Jupiter last night with my SPC880

[redneon]

The clouds managed to clear in the east for half an hour last night so I had a go with my SPC880 (modified to an SPC900). I’m still very much learning and the conditions weren’t ideal (bright moonlight, a fair amount of cloud and I don’t have a UV/IR filter) but I managed to capture 30 seconds or so of Jupiter. Had a bit of a play with Registax and produced this photo:

I’m quite happy with it because I don’t see Jupiter with anywhere near that level of detail through my eyepieces. Even with my 10mm lens I just see a small orange disc about half the size of the one in the photo.

I assumed I would attach the webcam to an eyepiece (so I could have different levels of magnification) but the webcam nosepiece just fits into the eyepiece slot. I’m a bit confused about how come I get that level of magnification without an eyepiece but I probably just don’t understand the workings of the optics Presumably I’m stuck at the “default” level of magnification unless I use Barlow or something.

Pretty happy with it for a first try, though.

[Skiddins]

What scope do you have?

I have been a bit frustrated with the level of detail I see through my 130mm scope, but I do see a sharper image than that. I can make out the two main equatorial belts even at low mag with moolight etc.

Is it properly collimated?

[Cornelius Varley]

What telescope do you have ? The field of view of a webcam is about the same as that of a 6mm eyepiece. You can increase the size of the planetary disk by using a barlow lens to give you a focal ratio of about F20 to F30 depending on your telescope to get the best resolution.

Peter

[redneon]

I've got a Celestron AstroMaster 114EQ. It's a 114mm (4.5") reflector with a 1000mm focal length.

Presumably, with a 6mm eyepiece on the webcam the magnification is working out at 166x?

I haven't collimated the scope since I got it at Christmas so maybe I should try doing that.

[redneon]

Also, I should point out that I haven't got a motor on my mount so the video was taken with Jupiter moving across the image. Registax seemed to do a good job of tracking it, though.

[redneon]

Actually, I'm a bit confused. The webcam doesn't have a lens on it so how can I have any magnification at all?

As I understand it, the light hits the back of the reflector, up to the diagonal and then straight across to the CCD chip on the webcam. There's nothing to magnify the image in that setup, is there?

[Cornelius Varley]

Actually, I'm a bit confused. The webcam doesn't have a lens on it so how can I have any magnification at all?

As I understand it, the light hits the back of the reflector, up to the diagonal and then straight across to the CCD chip on the webcam. There's nothing to magnify the image in that setup, is there?

Think of the telescope/webcam combination as a camera with a long telephoto lens. The area of light falling onto the sensor gives a field of view equivalant to the field of view of a 6mm eyepiece.

Peter

[redneon]

Did you mean focal length before? A 6mm eyepiece would have a 6mm focal length, not field of view, wouldn't it?

Sorry if it's a stupid question. I'm still fairly new to all this and it can get a bit confusing at times

[Cornelius Varley]

Cameras don't have any magnification themselves, but the field of view is about the same as the field of view of a 6mm eyepiece.

Peter

[jgs001]

Off to a nice start... it's not easy.. The moon won't be a problem for this as the exposures are so short... not having a UV/IR filter on the other hand would. Worth getting one. Also, look at getting a drive for the mount, or even see if you can track it manually ??

[redneon]

To track it manually I presume I'd just have to polar align it and then try and turn the DEC cable at the correct rate? Maybe that would still give me better results than allowing it to drift across the image, anyway. Registax would be able to deal with any errors, presumably...

[jgs001]

That's pretty much it, yes. Regi can deal with the out of alignment, but I've found better results if it doesn't have to work so hard.

[redneon]

I think I'm going to have to look into collimation. It doesn't look like an easy thing to do, though. Maybe I should fork out for a laser collimator to make things a bit easier.

[peteuplink]

I have a similar sized scope to you, but with a 10mm eyepiece and a 500m focal length. Your image doesn't look that much different from what I was seeing last night, but mine seemed a little shaper, I think, and yours is more magnified. No images for comparison, sadly, as I don't have a camera. I did knock together a diagram of my observation, though.

[astroandy101]

I would definetly collimate your scope if its never been done, I use a laser collimator just because i find it easier, also try for 1000 frames at 10 frames per second see if that helps,

[drewk1]

Looks good for a 1st attempt.

I have the same scope and am also just starting with webcam imaging.

Have a look in the embarrising Jupiter webcam thread for some of my images.

[steelfixer]

hi there

From experience with these webcams I would recomend you get an IR filter. The difference will amaze you.

Insted of a white ball with a small amount of detail you will get a super sharp image and in colour.

That is providing the collimation ect is right as has been mentioned in other replies.

You also need to make sure your capture rate is set to a max of 10 fps or on a night like you discribe yesterday you will need to cut it down to 5 fps.

graham