31 replies to this topic

[EboO]

On astrosurf a member tried to stack GPC with success.
One was screwed back of the diagonal and the other in the nose of the bino, no false color no vignetting.

[ols]

After experimenting with several configurations, I just wanted to follow-up with what seems to be the easiest way (for me - comparing what I’ve tried so far, at least) to swap between a low magnification set-up and high magnification set-up.  (One thing I learned here is that there are almost too many possible configurations. )

 

Anyway, my current set-up has the binoviewers screwed into a 1 1/4” nosepiece which then drops into a 1 1/4” clicklock mounted to the diagonal. I then have 2 nosepieces: one nosepiece has no GPC mounted, the other nosepiece is set-up with a pre-installed GPC. Just to clarify, the GPC is screwed into the threads in the top of the nosepiece (not the threads in the diagonal) so the GPC is pretty close to the binoviewers. To switch between low and high magnification, i just slide the binoviewers/nosepiece out from the clicklock, unscrew 1 nosepiece and then screw in the other nosepiece and slide the binoviewers back into the clicklock. 
 

It was cold and clear here last night (3 Farenheit) and I was able to do this several times while wearing gloves. Worked well and seems pretty easy.

A few notes:

-my set-up can come to focus with no GPC in the nosepiece and 24mm EPs.  (Phew!)

-i can still come to focus if I add a 1.25x GPC in the nosepiece (i need to rack focuser farther out 20mm compared to no GPC)

-the 2.6x GPC needs additional spacers to come to focus. I was able to add two 18mm extension tubes to the end of a nosepiece so that I dont have to add extension tubes anywhere else (I also added a parfocal ring to hold the binoviewers so they are just above the stop in the diagonal.) I did not notice any vignetting with this nosepiece.  (A pic is attached of this nosepiece set-up with the 2.6x GPC for clarity.)

-for higher magnifications, i still dont know if its better to use shorter FL EPs with the 1.25x GPC or longer FL EPs with the 2.6x GPC. FWIW, I tried both 1.25 and 2.6 GPCs last night and jupiter looked pretty nice both ways (max ~160x in both configurations) 

 

Extra thing, i decided to try some drift timing measurements to see what approximate magnifications I am getting compared to no GPC. (These are with the GPC screwed into the top barrel of a nosepiece which is then screwed into the binoviewers. I was timing the movement of a tower on a mountain a few miles away from sidereal tracking turned on in the mount):

1.25x GPC -  measured 1.20X

2.6x GPC - measured 2.70x

These both seem to be in the ballpark of the magnifications others have measured, so hopefully the GPCs are working as they should.

 

Thanks again everyone.

 

 

 

 

[Kunama]

Glad you found a setup that works for you 

I find that for me switching eyepiece pairs is quick and easy enough, just unlock the Clicklocks and pull out one pair of eyepieces, place them in the case and grab a different pair, takes about 5 seconds….

( I uncap all eyepieces at the start of the viewing session to make changes quicker)

 

Attached Thumbnails

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[balcon3]

After experimenting with several configurations, I just wanted to follow-up with what seems to be the easiest way (for me - comparing what I’ve tried so far, at least) to swap between a low magnification set-up and high magnification set-up.  (One thing I learned here is that there are almost too many possible configurations. )

 

Anyway, my current set-up has the binoviewers screwed into a 1 1/4” nosepiece which then drops into a 1 1/4” clicklock mounted to the diagonal. I then have 2 nosepieces: one nosepiece has no GPC mounted, the other nosepiece is set-up with a pre-installed GPC. Just to clarify, the GPC is screwed into the threads in the top of the nosepiece (not the threads in the diagonal) so the GPC is pretty close to the binoviewers. To switch between low and high magnification, i just slide the binoviewers/nosepiece out from the clicklock, unscrew 1 nosepiece and then screw in the other nosepiece and slide the binoviewers back into the clicklock. 
 

It was cold and clear here last night (3 Farenheit) and I was able to do this several times while wearing gloves. Worked well and seems pretty easy.

