Lodestar 2 and OAG

[cfpendock]

9 minutes ago, RayD said:

Rodd I'll leave Chris to help you as I think he has more experience of this issue than me

Thanks for your confidence, Ray, but I'm not at all sure of that!  It's just that my system seems to work, for whatever reason, and like you, I also look forward to seeing some more of Rodd's images,  which I am afraid leave my own looking distinctly amateurish....

15 minutes ago, RayD said:

The problem then is that your focal plane can be so far back that you can't wind the focuser in enough to actually get focus.

Exactly.   I was lucky as the C11 has an enormous range of focus, so once the Tak was ok, then it was easy to make the C11 work also.

Chris

 

[Rodd]

4 hours ago, Rodd said:

Don't have one.  I have always used the SBIG self guiding filter wheel.  I am seriously considering going that route though--but if the Lodestar is faulty, it won't work there either

 

3 hours ago, RayD said:

 

No problem Chris.  It probably would on the same scope with or without the FR, but Rodd has 2 different scopes with differing focal lengths and is using the spacing calculated for the FSQ on the TOA.  I have a feeling this is where the issue lies as in either case he will need to have the spacer between the OAG and the FW, which in itself is a little unusual, but if the other spacer (FR to OAG) is calculated using the FSQ but is being tested on the TOA it may never work.

It's always tough trying to help when you aren't there in front of the kit.

OK--lots to report.  Here is what I did:

1) I pointed the scope at some distant trees.  I am fortunate to be using a camera that can take .001 sec exposures with an Ha filter, as it is a very sunny day.  See image 1 to verify main focus (not perfect but OK).

2)  I tried the lodestar without a spacer between the OAG and filter wheel, with a 16.5mm spacer, with a 21 mm spacer--and with the 16.5 AND the 21 (I was wrong--they can be coupled together as the wing nut portion threads off).

3)  One problem is the Lodestar can't take short enough exposures.  Hence, there is no way to verify focus.  However, based upon what I did see, the best is without a spacer and the prism out as far as it will go  into the Lodestar housing.  See image 2.  You can see that the prism is not really in the light path far enough--the prism arm needs to be longer.  

When I tried with the 21mm and 16.5mm spacer together, I could not achieve focus with the ASI 1600--not enough inward travel. The only way I could get the Loadstar to display anything but pure white, or a view that resulted from the prism not  penetrating the light cone--was with no spacer as in image 2.  I have no way to know if its in focus or not--the signal is too high due to sunlight.  I tried making a pin hole (taped up my B-Mask except for a small opening in middle.  It did not make any difference--it may have cut the overall brightness a bit--but image 2 still looked like image 2.

Doing it during the day is very tricky.  Too much light.  Not sure what to do now.

ASI 1600 Ha .001 sec focus

Best Lodestar image

[cfpendock]

Good start - it seems to me that the camera works, except I'm not sure why the image shows white where no light is on it.  

When I look down my scope (from the objective end), I position the Loadstar prism so that it is just up to the side of the sensor (which is quite big on the Atik 4000).  Of course, you can only do this with the Lum filter (or no filter) - otherwise you won't see the sensor.  That way, I know that the prism will not interfere with the light falling on the sensor, but is easily far enough in to pick up plenty of light.  This is not so difficult with the Tak 106 because it has an enormous image circle.  

I will try and photograph it if you give me an hour or so - it's rather cold and snowy here.

Chris

[Rodd]

3 minutes ago, cfpendock said:

Good start - it seems to me that the camera works, except I'm not sure why the image shows white where no light is on it.  

When I look down my scope (from the objective end), I position the Loadstar prism so that it is just up to the side of the sensor (which is quite big on the Atik 4000).  Of course, you can only do this with the Lum filter (or no filter) - otherwise you won't see the sensor.  That way, I know that the prism will not interfere with the light falling on the sensor, but is easily far enough in to pick up plenty of light.  This is not so difficult with the Tak 106 because it has an enormous image circle.  

I will try and photograph it if you give me an hour or so - it's rather cold and snowy here.

