Collimating- 10” quattro

[iapa]

Stripped right down

centred vanes, still around 0.5mm off?

measured and marked centre point t opposite focusser using a silver gel fine tip pen.

 

adjuated focusster using Cheshire, difficult to get image through Cheshire but I think you can see it’s close.

checked  laser, which seems to match Cheshire, so, I’ll take it the laser collimating is good (I rotated it gently and spot stayed in centre of cross) The silver gel mark shows nicely here.

The near vertical measured at 11.8mm using my micrometer. Measure the image and the focusser is about 0.5-0.7mm of the cross centre

cant find pix of secondary alignment, but it measures as a circle - Dion’s video using sharp cap & mire de collimating was the method I used

 

[iapa]

Refitted the secondary and a wee tweak of secondary gives this

 

 

[iapa]

On 23/08/2017 at 19:42, spillage said:

 Spa..Now that sounds like a nice idea.

Spa was great, just outside Pitlochry. Fully body massage and a pedicure - yup, you read that right. 6' 2", 20st getting a pedicure LOL

Potential site for imaging too clear views from south through west to Nth, highest peaks <30 degrees above horizon, and fairly dark.

Anyway, back to work.

 

 

[iapa]

total of 50m exposure; 27 x 30s Blue, 23 x 30s green, 27 x 30s Red, 23 x 30s Lum

Stacked and stretch in Nebulosity to within .0001% of it's death.

Pier mounted CGEM-DX, Quattro 10" CF, ZWO 1600 mono cooled, ZWO mini few, ZWO LRGB filters for 1600.

Unguided, Bahtinov mask for focussing - my eyes are not good enough even with that; focus motor to be fitted shortly.

 

[Dave In Vermont]

This is a wonderful thread on collimation - good job to all!

I actually enjoy collimating fast-Newtonians (I know I'm weird). And the thing to remember in fast scopes is that there will be offset in the view. This was very well pictured in Mel's (Astro_Baby) excellent guide. So you'll never get the perfect, centered-circles in an F/4 or F/5 that are sought in F/6 and slower Newts.

The other thing one needs to take into account is that one shouldn't spend a week trying to get it perfect (close-yes) indoors - save that for doing an actual 'star-test' outdoors. And I think the greatest recent invention in the art of collimation isn't the laser-collimator (great that they can be) - but the "Artificial-Star" which allows the convenience of brightly lit seeing conditions (so you can see what you're doing without the high risk of dropping a screwdriver down inside the OTA), as well the precision of the 'star-test.' I'm fond of my Chinese-made Hubble Artificial-Star I bought from Hong Kong for $20US.

And a willing neighbor, in my case, who let's me climb-up his house to put my Hubble on. What a guy!

Carry on! And remember - after you do this once, it's like riding a bicycle - it's easy!

Dave

[iapa]

9 hours ago, Dave In Vermont said:

I actually enjoy collimating fast-Newtonians (I know I'm weird). And the thing to remember in fast scopes is that there will be offset in the view. This was very well pictured in Mel's (Astro_Baby) excellent guide. So you'll never get the perfect, centered-circles in an F/4 or F/5 that are sought in F/6 and slower Newts.

Yeah, that's one thing I need to capture in an image is that offset. I think I'll glue a webcam onto my cheshire, or collimation cap - hell maybe do both

Artificial star is on my shopping list - balked at £100 - for a box with an LED in it. Will check for alternatives.

Thanks

[Dave In Vermont]

The Hubble is excellent. You might be able to find a dealer in your nation. Here's the animal itself:

http://agenaastro.com/hubble-optics-5-star-artificial-star-testing-collimating-telescopes.html

£100 is rather ridiculous in my book.

All the Best,

Dave

[iapa]

found Hubble Artificial Star for $24.95 inc world wide shipping at http://www.hubbleoptics.com/artificial-stars.html

 

 

[Dave In Vermont]

1 hour ago, iapa said:

found Hubble Artificial Star for $24.95 inc world wide shipping at http://www.hubbleoptics.com/artificial-stars.html

 

 

That's where I got mine: Arrived within 10 days. Well-packed. From Hong Kong.

And nary a scratch!

Good job,

Dave

[iapa]

ah, well, not long in the grand scheme of things.

