CPC925 XLT - Wedge Mounted

[AndrewG]

Does anyone know what payload the CPC 925 wedge mounted can take if counterbalanced?

Does a 4kg astro plus 1kg camera sound too much.

[Psychobilly]

My CPC800 has a Megrez 72 in 5" rings usually with a DSLR on top of it.., a 500mm f8 telephoto lens in custom rings with a DSI II as a guidescope along side the 72... And abalance rail with 9lb of brass underneath it to counterbalance it in ALT - Which becomes DEC on the wedge... I used to strap a couple of kgs of leg weights to the carrying handle to balance it in AZM - RA on the wedge...

Another DSLR on a x0.63 reducer would be fitted to the back of the SCT...

The brass weight could be moved back and fore and the offset from the tube adjusted to alter the balance...

I did some work on the AZM bearings replacing the standard nylon ones with high grade steel ones and fettled the casting...

When I am on the PC next i will dig out the pics...

I had forgotten about the piggybacked DSLR and lens setup...

Peter....

Sent from my P-7300 but still can't type

[AndrewG]

Peter, What a great setup, thanks for the info so I guess the 4kg OTA should be ok.

Being an engineer I am interested in more info regarding the bearing upgrade; any further info / details would be most useful, how dificult is it to do the upgrade?

Thanks again.

[Psychobilly]

I did a search for CPC Bearing upgrades...there used to be a really good guide out there... I decided to upgrade mine when moving from alt/az without the extra scopes to "EQ" with all the extra weight on it...

I cant remember how much info I posted at the time but ill try and dig out the old threads...

As part of the process I had the scope slewing in az continously for a couple of weeks using a battery pack hung under the OTA...

I think this was the guide do a google search for cpc azimuth copy and paste was corrupting the link the one you want is apdf on the nexstarsite

Peter...

Sent from my P-7300 but still can't type

[AndrewG]

I did a search for CPC Bearing upgrades...there used to be a really good guide out there... I decided to upgrade mine when moving from alt/az without the extra scopes to "EQ" with all the extra weight on it...

I cant remember how much info I posted at the time but ill try and dig out the old threads...

As part of the process I had the scope slewing in az continously for a couple of weeks using a battery pack hung under the OTA...

I think this was the guide do a google search for cpc azimuth copy and paste was corrupting the link the one you want is apdf on the nexstarsite

Peter...

Sent from my P-7300 but still can't type

Peter,

I eventually took your great advice over the summer months and decided to take the plunge and complete the bearing upgrade,  as when I managed to have any clear weather (not very often that is) during the early months of the year I had tracking issues and thus poor imaging..   

See the following images of the before and after and the final result all mounted back in place  !

Over the past couple of months I have tweaked the setup, balanced and drift aligned etc...  and finally last week managed to get about 4 hours of clear skies    and managed my first image with the upgrade; I have attached the final result which had no rejected frames for tracking issues  .

Thanks everyone for your help and hope you like the image!!!

Andrew

[brantuk]

First time I've seen a Tak FSQ used as a guide scope lol :icon_mrgreen:

[ollypenrice]

First time I've seen a Tak FSQ used as a guide scope lol :icon_mrgreen:

I trust that the merely mortal SCT is the guide scope and, if it isn't, this man needs excommunicating for heresy!      

Andy, you have a super result there but I really wouldn't like the idea of holding the dewshield in guide rings. In fact I don't like guide rings at all because of the flexure risk. This is greatly increased here because the dewsheild isn't (normally) firmly attached to the main tube. (Tell me you didn't Araldite the dewsheild firmly in place...  )

Olly

[AndrewG]

I trust that the merely mortal SCT is the guide scope and, if it isn't, this man needs excommunicating for heresy!      

Andy, you have a super result there but I really wouldn't like the idea of holding the dewshield in guide rings. In fact I don't like guide rings at all because of the flexure risk. This is greatly increased here because the dewsheild isn't (normally) firmly attached to the main tube. (Tell me you didn't Araldite the dewsheild firmly in place...  )

Olly

I didn't realise when I took the photo  how I had mounted it on the dew shield; lucky for me when I balanced it I moved the guide rings so it is now below the dew shield...few.. When I get a minute I should take another pic  !!