Chris

It shows white where too much light is on it.  That's what I was talking about with focus--no way to determine--its just flooded with light.  The prism is only partially in the light cone--you can see the line--but there is enough light to wash that area too--just not as badly.  I think the prism needs to be longer, as that is one way to (the only way) to focus the lodestar--bringing the end of the prism stalk closer or farther from the lodestar sensor.  But it can't go any closer because then there won't be enough stalk to stick into the light cone. 

[cfpendock]

Ok, so I could't get enough light to photograph the set-up through the scope, so I took the OAG package off the scope so you can see the extension of the prism into the nose piece - which either fits directly into the Tak or into the C11 - you can see the prism is clear of the sensor - especially because I lined it up so the edge of the prism was in line with the sensor.  Sorry about the quality of the photo - it's rather cold, but it's good enough to see.  This complete assembly is simply attached either to the Tak or to the C11 - no changes to it at all.

Chris

 

[Freddie]

Odd that the lodestar will not do short enough exposure what are you controlling it with?

[Rodd]

7 minutes ago, Freddie said:

Odd that the lodestar will not do short enough exposure what are you controlling it with?

Maxim... The exposure is set to .001 sec--the lodestar can't do that short.  Its a bright sunny day--the main image was taken at .001 sec through an Ha filter.  The lodestar has no filters

[cfpendock]

With the prism in the position shown in the photo, it is picking up a good view of the sky.  The attached screen shots show the stars, one for the Tak and one for the C11 (labels on the blue line at the top of each image).  Just to keep you going and show that it can work with no fiddling between scopes.  

Chris

 

 

[Davey-T]

It would appear to be incompatible Rodd though you would think the supplier would be aware of this

So ignoring the imaging camera it should be possible to bring the Loadstar to focus regardless of how far it is from the prism

If this can’t be done something is wrong somewhere along the line

I have an Atik OAG on my SCT and the Loadstar is in an adjustable holder to raise and lower it I don’t see how they expect you to focus it with no adjustment 

Away at the moment but will check how far it is from the prism when get back

If you look down the scope you can adjust the prism so it just protrudes into the light path and that’s where it wants to be then look down the guide camera hole and find a bright star focusing the scope, then slide the Loadstar in and lift it manually up and down and twiddle the main focus, you can use a par focal ring to hold it.

If the main camera then won’t focus without loosing the guide camera then the gear they sold you is simply incompatible 

Dave

[Rodd]

7 minutes ago, cfpendock said:

With the prism in the position shown in the photo, it is picking up a good view of the sky.  The attached screen shots show the stars, one for the Tak and one for the C11 (labels on the blue line at the top of each image).  Just to keep you going and show that it can work with no fiddling between scopes.  

Chris

 

 

I do not doubt you.  I hope I am as fortunate as you

Rodd

[Rodd]

1 minute ago, Davey-T said:

It would appear to be incompatible Rodd though you would think the supplier would be aware of this

So ignoring the imaging camera it should be possible to bring the Loadstar to focus regardless of how far it is from the prism

If this can’t be done something is wrong somewhere along the line

I have an Atik OAG on my SCT and the Loadstar is in an adjustable holder to raise and lower it I don’t see how they expect you to focus it with no adjustment 

Away at the moment but will check how far it is from the prism when get back

If you look down the scope you can adjust the prism so it just protrudes into the light path and that’s where it wants to be then look down the guide camera hole and find a bright star focusing the scope, then slide the Loadstar in and lift it manually up and down and twiddle the main focus, you can use a par focal ring to hold it.

If the main camera then won’t focus without loosing the guide camera then the gear they sold you is simply incompatible 

Dave

But its not--Folks use the ASI 1600, ZWO OAG, and Lodestar.  From my understanding its a common setup.  Its not like I designed this myself.

[Davey-T]

So I’d just fit the Loadstar as I said and it should come to focus ignoring the main camera

Is there anyone you can borrow a C lens and adapter from to check that the Loadstar actually works as a stand alone camera ?

Dave

[Davey-T]

Are you sure the prism is fitted properly ?

mine came loose once and actually fell out as it’s only held by a small nylon screw

Dave

[Rodd]

2 minutes ago, Davey-T said:

Are you sure the prism is fitted properly ?

mine came loose once and actually fell out as it’s only held by a small nylon screw

Dave

No one to borrow things from.  The prism arm is pretty stable--tight.  

