Jump to content

SkySurveyBanner.jpg.21855908fce40597655603b6c9af720d.jpg

ASDA £2.93 webcam

jordanclarke89

By jordanclarke89
in Discussions - Cameras

Recommended Posts

JamesF

JamesF

Posted
Posted

The planets seem to be something of a struggle at the moment nytecam. Perhaps that's just the way things are right now. Neither Saturn nor Mars is ideally placed. That Alpine Valley image is a corker though. Very nice indeed. In fact, quite possibly the best one I've seen from that camera yet. Beautiful definition on the shadows across the floor of Plato. Could be that the camera responds better when there's a bit more light, I guess. Who can say what's going on inside the firmware?

James

Link to comment
Share on other sites
  • Replies 383
  • Created
  • Last Reply
nytecam

nytecam

Posted
Posted

Planets have never been 'my thing' image-wise so a steep learning curve. :(

The views of the moon on the laptop in closeup at f/10 are amazing and tweaked in Registax shows a crater/peak central in Plato - don't recall viewing similar via an EP in the past.

The cam is a perfect way to show the moon in detail to an astro-party and Sharpcap provides an excellent picture with good control :D

If I stay with it I'd like to record in good seeing and the right illumination the central rille through the Alpine Valley sometime but a very tough one:hello2:

Link to comment
Share on other sites
Stargazer33

Stargazer33

Posted
Posted

A couple of pics from last night. Both using SharpCap as capture programme and Registax 6 to stack and clean them up.

Skymax 102 with the Asdacam straight into the back of the OTA - no mirror diagonal or filters. Focus was done off of the laptop screen (I must get/make a bahtinov mask).

I'm quite happy with the results as they are my first for Mars and Saturn.

Both were hand tracked :hello2: as I haven't got a motor drive for my mount yet.

There is definitely some shading going on in the Mars shot.

Bryan

post-34179-133877770032_thumb.jpg

post-34179-133877770034_thumb.jpg

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted

southerndiver, have you tried the "RGB align" option in Registax wavelets? Your Mars image particularly looks like it's suffering a little from atmospheric refraction of the blue and red (the image looks like it has a blue fringe at the top and a red one at the bottom). Doing the RGB align may sharpen it up a little.

James

Link to comment
Share on other sites
Stargazer33

Stargazer33

Posted
Posted

Thanks guys!

James: I was playing with most of the adjustments in RS6. I think I used the RGB align but not too sure what I did with it or why if you know what I mean.

The original images were really fuzzy, due to hand tracking and probably poor focus - hence the need for the focus mask.

I will have another go at cleaning it up and see if I can improve on it.

Thanks for the advice anyway. :hello2:

Bryan

Link to comment
Share on other sites
Stargazer33

Stargazer33

Posted
Posted

Wow!

Just watched your moon video Nytecam. That is fantastic! :hello2:

The shadows from the peaks are so clear and sharp. Even with the atmospheric shimmer they are some superb shots and something for me to aspire to.

Friends and family would be amazed if I could show them something like that.

I love this forum. :)

And all from a webcam that cost less than a cup of coffee!

Bryan

Link to comment
Share on other sites
Ender Of Days

Ender Of Days

Posted
Posted

Quick question .. Compared to a 35mm type camera what's the 'magnification' when using one of these camera's,

My scope is f15 mak cass,

Is it easy to figure out as I imagine it all depends on the fl of each individual scope,

Just thinking it'd be cool to mention the equivalent magnification to non Astronomers.

JJ..

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted
Quick question .. Compared to a 35mm type camera what's the 'magnification' when using one of these camera's

People sometimes say the image produced by a webcam is about the same as you'd get with a 6mm eyepiece. But...

When imaging it's more helpful to think about "image scale" or "plate scale" rather than "magnification". Image/plate scale is the "amount of sky" corresponding to a given linear measure of the camera (in this case) sensor. So you might say that with a given camera and optical train the image scale is X arcseconds per mm, or Y arcseconds per pixel.

If we take the SPC900 as an example (because I happen to know the pixel size -- 5.6um, or 5.6 x 10^-6 m), if you have a scope with a focal length of 1200mm then the image scale can be calculated as

206265 x 5.6 x 10^-6 / 1.2 arcseconds per pixel

or 0.96 arcseconds per pixel.

You can see why the idea of magnification runs into trouble here. If you swap the camera for, say, a Lifecam, which has pixels (almost) half the size, then you've not changed anything optically, yet if you capture an image at the native resolution of both cameras then the Lifecam version will appear almost twice as big on-screen because the same size patch of light on the camera sensor will have covered twice as many pixels.

