Wide Field Mounting for Atik 314L+ with Camera Lens

[Gina]

With the guide scope rings I ordered being delayed by weeks, I decided to make my own from a pair of ordinary scope rings I already had. I bought a metric tap and die set from Axminster Tools (something I've wanted for a while) and drilled and tapped some M6 holes. Then used some roofing bolts as adjustable supports. I mounted the new rings on top of the guide scope using the camera attaching points.

The photos show a single ring used for short FL lenses and two rings to cater for telephoto lenses. The lenses shown are Asahi SMC Takumar 55mm f1.8 and 200mm f4.

[Gina]

I think my rig is beginning to look a little OTT So I'm having a rethink. Now I have the 314L+ for narrow band imaging with both ED80 and lenses for widefield I no longer need a twin barrel DSLR setup. DSLRs are not really suitable for NB - there's too much waste of photons. Even gathering two lots at the same time it's still a lot less efficient than an astro CCD camera. So I plan to remove one DSLR from the WF rig and keep the other as electronic finder. But I won't just keep it where it is - I'll remount it on the centre line for balance. I can still use the finder camera as WF colour.

[fwm891]

Gina, Why have you stacked you kit vertically, there would be less effective 'weight' if you put your cameras horizontally on a short bar....

Although you're way under the max loading for the NEQ6 (what else can you add...)

[ianaiken]

It looks like some sort of military launcher I like it. Side by side may distribute the weight better and put less strain on the mount.

[Gina]

Gina, Why have you stacked you kit vertically, there would be less effective 'weight' if you put your cameras horizontally on a short bar....

Although you're way under the max loading for the NEQ6 (what else can you add...)

It was the easiest with what Ive got I was thinking side-by-side would distribute the weight better.

[Gina]

It looks like some sort of military launcher I like it. Side by side may distribute the weight better and put less strain on the mount.

Yes, I agree

[Gina]

I think perhaps ED80 and ST80 side-by-side with Atik WF on top of ST80 and finder camera (also OSC WF) on top of ED80. That would make a nice little quad

[Gina]

Looks like I shall be making up a dual mount framework. I have some mild steel angle though I might be better getting aluminium angle or channel to save weight. A bit of designing needed then

[Davey-T]

How did you attach the lens to the filter wheel Gina ?

Have you posted any pics ? had a quick browse back a few weeks but couldn't find any.

Dave

[Gina]

How did you attach the lens to the filter wheel Gina ?

Have you posted any pics ? had a quick browse back a few weeks but couldn't find any.

Dave

Two adapters

• Atik T2 adapter for the EFW2 from FLO :- http://www.firstligh...-t-adapter.html
  
• Pentax/Praktica M42x1 thread mount to T2 adapter from Teleskop Express :- http://www.teleskop-...objectives.html
  

[Gina]

I've been thinking carefully about a dual mounting system. I've had the scopes and mountings off the mount and done some measuring up and working out. Two possibilities - I could make my own using a 3" by 3/16" aluminium plate about 8" long clamped in the mount jaws with the two dovetails bolted on to that OR I could buy a dual mounting bar from FLO (just back in stock) :- http://www.firstlightoptics.com/adm-guidescope-rings-and-systems/adm-vixen-type-dual-mounting-bar.html

The advantage of the ready made bar is that it should be virtually guaranteed strong enough to take the weight and it will fit the mount jaws perfectly to provide a really solid and rigid mounting. It should also allow easy adjustment of the scopes relative to the mount, providing more balance adjustment than the scope rings. The disadvantage is the cost - I can make up a dual mounting rig for under ten pounds - the FLO one costs £130 plus carriage. OTOH the equipment mounted on it amounts to well over a grand's worth and I'm wondering if I can be sure of a 100% reliable fixing of the cross bar in the mount jaws.

Decisions - decisions

[Astrokev]

I'd make your own Gina. You could always chamfer the edge of an Al bar to increase the points of contact with the dovetail. Commercially available dovetail bars are all well and good, but are hugely over-priced in my opinion. The design of a dovetail is such that it won't fall out, so I'm sure the risk of losing your precious kit is negligible.

From another angle of course, you could always ask yourself if the work you try and do warrants all the kit!

[RAC]

With the focal lengths you're imaging at i would move to a finder scope for a guider. I would mount the finder guider where you have the twin cams. This would make space and keep weight way down.

[Gina]

I'd make your own Gina. You could always chamfer the edge of an Al bar to increase the points of contact with the dovetail. Commercially available dovetail bars are all well and good, but are hugely over-priced in my opinion. The design of a dovetail is such that it won't fall out, so I'm sure the risk of losing your precious kit is negligible.

