Willam Optics Star 71 5 element Apo Astrograph

[PhotoGav]

Ah, even better! I still want one...!

Hope you enjoy the scope and I look forward to seeing your images over the coming months.

[buzz]

Give me a few weeks to get enough narrowband exposures in the bag and I'll post a lovely heart to the forum. 

[Blazar]

Nice...Mind you Chris, That is a very nice camera as well ;-) Somehow I doubt I will be able to match you on this...but perhaps an Atik in the future might be do-able. Might ping you a few messages about how to connect it all up, as still unguided at the moment!

[r3i]

Very nice sub Chris - as Will Smith succinctly put it in Independence Day: "I have got to get me one of these!!!"

[buzz]

The forecast is favorable tonight for 2nd light. I think the mount might be a teeny weeny bit overkill but no wind is going to budge this one!  If I can get a little more weight up front, I will be able to slide the scope back a bit and the camera will be able to rotate without hitting the Losmandy plate.

[ollypenrice]

An alternative to attaching weights would simply to be to use a longer Losmandy dovetail and slide it in the saddle plate. Cheaper and simpler, I'd have thought, and probably stiffer, though you have at least an order of magnitude of stiffness beyond what you need, I would say!

Olly

[buzz]

Olly - that is kinda what I'm going to do. I already use an 11" ADM plate and as forward as the tube ring fixings will allow. I have a spare short Lozmandy plate and I'll attach a steel weight to its end. This will insert from the top end of the Paramount's Versaplate. I need quite a bit more weight as far forward as possible.

The little Star 71 continues to deliver. Although the hood is short, I didn't notice any flare on 20 min subs from a local streetlamp.

[buzz]

I'm a bit stuck with the weather - I need another 5 hours of OII and an hour each of RGB for the stars - however, the performance of this scope is clear. I quickly knocked together this image. It is NOT fully processed - just stacked and stretched - no deconvolution, color balance, background neutralization etc.  In this way it does not hide any issues and shows the stars up as they are. I'm really impressed.  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.)

Once I get everything together I'll post the final result after I have PixInsighted it.

In terms of cropping - I only cropped a tiny slither off each side 

[ronin]

GREEN!

Think I prefer it to red.

[buzz]

Patience!   It is mapped using the HST palette and needs some work. I'm looking at the astroanarchy website and wondering how the heck he got that blue in the middle!

[buzz]

I found out the trick - once you color balance the entire image, you remove the pure green pixels - it is like a selective color removal. (Not the same as deleting the color channel) You then get the hues of green but not pure green dominating as before. The blues start to appear and can be enhanced. I have now got the color balance about right and once I have more image data, should be able to follow the same path quite easily. I might also play around with some PixelMath equations to emphasize image differences between the channels too. Just wish I could get another night to complete the acquisition.

[PNJ]

Hi All

received my W/O Star 71 yesterday,  and was surprised to see the focuser end upgraded.   Beefy Camera rotator/Tilt adapter/

Paul J

[buzz]

That is really interesting - does it end in a T-thread or a 48mm one?  It looks like they have changed the aluminium adaptor and upgraded the nylon fasteners to brass. On my one, you have to screw in a 48-mm to T-thread adaptor - and the focus position only requires a 5mm extension. It would be interesting to see if they have slimmed down the adaptor, which would then require more focus extension and the option to insert filters in front of the camera with focus extension to spare.

[r3i]

Hi All

received my W/O Star 71 yesterday,  and was surprised to see the focuser end upgraded.   Beefy Camera rotator/Tilt adapter/

Paul J

Interesting development, I wonder if some of the first versions have had issues with tilt? QHY started shipping their cameras with tilt adjustment mechanisms because they couldn't reliably get the CCD chips orthogonal.

Can you see how the tilt adjustment works?

[PNJ]

Hi All

i had problems with my first telescope, Got strange star shapes.  However my dealer was excellent and send me a replacement telescope.  the new adapter still terminates in a M48 thread.   I did not measure the original m65 to m48 adapter, but looking at my new model, i think i will be able to still get focus, on my original with QSI & Off axis guider i only racked out the focuser about 6-7mm.  I suspect with the new setup it will require a bit more outward travel.

