Imaging with the 130pds

[AKB]

1 hour ago, Susaron said:

A single shot from M42 from yesterday evening, I had problems with guiding, though my polar allignment was under 2 arc minutes on both axes.

60 seconds at ISO1600 with a unmodded Canon 70D

There's some great detail here - I've taken the liberty of doing a bit of processing to show this.  Hope you don't mind.

Of course, the core is inevitably blown out in a 60 second exposure, but nevertheless, nice pic!

[gazza]

Hi,

I was wrong about the Skywatcher f4 coma corrector not working on the 130PDS. I had allowed for filter thickness and ccd chip coverglass  in calculating spacer distance. This made threw me out. After a long night - 'til 3am last night experimenting, I came up with a distance that works perfectly. Using 52.5 mm physical distance - no allowance for filters etc, the corrector gives perfect correction on a KAF8300 chip. No longer need to buy a new corrector :-)

cheers

Gary

[Susaron]

15 hours ago, AKB said:

There's some great detail here - I've taken the liberty of doing a bit of processing to show this.  Hope you don't mind.

Of course, the core is inevitably blown out in a 60 second exposure, but nevertheless, nice pic!

Thanks AKB, of course I don´t mind, the picture I submitted was a simple levels adjustment made with Canon EOS tool. Looks really cool.

[Susaron]

Dear all

A steeper bracket for the original SW130 focuser is available in stl format made in FreeCad, the file is available in my Dropbox

https://www.dropbox.com/s/7qw33bij099qm7v/AddedBracketSW130OriginalFocuser.stl?dl=0

Please let me know is you like it.

Cheers.

[Stub Mandrel]

41 minutes ago, Susaron said:

Dear all

A steeper bracket for the original SW130 focuser is available in stl format made in FreeCad, the file is available in my Dropbox

https://www.dropbox.com/s/7qw33bij099qm7v/AddedBracketSW130OriginalFocuser.stl?dl=0

Please let me know is you like it.

Cheers.

I've downloaded it, but I'm not sure what it's for?

[Susaron]

5 minutes ago, Stub Mandrel said:

I've downloaded it, but I'm not sure what it's for?

It is a bracket complement to be used along with this bracket for a NEMA 17 Steeper motor:

http://eu.stepperonline.com/nema-17-stepper-motor-geared-stepper-motor-alloy-steel-mounting-bracket-p-241.html

The steeper conects to the focuser directly, so in order to fullfill the distance needed I had to design this small bracket, that matches to the one from Steeper Online with a couple of M4 screws.

It is the orange part in this assembly

 

[Stub Mandrel]

Ah! Forgive me but it's stepper not steeper - steeper relates to angles so I thought it was for tilting the focuser!

[JohnSadlerAstro]

Hi,

My 130P-DS is due at the door any minute  FLO certainly have quick dispatching and shipping!

John

[Stub Mandrel]

I'm waiting for a parcel too... for my wife

[Adam J]

I recently posted in another thread about a problem that I encountered with collimation of the 130PDS. I thought that it would be best to share here too as it may not just be me. 

When I first purchased my 130PDS it came with a 1.25" to 2" converter. 

I also purchased a 1.25" laser collimator. 

On first collimation following my purchase I placed the laser collimator into the 2" to 1.25" adaptor I noted that the laser was a long way off hitting the primary mirror centre spot. 

I adjusted the secondary to move the laser into the centre spot. I then rotated the laser collimator within the 2" to 1.25" adapter to see if the spot remained stationary and hence reassure myself that the laser itself was collimated. The spot did not move. 

I then adjusted the primary as normal. 

However, despite taking grate care with this procedure I found my results to be inconsistent, some sessions I would have apparently good collimation and in others collimation would appear very poor. 

As a newbie astronomer at the time it was only some months later that I worked out that if I rotated the entire assembly (collimator + 2" to 1.25" adapter) within the focusing tube then the laser spot moved in a 1 inch diameter circle as observed on the primary!

