DSLR + telescope FOV ?

[swlloyd3]

Hey,

There was this website that I found through a link on stargazers lounge that allowed you to input your camera and telescope details and then choose messier objects etc... and then it would show you how much of the FOV the object would fill?

I just cannot seem to find that link anywhere now and forgot to bookmark does anybody know what the website is?

Thanks.

Ste.

[Bizibilder]

CCDCalc is the one you want.

[swlloyd3]

That wasn't actually the one I was talking about but its even better!!!

Thank you!

Ste.

[swag72]

Is this the one you were thinking about?

[swlloyd3]

Bookmarked, Yes it was thank you!

Ste.

[lukebl]

If you use Carte du Ciel, you can set it so the Field of View comes up when you start the program. I find this really useful when planning my imaging. Here's a screen grab, showing the field of view of my Canon 450d at prime focus of my SW250PDS, and also the FOV with the camera rotated 90 degrees.

[ollypenrice]

I use SkyMap Pro but they all do the same thing. I couldn't live without these tools!

Olly

[Sparrow]

I've been using CCDcalc which I heard recently has dissappeared from availability to download - don't know if that's true or not. However, thanks for that tip Luke - I'm going to try Carte Du Ciel as it looks like it could be pretty useful.

Thanks

John

[cgarry]

If you use Carte du Ciel, you can set it so the Field of View comes up when you start the program. I find this really useful when planning my imaging. Here's a screen grab, showing the field of view of my Canon 450d at prime focus of my SW250PDS, and also the FOV with the camera rotated 90 degrees.

Thanks Luke. Yet another thing about Carte du Ciel I have learned.

Chris

[lukebl]

If you use Carte du Ciel, you can set it so the Field of View comes up when you start the program. I find this really useful when planning my imaging. Here's a screen grab, showing the field of view of my Canon 450d at prime focus of my SW250PDS, and also the FOV with the camera rotated 90 degrees.

For info, in Carte du Ciel you set the FOV rectangle by going Setup > Display > Finder rectangle(CCD) and you then have the option to set up to 10 CCD rectangles. For my setup with an f/4.8 250mm Newtonian + Canon 450d, the settings are Width:71, Height:47, Rotation:40, Offset:0. No idea where I got these figures from, but they certainly match the view in my camera.

[Merlin66]

CCDCalc is still available, in fact they've added many new images - all the Messier Objects etc.

A very good resource tool.

[carpman]

guys how do u work out the fov in arc mins of eps

[Merlin66]

Two ways:

If you know, from literature, what the apparent FOV (AFOV) should be ie 52degrees or 60 degrees etc then the FOV will be the AFOV/ magnification.

So, say a 20mm focal length 52degree plossl on a 200mm f5 scope..

The magnification will be (200 x5/20) = x50 so the FOV in that eyepiece will be 52/50 = 1.04degrees

Another way is to point towards a star near the celestial equator and time how long it takes to move from one side of the FOV to the other. This time in minutes x 15 is the FOV in minutes of arc.. so if it takes 3 mins to drift across then the FOV is 3x15= 45min of arc. (there's 60 minute of arc to one degree....)

HTH

[lukebl]

guys how do u work out the fov in arc mins of eps

I remember now how I worked out the FOV rectangle in Carte du Ciel. I took an image, then played around with the settings in CdC till it matched the photo. Not very scientific, I know, but it gave me the result I needed!

[carpman]

@ Merlin thanks for that

So if i have work this out right , my scope 750mm f5 with my eps

25mm with 50' fov = 97 arc mins

10mm with 52' fov = 84 arc mins

@ Luke camera settings was easy got them from ccdcalc but you need the arc mins not the chip size like i first thought

[Merlin66]

Carpman,

I get different answers...

Focal length of telescope =750mm

Magnification with 25mm e/p = x30, AFOV=50deg, FOV= (50/30)*60= 100 arc min, similarly the 10mm e/p, magnification= x75, FOV=(52/75)*60=41.6 arc min