Tool to block primary mirror reflections.

[wookie1965]

Hi can you people help me with a few dimensions please preferably for a 10" ,8",6, and 4" scopes.

I have joined a group near me and a few people have asked me look at collimation when we can have meetings I want to make a tool or tools to aid me to do this quickly.

So could you good people supply me with the measurements from the front of the scopes to say 3cm past the secondary and the same from the spider vanes please.

The tool (tools) will look something like this thank you.

Paul 

Edited July 12, 2021 by wookie1965

[Spile]

I prefer NOT to block the primary reflection when aligning the secondary. The direction of the offset secondary reflection shows any tilt/rotational errors.

A piece of coloured paper behind the focuser makes it easier to see the edge of the secondary. 

Edited July 14, 2021 by Spile

[wookie1965]

I do that as well I just like to get the secondary central but also it is for a teaching aid. I can collimate fairly easy but showing someone new can be a pain because of so many reflections this way I can show them which reflections they should be looking at first.

[AstroMuni]

4 hours ago, wookie1965 said:

The tool (tools) will look something like this thank you.

I like your idea. Its a good one for smaller scopes where your hand wont fit in. Is there a reason you dont place just a large sheet of paper in the tube to block the main mirror?

And if you are building a proper tool then suggest you provide for a) an adjustable arm b) a long arm (say 20cm) which is sure to block most scopes.

Edited July 12, 2021 by AstroMuni

[Tomatobro]

my SW 4.5 inch is 130 mm (100 from bottom edge of diagonal to top edge of spider) with your 30mm allowance

[wookie1965]

1 hour ago, AstroMuni said:

I like your idea. Its a good one for smaller scopes where your hand wont fit in. Is there a reason you dont place just a large sheet of paper in the tube to block the main mirror?

And if you are building a proper tool then suggest you provide for a) an adjustable arm b) a long arm (say 20cm) which is sure to block most scopes.

I have quite big hands and to get the card/paper through the gaps in the spider is rather difficult not so much with the bigger scopes, but when I make the tool it should accommodate all apertures. That is why I want measurements so I can make it long enough for the big scopes and say the handle/mounting part I can make it a universal fit.

[Richard Wesson]

On 12/07/2021 at 10:25, wookie1965 said:

Hi can you people help me with a few dimensions please preferably for a 10" ,8",6, and 4" scopes.

I have joined a group near me and a few people have asked me look at collimation when we can have meetings I want to make a tool or tools to aid me to do this quickly.

So could you good people supply me with the measurements from the front of the scopes to say 3cm past the secondary and the same from the spider vanes please.

The tool (tools) will look something like this thank you.

Paul 

I have been trying to come up with something to block the reflection of the main scope when using the concenter! I have a 130pds and trying to get a sheet of paper in there very difficult due to space. Your idea looks great and will try to make something similar!