8 inch DOBSONIAN telescope FIRST MODS

[Tiago Ferreira]

Important improvements you should do to your 8" DOBSONIAN telescope. This is the first wave of upgrades you can do in your Dob to properly prepare it to have much better visual and imaging sessions. A second wave will be needed which includes also the Telrad finder and it will be explained in another video. Have a nice weekend!

 

Edited October 1, 2021 by Tiago Ferreira

[dweller25]

Good video - nice handles 😁

A modification to improve contrast is to flock the tube opposite to the focuser 👍

[Tiago Ferreira]

6 hours ago, dweller25 said:

Good video - nice handles 😁

A modification to improve contrast is to flock the tube opposite to the focuser 👍

True. I have that mod in my 12" too. It's like looking through a black hole lol

This is a brand new 8" so i'm improving it step by step. To enjoy. 😁

[Merlin]

Many of the Newtonians we see today, including my own, have main tubes that are too short at the top, allowing a considerable amount of stray light to enter the tube and reduce contrast.

If we look through the drawtube and can see out through the top of the main tube ( ignoring the flat ), we need an extension. I made a foot-long extension for the 8-inched by rolling some camping mat material into a tube and lining it with Matt black art card.

The main tube extension fits like a glove and also acts as a dew shield for the flat. M anufacturers probably make the main tubes too short to make their ‘scopes look more compact, but this is at the expense of contrast and also makes the flat more prone to dewing.

[John]

3 hours ago, Merlin said:

Many of the Newtonians we see today, including my own, have main tubes that are too short at the top, allowing a considerable amount of stray light to enter the tube and reduce contrast.

If we look through the drawtube and can see out through the top of the main tube ( ignoring the flat ), we need an extension. I made a foot-long extension for the 8-inched by rolling some camping mat material into a tube and lining it with Matt black art card.

The main tube extension fits like a glove and also acts as a dew shield for the flat. M anufacturers probably make the main tubes too short to make their ‘scopes look more compact, but this is at the expense of contrast and also makes the flat more prone to dewing.

I agree with this.

I use a light shield at the top of my dobsonian and it makes a lot of difference to the contrast when I'm using the scope in my back garden, where there can be quite a bit of stray light about. I use one of the "half moon" shaped ones opposite the focuser and it seems very effective. I've also flocked the tube opposite the focuser and blackened the secondary mirror edge.

 

 

Edited October 2, 2021 by John

[Tiago Ferreira]

3 hours ago, Merlin said:

Many of the Newtonians we see today, including my own, have main tubes that are too short at the top, allowing a considerable amount of stray light to enter the tube and reduce contrast.

If we look through the drawtube and can see out through the top of the main tube ( ignoring the flat ), we need an extension. I made a foot-long extension for the 8-inched by rolling some camping mat material into a tube and lining it with Matt black art card.

The main tube extension fits like a glove and also acts as a dew shield for the flat. M anufacturers probably make the main tubes too short to make their ‘scopes look more compact, but this is at the expense of contrast and also makes the flat more prone to dewing.

Yes indeed. I have that in my 12" dob. And not only that. Looking through my 12" is like looking through a black hole.🙂