Besides, I should be able to do a real star test to night and then put the coma corrector on, which looks like it badly needed

[iapa]

I find it hard to believe that I can get a single 20s exposure, which allows the Bubble to be seen.

More work required of course

[alacant]

On 27/8/2017 at 19:50, iapa said:

total of 50m exposure;

That looks perfect. Stick in the cc and away you go. You'll love it. Well done and clear skies.

[iapa]

and we all know we have all sort of adapters, spacers and extension tubes. don't we.

Apart from that 10mm you were sure you have but can find no trace of..... need some more  to get the back space for the CC

[iapa]

Incorrect spacing shows, as does, I think, some signs of tilt.

It was windy enough that I took the dew shield off.

• total light     : 86min
• usable light  : 54min
• frames           R   G   B   L   Dark Bias Flat
• exposure (s)- 60 60  60 60 40     40   0
• #R:G:B:L    - 17 18 17 12
• guiding       - Y
• Mount         - CGEM-DP, pier mount
• OTA            - 10" Quatro cf, f4
• cropped      - yes, remove edges due drift/dithering.

 

 

[alacant]

5 hours ago, iapa said:

Incorrect spacing shows, as does, I think, some signs of tilt.

I think the spacing is OK -too far bottom left, too close top and right- so just make certain the camera is square in the focuser to even the tilt. HTH. 

Edit: and perhaps whilst testing take only snaps with a uv filter (luminance I think they call it) to remove any variables introduced by the fw.

[iapa]

 

12 minutes ago, alacant said:

I think the spacing is OK -too far bottom left, too close top and right- so just make certain the camera is square in the focuser to even the tilt. HTH. 

Edit: and perhaps whilst testing take only snaps with a uv filter (luminance I think they call it) to remove any variables introduced by the fw.

I was 10 mm short on spacing - found a Baader 20-29mm adjustable and a M48-M42 adapter; all measures good now.

i had kept shifting the camera assembly gently cw an acw while tightening 

Another shot tonight ....

 

[alacant]

3 minutes ago, iapa said:

10 mm short on spacing

Interesting; the bottom of the shot shows you're too far away. It's a dark art. A very good term for what we do!

[iapa]

2 hours ago, alacant said:

Interesting; the bottom of the shot shows you're too far away. It's a dark art. A very good term for what we do!

• ASI1600mm cooled - back focus 6.5 mm
• ASI 5 hole efw - 20mm thick

so last night I was, in theory, 26.5mm between sensor and corrector lens, nearly 30mm short.

See what tonight brings - supposed to be clear all night, so, as long as SWMBO agrees......

very dark - Alasdair Crowley would be proud

 

[iapa]

Corrected the spacing and tried again.

• total light     : 58 min
• usable light  : 51 min
• frames           R   G   B   L   Dark Bias Flat
• exposure (s)- 90  90  90 90 40     40   0
• #R:G:B:L    -   8    7    1 11
• guiding       - Y
• Mount         - CGEM-DP, pier mount
• OTA            - 10" Quatro cf, f4
• cropped      - yes, remove edges due drift/dithering.

[iapa]

Around 10 x 90s Ha

not sure what else needs sorted without getting a bit (more) OCD about it

 

 

[Skipper Billy]

Well done - looking good and worth all the effort !!!

[iapa]

Just wondering what next LOL

thwres a twisted vane, I I think but will need to take the spider out to check - later..... much later

 

[alacant]

6 hours ago, iapa said:

wondering what next LOL

Nothing. You're there. Good to see you've already discovered what fast reflectors do best; take great images! Well done and wishing you clear skies.

[iapa]

13 hours ago, alacant said:

Nothing. You're there. Good to see you've already discovered what fast reflectors do best; take great images! Well done and wishing you clear skies.

Phew,<longsighofrelief>

Thaks very much

my 1st OTA was 130mm f5 Newtonian based on a reveiw I read 

then I went to an other Newtonian, f5, 8”, then an 8” SCT, then the Q4.....

i liked the fov of the 8‘ Newtonian - 

[Adam J]

Its great to see the progression here from one shot to the next....but I think I will stick with my F5 Newtonian for now, F4 looks painful. 

I am not sure about tilt but doing a little pixel peeping I can see that your focus is soft across the entire image in the last one.