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Old 08-02-2013, 09:04 AM
Martin Pugh
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OS Veloce RH200 has arrived

Hi folks.
took delivery of an RH200 yesterday. Optical train will consist of an SBIG STF8300/FW8300-8 - full carousel/SBIG OAG/SBIG STi guider. Unbelievably, I had an adapter that was just the right length and style to interface the camera package to the scope, and put the system at optimum backfocus distance. With this, the focusser extends by 4mm, plenty of room to get FM VCurves.
I dont have the motor kit for motorised focussing yet but that is inbound.

System resolution will be 1.86asp. Scope was out of collimation on receipt so got close to fixing that last night, but will need to work the tip/tilt arrangements to fix the residual error.

Should be a fun system to work with.

Thumbails attached.

cheers
Martin
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  #2  
Old 08-02-2013, 10:44 AM
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Octane (Humayun)
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Best guidescope I've ever seen.

Congratulations!

H
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  #3  
Old 08-02-2013, 11:24 AM
DJT (David)
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Oh my..what a setup. Enjoy
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Old 08-02-2013, 01:09 PM
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LewisM
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That's a big guidescope alright

Then again, that RC makes most things pale in comparison.
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Old 08-02-2013, 04:17 PM
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Congrats Martin.

I am considering one of these puppies also. They seem to be the first fast F ratio scope to challenge the FSQ106's supremacy for some time.

I look forward to your images and think an 8300 camera is a good match.
STL11 would be another.

Greg.
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  #6  
Old 08-02-2013, 07:16 PM
Mighty_oz (Marcus)
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At twice the price one should hope so. Sweet setup there
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Old 08-02-2013, 08:04 PM
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Logieberra (Logan)
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Beautiful setup Martin, hope it clears for us soon! Logan.
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Old 08-02-2013, 10:34 PM
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marc4darkskies (Marcus)
Billions and Billions ...

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Congrats indeed Martin - that's a heck of a setup! That Officina Stellare gear sure looks pretty doesn't it?! Look forward to first light.

Cheers, Marcus

PS: Where did you get that oversized counterweight? Stainless?
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  #9  
Old 09-02-2013, 09:39 AM
Martin Pugh
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Should be fun once the 'new scope overcast' scenario dissipates.

Marcus - I had 3 made when I was in the US. Have two here in Aus and one left behind at my remote obs in California. Not stainless though, and the extension bar makes them all that so much more effective.

cheers
Martin
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Old 09-02-2013, 12:51 PM
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What an amazing setup Martin, pure art.

I'm glad that there isn't any drooling smilies to choose from.
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  #11  
Old 09-02-2013, 01:10 PM
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MrB (Simon)
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This one will do:
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Old 14-02-2013, 07:39 PM
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I agree with Homer.

Nice Martin! I cant wait to see the pics
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Old 15-02-2013, 09:06 AM
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That's nice - double the data & double the fun.
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Old 15-02-2013, 12:00 PM
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SkyViking (Rolf)
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That's looking rather stunning, congratulations!
Looking forward to the images from your new toy
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Old 16-02-2013, 11:26 PM
Martin Pugh
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Hi folks: Quick report after a few nights testing.
1. If you have the SBIG OAG (the one designed for the STF) you cannot use it with this scope, even though you can get to focus with 5mm to spare on the focusser. The OAG causes a vertical diffraction spike in bright stars in the upper half of the image, and the prism shadow extends a significant way into the optical path; about 1/5th of the way on an STF8300. This has proven difficult to flat out.
2. Focussing the STi with the OAG in the optical train is also very difficult, especially as the OAG is not fitted with a helical focusser. The built in 0.7x reducer does not help. After finally getting it to the best focus I can, stars were still very ill defined. That said, perfect guiding was achieved.
3. Having removed the OAG, I mounted the STi with the lens kit. After two nights of trying, I cannot fix the differential flexure I am getting, despite all of the SBIG rhetoric about this lens kit. I believe the single dovetail mounting on the RH200 is the culprit, so I have a pair of rings on order. I am now testing guiding using the RCOS/STL11K. No results yet. Frankly, I still do not understand how you could get satisfactory images when your guider has an image scale of 30 arcseconds, and your imager has a resolution of 1.86.

4. So, if you have differential flexure in your system using this scope, and the SBIG OAG does not work great, then you have a problem. Solution? Dual CCD cameras. I cant speak for any other brand of camera/OAG solution, but I suspect the extremely steep focus zone of this f3 scope is going to be a problem for any OAG.