My eventual conclusion was that the two sides of the Skywatcher 1.25" to 2" adapter supplied with the 130PDS are not parallel and by a long way.

Like I have said I have no way of knowing it this is a general issue or if this is just a problem with my adapter but be warned! 

 

 

 

Edited March 2, 2017 by Adam J

[Thalestris24]

8 hours ago, Adam J said:

I recently posted in another thread about a problem that I encountered with collimation of the 130PDS. I thought that it would be best to share here too as it may not just be me. 

When I first purchased my 130PDS it came with a 1.25" to 2" converter. 

I also purchased a 1.25" laser collimator. 

On first collimation following my purchase I placed the laser collimator into the 2" to 1.25" adaptor I noted that the laser was a long way off hitting the primary mirror centre spot. 

I adjusted the secondary to move the laser into the centre spot. I then rotated the laser collimator within the 2" to 1.25" adapter to see if the spot remained stationary and hence reassure myself that the laser itself was collimated. The spot did not move. 

I then adjusted the primary as normal. 

However, despite taking grate care with this procedure I found my results to be inconsistent, some sessions I would have apparently good collimation and in others collimation would appear very poor. 

As a newbie astronomer at the time it was only some months later that I worked out that if I rotated the entire assembly (collimator + 2" to 1.25" adapter) within the focusing tube then the laser spot moved in a 1 inch diameter circle as observed on the primary!

My eventual conclusion was that the two sides of the Skywatcher 1.25" to 2" adapter supplied with the 130PDS are not parallel and by a long way.

Like I have said I have no way of knowing it this is a general issue or if this is just a problem with my adapter but be warned! 

 

 

 

Hi

It may be to do with the thumbscrews or it could be the focusser assembly itself isn't square. Astronomyshed's youtube video on tweaking the quattro shows one way of checking and adjusting the focusser.

Louise

[Adam J]

15 minutes ago, Thalestris24 said:

Hi

It may be to do with the thumbscrews or it could be the focusser assembly itself isn't square. Astronomyshed's youtube video on tweaking the quattro shows one way of checking and adjusting the focusser.

Louise

No it was the adapter, this was a while back and its all great now with a better quality adapter. I only just thought to mention it on here because something in another thread prompted me.

 

Edited March 2, 2017 by Adam J

[JohnSadlerAstro]

22 hours ago, Adam J said:

Something in another thread prompted me.

Or, "Somebody"; I think that was me!  

I must try that out with my new P-DS.  

John  

[Stub Mandrel]

So impressed by the moon views through my finder I thought I'd pop an EP in the 130P-DS.

I can't rack the focuser in enough to get focus! Even with a barlow!

(Yes I've had it about eight months and this was my first attempt at looking through it!)

I'm not going to move the mirror - I don't want the focuser tube to give me funny stars again.

Perhaps I can find a shorter 1.25" ep holder.

[rotatux]

1 hour ago, Stub Mandrel said:

I can't rack the focuser in enough to get focus!

That's weird... and quite surprising given you did AP with it. If so, the focus plane must be well outside the tube, and the focuser should rack out to get focus with eyepiece.

What kind of adaptation do you use as 1.25" holder from the focuser ?

1 hour ago, Stub Mandrel said:

I'm not going to move the mirror - I don't want the focuser tube to give me funny stars again.

Err, do you mean you already moved up the primary to avoid the focuser tube going into the light cone ? Then your focus is even more outside the tube, and so I would understand the origin of the problem especially since IIRC your focal is ~20mm longer than mine.

For other uses I recently ordered a shorter 2">1.25" adapter (one with annular holder, like that) which I incidentally tried with EP but it proved too short for my focuser range (could not rack out enough). Maybe that kind of model would suit you. I just measured it to be 27mm±0.5 shorter than the stock adapter which came in my scope's package (the one with 2 parts which you unscrew to use for T2).

