Camera Imaging Advice

[RJP6089]

Hi All

Looking for some advice as a 'noob' and hoping i've posted this in the right place..!

I've recently purchased a SkyWatcher 150P scope with the EQ3 mount and having fun taking images of the moon with my Cannon DSLR EOS500. At the minute I'm screwing my Cannon t-mount straignt onto my Deluxe Barlow lense and taking photos through that. This is fine for the moon, but somewhat disappointing for objects further afield (such as Jupiter the other night).

I only have the standard eyepieces at the minute, a 10 and a 22 with a deluxe 2 x barlow (all 1.1/4 inch). The scope has the ability to take 2inch lenses and i've been told this may be the route to go down but not sure.

In escence, the question i'm asking is... is there a way of taking images through lenses in order to get closer photos of further planetary objects? Obviously can take an image down an eyepiece so not sure how this works.

Also, are there any good filters worth using to get better imagery, as so far i've only experimented with the moon!

Any help would be greatly appreciated. Thanks.

(I've attached a first attempt at a pic of the moon)

[jgs001]

Firstly, welcome to SGL...

An SLR is not the ideal tool for the planets, the large sensor size, and the low frame rate are going to work against you. To give some idea... if we take 35mm (full frame) as being 1X crop, then your SLR is 1.6X crop (multiply the focal length by 1.6). If you use a webcam (such as the SPC880 Buy Cheap Astronomy at Morgan Computers) you are using a camera with a much smaller sensor (about 8.5x crop)... therefore you will get in close. The frame rate is also faster, the benefit of which is you capture more frames of video in a shorter period, this can help overcome issues of the atmospherics (seeing)...

To do the maths...

Your 150p is 750mm...

using

a 35mm camera, that's 750mm

your DSLR, that's equiv of 1200mm

an SPC800, that's equiv of 6375mm

That's equivalent, as the tube length doesn't change, but the part of the view that's hitting the camera gives the field of view of that length lens on a 35mm camera.

As you can see, the SPC880 starts off, appearing to get in much closer, before you add any multipliers.

I tried to shoot an image of Venus with my 80ED and 450d, I had to use 20x worth of multipliers to get anything vaguely visible in the frame without cropping... Whereas with a webcam, you can get results directly attached to the scope (albeit still small) where you can tell what the target is.

You do need to learn to use some software, such as wxastrocapture (for the capture) and registax for the processing, but it's worth it.

I hope that helps, and makes sense.

[RJP6089]

Hi

Thanks for coming back to me so promptly. I under the math and logic used above (i think), but isnt resolution an issue?

The Cannon is something like 14mp but the webcam is only about 1.3mp from what I gather?

[jgs001]

Not really... Yes, the Canon might be 14Mp, and the webcam only 1.3Mp, but after you take the image on the Canon and crop it that far, to get a similar scale, you're probably gonna end up with far less pixels involved... and therefore much lower resolution in the image itself.

Just found some examples...

This is a major crop from my 450d, at 1200mm on my 80ED.. heavily processed and I was lucky to get this much.

and an uncropped image at about the same kit level with a webcam...

[Stargazer51N]

@jgs001

Hi John,

Thanks for posting the two comparison photos as I've recently got hold of an SPC880 and am just waiting for the opportunity (clear skies and work permitting) to have a go at Jupiter. Great to see what I can aim for

[RJP6089]

Will loom into the webcam side of things, but must admit I like the camera side of imaging rather than taking video and using frames (although I appreciate I'll have to eventually).

To answer my original question, can I buy something to increase the magnification down the camera? You reference having used 20x down yours, what attachments are required?

Thanks for your help

[jgs001]

I used 2 of 2x barrows and a 5x Barlow and ended up with a long exposure (over a second) on a planet. As for video, another way to look at it, a video is just a way of capturing a number of photos in quick succession and putting the 1000 or so photo frames in a convenient, single file, container. Some software will capture 1000 image files for you instead but that becomes, to my mind, a major headache.