Just waiting for clear skies now !

Paul J

[PNJ]

Chris, could you measure your M65 top M48 adapter please,  just curious , and hoping i still get focus

Paul J

[PNJ]

here is the new adapter photos

Paul J

[buzz]

Interesting development, I wonder if some of the first versions have had issues with tilt? QHY started shipping their cameras with tilt adjustment mechanisms because they couldn't reliably get the CCD chips orthogonal.

Can you see how the tilt adjustment works?

All I can say is that if you run the FITS file I posted earlier through CCDInspector, (using the ligher-weight cone shaped adaptor) the tilt is very slight and I could not detect anything in the star shapes. One of the other forums suggested that they were getting pinched stars, that they fixed by repositioning / slackening the tube rings. I took my scope apart and am puzzled by that remark since the main tube in the middle is not really connected to the optics, the optics are suspended inside an inner tube.  Looking at the design, unless the optics themselves are not right (and this new adaptor allows WO to tweak the outcome in manufacture), the main source of tilt will be the focus mechanism. I could not detect play in my adaptor, only overall in the focus tube. With a little care, the two brass adjusters on the top can be tuned and the play is perfectly reasonable with my QSI 683 WSG on the end. If there is play in the focuser, it would not be the best solution to change the settings on the adaptor plate, as the play will change with pointing direction.

[PNJ]

Hi Chris

thanks for info

could you measure the length of the cone shaped adapter for me please.

cheers

paul

[r3i]

here is the new adapter photos

Paul J

 

@Paul,

Thanks for the pictures of the adapter, the mechanism looks similar to the one used on the tilt plate that is available for aligning the optical path on the GSO RC scopes.

All I can say is that if you run the FITS file I posted earlier through CCDInspector, (using the ligher-weight cone shaped adaptor) the tilt is very slight and I could not detect anything in the star shapes.

...

@Chris,

I was very impressed with your image, nice and flat and I couldn't see any tilt.

[buzz]

Hi Chris

thanks for info

could you measure the length of the cone shaped adapter for me please.

cheers

paul

Paul , it appears to be 25mm from the back of the focus tube cylinder to the shoulder of the 48mm thread. There is a drawing on IKI website that shows the exact dimensions too I believe. I'm going to buy some stainless grubscrews and replace the nylon ones on the knurled ring on my model. By the way - have they increased the dewshield at all? The white bit on mine is about 100mm long.

[PNJ]

hiya guys

no the dew shield is the same,    Got a cloudy sky here in the north east, but had chance to get a few 30s shots just to see star shapes.  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, but it clouded, si I'm sitting here on standby to see if i get another clear patch.

anyway as a guide here is a crop of top left and top right.

what do u think ?

cheers

Paul

[buzz]

Those corner shots look very good.  I have been playing with the processing (still need another 5 hours OIII and RGB for the stars)  It is amazing what you can get from narrowband, these are just sketches to evaluate different processing options in PixInsight. The main difference between them is one has pure green pixels replaced by neutral pixels (The SCNR tool in PI).  Certainly some food for thought. (I applied LocalHistogramEqualization to the separate NB files to emphasize the structures before combining them into the RGB image.)  The magenta stars will be replaced by RGB stars in the final version and the plane trail will also get removed with a different SD setting during image integration.

I think if I get a more portable mount - this little scope will be a wonderful holiday package too.

[VIOLETBLUE]

Hello to all,

Can someone point me to an adapter so I can attach an Atik 460EX camera to the Star 71? I believe the camera has a 1.25 inch nose piece.

[buzz]

Hello to all,

Can someone point me to an adapter so I can attach an Atik 460EX camera to the Star 71? I believe the camera has a 1.25 inch nose piece.

I looked for a 48mm to 1.25" adaptor and came up blank.  You could use the t-thread adaptor and then fit a t-thread to 1.25" adaptor but I do not know if that would take up too much back focus.  What is the distance from the sensor to the shoulder of the 1.25" nosepiece?  I have a good solid T-thread to 1.25" adaptor which might work.