Yes, I could certainly chamfer the edge of the ali plate. I guess it would be just as safe as the professionally made one.

From another angle of course, you could always ask yourself if the work you try and do warrants all the kit!

I will be reducing the kit at the same time - I will no longer be doing dual NB imaging with the DSLRs. If found that the Atik 314L+ is several times more efficient than two DSLRs used at the same time for NB. I shall have just one WF DSLR with 200mm lens as finder and OSC WF imager plus one other DSLR (Peltier cooled) for use on the main scope.

[Gina]

With the focal lengths you're imaging at i would move to a finder scope for a guider. I would mount the finder guider where you have the twin cams. This would make space and keep weight way down.

That's an idea I haven't actually tried the QHY5 on the finderscope. I tried webcam on finder scope and webcam on ST80 but not QHY5 on the finder scope combination. I have the 9x50 finderscope that came with the ED80.

[Gina]

I have had another idea. I have some Ali sheet about 10" x 4" and 3mm thick that I could bolt onto the present long dovetail bar. Then I could bolt two short (21cm) dovetail b.ars onto that for the scopes

[Gina]

Here is a drawing of my current thought on a dual mounting system :-

[Chris]

I'm liking the super rig Gina but agree that side by side would be better for the mount in the long run. Good idea for making your own side by side bar but looking at your sketch up wouldn't it be stronger with less flex if the bottom dovetail was inline with the ali bar (hence turned 90 degrees) and hence 90 degrees to the the pair of dovetails on the top, basically like a conventional dual mouting bar.

I've just sold both a dual mounting bar and guide rings as well, it might have saved you some work?

Chris

[Gina]

OTOH taking this further how about this? Just a wide ali plate to take the scope rings :-

[pete_l]

Here is a drawing of my current thought on a dual mounting system :-

Some years ago I commissioned a piece like this. If I may be so bold as to offer my experiences

It's worth thinking about having the two "outboard" bars recessed on the underneath to the width of the crosspiece. That'll keep them square.

I have the main centre piece and crosspiece drilled with multiple holes at 1 inch spacing up the bar for versatility - both for attaching to the mount and so the crosspiece could be placed at different distances up the centrepiece and side-to-side to balance differently weighted scopes on each side.

I think I made a mistake by having the metalwork too thin (12mm) - as I get some flexture with heavy kit mounted on the side bars. (Or maybe I had too many holes drilled in it? ) I was trying to save some weight, but it might have been a false economy.

[Chris]

I think the second option would have less flexure.

[Gina]

I'm liking the super rig Gina but agree that side by side would be better for the mount in the long run. Good idea for making your own side by side bar but looking at your sketch up wouldn't it be stronger with less flex if the bottom dovetail was inline with the ali bar (hence turned 90 degrees) and hence 90 degrees to the the pair of dovetails on the top, basically like a conventional dual mouting bar.

I'm not sure TBH. I'm working with SketchUp trying various arrangements.

I've just sold both a dual mounting bar and guide rings as well, it might have saved you some work.

Not to worry - that always seems to happen

[Gina]

Some years ago I commissioned a piece like this. If I may be so bold as to offer my experiences

It's worth thinking about having the two "outboard" bars recessed on the underneath to the width of the crosspiece. That'll keep them square.

I have the main centre piece and crosspiece drilled with multiple holes at 1 inch spacing up the bar for versatility - both for attaching to the mount and so the crosspiece could be placed at different distances up the centrepiece and side-to-side to balance differently weighted scopes on each side.

I think I made a mistake by having the metalwork too thin (12mm) - as I get some flexture with heavy kit mounted on the side bars. (Or maybe I had too many holes drilled in it? ) I was trying to save some weight, but it might have been a false economy.

Thank you for your input Yes, I think this is a case when apparent over-engineering is a good idea - it needs a good rigid connection between any imaging scope and the guide scope. With the spacings required an OAG is not an option.

[Gina]

As a qualified engineer the H design doesn't look right to me - too much possibility of torsional flexing of the cross bar.

[Gina]

I've done some dismantling and brought it all indoors. Here are some photos of the original piggy back rings and how I might mount the rings on the plate and the plate on the dovetail. These are only approximate positions ATM. I'll go and get the scopes now and see how everything fits together. This is really only a test setup with the current ali plate - I may well decide to go for something a bit narrower but thicker as this plate is only 3mm thick.

1. Piggy back system with wide-field plate (camera without lens and focus drive belt but including focus motor)
   
2. Rings positioned on plate
   
3. Ditto
   
4. Plate placed on dovetail. I think dovetail will be more under ED80 (bigger scope) in final arrangement.
   
5. Ditto