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New Focusing Aid

George

By George
in Imaging - Discussion

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beamish

beamish

Posted
Posted

Nope :) although I have taken advantage of the poor weather to clean it, apply a nice coat of grey undercoat and 2x thin coats of flat, matt black Plasticote. Looks well cool :thumbright:

Gonna add some small squares of self adhesive felt pads to 3x of the tabs.

The weather is #$ap !!

Karlo

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barkis

barkis

Posted
Posted

Well the clouds descended over our fair city again, after a bright day, with loads of sunshine, a slight fog appeared, and cloud quickly became quite heavy, so No hope of testing the Mask tonight.

Here it is in place on the Mak/Newt. Hopefully tomorrow night will be a bit more cooperative.

Ron. :)

11259_normal.jpeg

(click to enlarge)

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RobH

RobH

Posted
Posted

Hello Peter,

I've had a chance to test the 14 inch masks properly tonight, although it is now cloudy!

I tested at F10 with a 25mm ep....excellent, really easy to find focus, although a fairly bright star was needed in order to see the diffraction pattern properly.

I tested at F5 with a DSI, again, really easy to find focus but a bright star was needed as I was using the view in PHD (rig is setup with the LX as guider at the moment), so I couldn't zoom in etc.

Although my gear is in a ROR observatory, there's still a small drop in temperature when the roof is opened, and it was interesting to watch the middle line move as the scope temperature equalised.

I then went to the ZS80 and changed the configuration of my imaging setup, putting a lumicon 0.5x FR in the front of the imaging train. Focus with the mask took just a few seconds with the display in Maxim zoomed in to 800% so it was easy to see while standing at the scope.

I then shot a couple of full res images of starfields to check focus. They were spot on, and the FWHM display agreed.

Focussing this way was just as accurate, and much faster, than using the focussing tools in Maxim.

Nice job Peter :) I'll be measuring up the TMB tomorrow (I pick it up at lunchtime :p ) and let you have the dimensions for whenever you do another batch.

Cheers

Rob

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Psychobilly

Psychobilly

Posted
Posted

Thanks for the update Rob,

GLad to here that the results are tying in with Maxims analysis.

I tend to use a Autostar envisage to do the focusing as it allows zooming then quit that and go over to PHDGuide for the guiding...

With the 350D I use DSLRFosua a 2s exposure at ISO1600 beign ample to clearly show the diffarction spikes.

With the 1000D i find that live view isnt sensitive enough to really show the spikes so i use it to pull the coarse fous (eveything merging into the center blob) then use the EOS utils with the preview option enabled to take 2s exposure at ISO1600 you can maximise the preview window and then the spikes become clearly vissible... you can use the LCD viefinder and zoom right in if your not connected to a lappy...

During a chat last night I was asked is the mask easier to use than DSLRFocus or Maxim focus routines ... I can't comment really as I have never used either. I do know that I can usually judge how much to adjust the focus just by looking at the image and can usually get spot on within 3 or 4 2s exposures over perhaps 30s to a minute...

I haven't tried using the masks visually.

Peter

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Psychobilly

Psychobilly

Posted
Posted

Cheers peeps glad to know that the various designs are all working which gives me confidence in the calcs i am using to define slot widths .....

Will try and get the comapny taht made them to workl soem prices out and I cant tehn test teh waters to see if people will want to buy them... I am confident they will be considerably cheaper than the Spike-A ones (ebven afetr his recent price cuts) ...and it will be interesting to see how much the Kendrick ones are going to be from Altair Astro...

Billy...

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Psychobilly

Psychobilly

Posted
Posted

No I havent Les,

To be fair trial they should both be laser cut... and I'm concentrating on the designs for first order ones as there's no point making 3rd order ones when the machine is capable of cutting slots down to 0.5mm with 0.01mm accuracy... I provide templates for 3rd order ones for people to cut by hand as they have fewer wider slots and so are easier to make.

I have some 40-50 designs done to date...

Billy...

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leshalfhill

leshalfhill

Posted
Posted

To any and all,

Referring to the attached image, my question is about the "triangle" on the right side of each mask. Specifically, the triangle with its base at the right edge of the mask, and its point aiming toward the center of the mask.

As is evident, the mask on the left has a much larger triangle. Do you think it is "better" than the one on the right? Which would you suggest I go with? (It will be laser-cut)

Les

post-13277-133877352462_thumb.jpg

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dark knight

dark knight

Posted
Posted

Hiya Billy, Ive been reading through the posts with great interest. The amount of time and effort you have put in is nothing short of true dedication to helping others, your a real gent..now then any chance of a laser cut one for a Skywatcher explorer 200p newtonian. I'm sure you have already done the design for this, just pm me with a price for the 1st order version. I don't want to make my own as accuracy is not my forte. :salute:

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Psychobilly

Psychobilly

Posted
Posted

Hello Peter,

Can I order a couple more masks please for a TMB 152 :)

I need one for F8, and one for about F4/5

Outside tube diameter is 22cm.

Cheers

Rob

No Probs Rob... whats the Native focal length ... I don't want to look it up myself or i'll go all dewy eyed and wont be able to do the drawings :p

Billy....

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