Evolution mount can’t approach zenith, can I extend dovetail?

[ObscuredView]

So as per title I wondered if anyone had any experience extending the dovetail to move OTA about 50mm further forward?

 

[Cosmic Geoff]

Why do you want to extend the OTA about 50mm further forward? Are you attaching bulky gear to the back end of the OTA?  I had obstruction with my CPC800  when attaching focal reducer + flip mirror diagonal + camera.  A solution was to dispense with the flip mirror and use a regular diagonal and precise GoTo.

If it's the same clamp as on the C8 SE, the OTA will not go any further forward unless you also move it sideways.

[ObscuredView]

I want to be able to clear the base.
I want to do this, see pic, but I’m not sure how it was achieved.

how was the ADM rail attached to the existing rail?

Any experienced tinkerers out there, I’d appreciate your input.

[Louis D]

Just put the fork mount in equatorial mode with an equatorial wedge, and you should be able to reach zenith just fine.  Of course, you then won't be able to reach objects near Polaris.  Have you tried this and still not been able to reach zenith?  Perhaps more photos would help.

[bilbo]

Instead of going "straight" Use a short diagonal such as the baader T2.  https://www.baader-planetarium.co.uk/shop/baader-90-32mm-t-2-prism-diagonal/

The optical length is much shorter.   Reducer/SCT to T adapter/T Diagonal/Camera & spacers (if needed)

Avoid wedges with Evo mounts

Steve

 

Edited February 3 by bilbo

[Louis D]

3 hours ago, bilbo said:

Avoid wedges with Evo mounts

So, do you then need to add a field derotator to image using one?  I didn't see one in the image above.  Is it done in software?  That is, derotating many short images during stacking?  Does that work well with DSO imaging? Thanks!

[bilbo]

47 minutes ago, Louis D said:

So, do you then need to add a field derotator to image using one?  I didn't see one in the image above.  Is it done in software?  That is, derotating many short images during stacking?  Does that work well with DSO imaging? Thanks!

That would be one alternative,  but they'e not cheap and can be problematic.  The HD pro wedge & matching CPC tripod costs the equivalent of $1,000 here in the UK and the guy would still have a low quality mount that doesn't like the pole area.

For long exposure AP the only real way to go is with an eq mount, 

Short exposure stacking works well enough in alt/az can be derotated in software, But really needs a very fast scope and the images will need to be cropped.

From what I can see in the pics, The OP also seems to be using a standard SCT reducer on an Edge HD which is not going to produce great results.

Steve

 

 

[Cosmic Geoff]

1 hour ago, Louis D said:

So, do you then need to add a field derotator to image using one?  I didn't see one in the image above.  Is it done in software?  That is, derotating many short images during stacking?  Does that work well with DSO imaging? Thanks!

Live stacking or post-stacking of a series of short exposures can work well with alt-azimuth mounts.  See the results from the Seestar S50, for instance.  Of course, the extremities of the image degrade with longer exposure runs, but can be cropped off.  It depends what one is trying to image.  If gathering hours of data on something faint, an equatorial mount would be more appropriate.

[ObscuredView]

So this thread seems to have been hijacked by people who whilst trying to be helpful have not any experience in extending the dovetail. 
I have a picture (see attached) of an extended dovetail, but have been unable to contact the guy who’s rig is pictured for advice on how he attached the ADM rail.

I also include a picture of my setup which serves me well apart from the clearance problem, which this guy has solved.

The advice I am seeking is how to attach the ADM rail as in pic one.

I am aware thanks very much of the benefits and disavantages of the different types of mount.

 

[Skipper Billy]

33 minutes ago, ObscuredView said:

The advice I am seeking is how to attach the ADM rail as in pic one.

It looks like the two plates are simply bolted together ??

[Louis D]

Just bolt the new, longer rail to your existing rail using 1/4-20 x 1/2" socket head cap screws.

[ObscuredView]

Doh!  
I didn’t see the second hole on the existing rail, I feel so stupid.

thanks for helping an idiot 👍😂

[Skipper Billy]

Sometimes the blindingly obvious us exactly that - blinding!

 

[saac]

7 hours ago, ObscuredView said:

Doh!  
I didn’t see the second hole on the existing rail, I feel so stupid.

thanks for helping an idiot 👍😂

We have all been there, trust me. If you still do not get enough clearance with that perhaps using a side by side mounted arrangement may help.  Mounting the scope on the rail furthest from the mount.  Anyway, hope you get it sorted, these things can be a real niggle that just gets in the way of what you want to be doing. 

Jim 

Edited February 5 by saac

[Skipper Billy]

If  you need even more clearance then a pair of these bolted to the plate on the mount would give you another 10mm or so.

https://www.firstlightoptics.com/adm-vixen-type-v-series/adm_vdpa_adaptor.html

 

[ObscuredView]

So I have ordered a dovetail rail I got to thinking that it might be wise to add some weight under the tripod.

I searched FLO and RVO for “tripod hammock” but no luck, does anyone know what those hammock things that hang under the tripod are called?

[Cosmic Geoff]

19 hours ago, ObscuredView said:

So I have ordered a dovetail rail I got to thinking that it might be wise to add some weight under the tripod.

Which tripod do you have?

[ObscuredView]

On 07/02/2024 at 10:08, Cosmic Geoff said:

Which tripod do you have?

The one that comes with the Evolution 8”Edge hd.

[Cosmic Geoff]

12 hours ago, ObscuredView said:

The one that comes with the Evolution 8”Edge hd.

That doesn't tell me much.  If it's the same as the Heavy Duty tripod (with the massive cast alloy spreader + folding low level spreader) that came with my CPC800, and also supplied with the CPC925 & CPC1100, the suggestion that it needs extra stabilisation, to be frank, makes me fall on the floor laughing.

The single arm Evolution mount is another matter. Read the second review of the C9.25 Evolution on the FLO site.  That might be your problem.

[ObscuredView]

On 11/02/2024 at 11:26, Cosmic Geoff said:

That doesn't tell me much.  If it's the same as the Heavy Duty tripod (with the massive cast alloy spreader + folding low level spreader) that came with my CPC800, and also supplied with the CPC925 & CPC1100, the suggestion that it needs extra stabilisation, to be frank, makes me fall on the floor laughing.

The single arm Evolution mount is another matter. Read the second review of the C9.25 Evolution on the FLO site.  That might be your problem.

Oh dear,  I hope you didn’t hurt yourself falling to the floor laughing  Geoff.

Please don’t try to help as you come across as a bit irritated by my problem.

All the info is in the thread. But please don’t bother yourself.

[Cosmic Geoff]

No comment. 😒

Edited February 17 by Cosmic Geoff

[ObscuredView]

I wish 😂