Anyone using a Sharpstar SCA 260?

[gregbradley]

I am looking at this scope. It seems to have had some issues but nothing that can't be handled.

Anyone using one that can comment on this scope?

Greg.

[benklerk]

I used to have one, returned it after 6 months after a long list of issues. Only got 2 images out of it. I spent more time troubleshooting problems. So not worth it, stay away.

I know this is my experience of it, but it was a bad one. Worst scope I have ever owned.

[gregbradley]

Thanks for the heads up Ben.

I was looking for a 1300mm focal length scope with some decent aperture but
able to be handled.

Perhaps Newts are the only option. Collimation is not something I wanted to look forward to though.

10inches and F4 with carbon fibre tube is a rough formula.
Not sure what is on the market that is reliable.

Greg.

[Startrek (Martin)]

Greg,
If you want to support locally made products, here’s a Carbon fibre 10” f4 from Sidereal ( Astroworx )
At least you have the confidence of excellent technical and product support from Diego and the boys out of Melbourne
Not sure about optical performance though ?
Diego would be happy to discuss

https://www.siderealtrading.com.au/p...ube-newtonian/

Martin

[gregbradley]

Originally Posted by Startrek

Greg,
If you want to support locally made products, here’s a Carbon fibre 10” f4 from Sidereal ( Astroworx )
At least you have the confidence of excellent technical and product support from Diego and the boys out of Melbourne
Not sure about optical performance though ?
Diego would be happy to discuss

https://www.siderealtrading.com.au/p...ube-newtonian/

Martin

Thanks martin.

Yes I saw their Newt for sale. There is a Teleskop Services Newt for sale that is customisable for similar cost with made in Germany components
(except the mirrors which I think are GSO).

I'll give him a call though.

Greg.

[Startrek (Martin)]

I bought my 10” and 8” carbon tubes ( undrilled ) through Sidereal from Klaus Helmerich in Germany ( Teleskop Express Carbon newts both the basic Photon and UNC high end are from Klaus Helmerich as well )
I just bought GSO mirrors , Spiders , focusers , tube rings etc…. and built them myself.
I was thinking about moving to higher end commercial Newts next year but I just don’t find the time in the hobby ( and clear nights ) to warrant dishing out serious cash on premium gear.
I have a busy retirement with family and friends. Still trying to get OS this year too , my Wife and I love to travel.

Martin

[Paul Haese]

I have looked over one of the Astroworx's scopes Greg. The ones in Germany are not going to hold a patch on the Astroworx gear. I know that Diego is really finicky with assembly of the units that they manufacture. The scope will be built tough enough to handle the effects of gravity.

The other option is to look at Stefan's scope with Beamtech 10" scope. Another quality assembly. My business partner is buying one and I am sure knowing Stefan the scope will be excellent in all respects.

[Stefan Buda]

Originally Posted by benklerk

I used to have one, returned it after 6 months after a long list of issues. Only got 2 images out of it. I spent more time troubleshooting problems. So not worth it, stay away.

I know this is my experience of it, but it was a bad one. Worst scope I have ever owned.

Hi Ben,
I would be very interested to hear some details about the problems you encountered with the SCA260. My CDK250 is of a similar design and I'd like to learn more about where they went wrong.

[gregbradley]

Originally Posted by Startrek

I bought my 10” and 8” carbon tubes ( undrilled ) through Sidereal from Klaus Helmerich in Germany ( Teleskop Express Carbon newts both the basic Photon and UNC high end are from Klaus Helmerich as well )
I just bought GSO mirrors , Spiders , focusers , tube rings etc…. and built them myself.
I was thinking about moving to higher end commercial Newts next year but I just don’t find the time in the hobby ( and clear nights ) to warrant dishing out serious cash on premium gear.
I have a busy retirement with family and friends. Still trying to get OS this year too , my Wife and I love to travel.

Martin

The ONTC range look good.

Originally Posted by Paul Haese

I have looked over one of the Astroworx's scopes Greg. The ones in Germany are not going to hold a patch on the Astroworx gear. I know that Diego is really finicky with assembly of the units that they manufacture. The scope will be built tough enough to handle the effects of gravity.

The Astroworx scope does look good..

The other option is to look at Stefan's scope with Beamtech 10" scope. Another quality assembly. My business partner is buying one and I am sure knowing Stefan the scope will be excellent in all respects.

Yes that is a good offering.

Originally Posted by Stefan Buda

Hi Ben,
I would be very interested to hear some details about the problems you encountered with the SCA260. My CDK250 is of a similar design and I'd like to learn more about where they went wrong.

[gregbradley]

Originally Posted by Stefan Buda

Hi Ben,
I would be very interested to hear some details about the problems you encountered with the SCA260. My CDK250 is of a similar design and I'd like to learn more about where they went wrong.

I've read the bulk of the complaints on Cloudynights.

Difficulty of collimating.
Light leaks that led to a longer primary baffle in the V2 model.

There are probably other issues.

Greg.

[benklerk]

Originally Posted by Stefan Buda

Hi Ben,
I would be very interested to hear some details about the problems you encountered with the SCA260. My CDK250 is of a similar design and I'd like to learn more about where they went wrong.

