130pds focuser replacement?

[gazza]

Hi,

I have started using my 130pds for imaging, but, like others I've struck image tilt due to the sloppy focuser fit/screws. Have tried a third screw to no avail. Are there any focusers other than Moonlight that fit it? Have had issues with anodising breaking down on Moonlights where the rollers contact. This has happened on 3 of them that I've previously owned, so I would prefer not to buy another. Can a Baader Diamond Steeltrack fit? Other options?

TIA 

Gary

[cuivenion]

You can adjust slop, tension and tilt on the 130pds focuser.

https://teleskop-austria.at/information/pdf/Justieren_Adjusting_Crayford_focuser.pdf

[gazza]

Hi,

when I meant sloppy focuser fit I meant that when you fit a coma corrector to the focuser, it is so loose that when you tighten the screws on the 2" adapter it tilts the corrector ? Sorry if I was being unclear!

cheers

Gary

[cuivenion]

Ah, I see what you mean, I've been buying adapters to fit my cc and camera to the T2 to dovetail adapter, so that everything is attached by threads to the dovetail adapter. I am having to use an m54 to dovetail adapter from an older 200p focuser rather than the m54 to 2" that comes with the 130pds due to the width of some of the adapters. I'll add some pics when I get back from holiday.

[cuivenion]

Here you go:

I must stress that this is an M54 to dovetail adapter that fits onto the focuser, not the M54 to 2" that comes with 130pds. There's not enough width in the M54 to 2" for the t2 extenders. Equipment used is:

ZWO Asi224 camera

20mm male to female T2 extension

Dovetail to 1.25" (T2) adapter

M54 to Dovetail adapter

34.6 to T2 adapter

10mm female to male T2 adapter 

9mm T2 female to female converter

2mm of Delrin spacers

Baader mpc mark iii CC

This gives me the 55mm distance needed for the CC, and there is none of the focuser protruding into the light path.

I've yet to test this configuration out on stars, but I'm hopeful of good results.

Unfortunately this won't work with a canon DSLR because you need about 20mm of Space between the M36.4 thread and the CC to stop the CC fouling on the M54 thread, and the canon sensor distance is 45mm. It should be good with cameras with sensor distances up 34mm, although you might want to give yourself a few mm wiggle room to get the CC spacing right.

[cuivenion]

Just to add that unfortunately the above setup does not work, I didn't realise that the Baader MPCC III moved the focus out by 10mm. I can't reach focus withe above setup with the 130pds.

[bottletopburly]

Why not change the the adapter  2” m54 to a compression type I use it on my 200pds  with a mpcc111 can’t say I have noticed any tilt I got mine from modern astronomy has lasting screws , FLO  one has metal screws 

[RolandKol]

I would not bother my self about the "Fit bolt Tilt", as focuser has 2 bolts and you can tighten them quite equally and leave it for good

The main pain is the focuser's tube Tilt while you Lock the Focuser....
You can play 5 min, achieve "SuperDuper" Focus, -  and Lose it in a second once you lock it... I have to play with focus offset all the time and it's even more tricky...

I hope my DIY autofocuser will make my life easier....

 

[Adam J]

On 07/11/2018 at 20:34, gazza said:

Hi,

I have started using my 130pds for imaging, but, like others I've struck image tilt due to the sloppy focuser fit/screws. Have tried a third screw to no avail. Are there any focusers other than Moonlight that fit it? Have had issues with anodising breaking down on Moonlights where the rollers contact. This has happened on 3 of them that I've previously owned, so I would prefer not to buy another. Can a Baader Diamond Steeltrack fit? Other options?

TIA 

Gary

This is a fatal issue with the Baader MPCCMK3. Its caused by the grove on the barrel and how it interacts with the screws / compression ring. 

There are other..possibly better coma correctors available, TS optics sell some interesting models for example or you could go with the Skywatcher coma corrector and live with some reflections. 

https://www.teleskop-express.de/shop/product_info.php/info/p3822_TS-Optics-2--3-element-MaxField-Newtonian-Coma-Corrector.html

I am having this exact issue at the moment. But I blame the Baader CC not the focuser.

The problem is that even with a compression ring it will still tilt because of the CC design. 

Adam 

[bottletopburly]

1 hour ago, Adam J said:

This is a fatal issue with the Baader MPCCMK3. Its caused by the grove on the barrel and how it interacts with the screws / compression ring. 

There are other..possibly better coma correctors available, TS optics sell some interesting models for example or you could go with the Skywatcher coma corrector and live with some reflections. 

https://www.teleskop-express.de/shop/product_info.php/info/p3822_TS-Optics-2--3-element-MaxField-Newtonian-Coma-Corrector.html

I am having this exact issue at the moment. But I blame the Baader CC not the focuser.

The problem is that even with a compression ring it will still tilt because of the CC design. 

Adam 

I will have a better look at mine ?

[tooth_dr]

I have a moonlite focuser and I have this issue with my MPCC, it only catches on the edge of the groove and is almost impossible to have it working without any tilt happening.