RASA 11 dimensions, anyone?

[ollypenrice]

If anyone knows it, I'd like to learn the distance from the middle of the saddle plate to the very front of the camera once the setup is balanced. It's possible to look up the length of the OTA and the camera and add them together to get the full length of the system but what is critical for us is the extent to which the camera extends forward of the centre of the saddle plate. (This is because it needs to fit in an existing roll-off with no possibility whatever of collision with the roof. Roof hits camera, shatters corrector and the bits drop onto the primary...   Let's change the subject!!!

So it's the indicated distance in this picture from the point of balance in Dec to the front of camera. If you could also give your model of camera or the distance from the end of the OTA to the very front of your camera that would also be great. I know it's a rare beast.

Thanks,

Olly

 

 

[fwm891]

Why not just place the whole OTA assembly on a piece of dowelling. Roll the whole unit back and forth and find the tipping/balance point from both directions and take an average. That will give you your balance distance.

Edited June 25, 2021 by fwm891

[Stuart1971]

1 hour ago, fwm891 said:

Why not just place the whole OTA assembly on a piece of dowelling. Roll the whole unit back and forth and find the tipping/balance point from both directions and take an average. That will give you your balance distance.

I guess because they do not yet own the scope, hence the question….🤔

[tomato]

Don’t forget the cable connections coming straight out of the back of the camera. If formed into a circle I think there is a risk that they could be rigid enough on a cold night to impart sufficient force onto the corrector plate to break it if they hit the roof.

90 degree connectors would be good if you can get them.

I have the 8” so can’t help with the dimensions, but I did find this photo of the RASA11 in use that you might be able to get an estimate from.

[Tomatobro]

I scaled tomatoes image and I got 825 mm from the balance point to the camera end. I also did the same on other pictures on the net and I reckon the number is not too far out. Hopefully someone will confirm

[Roy Foreman]

Just measured mine. It is 620mm from the balance point to the tip of the camera - ZWO 6200MC Pro full frame, which is a large camera. Cables will obviously require another 75mm or so depending on how you route them, and in use you will almost certainly require a dew shield as well.

Attached a photo just in case it helps.

According to Celestron, it takes 55 lbs of weight to break the corrector plate - a figure I find very hard to believe !

[Tomatobro]

Hmmm...scaling from side on photos  not so good. Worth remembering.

[Roy Foreman]

It was worth a try but I imagine there can be some distortion in a photo especially if a wide angle lens was used. And the balance position could be in a different place too.

[Robindonne]

2 hours ago, Roy Foreman said:

Just measured mine. It is 620mm from the balance point to the tip of the camera - ZWO 6200MC Pro full frame, which is a large camera. Cables will obviously require another 75mm or so depending on how you route them, and in use you will almost certainly require a dew shield as well.

Attached a photo just in case it helps.

According to Celestron, it takes 55 lbs of weight to break the corrector plate - a figure I find very hard to believe !

They performed a test on the c14.  Testing looks easy enough to try it yourself.  

 

Are the 90 angle connectors an option when you’re too long?

[Roy Foreman]

What an awful thing to do to a telescope, but I suppose they have to test these things so we can enjoy our equipment safe in the knowledge that we can hang heavy cameras on the corrector plate and its gonna be ok !

[Tomatobro]

it lay down just for an instant and then blew up......

[ollypenrice]

3 hours ago, Roy Foreman said:

Just measured mine. It is 620mm from the balance point to the tip of the camera - ZWO 6200MC Pro full frame, which is a large camera. Cables will obviously require another 75mm or so depending on how you route them, and in use you will almost certainly require a dew shield as well.

Attached a photo just in case it helps.

According to Celestron, it takes 55 lbs of weight to break the corrector plate - a figure I find very hard to believe !

Thanks very much indeed for taking the trouble. Much appreciated. We would probably go for a similar camera. I'll work with 700mm.

 

5 hours ago, Stuart1971 said:

I guess because they do not yet own the scope, hence the question….🤔

You're right! This is a potential joint venture and would be fully robotic, but compatibility with the shed has to be a first thing to verify.

Placing an extra weight well forward of the normal point of balance does give some leeway for sliding the tube downwards but we need to be sure the thing would fit.

SGL as incomparable as ever. Thanks all.

Olly

[gorann]

Olly, if you aim at buying as used RASA11 make sure you get the new version - the original one had severe issues with the focusing/holding of the primary mirror. I am also not sure what the gain is with a RASA11 with an 24 x 36 sensor compared to a RASA8 with a 24 x 18 sensor. FOV will be about the same. I am setting up a dual RASA8 + ASI2600MC rig to either get immedeate mosaics or RGB + dual band. The cost for my two RASA8 and ASI2600MC was the same as for one RASA 11 and ASI6200MC but I get twice the FOV and more options. The weight is also about the same.

[tomato]

2 hours ago, Robindonne said:

They performed a test on the c14.  Testing looks easy enough to try it yourself.  

 

Are the 90 angle connectors an option when you’re too long?

Is the sheet on the floor ready to collect the glass fragments?

File this alongside someone standing on a Mesu 200.😄

[gorann]

Ps. Olly you will also need to incude the space for a dew shield for a RASA.

[ollypenrice]

2 hours ago, gorann said:

Olly, if you aim at buying as used RASA11 make sure you get the new version - the original one had severe issues with the focusing/holding of the primary mirror. I am also not sure what the gain is with a RASA11 with an 24 x 36 sensor compared to a RASA8 with a 24 x 18 sensor. FOV will be about the same. I am setting up a dual RASA8 + ASI2600MC rig to either get immedeate mosaics or RGB + dual band. The cost for my two RASA8 and ASI2600MC was the same as for one RASA 11 and ASI6200MC but I get twice the FOV and more options. The weight is also about the same.

That is very persuasive! Thanks,

Olly