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Small VIDEO Finder

Macavity

By Macavity
in DIY Astronomer

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Macavity

Macavity

Posted
Posted

Tired of trying to locate / reach optical finders in the dark,

I came up with a simple video finder for Video Astronomy. :p

I sense it might have applications for general "finding" too!

The lens: 50mm, D-thread f/2.5 "board" lens (Stock Optics)

The manufacturer Genie CCTV but often available on Ebay  

The camera is a standard "mini" B/W camera of 0.003 lux.

Ex-View, Super HAD etc. "IR sensitive" chips are needed. 

Viewable on ultra-budget 3.5" car reversing monitors etc.

The field is 8 degrees (by intention) but to be confirmed  ;)

The limiting magnitude is (easily) +4 (+6...+7...+ 8 maybe).

Great for *remote* star alignment of EQ mounts from park!  

Happy to provide more details if anyone is interested...  :)

post-539-0-22769600-1409665951.jpg

The next stage is some sort of adjustable mount. Looking

at small LASER pointer rings with 3-point screw adjusters...

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Alien 13

Alien 13

Posted
Posted

Nice idea, i have an old IR monochrome camera and lens that is super sensitive in the dark and quite small about 2" x 1.5" but only has video output so never new what to do with it.

Alan

P.S i have just dug it out and it appears to have a 20mm lens around about F3 but it would be ideal mounted on my DSLR hotshoe, oh no not another project.

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Ptarmigan

Ptarmigan

Posted
Posted

Tired of trying to locate / reach optical finders in the dark,

Ex-View, Super HAD etc. "IR sensitive" chips are needed.

Happy to provide more details if anyone is interested...

A neat idea ! And as you say if it doesnt reach down to silly mag. then one is not going to get confused by too many stars :)  (i'm easily confused ! and I've been plagued with sore neck syndrome by finders for years now )

Yes please count me as interested, at least I will be when I get my new scope :) , and I will be watching how you get on, thanks for sharing.

I was going to call for more info on that "Ex-View, Super HAD" stuff which I did not understand at first, but thanks for your later link I see now :)

(dream)

I wonder, , can someone do a mini plate solve prog for an arduino or RPi, then it could give an RA/Dec readout as well :) :)

(/dream)

PS

I've still got my filmSLR lenses, and some of my dad's brass plate-camera jobs too !

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Ptarmigan

Ptarmigan

Posted
Posted

I know how you feel Chris  - some folk have forgotten/ignore "the friendly internalional..." bit with their throwaways and 'wit' :smiley:   

Gosh, try the other side of the bed tomorrow morning !

Your substantive and enlightening comment on the topic of a small and  economic video finder is , , , ?

Me ? I was trying to sound appreciative of Chris taking the trouble to post his experiments.

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pete_l

pete_l

Posted
Posted

Personally, I'd buy a Watec 902H2 Ultimate:

http://www.modernastronomy.com/camerasAstroVideo.html

What I use is a £50 LN300 from China. with  some sort of cheapo EZCap frame grabber (not a very good one as it turns out. It only has a resolution of 640x480 cf. 720x576 for the LN300, so it loses lines & stars mysteriously disappear when they're on a lost line. I have a new, hopefully better, grabber on the way. It might even work with a Raspberry Pi)

At 2.56 second integration time (x128) and a 12.5mm F/L @ F1.4 C-mount lens I'm getting images like this:

post-651-0-93078200-1410148475.jpg

The left side is a large part of Cassiopeia and the stars in the image are down to Mag 6.6

P.S. I should say that this image was taken a few nights ago with a v. bright half-full moon.

P.P.S. No image processing involved. This is a straight screenshot as it came out of the camera

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nytecam

nytecam

Posted
Posted

Gosh, try the other side of the bed tomorrow morning !  Your substantive and enlightening comment on the topic of a small and  economic video finder is , , , ? 

Me ? I was trying to sound appreciative of Chris taking the trouble to post his experiments.

Sorry PT - in SGL one can't direct a comment unless one includes a 'quote' so there's no way of knowing who a comment is directed at ...and mine certainly wasn't directed at you but a general comments to OP on some 'witty' Twitteresk posts that occur in the fora nowerdays that I find unhelpful :grin: . 

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Ptarmigan

Ptarmigan

Posted
Posted

Sorry PT

mine certainly wasn't directed at you

Ah, oh, I see, thanks.

Oooops,

sorry I mistook you,

a thousand apologies.

There had been a few days delay/quiet in the thread until I poped in with my waffle, then yours made me think that I had upset you.

I couldn't see any (of my usual brilliant ?! lol ) wit in my waffle but as it was the only long-winded bit perhaps it was something to do with my call for an improvement via plate solving, I wondered.

Oh dear, sorry I sank my teeth in, I'll send a courier round with some liniment and sticking plasters :)

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Macavity

Macavity

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Nah - As much *my* (Grumpy Cat!) fault as anyone else...  :o  :D

post-539-0-46487300-1410174489.jpg

Just me getting "fed up" re. limited funds for astro projects... bills, bills, bills! etc.

And I doubt that is unique in SGL? lol. I have a "LOT of time" for Ken (merlin66) 

I have "the book" - I do intend to return to Spectroscopy at some stage... :p

The idea of the project is to have something to replace a "Red Dot Finder" in

my remote control setup. No computer, No USB, just coax and mini monitor...

Or 30m COAX indoors.To use the finder ONCE to center the "1st star"  ;)

The concept works FINE for my f / 800 mm "Video Newt" - Objects are the

always in the 30' x 20' field of view of the MAIN scope via EQMod / HEQ5.

This is not always so with my (Barlowed etc.) MAK150. For that, I do *need*

an additional (modded 50mm Skywatcher) "electro finder" - Which see...

As ever my "economies" rarely work out. By the time I've built the custom

finder *bracket*, I could probably have afforded a QHY-Whatever... :D

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Macavity

Macavity

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Oh this would be very handy, can you pm the links to get the gooies.

The *exact* lens I used was:

http://www.ebay.co.uk/itm/50mm-Board-Lens-for-CCTV-Cameras-Security-Cameras-CCTV-BL-DW-50-Stock-Optics-/111123817577?pt=UK_CCTV&hash=item19df7ee469

The *exact* camera I used (THIS TIME) was:

http://www.cameras-cctv.com/low-light-cameras/CB-29BSHRX-B36A-BW-Low-light-Sony-EXVIEW

As ever, you should look for an ExView or "Super HAD" Chip with sensitivity >= 0.003 lux etc. ;)

http://www.cameras-cctv.com/low-light-cameras

There are many of this general ilk? But, to fit the LENS above, you will need a mini camera body

that takes a full depth 12mm / 0.5mm thread CCTV lens, rather than the "cone lens" cams etc. :)

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nytecam

nytecam

Posted
Posted

Chris - as you're aware its gross lens aperture, not f/ratio, that reveals faint stars for an e-finder. Does turning the video screen brightness and contrast reveal fainter stars?

I use a 42mm diam lens [85mm fl f/2 lens on my e-finder] + Lodestar camera. I've put tiny marks [on clear plastic screen overlay] for centre of fov for my main scope and piggybacked scope - no they don't coincide! I insert the barlow [when rarely used] after I've located and centred the target in the main scope - helped of course initially by the e-finder ;-)

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