5. If you have any sort of tilt in your optical system whether it be a crap adapter or a sloppy filter wheel, it shows up like a sore thumb. The addition of the tip/tilt plate on the back of the scope is an excellent design feature, and why no other scope manufacturer has thought of it before is beyond me. Removing tilt by using this adapter is certainly possible, but man you need patience.

6. Focusmax - I have not yet successfully achieved a usable v-curve. In fact, the Focusmax vcurve tutorial speaks of how fast scopes will struggle in this regard. The approach to focus occurs extremely quickly as you get closer to focus - obviously, since the CFZ is extremely tight.
I have tried multiple step sizes and increments to no avail so far. When I quizzed John Gleason on this, he stated that he manually focusses having not succeeded with FM.

HTH
Martin
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Old 22-02-2013, 09:53 AM
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dvj (John)
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Quote:
Originally Posted by Martin Pugh View Post
Hi folks: Quick report after a few nights testing.
1. If you have the SBIG OAG (the one designed for the STF) you cannot use it with this scope, even though you can get to focus with 5mm to spare on the focusser. The OAG causes a vertical diffraction spike in bright stars in the upper half of the image, and the prism shadow extends a significant way into the optical path; about 1/5th of the way on an STF8300. This has proven difficult to flat out.
2. Focussing the STi with the OAG in the optical train is also very difficult, especially as the OAG is not fitted with a helical focusser. The built in 0.7x reducer does not help. After finally getting it to the best focus I can, stars were still very ill defined. That said, perfect guiding was achieved.
3. Having removed the OAG, I mounted the STi with the lens kit. After two nights of trying, I cannot fix the differential flexure I am getting, despite all of the SBIG rhetoric about this lens kit. I believe the single dovetail mounting on the RH200 is the culprit, so I have a pair of rings on order. I am now testing guiding using the RCOS/STL11K. No results yet. Frankly, I still do not understand how you could get satisfactory images when your guider has an image scale of 30 arcseconds, and your imager has a resolution of 1.86.

4. So, if you have differential flexure in your system using this scope, and the SBIG OAG does not work great, then you have a problem. Solution? Dual CCD cameras. I cant speak for any other brand of camera/OAG solution, but I suspect the extremely steep focus zone of this f3 scope is going to be a problem for any OAG.

5. If you have any sort of tilt in your optical system whether it be a crap adapter or a sloppy filter wheel, it shows up like a sore thumb. The addition of the tip/tilt plate on the back of the scope is an excellent design feature, and why no other scope manufacturer has thought of it before is beyond me. Removing tilt by using this adapter is certainly possible, but man you need patience.

6. Focusmax - I have not yet successfully achieved a usable v-curve. In fact, the Focusmax vcurve tutorial speaks of how fast scopes will struggle in this regard. The approach to focus occurs extremely quickly as you get closer to focus - obviously, since the CFZ is extremely tight.
I have tried multiple step sizes and increments to no avail so far. When I quizzed John Gleason on this, he stated that he manually focusses having not succeeded with FM.

HTH
Martin
All that pain. Why anyone would buy one of these is beyond my understanding.
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  #17  
Old 22-02-2013, 10:48 AM
Mighty_oz (Marcus)
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Martin have u had a chat with Bert (avandonk ) he has one and seems to have most of the problems sorted ?

Marcus.
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Old 22-02-2013, 04:42 PM
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Welcome to the Matrix!

Bert
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Old 22-02-2013, 05:04 PM
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To get back to being serious any system at F3 will present problems that are very minor at slower F ratios.

OAG's are useless as the steeply convergent light beams will interact with any prism or even a coherent light pipe edges due to diffraction and leave scatter all over your image. Dual chip cameras are next to useless for guiding behind 3nm filters.

Focus is very terse so temperature control of the whole optical train is vital.

Sensor alignment is a nightmare as the slightest differential flexure will be readily apparent in every exposure that is longer than a few tens of seconds.

The only thing going for a 200mm diameter optic at F3 is speed. If all the problems can be minimised it will be worth it.

I may look a bit crazy by how I approached these very real problems. I think I am almost there.

Do not be discouraged, as it all needs a totally new mindset.

All the 'rules' of the past are simply myth!

Bert
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Old 22-02-2013, 05:11 PM
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Bassnut (Fred)
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Ultra wide field is evil, the work of the devil. Those that fiddle in ultra WW territory will suffer, and rightly so, astronomy is all about zooming in .
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