using the Watec 120N+ ??

[jonstarrysky]

Just wanting to touch base with folks actively using this camera.

Be interested to hear experineces eg what people use it for, kind of scopes being used, hints n' tips, filters, mods (eg cooling).

I recently bought one for an 18" f/4  dob with ServoCAT tracking. Also for a 4.5" f/4 Newt OTA that rides on the back of the 18"........

Looks like a lot of the discussion on the forum related to the Lodestar. In the first instance I was wanting to get into video with an analogue video output to keep things simple. I really like the analogue feel of the Watec and its controller, good old knobs !

Cheers, Jon

[Macavity]

Hi Jon!

I see they are currently available again! The "Rolls Royce" of video cameras?

http://www.modernastronomy.com/camerasAstroVideo.html#watec120n

I have owned one for a few(?) years now ... Happy to share random thoughts!

In a nutshell, it gets most use on my TS/GSO 8" F4 Newt - I am about half way 

through a video imaging "Messier Marathon" - The Website is "coming soon"?

The Watec is "prime mover" for all my astronomy now. (Hope it doesn't break!)

I also do a bit of planetary, (white light) solar etc., with my SW MAK150...

Starting "wide field" with my late Dad's manual 70's SLR lenses?

I do all my video stuff from (relative?) comfort of my "lounge" via 30m cables.

All "remote control" (EQMod, focussing etc.) now. A big part was making up a

LONG 16-way extension for the Watec control box. (Far cheaper than buying!)

Also made up a couple of *video finders* with budget high sensitivity minicams.

Happy to say most of the "carpentry and metalwork" (and spending?!?) is over!

Can get on with a bit of "real work"? (My imaging techniques are improving? lol)

I now have broad ideas of viewing / processing things. Determined to document

more stuff from now on! Have a few filters myself: Neodymium, UHC, (L)RGB... 

Sorry it's more "ideas and tests" than definitive experience. But "you know"? lol

Whatever, any video astronomy through your 18" / F4 should be Mind Blowing? 

[Peter Drew]

Hello Jon.

I have a couple of 120n+ cameras and have had great results using a 12" SCT with F3.3 focal reducer. I did have one of the models with Peltier cooling which provided benefits during warmer times of the year. I have never bothered with stacking or processing, I actually prefer monochrome images as being nearer to those seen visually in the telescope.

I have a 18" F3.6 "videograph" as an incomplete project, I'm planning to mount the camera at the prime focus instead of a secondary mirror. 

[DoctorD]

Hi Jon

Welcome to the group - all kinds of electronically assisted viewing are welcome here

The Lodestar Live software is every impressive with its real time stacking, however I agree that the analogue video feed is very satisfying - no extra computer needed, just scope, camera and a screen.

Looking forward to any screen captures that you can show us with you 18"!

Clear skies

Paul

[jonstarrysky]

Hey thanks for the posts you three. Good to know there are some users of the Watec left, with all the Lodestar talk. I guess this (or similar) will be the inevitable conclusion at some point. Or the Mallincan Universe....For now, my 18" dob has been set up for analogue video astronomy keeping things simple, using a classic analogue vid camera. The whole video thing - power, cables, monitor etc is integrated into my dob (no trailing cables or table)

Peter, interesting you advocate mono. I was led to this via the Watec possibly running out of stock, my kneejerk entry into video, and later realised mono actually makes a lot of sense (eg sensitivity, allowing filters that mess up colours, taking in IR etc). I enquired about the peltier cooling, this mod is still available in the USA, so looks like a likely trip for my Watec...Your camera at prime focus project sounds interesting, I've heard of this being done. How will you collimate ?

I bought several filters. Astronomik CLS & UHC and Lumicon "H-alpha Night Sky". Three choices of increasing severity. They all retain long wavelengths of >650nM, but progressively chop away at the shorter wavelengths. The Lumicon is a long wavelength pass filter that only lets through wavelengths longer than 650nm; all else is blocked. Apparently works well on DSOs including galaxies, which are actually bright in the longer wavelengths.

