CPC 1100 and F-Reducer problem

[Simon128D]

Hi all, 
I've been shopping for a focal reducer for my C11 for some time now but am stumped by it all. I made a video that will explain it better so if anyone could help me figure this out I would be so happy. 

Just to add to this. The Meade 4000 I was trying in the video is exactly the same as this 
https://www.firstlightoptics.com/reducersflatteners/celestron-f63-focal-reducer.html

 

Thanks
Simon

 

 

[fozzybear]

your scope has a 3.25" thread on the back of it and you are using a baader click-lock what you need to achieve is 3.25" to SCT in order to use the FR. is by chance your baader unit Baader item#: 2956233

have a read of this thread https://www.cloudynights.com/topic/390670-connecting-2-accessories-to-back-of-cpc1100/

[vlaiv]

I'm no expert on SCTs, but I think you need something like this:

https://agenaastro.com/meade-3-25-2-sct-reducing-adapter.html

SC thread comes in two sizes - 3.25" and 2" versions.

Your reducer seems to be made for 2" SC thread while scope features 3.25" SC thread on rear port (all Meade and Celestron models 10" or larger have this version at the back apparently). You need adapter like above one to connect focal reducer to read port of the scope - you'll also need to change click lock to different version.

https://www.firstlightoptics.com/adapters/baader-click-lock-2-for-celestron-meade-sct.html

You now seem to have 3.25" version or this one:

https://www.firstlightoptics.com/adapters/baader-planetarium-2-clicklock-adapter-for-large-325-sct-thread.html

Or maybe consider getting diagonal with SC thread because there is 105mm working distance for that reducer:

https://www.teleskop-express.de/shop/product_info.php/info/p87_TS-SC-star-diagonal---99--reflection---quartz---1-12-lambda.html

 

[fozzybear]

13 minutes ago, vlaiv said:

I'm no expert on SCTs, but I think you need something like this:

https://agenaastro.com/meade-3-25-2-sct-reducing-adapter.html

SC thread comes in two sizes - 3.25" and 2" versions.

Your reducer seems to be made for 2" SC thread while scope features 3.25" SC thread on rear port (all Meade and Celestron models 10" or larger have this version at the back apparently). You need adapter like above one to connect focal reducer to read port of the scope - you'll also need to change click lock to different version.

https://www.firstlightoptics.com/adapters/baader-click-lock-2-for-celestron-meade-sct.html

You now seem to have 3.25" version or this one:

https://www.firstlightoptics.com/adapters/baader-planetarium-2-clicklock-adapter-for-large-325-sct-thread.html

Or maybe consider getting diagonal with SC thread because there is 105mm working distance for that reducer:

https://www.teleskop-express.de/shop/product_info.php/info/p87_TS-SC-star-diagonal---99--reflection---quartz---1-12-lambda.html

 

@vlaiv would this work with current setup or push focus out so he can attach FR and then attach whatever?

https://www.firstlightoptics.com/adapters/moonlite-smooth-bore-2-inch-to-sct-adaptor.html

[vlaiv]

18 minutes ago, fozzybear said:

@vlaiv would this work with current setup or push focus out so he can attach FR and then attach whatever?

https://www.firstlightoptics.com/adapters/moonlite-smooth-bore-2-inch-to-sct-adaptor.html

Yes, I believe it would work. That is probably cheapest option.

SCT reducer would thread onto SC thread of that adapter and then it can simply be inserted in existing Click Lock Baader adapter like regular 2" accessory.

[Simon128D]

Thank you all for the help! That's a lot of good suggestions. 

@fozzybear I will need to check that and see but its likely to be one of the earliest models. 

I will have to look into what you've all suggested, the 3.25 to 2" adapter seems like the right thing for me but I cannot find anywhere in the UK selling one. 

[fozzybear]

Simon, Maybe fire off an email to FLO and see what they can do for you, explain what you are trying to do and you never know....

[Simon128D]

Thanks again all for your help. 
I was able to get sorted and find an original visual back for this scope. It's only the 1.25" so now looking to see if I can get a 2" adapter. 

What difference it is to get this scope down to F6.3, images at the eyepiece as so much brighter and more defined. It's going to make for a usable DSO scope.
Imaging Jupiter and Saturn was much easier. ZWO camera was getting so much more light so could knock the gain all the way down to 14-16 and get 82fps versus the 25-40 with gain at 20 or more in the stock F10 configuration. 

The scope was slightly out of collimation, which is why the images have a slight blur - especially Saturn's rings - but I collimated the scope the next day and am looking forward to the next clear night now. 

 

2021-07-25-0026 Regi.tif 2021-07-25-0016 Regi.tif

Edited July 28, 2021 by Simon128D

[fozzybear]

11 hours ago, Simon128D said:

Thanks again all for your help. 
I was able to get sorted and find an original visual back for this scope. It's only the 1.25" so now looking to see if I can get a 2" adapter. 

What difference it is to get this scope down to F6.3, images at the eyepiece as so much brighter and more defined. It's going to make for a usable DSO scope.
Imaging Jupiter and Saturn was much easier. ZWO camera was getting so much more light so could knock the gain all the way down to 14-16 and get 82fps versus the 25-40 with gain at 20 or more in the stock F10 configuration. 

The scope was slightly out of collimation, which is why the images have a slight blur - especially Saturn's rings - but I collimated the scope the next day and am looking forward to the next clear night now. 

 

2021-07-25-0026 Regi.tif 1.56 MB · 1 download 2021-07-25-0016 Regi.tif 1.27 MB · 1 download

at least you are on the way now images look promising and as you say coll was out so a step forward

[vlaiv]

11 hours ago, Simon128D said:

Thanks again all for your help. 
I was able to get sorted and find an original visual back for this scope. It's only the 1.25" so now looking to see if I can get a 2" adapter. 

