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First light with 8" Ritchey-Chrétien


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So the clouds finally passed last night which gave me a chance to finally test out my new scope. It has been almost a month since I bought this scope. The weather has been partly to blame for the long delay in getting a first light, and also a lot of the additional accessories have taken a while to come. For example, this scope was ordered brand new, and it didn't come with a focuser. Apparently the focuser that initially came supplied was pretty rubbish so the manufacturer thought to get rid otherwise it might detract from what is otherwise a nice product. Once some of the accessories came it was time to put it all together. Here's how it looks on its mount. I still haven't had a chance to collimate the scope as I am waiting for a laser to get delivered and a focuser tube tilt adjuster. I have heard that collimating an RC is fun and games so lots to look forward to!

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I am mainly going to be using this scope to image galaxies and other slightly smaller DSOs, the camera I am using for the moment is the ZWo 1600 pro. I had an interesting discussion on the right kind of scope for the job and the camera to use, see below.

Basically in summary: given that the focal length of this scope with a reducer is 1088mm we need to bin at 2x2 to reduce sampling issues, guiding needs to be particularly good and I decided that this scope, TS-Optics 8" f/8 Ritchey-Chretien, was going to work for me. 

As I was setting up last night, I noticed that balance was completely off in Dec. I am going to need to order a longer vixen bar or get some weights to improve it. Set up was otherwise quite straightforward. After a lot of playing around and fiddling I was able to take some basic photos to show you. They are nothing special and my focus won't be 100% because I was mainly focusing by eye, and I haven't tried collimating the scope yet! This was more about getting a feel for what else I might need to think about, and addressing any problems I might have.

First up we have M13. 

10 x 90 seconds of LRGB 

I calibrated with some darks, but no flats, or dark flats. In photoshop I only quickly breezed through some levels stretches.

 

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I thought it would be cool to compare this to a single light frame taken with a Skywatcher Esprit 100, just to see the FOV difference.

 

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Finally after having enough of a play around with M13 I wanted to see what the bubble nebula might look like through this scope. Here is a single 10 minute frame taken with a H-alpha filter. I wasn't disappointed at all, and now I am really looking forward to collecting more data on this in the future.

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Overall, I am really looking forward to getting this scope in action more. There's plenty to look forward to.

 

 

 

 

 

 

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20 minutes ago, 5haan_A said:

Here is a single 10 minute frame taken with a H-alpha filter

Looking really good.....have fun when you do go for the Bubble Nebula....always a favourite of mine when it gets the time it deserves.

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1 hour ago, 5haan_A said:

As I was setting up last night, I noticed that balance was completely off in Dec.

Yes, scope is very back heavy - add extension tubes, replacement focuser and camera and accessories and you'll need one of these to compensate:

https://www.teleskop-express.de/shop/product_info.php/info/p752_Baader-Balance-Weight-1kg-with-Vixen-Level-Clamb.html

I put mine almost to the front of the scope

1 hour ago, 5haan_A said:

guiding needs to be particularly good

I think that you might want to think about switching to OAG at some point.

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8 hours ago, Kinch said:

Looking really good.....have fun when you do go for the Bubble Nebula....always a favourite of mine when it gets the time it deserves.

Im looking forward to it, also I just had another look at that sub and I do believe there is something to be said for black and white images. 

 

7 hours ago, vlaiv said:

you'll need one of these to compensate:

https://www.teleskop-express.de/shop/product_info.php/info/p752_Baader-Balance-Weight-1kg-with-Vixen-Level-Clamb.html

I put mine almost to the front of the scope

Cheers mate. I will look into this for sure. I have been looking into an OAG and it is starting to make more and more sense to me. Still though you can see from the 10 minute sub that the guiding is not bad as it is for the moment. We will see if any flexure or other issues start cropping up.

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