Hello Stefan

The biggest problem I had is the corrector on the SCA260, I also had one corner that made the stars triangle shaped. I also had light leak issues. Also my QHY600 wasn't fully corrected. I also live in a very dewy area so if I wanted to put on dew heaters I had to dismantle the whole scope to install dew heaters.

Basically the SCA260 I had, had to many problems. Your CDK250 is a much better scope than the SCA260. I just think the SCA260 cut to many corners to save on costs on you either get a good one or one that needs fiddling around to make it work.

But I don't have it anymore, and never been happier. Got a much better scope on the way.

Ben

[OzEclipse (Joe Cali)]

Greg,
This is a smaller aperture than the 260:

Vixen VC200L 8" f9 f6.4 (1280mm FL) with dedicated reducer.
Mechanically very sound, holds collimation well
No front corrector plate so optics resistant to dew/fog
Corrected image circle just clips the corners of a full frame sensor

Joe

[Stefan Buda]

Originally Posted by gregbradley

I've read the bulk of the complaints on Cloudynights.

Difficulty of collimating.
Light leaks that led to a longer primary baffle in the V2 model.

There are probably other issues.

Greg.

Thanks Greg,

They probably tried to reduce vignetting by not making the primary baffle fully cut off direct view of the sky from the sensor. The SCA260 is a bit faster than my CDK250 and that would've made full cutoff more difficult.

Originally Posted by benklerk

Hello Stefan

The biggest problem I had is the corrector on the SCA260, I also had one corner that made the stars triangle shaped. I also had light leak issues. Also my QHY600 wasn't fully corrected. I also live in a very dewy area so if I wanted to put on dew heaters I had to dismantle the whole scope to install dew heaters.

Basically the SCA260 I had, had to many problems. Your CDK250 is a much better scope than the SCA260. I just think the SCA260 cut to many corners to save on costs on you either get a good one or one that needs fiddling around to make it work.

But I don't have it anymore, and never been happier. Got a much better scope on the way.

Ben

Thanks Ben,
It seems that they pushed the design into very difficult territory that is very unforgiving for any misalignments.
When I designed the CDK250, I wanted to make it f/5.6 and it turned out that it was impossible to achieve full correction over a full size sensor by using only two lens elements. I'm sure that is why they had to use 3 lens elements and that makes the design even more prone to alignment problems.

[gregbradley]

Originally Posted by OzEclipse

Greg,
This is a smaller aperture than the 260:

Vixen VC200L 8" f9 f6.4 (1280mm FL) with dedicated reducer.
Mechanically very sound, holds collimation well
No front corrector plate so optics resistant to dew/fog
Corrected image circle just clips the corners of a full frame sensor

Joe

Thanks Joe. There is also a 260mm version of it. Often seen this one over the years.

I'll check on Astrobin to see what images others have managed to get out of it.

Although I think I will concentrate on wider field objects using an AP130 and AP110 and QHY600 and a CFF 105 F6 and Proline 16803.
I plan on spending more time at my dark site.

At home I will image using my CDK17 and reducer at F4.5. That will be the galaxy machine.

Surprisingly I do not see a great deal of difference between images taken from my home and those taken from my dark site. There are differences but not as much as I thought. My home is also pretty dark though just not as dark as my dark site. Seeing at home is just as good often if not better.

I wonder how much of how important the darkness of a site is. Still plenty important but good scope design with lots of baffles and a long dewshield and flocking goes a long way.

Greg.

[gregbradley]

Plane wave have said that with the cdk design it's a compromise between vignetting and F ratio. Hence they went with F6.8 which is what most CDK designs have had (more or less).

F6.8 is still pretty fast. Planewave's reducer is .66X a pretty savage and takes the F ratio down to F4.5 or so. The problem with that with this iteration of reducer is optimum spacing is something like 54mm which means I can't use my current OAG and I would have to do guide scope autoguiding which is hit and miss.

I may switch to a zwo or qhy OAG they are thinner than my MMOAG (40mm thick).

I have found my Planewave very easy to collimate and it holds collimation well.

The whole design seems very user friendly.

Greg.

Originally Posted by OzEclipse

Greg,
This is a smaller aperture than the 260:

Vixen VC200L 8" f9 f6.4 (1280mm FL) with dedicated reducer.
Mechanically very sound, holds collimation well
No front corrector plate so optics resistant to dew/fog
Corrected image circle just clips the corners of a full frame sensor

Joe

Originally Posted by Stefan Buda

Thanks Greg,

They probably tried to reduce vignetting by not making the primary baffle fully cut off direct view of the sky from the sensor. The SCA260 is a bit faster than my CDK250 and that would've made full cutoff more difficult.


Thanks Ben,
It seems that they pushed the design into very difficult territory that is very unforgiving for any misalignments.
When I designed the CDK250, I wanted to make it f/5.6 and it turned out that it was impossible to achieve full correction over a full size sensor by using only two lens elements. I'm sure that is why they had to use 3 lens elements and that makes the design even more prone to alignment problems.