What difference it is to get this scope down to F6.3, images at the eyepiece as so much brighter and more defined. It's going to make for a usable DSO scope.
Imaging Jupiter and Saturn was much easier. ZWO camera was getting so much more light so could knock the gain all the way down to 14-16 and get 82fps versus the 25-40 with gain at 20 or more in the stock F10 configuration. 

The scope was slightly out of collimation, which is why the images have a slight blur - especially Saturn's rings - but I collimated the scope the next day and am looking forward to the next clear night now. 

 

2021-07-25-0026 Regi.tif 1.56 MB · 2 downloads 2021-07-25-0016 Regi.tif 1.27 MB · 3 downloads

When doing planetary imaging - don't use focal reducer.

Which ZWO camera do you have?

For 2.4µm pixel size, don't use barlow - go with native F/10, that is good F/ratio for that pixel size.

With 3.75µm pixel size - get x1.5 barlow lens to get to F/15 (use barlow element that screws into nose piece of camera and then use some sort of distancing ring to get x1.5 magnification - you can test that during the day by examining images of distant object, with barlow you want size of object to be x1.5 versus no barlow - closer to sensor less magnification, further away from sensor more magnification).

In any case, once you get to critical F/ratio for your pixel size - then set exposure time to about 5-6 milliseconds and boost gain as much as you can.

Don't worry about histogram or image looking dark - that is ok and nothing wrong with that for planetary imaging. Point is to minimize read noise (high gain) and to freeze the seeing (short exposure length). Stacking will make everything all right and your image will have proper brightness once you process it.

[Simon128D]

F10 is unusable for me. N.Ireland skies are so unstable that using F10 is impossible to see anything. The planets are just a blurry mess and impossible get focus. I've tried to do it many times and all results were disastrous. Using the FL was the best result I've had in years. I would never use a barlow as I rarely get stable seeing that low down. 

Camera is the ZWO ASI290MC

Some useful tips there vlaiv, thanks. 

 

[vlaiv]

43 minutes ago, Simon128D said:

F10 is unusable for me. N.Ireland skies are so unstable that using F10 is impossible to see anything. The planets are just a blurry mess and impossible get focus. I've tried to do it many times and all results were disastrous. Using the FL was the best result I've had in years. I would never use a barlow as I rarely get stable seeing that low down. 

Camera is the ZWO ASI290MC

Some useful tips there vlaiv, thanks. 

 

ASI290 has 2.9µm pixel size and optimum sampling rate is about F/11.4.

F/10 is fairly close to that so I would probably use just F/10.

I don't know how poor your seeing is, but seeing here is not great either. I happily image at say F/13 and obtain good results.

Here, I managed to find some old recordings and to make Gif animation so you can see what sort of seeing I'm getting (just 100 frames in sequence from about 40000 in recording):

This is with exposure time of 4ms and gain of 350 on my ASI178.

Resulting image would look like this (this is actually from same session - not sure if it is from above recording, I made 4 or 5 runs that evening):

Edited July 29, 2021 by vlaiv
double animation removed

[Simon128D]

That is very helpful Vlaiv, I have been keeping my exposure around 10 and my gain at 220/250, I did not know having it lower would be beneficial. I have not read up on anything or look into anything with planetary imaging, just doing what I think makes sense. I will try that next time. 
If I may ask, what resolution do you image at? Full res of the camera or do you lower your res to have the planet fit the frame as much as possible? 
Hoping to see a crack in the clouds tomorrow night. 

 

[vlaiv]

1 hour ago, Simon128D said:

If I may ask, what resolution do you image at? Full res of the camera or do you lower your res to have the planet fit the frame as much as possible? 

I use ROI to get small size of video - something like 640x480 or so. That helps with getting high FPS as there is less data to transfer.

If you use say 5ms exposure length, that will give you max theoretical FPS of 200 (1000ms / 5ms). In that case - you'll be limited by USB transfer speed and it helps to have less data to transfer.

[Simon128D]

That all makes sense. I was capturing at full resolution to try and capture the moons you see but I shall knock the res down and play with that. 
The biggest appeal is not having 20GB plus files for 10k frames at full res lol 

[vlaiv]

32 minutes ago, Simon128D said:

That all makes sense. I was capturing at full resolution to try and capture the moons you see but I shall knock the res down and play with that. 
The biggest appeal is not having 20GB plus files for 10k frames at full res lol 

Yes, sometimes when trying to capture whole system, using larger FOV is advantage.

I really like animations with moons dancing around the planet. In that case, I'd say that it even makes sense to use reducer. Maybe Jupiter won't be captured at highest resolution possible - but result will be very nice.

[Simon128D]

Moon and shadow transit animations is exactly what I am trying to achieve in the future. 

Do you use a mask for getting fine focus? 

Edited July 31, 2021 by Simon128D

[vlaiv]

10 minutes ago, Simon128D said:

Do you use a mask for getting fine focus? 

No, I use same technique as I do when observing - tweak focus back and forth until I get best looking image. Only difference is that I observe image on screen in live mode versus at the eyepiece.

[Simon128D]

That's what I am doing too. 

Getting back to my original topic - sort of. Could anyone recommend a 2" adapter/visual back that I can screw onto the Celestron Focal Reducer? 
Would there be a version of the Baader Click Lock that would screw onto it? Say like this one? 
https://www.firstlightoptics.com/adapters/baader-click-lock-2-for-celestron-meade-sct.html

I first saw this but have no idea if it would fit the threads on the FR
https://www.firstlightoptics.com/adapters/astro-essentials-2-visual-back-eyepiece-holder-for-sct-telescopes.html