Some tech questions:

1.  With a f/4 newt the Watec wont show much coma ? How about with a reducer added on ?? Presumably going to cameras with bigger chips coma starts to take effect ??

2.  What do folks think of focal reducers on already fast Newts. I have a few to try, and spacers. I am reliably led to believe that reducing from a starting point of f/4 is tricky in terms of optical aberrations. I was told f/5 reduced to f/3 is easier than f/4 to f/3.....The bigger I can get my field the better. I was led to believe the Watec will behave like a 6-8mm eyepiece, which is pretty high mag on am 18" scope

[DoctorD]

Hi Jon

I have no experience of focal reducers with newts - I have a MAK an SCT and a refractor.

The MAK and SCT both show some distortion when using my SCT F3.3 reducer, focusing is fine with a Bahnitov mask.

I run  the refractor (native F6) at about F4.5 using a SCT F6.3 reducer and a 20mm spacer which is the maximum reduction I can get before running out of focus.

The smaller your F ratio, the harder it will become to focus so bear this in mind.

Your 18" should be great for the planetary nebulae and distant galaxy hunting. Looks like you could piggy back other OTA's to get the desired field of view, may be a little refractor should be on your shopping list to complement the 4.5" F4 newt?

As long as you are at about F4 you should be fine with video - and you have a reason to buy more scopes!

Clear skies

Paul

[Martin Meredith]

Hi Jon

I was pleasantly surprised by the absence of coma in my Quattro 8" F4 for the Lodestar chip. I use Catseye tools for collimation and find that the critical tool is the autocollimator.

I too am looking forward to seeing what you can get with the 18"… and to see how good the ServoCat tracking is for this ind of application.

cheers

Martin

[Martin Meredith]

I have a 18" F3.6 "videograph" as an incomplete project, I'm planning to mount the camera at the prime focus instead of a secondary mirror. 

Hi Peter

Funny you should say this: I'm considering doing the same (prime focus camera) with the Quattro at some point. In theory there are lots of advantages (smaller obstruction, possibly simpler collimation, fewer reflections…).

My idea is not to make an irreversible mod -- just removing the secondary and adding an extension tube with the camera. I haven't yet worked out a good way to collimate/focus though… Maybe it can be done simply by adjustments to the primary since there is only one optical axis, although the idea of confounding focus and collimation seems like a challenge. 

As an extension, I wonder also whether a tilted primary might be an option to get the camera out of the light path altogether -- at least for small CCD work.

cheers

Martin

[Macavity]

This is a "warts and all" Watec result from my GSO 8"/F4

100 frames @ 2.56 sec, gamma LO, stacked in Registax.

And frankly (I know) the collimation was significantly out! 

You can see the stars get a "bit distorted" at the top left?

But I claim this is more a result of the poor collimation or 

(then) mount jitter (= stacking issues), rather than coma.

Aside: As far as I can make out, there's no allowance for 

the known secondary offset so the whole scope "squints"! 

(I DO intend to experiment further and potentially fix this) 

Ever happy to hear from experienced fast Newt users...

The Watec chip is about 6.4 x 4.8mm (8mm diag), so is

indeed equivalent to typical "wide field" 6mm eyepieces.

I have, tried various experiments with various reducers.

Results broadly similar to above? OK with 0.5x reducer 

in a MAK150. "Some" coma when used to get to 0.33x! 

I recall a quick experiment with the F/4 Newt at 0.5x = F/2!

The results were "not promising"? lol! But I certainly want

to retry a lesser (say) 0.7x reduction to give F/2.8... But I

think it is a rule of thumb that "alignment issues" go as the

CUBE of f-number ratio. And Hey, Borg Sorensen do this!

An f/800 + Watec is great for *most* globulars... galaxies,

but needs a bit extra for framing Messier's open clusters!

Indeed, a small APO might be "quite useful" too, but...

P.S. To focus a (hypothetical) diagonal-less Newt (I too

had thought! lol) maybe a Borg 7315 Helical focusser?

http://www.firstlightoptics.com/helical-focusers/borg-helical-focuser-s-7315.html

I once had one - Just(?) sufficient for use with a Watec...

