Moon 24th June - 10" Classical Cassegrain

[Roy Foreman]

Finally got the collimation sorted to the point where I'm happy with it.  This is the first successful lunar imaging session that has produced acceptable results with this scope.  Seeing was very turbulent and the ever present haze from water vapor in the sky didn't help.

This scope is about on par with the C9.25 XLT for sharpness, but has a much larger, flatter field approaching full frame coverage.  And is double the weight !

Stella Lyra 10" F/12 Classical Cassegrain

ZWO ASI 183MM at 19fps

Pro Planet 642 IR filter.

30% of 2000 frames.

5 pane mosaic, plus some selective enlargements from the main image.

Thanks for looking.

 

 

[Grotemobile]

You have got a good set of pictures there. Wel done. Never tire looking @ the moon.

[neil phillips]

First images I've seen from any 10"CC. It has that CC vibe doesn't it. hard to quantify that statement i know. Hard to tell looking at images. But it does look collimated. No obvious blur factor going on.

Moon wasn't ideal on the 24th some 40 odd degrees in broad daylight max. quite a bit less at anything approaching dusk. As such i think its looking very promising. Has that CC sharpness vibe that i like. Are you at F12 ? Because the single images are coming up huge ? did you drizzle or something ?

images not really usable full size, look far better with big reductions ? trying to understand this ?

A couple of alignment box lines top right. might be worth running larger boxes on that edge ? 

But overall congrats Roy, scope seems to be performing nicely. I have a feeling flatness of field aside. You may find under the right conditions the 10"CC Could well outperform the Celestron 9.25 sct  just a guess based on my experiences with 7.3 of clear aperture CC Performance that i get. Namely sharpness.

These scopes can be supremely sharp. And it looks to me, conditions considered, your scope is showing those traits nicely already.  Excellent Roy.  Great early result. 

How hard did you find collimation ?  How did you eventually achieve it. I did mine using star testing. My avatar under my name is the de focused 7.3 CC

Edited June 28, 2023 by neil phillips

[Roy Foreman]

Hi Neil and thanks for your comments. Yes, the CC does seem to have a special clarity. I think it may be due to it being an all mirror system with no lenses in the train. I was working at F/12 which is 3045mm FL.

I thought I had eliminated the alignment box problems but some obviously slipped through. It comes from shooting in daylight with hazy skies. AS3 is probably trying to align the sky glow. Tried all different box sizes and brightness thresholds and even tried manual placement, but nothing seemed to work reliably.

The selective enlargements showed too much pixellation so I resized them in PS. I guess I may have overdone it a bit.

As for collimation, first I used a regular laser to adjust the focussed so that the beam hit the secondary centre mark, then adjusted the secondary to get the laser to return to origin. For the primary I had to resort to real star as it seemed to be the only way that worked accurately. It was a bit of a pain but hopefully wont need doing again for some time.

[neil phillips]

2 hours ago, Roy Foreman said:

Hi Neil and thanks for your comments. Yes, the CC does seem to have a special clarity. I think it may be due to it being an all mirror system with no lenses in the train. I was working at F/12 which is 3045mm FL.

I thought I had eliminated the alignment box problems but some obviously slipped through. It comes from shooting in daylight with hazy skies. AS3 is probably trying to align the sky glow. Tried all different box sizes and brightness thresholds and even tried manual placement, but nothing seemed to work reliably.

The selective enlargements showed too much pixellation so I resized them in PS. I guess I may have overdone it a bit.

As for collimation, first I used a regular laser to adjust the focussed so that the beam hit the secondary centre mark, then adjusted the secondary to get the laser to return to origin. For the primary I had to resort to real star as it seemed to be the only way that worked accurately. It was a bit of a pain but hopefully wont need doing again for some time.

Yes i understand sky brightness causing the dreaded box problems. When you get better conditions, when the moon gains elevation again. And in darkness the box problem should resolve.  Its worth doing these runs in prep for the better sessions you can now look forward too. Experienced gained will help when conditions are right.

Each to there own of course Roy but at F12 personally i would be reducing size a little. Ideal sampling with your camera is around the F 9 to 10 mark i believe. Though a little more isn't always a bad thing I've found.

Taking the images from F12 and testing slight reductions 90% or 80% so forth should work wonders with great data. You may not agree, but its something I've found can tighten the images quite a bit. Even just down to 90%. From F12

Just the finer things of processing worth contemplating. I've watched your work for sometime and can tell your on the verge of world class performance. As with all things everything has to be perfected.  I reckon when the conditions come your going to knock it out of the ball park. Its easy to see the great quality your getting now. 

[Roy Foreman]

Thanks Neil for your comments and words of encouragement. I will take it all on board and put into practise if and when sky conditions improve. We are now past the days of high spring crescents so it will be a case of imaging the later phases. And some early rises too.

Cheers

Roy

 

[Kon]

Excellent images and nice details.

[The60mmKid]

These are beautiful. Thank you for sharing.

[bosun21]

Great captures Roy. You are causing me to develop a lunar itch that needs scratching 

[Roy Foreman]

1 hour ago, bosun21 said:

Great captures Roy. You are causing me to develop a lunar itch that needs scratching 

Ha ha sorry about that !  The moon isn't best placed at the moment, but it will be again soon enough, then you can scratch that itch to your heart's content !

Be sure to let us see the results !

