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focal reducers on Samsung scb2000

shirva

By shirva
in EEVA - Reports

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shirva

shirva

Posted
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Hi Carl.if I remember your on the eq3/2 and a 130....I've had the 203mm on the eq3/2 extension legs down position and a pile of weight on counter balance to balance scope with dslr ect ...it can be done... not tried Sammy on it but dslr heavier, extension tube will need to be used think about 25mm may be enough. ..will stick the 200 on the mount and try next week...Davy

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Carl Reade

Carl Reade

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Cheers Davy, its a 150p on the eq3/2, I agree mount specs are a bit hit and miss, appreciate your trial with the 200. I was thinking of trying the barlow tube as an extender with the lens removed.

On another note got a brand new weatherproof cam housing on the usual with dew heater for less than £20 for meteor setup I have had a second Sammy new in the box doing nothing but I'll update that on the Persids thread.

Cheers mate

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johnno

johnno

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I've just tried the focal reducer with the Sammy and it works fine on the 80ED, but I can't use it with the flip mirror in line, just won't focus, doesn't matter where I put the reduser in front or behind the flip mirror.

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Carl Reade

Carl Reade

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I've just tried the focal reducer with the Sammy and it works fine on the 80ED, but I can't use it with the flip mirror in line, just won't focus, doesn't matter where I put the reduser in front or behind the flip mirror.

Cheers Johnno, I think I will have a go with the Barlow tube and see what happens.

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johnno

johnno

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Just want to thank you Davy for putting this thread up .. :laugh: you've just solved a problem I had and its got nothing to do with the reducer. I've had the Sammy for a good couple of months and when I first got it I removed the ir filter and set up the WB with the lens that came with the camera and left it at that , well today when I tried the focal reducer in daylight in the ED80 the WB was way out. What was happening I was getting a green tint on all my images and I thought it was amp glow so I never bothered about it and was removing the tint with software. So now I've re-adjusted it and it looks bob on, just got to try it at night and see if its made a difference. Just shows the difference in lens type.

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johnno

johnno

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Just a bit of a update on using focal reducer on ED80, when I tried the other day in daylight I could get focus ok about a couple of miles away. Last night / this morning I thought I would have ago at Pleiades with focal reducer and found I couldn't get focus, about 2 turns short on focuser knob inward travel. Just want to know what you guys are using to get focus. tried a barlow with lens removed but could not find focus at all. john

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Macavity

Macavity

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Hmmm... I have an ancient "Teleconverter" for Pentax threads - But that's going the wrong way, right? :p

As a semi-random comment: The 1.25" Atik reducer (for example) has a focal length of (minus) 80mm. To get a reduction of 0.5x it needs to be 40mm from the chip (on camera nose-piece etc.) and correspondingly 40mm inside focus. Somehow this seems to be right on the "hairy edge" (of in-focus) for many scopes. Almost so with my Photo-Newt - Except for 2mm? Of course you can limit the distance between chip and reducer, content yourself with less (but useful) reduction, but... ;)

I also have one of these reducers:

http://www.opticstar...=0_10_5_0_3_510

My impression is that this one has a slightly shorter focal length (-70mm? To be confired!) and thus less in-focus required. But I'm not 100% certain. When I bought mine, I didn't notice the 5mm rings (they weren't stocked?). Must get myself a set of these - Then you can have reductions of anything from 0.7x to 0.3x - If the latter can get enough in-focus of course. But quite a useful item, which attaches DIRECTLY to the C-thread. :)

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shirva

shirva

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Ed80 settings on the pd1. ...camera pd..c to t adapter. .t to nose cone adapter .. .5 focal reducer. ..revelation ir blocking filter. 2" to 1.25 adapter...focusser out approx two finger width. .focal distance approx 3 miles...next settings......pd1 camera. .c to t adapter. .t to nose piece adapter. Revelation astro ir blocking filter... 2" to 1.25 adapter.....revelation astro 80mm 2" focal tube to focusser. ..focusser out 1.5 finger width...focal distance 5 miles... hope this helps ....some issues. ....Davy....daylight testing. ....

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johnno

johnno

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I'm about the same as you Davy, its just when going skywards so to speak I just short of focus. normally I look at Pleiades thru my bino's on a tripod mount, but I thought i'll have a crack at it with the cam and reducer. this is what I was getting. No tracking or filters . steet light about 10 mts away andjust below FOV.Snapshot_0069.bmp

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shirva

shirva

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I would change the camera setting think its a bit bright.is the focusser right in and how is your focal reducer mounted. ...I switched the order on my reducer specs list ..I had the filter before reducer. ..makes a big diff swapping the order of lens/reducer...Davy

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shirva

shirva

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Try focussing on the brightest star near and switch back to paladies. ...had to do that with my dslr. ..I use a bahtinov mask can see the diff I used it on a street light a mile away. ...faster shutter might be Better as well slightly over exposed I thought...Davy

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johnno

johnno

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You could be right Davy, maybe to much exposure and its bloated a couple. yep I keep saying I'll get a mask

I thought if I couldn't get enough inward travel I would need extensions, but when I put in a stripped down barlow tube and put the reducer on the end of that I couldn't find focus at all. Am I going the wrong way, should the reducer be closer to the ccd

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johnno

johnno

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just tried it out, can only manage 1, 5mm ring and that gives me about 12mm gap to play with before focus travel is all the way in, so that's about F0.66 reduction. next time i'll try it on my mak 127 should be able to use all the rings

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Macavity

Macavity

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Hi Johnno! Glad I fooled persuaded someone into getting one too? ;)

But a useful thing to have around. And it will work with the MAK127...

A big favour though? Some time ago "Macavity" put a big PAW print on the lens of his. Full of

good intentions, removed the lens for cleaning. But then forgot which way round it goes. :p

It is a plano-convex doublet lens. I'm pretty sure the FLAT side goes nearest the camera?!?

Can you check for me? Doubtless "testable", but a little peace of mind would be useful... :)

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