[jonstarrysky]

So some interesting feedback re focal reducers. Indeed autocollimation is the way to go for alignment accuracy. I'll be using a Catsete XLK infinity.

My Servo-CAT 18" scope with the Watec will be an interesting experiment then..... The 18" will also have a new quartz primary mirror in a few months (of no relevance here, but I just cant wait for that !!!)

OK, so equivalence to 6mm eyepiece is really pushing it. Technically and the kind of target objects. It the tracking is up to it, potentially awasome. But I can see my piggybacked 4.5" f/4 Newt getting most of the Watec action, as a worst case. Visual on the 18" and monitor on the piggyback 4.5"....

I have several reducers to play with. One from modern astronomy, and two from Mallincam with variable spacers: MFR-3 and MFR-6. The MFR-3 is supposed to be ideal for Newts. And MFR-6 has a modest reduction ratio (0.7x I think). I plan to incrementally increase the redution factor till either there are image quality issues or .....I run out of in-focus. I asked for an inch longer FL for the new primary mirror, so will have more in-focus to spare (focus position moved out by an inch). And I bought a 1.25"-2" camara adapter that in effect buys some in-focus vs using a normal 1.25"-2" focusser adapter -  the camera body goes flush against the 2" focusser drawtube opening. See http://mallincam.tripod.com/sitebuildercontent/sitebuilderpictures/2inchadapter.jpg

I guess an image capture device may be called for at some point to document some of the results.... (not that imaging is the prime objective).

[jonstarrysky]

This is a "warts and all" Watec result from my GSO 8"/F4

100 frames @ 2.56 sec, gamma LO, stacked in Registax. 

C23a.jpg

Lovely picture Macavity !!  Seems like 8" is a sweet spot of imaging/ video. And presumably you chose a short 2.56" exposure time to keep tracking drift to a minimum. Can I ask how you got digital images from the Watec ?  Is this a straightforward process ?

[Peter Drew]

Hello Martin.

My 50% completed 18" video project is an alt azimuth arrangement. The primary and its cell are fitted to a stretched fork from a 12" LX200, the intention being to use the drive and GOTO facility. There is no main tube as such, just a 60% of the focal length formed by a 60mm square aluminium tube  topped by a smaller square tube running inside the 60mm on linear bearings. A single arm support for the camera attached to the upper tube is focused by a spring loaded threaded rod operated from the primary end. I'm assuming collimation will be achieved by the usual secondary adjusters whilst looking at a video star image.  

[Macavity]

Lovely picture Macavity !!  Seems like 8" is a sweet spot of imaging/ video. And presumably you chose a short 2.56" exposure time to keep tracking drift to a minimum. Can I ask how you got digital images from the Watec ?  Is this a straightforward process ?

Well, let's say most of the deficiencies are fairly well understood and can be worked on. 

Whether you decide to do any imaging or not, there is certainly no great difficulty involved.

I am just keeping a "video diary" of objects seen. No substitute for the full-blown "classical

imaging" setup (nor visual astronomy!) but has impressed the devotees of either / both?

I use a generic, budget, USB capture device. This is just a somewhat oversize "dongle" - In

my case bearing the name "EasyCAP". These are available on Amazon etc. As a TIP, there

are known to be identical "knock off" versions that don't work well, so check the *star rating*

of the device. It should come with a driver disk. Just follow the usual setup for your machine.

I use the *GSTAR4* capture software: http://www.myastroshop.com.au/guides/gstar/

This software is written for their GSTAR-EX camera(s) - Or essentially any Watec type!

You just set the capture rate (planetary or deep sky) to match the data (LED Flash) rate...

N.B. The capture process is entirely *asynchronous* - The Watec picture only changes at

intervals of ... 2.56, 5.12... 10.24 seconds, so you should sample output at the same rate.

This simply to avoid writing duplicate frames to disk - wasting disk space, stacking time etc.

You can then take "snapshots" to disk or write an AVI video file. The latter is easily stacked

by (notably) Registax! Provided you have a *solid* mount (keeps the scope "steady" for the

maximum integration time of 10s) Registax will follow random errors of any *tracking* mount.