[Guest]

I have been tossing around the idea of a CC just for planetary visual observing.  How does stuff look visually with it, inquiring minds want to know

[Roy Foreman]

2 hours ago, Mike Q said:

I have been tossing around the idea of a CC just for planetary visual observing.  How does stuff look visually with it, inquiring minds want to know

Hi Mike,

I haven't done a huge amount of visual with this scope as I got it mostly for imaging, but from what I have done it seems to be about on par with my Celestron C9.25 XLT visually, any differences being masked by the seeing mostly at my location, and somewhat better for imaging due to its wider, flatter field.  For planetary viewing you don't need a wide flat field, and the C9.25 is smaller, lighter, much cheaper, and a lot easier to collimate ! Also, if you were thinking of the smaller CC models, they do not give the true stated aperture - I think the 8" model is actually 7.3".  The 10" is a true 10", but it is very large piece of kit - 17Kg.  On the plus side the long 3045mm focal length makes it easier to get high magnification.

Sorry I can't be more precise, but I hope this gives you some food for thought.

Cheers

Roy

 

[Guest]

1 hour ago, Roy Foreman said:

Hi Mike,

I haven't done a huge amount of visual with this scope as I got it mostly for imaging, but from what I have done it seems to be about on par with my Celestron C9.25 XLT visually, any differences being masked by the seeing mostly at my location, and somewhat better for imaging due to its wider, flatter field.  For planetary viewing you don't need a wide flat field, and the C9.25 is smaller, lighter, much cheaper, and a lot easier to collimate ! Also, if you were thinking of the smaller CC models, they do not give the true stated aperture - I think the 8" model is actually 7.3".  The 10" is a true 10", but it is very large piece of kit - 17Kg.  On the plus side the long 3045mm focal length makes it easier to get high magnification.

Sorry I can't be more precise, but I hope this gives you some food for thought.

Cheers

Roy

 

Nope that is fine info to know.  The weight doesnt bother me as compared to my dobs that is light.  The reason i am considering a CC is really just to be different then everyone else.  SCTs and Fracs are everywhere.... but a CC.... that is out of the norm.  

[Roy Foreman]

16 minutes ago, Mike Q said:

Nope that is fine info to know.  The weight doesnt bother me as compared to my dobs that is light.  The reason i am considering a CC is really just to be different then everyone else.  SCTs and Fracs are everywhere.... but a CC.... that is out of the norm.  

That's exactly why I bought mine. It's a lovely instrument and a bit special. Good luck with your decision.

[Guest]

11 minutes ago, Roy Foreman said:

That's exactly why I bought mine. It's a lovely instrument and a bit special. Good luck with your decision.

It is still at least a year out, but i keep coming back to a CC 

[bosun21]

1 hour ago, Mike Q said:

It is still at least a year out, but i keep coming back to a CC 

You’ll drive yourself mad collimating it. I consider myself quite adept at collimating reflectors, SCT’s and Maksutovs but was pulling my hair out with a new CC. Collimation of the secondary is pretty straightforward with a laser but the primary is a different matter. I did eventually get it very close by being under the stars and doing star tests. I returned it and bought a 4” frac. 

[Guest]

3 minutes ago, bosun21 said:

You’ll drive yourself mad collimating it. I consider myself quite adept at collimating reflectors, SCT’s and Maksutovs but was pulling my hair out with a new CC. Collimation of the secondary is pretty straightforward with a laser but the primary is a different matter. I did eventually get it very close by being under the stars and doing star tests. I returned it and bought a 4” frac. 

Yeah i know collimation can be quite the adventure, but i have lots of hair to pull lol.  I still need to see one of these things in the wild and get a lesson in how to use it before i would ever pull the trigger on one, but the urge to go a different route then everyone else is very strong.  

[Roy Foreman]

I don't consider myself an expert at collimation but I didnt find it too difficult. The real pain was trying to use an RC/CC collimation tool. Once I ditched that and used a laser to adjust focusser and secondary, collimating the primary on a star was just like doing any other primary mirror. I found it easier to use a camera and view the image on a computer screen. Use the mount controls to move the out of focus star around the screen until it shows the least amount of eccentricity,  then adjust the primary to bring it back to center. Repeat this several times until the image looks perfectly concentric. Bit of a faff but if I can do it ........ !

[bosun21]

I always keep the star centered and adjust the collimation, then re centre the star each adjustment. I also use high magnification once I get close to being collimated to get better accuracy while moving the disc in and out of focus.

[josefk]

On 05/07/2023 at 13:57, Mike Q said:

I have been tossing around the idea of a CC just for planetary visual observing.  How does stuff look visually with it, inquiring minds want to know

Hi Mike,

I don’t want to rain on anyone’s parade but I strongly recommend you do take a look through the middle sized GSO CC before pulling the trigger if that one is on your short list. I have this scope and it is fantastic at a few things (I do really like the scope) but planetary observing for my taste isn’t one of those things and I’m surprised it’s described as an “ideal planetary scope”. Mars and Venus especially are not so nice through it. The secondary mirror supports are quite thick (creates quite bright diffraction on on the brighter planets) and the secondary is quite large. It is overall also undersized for its stated aperture too at ~185mm (flashlight test) which means the secondary is quite big in percentage terms.

cheers

 

[Guest]

56 minutes ago, josefk said:

Hi Mike,

I don’t want to rain on anyone’s parade but I strongly recommend you do take a look through the middle sized GSO CC before pulling the trigger if that one is on your short list. I have this scope and it is fantastic at a few things (I do really like the scope) but planetary observing for my taste isn’t one of those things and I’m surprised it’s described as an “ideal planetary scope”. Mars and Venus especially are not so nice through it. The secondary mirror supports are quite thick (creates quite bright diffraction on on the brighter planets) and the secondary is quite large. It is overall also undersized for its stated aperture too at ~185mm (flashlight test) which means the secondary is quite big in percentage terms.

cheers

 

Thats the plan if i can find one around to look at.   I have seen reviews of them here and there and they very from they are ok to they are awesome.  Have only seen one negative review as of yet.  Tha ks for your input.