubs (on top of each other!) in the second hole.  Given the clearance around the knob in the barrel, it's pretty near impossible to loosen the bottom grub because the top screw cannot be taken out through the access hole or even moved out of the way of the hole.  If it's lose in the barrel when you move the focuser you also run the risk of it getting stuck.

Got there eventually, but not a pleasant surprise.  This is the only issue i've had with the scope, it's been magic until now.  Here's hoping it continues to perform going forward and my hiccup has not damaged the focuser (don't think it has).  This shouldn't put anyone off the scope - i was probably just 'lucky', just be aware in case you face a similar challenge.

Thanks,

Putting two grub screws on top of each other is an old engineering trick to secure the component with grub screw without resorting to a permanent bond such as Loctite. It is also a warning that the part is crucial to the function of the apparatus and not to be messed with. Whether this practice is justified here is another matter. Telescopes should be designed to be serviced easily and be put together back and be adjustable, at least the good ones are so.

Regards,

A.G

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  • 1 month later...

...  I tightened up the top adjuster on the focuser a little and the tilt in the image improved to about 1", (as reported by CCD inspector.)

....

....Most of my image was fine, big difference, but noticed a slight sag on the focuser after i took some test shots, so adjusted the back brass screw and you could see the camera squatter up even under torchlight, ....

Paul

Can either of you chaps clarify what it is you are adjusting to take out the focuser sag?  My scope came with no manual.  I can see some brass slotted screw heads around the adapter - is that what needs to be tightened?

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Can either of you chaps clarify what it is you are adjusting to take out the focuser sag?  My scope came with no manual.  I can see some brass slotted screw heads around the adapter - is that what needs to be tightened?

Hi Gnomus,

I noticed a bit of play in my focuser and I was able to address this by gently tightening those brass slotted screws. They really should have provided some documentation for the scope.

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Hi Gnomus,

I noticed a bit of play in my focuser and I was able to address this by gently tightening those brass slotted screws. They really should have provided some documentation for the scope.

Thanks Mike

Did you just give each screw the same 'tweak' (quarter turn/half turn) or is it more technical than that?  (I agree about the manual)

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Thanks Mike

Did you just give each screw the same 'tweak' (quarter turn/half turn) or is it more technical than that?  (I agree about the manual)

Just a few tweaks until I couldn't detect any more play, nothing more complicated than that.

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  • 2 weeks later...

I am looking at purchasing a Moravian G2-8300 Mono CCD with an internal filter wheel sometime this year (if this weather actually ever clears up) and attaching it to my Star 71.

http://www.gxccd.com/art?id=441&cat=22〈=409

Since contributing to this thread for a while I have gone through a steep learning curve of learning what I want to achieve from a CCD as well understanding how to get Plate Solving working, types of filters and filter wheels etc.

Whilst this is all very well one thing I have realised is that there are obviously numerous permutations for different cameras being attached to the WO Star 71 refractor.

One of which I am trying to understand more clearly is back focus.

After re-reading the thread the consensus is that it requires 55m of back focus?

So my question is will I need to purchase this additional adapter with the camera:

(The telescope adapters are listed about half way down the web page)

M48 × 0.75 thread with 55 mm BFD

M48 × 0.75 inner thread.

Preserves 55 mm back focal distance.

There is still some confusion on my part as to whether this will applicable as it has an internal filter wheel though whether this has an affect I am not sure.

I have emailed Moravian but understandably they may not know anything about the WO Star 71 scope hence the reason for asking the question here.

Thanks

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The 55mm back focus is for DSLRs, no reducer on the Star 71 so you don't need to worry about back focus, my S71 came with a couple of adapters one of which attaches my QSI683.

I wouldn't buy any adapters until you've got the camera in your hands.

Dave

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Thanks Dave.

I am sure I read that some of the CCD guys were discussing back focus of 55mm? The camera comes with a 2" barrel adapter which I will have no way of attaching to my M48 male thread adapter so I will need something. There is a M48 0.75 thread short adapter so this would work I guess...

As you say I wont be purchasing anything until I have the camera but it will be good to get this information ready as I have found on numerous occasions that there is rarely a "standard" setup with any Astronomy gear.

I currently use the supplied Canon M48 adapter ring with my Canon 1100d when attaching it to the Star 71. I find I have to extend the tube out to around the 17th mark on the telescope.

This is in stark contrast to what the CCD may require where 5mm is mentioned?

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Thanks Dave.

I am sure I read that some of the CCD guys were discussing back focus of 55mm? 

The 55mm only applies to focal reducers / flatteners which are usually designed for DSLRs and have a back focus to suit, as the Star 71 has it all built into the scope you don't have to worry about it.

Dave

Edited by Davey-T
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