[Rodd]

1 hour ago, cfpendock said:

Ok, so I could't get enough light to photograph the set-up through the scope, so I took the OAG package off the scope so you can see the extension of the prism into the nose piece - which either fits directly into the Tak or into the C11 - you can see the prism is clear of the sensor - especially because I lined it up so the edge of the prism was in line with the sensor.  Sorry about the quality of the photo - it's rather cold, but it's good enough to see.  This complete assembly is simply attached either to the Tak or to the C11 - no changes to it at all.

Chris

 

There is no way to get the prism parallel to the sensor like that--the 3 wings of the connector that the lock screws tighten against are situated so that the prism pedestal must come in at an angle.  I am beginning to hate threaded connections--its all the way or nothing--no room for positioning.  As a result--my prism is at an angle--not right on a corner--but not like yours either

[cfpendock]

Ok.  Sorry Rodd, but I'm not familiar with your camera and filter wheel set up, it seems the difference is the filter wheel / OAG assembly.  So I don't think that I can help anymore.  But I wish you luck with it and keep my fingers crossed for you....

Chris

[Rodd]

39 minutes ago, cfpendock said:

Ok.  Sorry Rodd, but I'm not familiar with your camera and filter wheel set up, it seems the difference is the filter wheel / OAG assembly.  So I don't think that I can help anymore.  But I wish you luck with it and keep my fingers crossed for you....

Chris

I think the filter wheel is pretty standard--but thanks for you help.  Maybe I'll get lucky in about a hour and it will be in focus.

Rodd

[Rodd]

Well--I am signing off now--it does not work.  I can't even get full illumination out of the Lodestar--Its dark and the images still look like white off center half circles.  Same as before.  So I am done.  Supplier has not responded to emails or calls (all weekend).  I will return the OAG and go with a guide scope.  I really wanted better guiding though.  Oh well.  I am thinking of the Sky watcher EVO guide.  Any Good?  Thanks for everyone's help--the response was simply amazing.  I hope I can one day return the favor.

 

Rodd

[AngryDonkey]

Sorry if this has been suggested before (it's a long thread and I didn't manage to read it all) but I would ask your question on the SX Yahoo support group. Terry is usually very quick in responding and he does know most about this equipment, I'm sure he will be able to help or confirm that it is faulty (not sure about weekend support though, I don't think many suppliers do that):

https://groups.yahoo.com/neo/groups/starlightxpress/

 

[Yawning Angel]

Rodd, before you send it back, could you snap a photo of the imaging train please? There may be something easily identifiable that is not being picked up purely off descriptions

[Rodd]

6 hours ago, AngryDonkey said:

Sorry if this has been suggested before (it's a long thread and I didn't manage to read it all) but I would ask your question on the SX Yahoo support group. Terry is usually very quick in responding and he does know most about this equipment, I'm sure he will be able to help or confirm that it is faulty (not sure about weekend support though, I don't think many suppliers do that):

https://groups.yahoo.com/neo/groups/starlightxpress/

 

Thanks Alex--I will look into that today.

Rodd

[Rodd]

2 hours ago, Yawning Angel said:

Rodd, before you send it back, could you snap a photo of the imaging train please? There may be something easily identifiable that is not being picked up purely off descriptions

There is a photo a couple of pages back.

Rodd

[Rodd]

13 minutes ago, Rodd said:

Thanks Alex--I will look into that today.

Rodd

Sorry Alex--That link does not seem to be working

[AngryDonkey]

Sorry I'll try again:

https://groups.yahoo.com/neo/groups/starlightxpress/info

[Yawning Angel]

13 minutes ago, Rodd said:

There is a photo a couple of pages back.

Rodd

Aha, got it now.

The light path to both sensors needs to be the same length, as governed by the focal reducer / scope spec . Looking at the photo, the 1600 is much closer to the reducer than the SX (my blue arrows). You might be assess this roughly like so (in daylight):

Rack the focus in, as far as it will go to start

Remove (unscrew) the adaptor, marked in red

Extent the OAG prism turret down into the light path until it's basically flush with the top plate

Hand hold the SX to the top plate of the OAG

Move the focus out and see if you can get anything - it'll be hit and miss, but you should spot a roughly focused image

It that works, you can look at replacing the adapter with a slim T2 to C mount...I linked one back in the depths of this thread :-)