To be fair I have never really liked the mounting method either... I already had the rings for my guidescope,  so  when I bought the Tak I did ask the question of mounting as I would have preferred some alternative but the guy at the shop thought this was the best method .

Olly I would be very grateful if you could suggest a better method of mounting / confirm a proposed bit of kit?

Thanks in anticipation.

Andy

[ollypenrice]

I didn't realise when I took the photo  how I had mounted it on the dew shield; lucky for me when I balanced it I moved the guide rings so it is now below the dew shield...few.. When I get a minute I should take another pic  !!

To be fair I have never really liked the mounting method either... I already had the rings for my guidescope,  so  when I bought the Tak I did ask the question of mounting as I would have preferred some alternative but the guy at the shop thought this was the best method .

Olly I would be very grateful if you could suggest a better method of mounting / confirm a proposed bit of kit?

Thanks in anticipation.

Andy

I'd have thought that the obvious thing would be the Tak clamshell, as seen here.

I don't noramlly guide with a solarscope! 

You can see the Tak clamshell attached to a Tak offset foot, also in Health Service Green. Looking at your setup it seems you might not need this since the setup would balance with the clamshell bolted directly to the rail currently holding your guide rings. On the other hand the offset foot lifts the scope up a bit.

Olly

[AndrewG]

I'd have thought that the obvious thing would be the Tak clamshell, as seen here.

I don't noramlly guide with a solarscope! 

You can see the Tak clamshell attached to a Tak offset foot, also in Health Service Green. Looking at your setup it seems you might not need this since the setup would balance with the clamshell bolted directly to the rail currently holding your guide rings. On the other hand the offset foot lifts the scope up a bit.

Olly

Thanks for the info most helpful.

Maybe it would be better to swap my MDS ADM bar for a larger type D bar and use a ADM Max F aiming device like this one so that I can adjust the TAK to frame the picture?

Again any help would be great!

If the above is a decent solution I think it will have to be on my wish-list for the new year (looks like quite a few £s) given we are all feeling the pinch (electric / gas going up again)  ; I think at this rate I will be rigging up our bike machine with a dynamo to feed the obs and hope the wife will peddle !!! 

Thanks

[AndrewG]

Finally saved enough cash to upgrade the FSQ mounting method - see below.

The thing is though that the extra mounting kit has really increased the weight, so I have had to add some more mass to balance  :-

I do hope tracking accuracy is not going to go down the pan or I will have wasted my money  .  I did manage to Auto-guide of Sadr last night and a 400 sec sub looked ok near the guide star but out from the centre had field rotation.  I guess the extra weight has pushed out the Polar alignment so I will try to align soon and see how it fairs.

The mount does seem a little more loud when guiding, so if this all goes down in flames guess I will be looking for a new mount  !

Thanks for any comments.

[Psychobilly]

I can't tell from the pics (on the phone) ...Have you got any balance weights under the OTA?

I had a very heavy brass counterweighg under the ota the I could adjust the position of for balance in dec.. I also added weight to the carrying handle to balance in ra...

Peter...

Sent from my GT-I9505 using Tapatalk

[AndrewG]

Hi Peter,

Good to here from you again Peter, yes I have added extra weights to balance.

One of the pictures shows the counter weights which comprise of 3 x ADM weights and an extra 2 to 3 kg of dumbbell weights.

From my initial tests (the other night) it appears I have some field rotation so I guess the extra weight has altered the wedge alignment?

I just hope the mount can take it otherwise I will have to talk to my bank manager  eek !

Thanks

[AndrewG]

So I have spent several nights to get better PA and decided last night to see how the tracking was... have only tried a few subs and found that the stars were slightly egg shaped and the tracking issue was the same for 180s subs and 400s subs .

I will try again and mess around with the guider settings but I am starting to think along the new mount route.... I know that long term to ditch the Wedge and have a EQ mount is the only way to go (I am sure Olly agrees).  My question is for anyone out there with experience what would be the EQ mount to get as I would like one that is just for the OBS that I could use with my existing equipment (maybe I could de-fork the CPC)?

Any help and recommendations would be great!

Regards

[Davey-T]

Might as well go for it and get an EQ8 as it's for obsy use, they seem to be performing OK and you can bung loads of stuff on it.

Dave