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iapa

Collimating- 10” quattro

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iapa    520

Tbh, taking you time, it’s not much different to an F5

as above, Istarted with F5 reflectors.

 

Edited by iapa

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alacant    865
4 hours ago, Adam J said:

F4 looks painful

If you can collimate an f5, you can also collimate an f4; it's exactly the same procedure!

Cheers everyone and clear skies. 

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Adam J    440
12 minutes ago, alacant said:

If you can collimate an f5, you can also collimate an f4; it's exactly the same procedure!

Cheers everyone and clear skies. 

Its not the collimation that worries me its tilt and CC spacing.

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alacant    865
8 hours ago, Adam J said:

tilt

Hi. Avoid sw focusers and you'll be fine.

8 hours ago, Adam J said:

CC spacing

Again, it's the same at f4; it depends upon focal length rather than the f ratio.

There are other more pressing issues with cheap f4s though, but which are easily fixed; the mirror springs and the dovetail. Fit three extra springs over the locking screws (and don't use them as locking screw) , a wide dovetail and a bar (which doubles as a guidescope plate) along the top of the top of the tube rings.

Go on, be a devil. Go for it. You know you want to!

HTH

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Adam J    440
3 hours ago, alacant said:

Hi. Avoid sw focusers and you'll be fine.

Again, it's the same at f4; it depends upon focal length rather than the f ratio.

There are other more pressing issues with cheap f4s though, but which are easily fixed; the mirror springs and the dovetail. Fit three extra springs over the locking screws (and don't use them as locking screw) , a wide dovetail and a bar (which doubles as a guidescope plate) along the top of the top of the tube rings.

Go on, be a devil. Go for it. You know you want to!

HTH

Not sure on that one, the light cone will converge at a higher angle at F4 and that makes the sweet spot for focus smaller meaning that any tiny amount of focuser tilt is more apparent, its probably not an issue you would have encountered only hanging a DSLR off the focuser. I hang allot of weight off my 130PDS focuser and its borderline causing it to sag enough to result in tilt I am quite sure I would have issues at F4. You are also more likely to see vignetting with certain sensor / filter combinations. 

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alacant    865
3 hours ago, Adam J said:

I hang allot of weight off my 130PDS focuser

Ah, OK. Yeah, sw focusers and weight is not a good combination. I'm sure many of the OPs issues are maybe due to that. 

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iapa    520
5 hours ago, alacant said:

Ah, OK. Yeah, sw focusers and weight is not a good combination. I'm sure many of the OPs issues are maybe due to that. 

My initial issues were due to spider vanes being offset, secondary mirror nowhere near oriented, and focusser not being centred (I’ve spoken to it’s previous caretaker and we  have discussed, and resolved, in turn, the issues that they had).

weight wise, a filter Wheel and CMOS camera, nothing excessive. It was one thing that’s not caused me issues. So far :)

Apartfromfocus, which is bybahtinov mask just now,until I get a suitable bracket for a motor , 

I’ve a predicted cloud free night tonight..........

see what comes out if the forecast is right.

 

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alacant    865
1 hour ago, iapa said:

weight wise, a filter Wheel and CMOS camera

Just my experience with sw that's all. I gave up with my ed80 altogether and needed to have my 130pds replaced; both focuser problems. My bad luck I'm certain as I still need to jam in a cocktail stick to make it hold my dslr!

1 hour ago, iapa said:

see what comes out if the forecast is right

Hey, everything crossed for you. Good luck.

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