There is NO need for auto-guiding etc. In principle it could follow a Dobsonian image across

the field(?!) But, as with visual use, some kind of tracking helps, even if you eschew GoTo!

Aside: I bought few 12V *video splitters* (drivers) to provide multiple outputs from the Watec.

http://cpc.farnell.com/genie-cctv/gcd02/distribution-block-1-in-2-out-bnc/dp/SR06405 (1:2) and http://cpc.farnell.com/genie-cctv/gcd04/video-distribution-unit-bnc-1-in/dp/SR06903 (1:4)

You can then have coaxes to a local monitor AND the capture device... the family TV even.

[Martin Meredith]

Peter: Sounds interesting. I'm looking forward to seeing how it turns out. 18" F3.6 will certainly eat up the photons. And yes, screen-based collimation seems necessary. I'll miss my autocollimator though.

Chris: I'm considering the Borg helical focuser too but it increases the obstruction. Given the small diameter of the Lodestar it would be good not to increase it too much.

Jon: Sorry for hijacking your thread. Probably we should start a new one for discussing the pros and cons of prime focus scopes.

Martin

[Phil Fargaze]

Another Watec 120N+ user here! I use mine primarily for occultation observations at fast frame rates.  The camera output is put into a usb video grabber to be recorded onto laptop. I use it with my C9.25 scope on an HEQ5 mount and a focal reducer from Modern Astronomy. When not doing occultations I turn up the integration time to obtain basic images of deep sky objects.

One recent surprise for me was obtaining an image of Hickson 68 galaxy group with the Watec.  I can only wonder what would be achieved with an 18".

It`s also come in handy for when I`m doing public outreach sessions with the astro club. I simply hook it up to a portable TV so then everyone can see the image at the same time. 

[jonstarrysky]

Well, let's say most of the deficiencies are fairly well understood and can be worked on. 

Whether you decide to do any imaging or not, there is certainly no great difficulty involved.

I am just keeping a "video diary" of objects seen. No substitute for the full-blown "classical

imaging" setup (nor visual astronomy!) but has impressed the devotees of either / both?

I use a generic, budget, USB capture device. This is just a somewhat oversize "dongle" - In

my case bearing the name "EasyCAP". These are available on Amazon etc. As a TIP, there

are known to be identical "knock off" versions that don't work well, so check the *star rating*

of the device. It should come with a driver disk. Just follow the usual setup for your machine.

I use the *GSTAR4* capture software: http://www.myastroshop.com.au/guides/gstar/

This software is written for their GSTAR-EX camera(s) - Or essentially any Watec type!

You just set the capture rate (planetary or deep sky) to match the data (LED Flash) rate...

N.B. The capture process is entirely *asynchronous* - The Watec picture only changes at

intervals of ... 2.56, 5.12... 10.24 seconds, so you should sample output at the same rate.

This simply to avoid writing duplicate frames to disk - wasting disk space, stacking time etc.

You can then take "snapshots" to disk or write an AVI video file. The latter is easily stacked

by (notably) Registax! Provided you have a *solid* mount (keeps the scope "steady" for the

maximum integration time of 10s) Registax will follow random errors of any *tracking* mount.

There is NO need for auto-guiding etc. In principle it could follow a Dobsonian image across

the field(?!) But, as with visual use, some kind of tracking helps, even if you eschew GoTo!

Aside: I bought few 12V *video splitters* (drivers) to provide multiple outputs from the Watec.

http://cpc.farnell.com/genie-cctv/gcd02/distribution-block-1-in-2-out-bnc/dp/SR06405 (1:2) and http://cpc.farnell.com/genie-cctv/gcd04/video-distribution-unit-bnc-1-in/dp/SR06903 (1:4)

You can then have coaxes to a local monitor AND the capture device... the family TV even.

thanks Macavity, Good point about capture being asynchronous....Just noticed they do a cheap USB capture dongle at Modern Astronomy. Might be useful for evaluating tweaks and kit options (eg comparing filters and focal reducers) when it's cloudy...