[Stub Mandrel]

32 minutes ago, rotatux said:

What kind of adaptation do you use as 1.25" holder from the focuser ?

Its a 2" to 1.25" adaptor that hold the EP about 1 1/2" further out than a 2" EP would be.

[Stub Mandrel]

34 minutes ago, rotatux said:

Err, do you mean you already moved up the primary to avoid the focuser tube going into the light cone ? Then your focus is even more outside the tube, and so I would understand the origin of the problem

No i chopped the end off the focus tube.

I think I must have the two-part adaptor, it has a T2 thread on it and I can't see how you would use it with the EP tube sticking out the middle!

I can turn up a new holder from a lump of ally, or maybe knock 1/2" off the existing one, which should be ample.

 

[richyrich_one]

As has been said are you sure it's infocus you need?

Even with my primary moved back to it's original position, I've been trying to get my autocolimator at the focal plane and I need a 2" extension to do it.

If you have chopped the focus tube does that not make the situation worse as you have less draw tube to extend out?

Can you focus with a 2" eyepiece?

[Stub Mandrel]

4 minutes ago, richyrich_one said:

As has been said are you sure it's infocus you need?

Even with my primary moved back to it's original position, I've been trying to get my autocolimator at the focal plane and I need a 2" extension to do it.

If you have chopped the focus tube does that not make the situation worse as you have less draw tube to extend out?

Can you focus with a 2" eyepiece?

Well its damn weird if you ask me. Holding a 10mm EP in place, I could get the moon into wobbly focus if it was held well into the tube.

edit - I don't have a 2" EP.

Edited March 9, 2017 by Stub Mandrel

[richyrich_one]

2 minutes ago, Stub Mandrel said:

Well its damn weird if you ask me. Holding a 10mm EP in place, I could get the moon into wobbly focus if it was held well into the tube.

edit - I don't have a 2" EP.

That is wierd, after all where does you DSLR sensor lie when it is at focus? 55mm outside the drawtube.

 

[Stub Mandrel]

8 minutes ago, richyrich_one said:

That is wierd, after all where does you DSLR sensor lie when it is at focus? 55mm outside the drawtube.

 

I've only ever used it with the coma corrector.

Perhaps the mirror is too far down the tube? Still It focuses in the middle of its range with the camera so I'm not complaining.

[Uranium235]

2 hours ago, Stub Mandrel said:

I've only ever used it with the coma corrector.

Perhaps the mirror is too far down the tube? Still It focuses in the middle of its range with the camera so I'm not complaining.

For an ep you need to be adding length to the focuser with an extension tube, not removing it.

Also try it without the CC first, that will simplify the optical train.

[Stub Mandrel]

33 minutes ago, Uranium235 said:

For an ep you need to be adding length to the focuser with an extension tube, not removing it.

Also try it without the CC first, that will simplify the optical train.

This is without the CC, I can't fit an ep into the CC

I''m confused.com here.

[Uranium235]

6 minutes ago, Stub Mandrel said:

This is without the CC, I can't fit an ep into the CC

I''m confused.com here.

I wasnt sure which CC you had because the SWCC comes with a 2" EP adaptor (it has an M48 thread at the base for connecting to the corrector).

So, disregarding the corrector issue - just use an extension tube. Or if you have a 2" barlow, remove the element (it normally just screws off) and use that as your extension.

[Stub Mandrel]

5 minutes ago, Uranium235 said:

I wasnt sure which CC you had because the SWCC comes with a 2" EP adaptor (it has an M48 thread at the base for connecting to the corrector).

So, disregarding the corrector issue - just use an extension tube. Or if you have a 2" barlow, remove the element (it normally just screws off) and use that as your extension.

Right, that explains what the tube with an m48 internal thread that accepts a 2" EP is for.

I have been using a 'top hat' shaped adaptor about 2" high that fits into the end of the focuser where I would normally put the CC.