James

Link to comment
Share on other sites
nytecam

nytecam

Posted
Posted
Quick question .. Compared to a 35mm type camera what's the 'magnification' when using one of these camera's,

My scope is f15 mak cass, Is it easy to figure out as I imagine it all depends on the fl of each individual scope, Just thinking it'd be cool to mention the equivalent magnification to non Astronomers.

JJ..

An eyepiece, on a given scope, gives a known fixed magnification eg scope fl/EP fl.

When the cam replaces the EP you get image scale not magnification and the apparent magnification when viewing the image depends on the fl of scope and how big the imaging chip is and pixel size, how far the eye is from the viewscreen, what size that screen is eg all completely variable ;)

Link to comment
Share on other sites
Gfamily

Gfamily

Posted
Posted
Ok, I think that's covered that ok and I can understand it a little better !,

sorry to have briefly scewered off the thread a bit,

JJ..

Although what JamesF and nytecam have said is technically correct, you can give an approximate answer.

You asked about a comparison with a 35mm camera: let us suppose that the webcam has the same field of view as your camera with a 40mm lens on (i.e similar to the old Olympus Trip).

Assuming you have removed the lens from the webcam, so you're using the simply using the sensor in the focal plane,

to find the 'equivalent' magnification*, just divide the focal length of the webcam lens by 40mm, and multiply by the focal length of your telescope.

Typically, webcams have 6mm lenses, so if your scope had a 1000 mm fl, you could reasonably say that the magnification is about x150.

* not strictly accurate, but if you're speaking to non experts it probably does what you want it to do.

Link to comment
Share on other sites
Ender Of Days

Ender Of Days

Posted
Posted

I get about 300x in that case :-) its just a figure I can throw round thanks,

I managed to get some avi's of Mars last night but got nothing more than an amorphouse over exposed blob,

At least I know it all works,didn't have the scope tracking just kept tapping the controls to keep Mars roughly centred,

The FOV with the asda cam is very small and it took about 5 mins of searching to actually get Mars on the screen,

It feels like a steep learning curve :-)

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted
The FOV with the asda cam is very small and it took about 5 mins of searching to actually get Mars on the screen

It's the same imaging any of the planets with any webcam...

If you don't have accurate GOTO (as I don't on my EQ3-2), the way I do it is to start off with a fairly long focal length eyepiece and centre the planet, then step up a few focal lengths, centering each time, until I get to somewhere around 6mm. If I'm using a barlow then I might stop with a 12mm ep, add the barlow and centre. Then if I'm using an extension, add that and centre once more. Then I fire up sharpcap, get the settings about right and push the gain up high before swapping the eyepiece out for the camera.

That way I stand a reasonable chance of the planet being in the field of view of the camera from the start, and probably visible even if it's faint or out of focus. (In fact, if I was using the scope for imaging last time I used it I don't even bother changing the focus for centring the planet -- a fuzzy blob is quite sufficient for judging position.)

An illuminated reticle eyepiece helps massively with judging the centre position. It's surprising how far you can be out when judging purely by eye. A cheap one is fine. I think mine was less than £40. It's not like you're going to use it for teasing out the fine detail in some nebula or globular cluster...

James

Link to comment
Share on other sites
nytecam

nytecam

Posted
Posted

Finally mounted 1-1/4" [32mm] EP adapter to Asda cam as below that didn't use BlueTack :clouds2:

Peeled-off the top cover

and cleaned off adhesive [a beast!] to cam lid and superglued old EP tube centrally over sensor. This exposed two crescent shaped areas either side of cam body - these covered with black adhesive tape - job done and awaiting [if ever] another clear sky:hello2:

post-33671-133877771988_thumb.jpg

Link to comment
Share on other sites
BigBlueOne

BigBlueOne

Posted
Posted

Hi Nytecam,

How the hell did you get that glue off I tried meths,turps I just could'nt budge it.

I managed to get 3 more webcam's so I could try to adapt it

just a bit better now if you could let me know how it was done

I would be grateful.

Cheers BigBlueOne.

Link to comment
Share on other sites
c3po

c3po

Posted
Posted
Hi Nytecam,

How the hell did you get that glue off I tried meths,turps I just could'nt budge it.

I managed to get 3 more webcam's so I could try to adapt it

just a bit better now if you could let me know how it was done

I would be grateful.

Cheers BigBlueOne.

i couldn't get the glue off either BBO, so instead I covered it with black electrical insulation tape - if you can't beat it, join it! :clouds2:

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.