A few notes:

-my set-up can come to focus with no GPC in the nosepiece and 24mm EPs.  (Phew!)

-i can still come to focus if I add a 1.25x GPC in the nosepiece (i need to rack focuser farther out 20mm compared to no GPC)

-the 2.6x GPC needs additional spacers to come to focus. I was able to add two 18mm extension tubes to the end of a nosepiece so that I dont have to add extension tubes anywhere else (I also added a parfocal ring to hold the binoviewers so they are just above the stop in the diagonal.) I did not notice any vignetting with this nosepiece.  (A pic is attached of this nosepiece set-up with the 2.6x GPC for clarity.)

-for higher magnifications, i still dont know if its better to use shorter FL EPs with the 1.25x GPC or longer FL EPs with the 2.6x GPC. FWIW, I tried both 1.25 and 2.6 GPCs last night and jupiter looked pretty nice both ways (max ~160x in both configurations) 

 

Extra thing, i decided to try some drift timing measurements to see what approximate magnifications I am getting compared to no GPC. (These are with the GPC screwed into the top barrel of a nosepiece which is then screwed into the binoviewers. I was timing the movement of a tower on a mountain a few miles away from sidereal tracking turned on in the mount):

1.25x GPC -  measured 1.20X

2.6x GPC - measured 2.70x

These both seem to be in the ballpark of the magnifications others have measured, so hopefully the GPCs are working as they should.

 

Thanks again everyone.

 

 

 

GPC1.jpeg

 

GPC2.jpeg

Thanks very much for the follow up. You seem to have found a good setup. Could you share the part numbers for the 18mm extensions and parfocal ring you are using? Thanks !
I was wondering if you could add a Quickchange ring to the top of the nosepieces and a bayonet to the end of the binoviewer, and therefore swap nosepieces without needing to unscrew anything. The disadvantage would be the extra cost of two Quickchange rings and a small increase in path length. 

[ols]

No problem! - here are the Baader part numbers:

Baader 1905131 - FR4 Focusing ring (parfocal ring) collar

Baader 1905130 - DT4 Eyepiece sleeve extender

 

I did see in the Maxbright manual that you can change the T2 coupling nut into the Heavy Duty Quick changer, but I did not try it. At least with fairly warm gloves on, I found it easier to screw and unscrew a nosepiece into the Binoviewer’s T2 coupling nut (compared to unscrewing and re-screwing the clamping bolt in the Heavy Duty quick changer, which needs me to have more dexterity (ie, no gloves) to twist the clamping bolt between index finger pad and thumb pad.)

[balcon3]

No problem! - here are the Baader part numbers:

Baader 1905131 - FR4 Focusing ring (parfocal ring) collar

Baader 1905130 - DT4 Eyepiece sleeve extender

 

I did see in the Maxbright manual that you can change the T2 coupling nut into the Heavy Duty Quick changer, but I did not try it. At least with fairly warm gloves on, I found it easier to screw and unscrew a nosepiece into the Binoviewer’s T2 coupling nut (compared to unscrewing and re-screwing the clamping bolt in the Heavy Duty quick changer, which needs me to have more dexterity (ie, no gloves) to twist the clamping bolt between index finger pad and thumb pad.)

Thanks! I think you found a good solution. I am going to try and adopt it for my FC100DF. Since I don't need gloves when I observe, I may try the Quickchange version, but maybe not worth the money. You are right, there are a seemingly infinite number of possible permutations.

[EboO]

Thanks! I think you found a good solution. I am going to try and adopt it for my FC100DF. Since I don't need gloves when I observe, I may try the Quickchange version, but maybe not worth the money. You are right, there are a seemingly infinite number of possible permutations.

I have the quick change (not the heavy duty) and found it's enough sturdy. Perhaps heavy duty version can avoid easily a wrong installation ?
About setup with 1.25" nosepiece I need to try too, I would be easier to use filters. Actually I need to screw it in 2" nosepiece with an adapter.