From 102mm apo to 6 inchRC?

[Mr_42tr0nomy]

Hello all!

So galaxy season will be among us shortly! The past 6 months or so I have been thinking of treating myself to a GSO 8 inch RC for imaging... this is a little outside my budget right now so I think the 6 inch RC is a little more realistic. If i have done my math right, there is a 32% increase in aperture from a 102mm apo to this 6 inch RC... central obstruction included in calculations.. (maybe check my calculations). My field of view would be perfect for galaxies as I use the ATIK 414..

Is this jump in aperture worth it you think? With the new setup, I would be looking at a .92 pixel/" resolution which seems to be pretty close to whats recommended. I have read some reviews on the 6inch RC and have gotten mixed reviews.. although a lot have said its not too bad of a scope for imaging. Thoughts??

Thanks and clear skies!

[wimvb]

Have a look in the imaging sections and astrobin to get an idea of what can be achieved. I've also read a about focusers needing replacing. So, be prepared for extra investments. An alternative to the rc would be a long fl newton reflector.

[johnrt]

I have used a 6" RC exclusively for a few years now, check out my flickr page https://www.flickr.com/photos/skywatcher150/ or my website http://cloudedout.squarespace.com/blog/ to have a look at what I get up to with mine.

I have upgraded the focuser to a Starlight (cost more than the OTA!!), the out of the box foccuser is pretty rubbish & be prepared to spend some time getting it collimated. They aren't an "easy" scope to get up and running. They are very slow out the box at f/9, so I run mine with an APCCDT67 reducer.

However once they are set up the 6" RC is possibly the most underrated imaging OTA out there, they can deliver some exceptional results.

[Mr_42tr0nomy]

44 minutes ago, johnrt said:

I have used a 6" RC exclusively for a few years now, check out my flickr page https://www.flickr.com/photos/skywatcher150/ or my website http://cloudedout.squarespace.com/blog/ to have a look at what I get up to with mine.

I have upgraded the focuser to a Starlight (cost more than the OTA!!), the out of the box foccuser is pretty rubbish & be prepared to spend some time getting it collimated. They aren't an "easy" scope to get up and running. They are very slow out the box at f/9, so I run mine with an APCCDT67 reducer.

However once they are set up the 6" RC is possibly the most underrated imaging OTA out there, they can deliver some exceptional results.

i have heard that the focuser leaves a bit to be desired so yes I will eventually replace that. I understand that collimation is different than a dob but I have gotten pretty good at that..so hopefully that somewhat carries over to the RC. As for the reducer.. I like the field of view without it.. cropping to the native FOV from the reduced ROV will cause loss of resolution I feel like.

[johnrt]

46 minutes ago, Mr_42tr0nomy said:

i have heard that the focuser leaves a bit to be desired so yes I will eventually replace that. I understand that collimation is different than a dob but I have gotten pretty good at that..so hopefully that somewhat carries over to the RC. As for the reducer.. I like the field of view without it.. cropping to the native FOV from the reduced ROV will cause loss of resolution I feel like.

From experience, and especialy for DSO galaxy imaging the native f/9 is veeerrrrryyyy slow, unusable in UK conditions where time is limited due to weather.

[Mr_42tr0nomy]

Just now, johnrt said:

From experience, and especialy for DSO galaxy imaging the native f/9 is veeerrrrryyyy slow, unusable in UK conditions where time is limited due to weather.

Ahh.. well i could definitely get the flattener and the telecompressor and not use them if i so choose. I have done some f/10 image with an 8se back when i first started this hobby.. never galaxies though. Thanks for the input, much appreciated. And your gallery is incredible.."cloudedout". Are you imaging at f/9 in any of those?

[johnrt]

25 minutes ago, Mr_42tr0nomy said:

Ahh.. well i could definitely get the flattener and the telecompressor and not use them if i so choose. I have done some f/10 image with an 8se back when i first started this hobby.. never galaxies though. Thanks for the input, much appreciated. And your gallery is incredible.."cloudedout". Are you imaging at f/9 in any of those?

Thank you for the compliment! All my images are reduced to f/6.3, my APCCDT67 is set to reduce at about x0.7, with the APCCDT67 you can vary the distance from chip to reducer to dial in a varying amount of reduction to the image. I have tried to image at f/9 but I found it unworkable, but if you get better weather than here in the UK you could be more successful, it's just too restricted by poor weather here.

[Mr_42tr0nomy]

1 hour ago, johnrt said:

Thank you for the compliment! All my images are reduced to f/6.3, my APCCDT67 is set to reduce at about x0.7, with the APCCDT67 you can vary the distance from chip to reducer to dial in a varying amount of reduction to the image. I have tried to image at f/9 but I found it unworkable, but if you get better weather than here in the UK you could be more successful, it's just too restricted by poor weather here.

Are you reducing the RC to f/6.3? And weather here is nice.. 300 days of sunshine out here in western USA

[tomato]

John's outstanding results with his 6" RC and other RC users, plus my preference to image small galaxies has convinced me to move to this design of scope from my 102 mm refractor once  I have improved my image calibration and processing skills to a higher level. 

Mr_42tr0nomy, if you do decide to go with this setup, I'll be very interested to see how you get on.

Steve