THE FAULKS 20" F4 DOB BUILD

[faulksy]

your right damian, just come off the phone to them, they said they will let me know before 3 ish to give me time to get there

[swamp thing]

33 minutes ago, mapstar said:

Hmmmmm it's not looking too good for Elan mate. At least you'll have a great Strehl ratio with no central obstruction! Not much good for observing though 

We could be sharing my secondary at this rate.  

Pity you did't use Webster clamps on your scope Mike or we could just take it in turns to use my UTA  

[faulksy]

all sorted now, 00 have said it was the kendrick dew heater that twisted the mirror so they are giving me a replacement FOC

[swamp thing]

Just knew it would be your fault.............Yeah right!! 

At least it's sorted mate. 

[estwing]

So your dew heater gets that hot it's twisted the secondary?...won't bother bringing my stove I'll cook my chilli on your Kendrick...

[Pig]

1 hour ago, estwing said:

......won't bother bringing my stove I'll cook my chilli on your Kendrick...

<<<<<<<<<<<<< sings  "There may be trouble ahead"  Not the dreaded chilli !!!!!

[faulksy]

back home now safe and sound with my foc secondary from john at orion optics. thanks john/barry

[mapstar]

Just now, faulksy said:

back home now safe and sound with my foc secondary from john at orion optics. thanks john/barry

FOC thought you'd already paid for a flat 

[faulksy]

1 minute ago, mapstar said:

FOC thought you'd already paid for a flat 

that was my thought, but i fitted the dew heater as per the instructions

[mapstar]

New spider is well under way, how's the new secondary holder looking Mike

[faulksy]

10 minutes ago, mapstar said:

New spider is well under way, how's the new secondary holder looking Mike

still in customs

[mapstar]

Just now, faulksy said:

still in customs

 yeah it's extortionate!!!!!

[faulksy]

3 hours ago, estwing said:

So your dew heater gets that hot it's twisted the secondary?...won't bother bringing my stove I'll cook my chilli on your Kendrick...

calv, what i think they ment was with it being bonded to the back its the heater its self that twisted it, switched  on or off nothing to do with the heat

Edited October 26, 2016 by faulksy

[James Vincent]

One of the biggest issues with a Newtonian is way secondary mirror is attached to the holder, if it is bonded with silicon it can distort the mirror causing an astigmatic image.

The secondary should be quite thick at least 15 to 20mm for a 110mm  flat to prevent distortion.

hope you get it sorted out.

Jim

 

[faulksy]

On 30/10/2016 at 11:34, James Vincent said:

One of the biggest issues with a Newtonian is way secondary mirror is attached to the holder, if it is bonded with silicon it can distort the mirror causing an astigmatic image.

The secondary should be quite thick at least 15 to 20mm for a 110mm  flat to prevent distortion.

hope you get it sorted out.

Jim

 

hi jim, its a 100mm flat and 15mm thick. its not siliconed on, it fits inside a wrap around holder, its astrosystems.

nice dob by the way, obsession ?

Edited November 1, 2016 by faulksy

[faulksy]

small update, had to strip the dob back down to the boxs, it looks like i used the wrong varnish and it was delaminating , so sanded back to wood, re stained and bought polyurethane in spray form. so will lightly sand tomorrow, polish and rebuild. hope to get it up and running tomorrow night

[faulksy]

On 26/10/2016 at 19:11, mapstar said:

New spider is well under way, how's the new secondary holder looking Mike

i can answer that now brendan it fits perfect, just like it should of in the beginning

[faulksy]

just finished fitting my dew guard, and new secondary to the new holder, what a difference. pics tomorrow

[faulksy]

all rubbed down and machine polished, feels harder than before.

the mirror box inside the rocker box always sat slightly out of square to each other probably by 1 - 1.5mm, this done my head in and the dob mob had heard me mention it. this is now cured and sits perfect, so i can now sleep

side bearings fitted, i used some 1mm thick fibre washers under each mounting point, because they squeaked sometimes, so hopefully cure that as well

hope you dont mind me putting this in your section gina

only kidding girl

Edited November 2, 2016 by faulksy

[swamp thing]

Good stuff Mike

Lets have some pics then.........

[faulksy]

40 minutes ago, swamp thing said:

Good stuff Mike

Lets have some pics then.........

wont be long

[swamp thing]

1 hour ago, faulksy said:

wont be long

Waiting............. 

[estwing]

...waiting 

[Pig]

.....waiting......

[swamp thing]

Still waiting........