Projection astrophotography

[Si Rollett]

Hi everyone, been a while but I am back.

I am looking at buying the equipment / Adaptors to do some projection photo's using my scope and ep's I have a t ring and t adaptor for my Canon DSLR but with the scope being basic I don't have the magnification just using the camera with it, Id like to get some shots a little closer up?

Can anyone please help me

[Peter Drew]

Eyepiece projection is a good way to get a larger image scale but the problem remains as to how to attach the camera to it. Some Barlow lenses have a T thread on them which is another method of increasing the image scale. 

[Si Rollett]

I have read about adaptors that take an ep's but I haven't a clue where to get them or even if you can?

[Alien 13]

This is the one i have http://www.scsastro.co.uk/catalogue/orion-universal-camera-adapters.htm

Alan

[Langy]

Some here too but out of stock.

This here should is the search on eBay.

However I would be interested to know how big projection would actually make it? If I stick my cheap xBox webcam with a 2x Barlows an image of jupiter is bigger that what I can get with my best EP and 2x Barlows which is around 160x magnification.

[Andy Milner]

Hi can I chip in? This is relative to the topic. I have a Celestron Zoom lens ( here's a link http://www.celestron.com/astronomy/celestron-zoom-eyepiece-1-25-in-8-24mm.html )

Does anyone know if it will fit in a projection adaptor? I've read that some EP's maybe too big. If love to know if anyone out there would know? Alternatively I will speak to my nearest drive to astro shop. Cheers.

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[Alien 13]

Hi can I chip in? This is relative to the topic. I have a Celestron Zoom lens ( here's a link http://www.celestron.com/astronomy/celestron-zoom-eyepiece-1-25-in-8-24mm.html )

Does anyone know if it will fit in a projection adaptor? I've read that some EP's maybe too big. If love to know if anyone out there would know? Alternatively I will speak to my nearest drive to astro shop. Cheers.

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The internal diameter of the orion one is about 38mm so some barlows/eyepieces wont fit unless you can unscrew the lens cell.

Alan

[wxsatuser]

Another way of doing it.

If you can run to EPs like Baader it's easy just to mount the camera directly onto the EP.

Baader need a 43mm adapter then t-ring, you can of course add extensions if needed.

http://www.firstlightoptics.com/user/baader_hyperion_imaging.pdf

[Langy]

With projection are you using a camera without the lens like prime focal or with the lens still on like afocal?

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[PeterCPC]

If you do eyepiece projection you using the camera without the lens. You fit a telescope eyepiece inside the EP and then the camera onto the back using a T ring. The EP then just goes into the telescope focuser just like a normal eyepiece. I have one and I must say that it is not as easy as just using a Barlow. The focusing can be tricky and, of course, it adds more weight to the rear of the scope which affects balance. I got mine from Opticstar. Check what diameter of lens the EP will accept as lots of eyepieces will not fit.

Peter

[Ant]

I did this last weekend, and managed to cobble something together using the bits I had lying around. Took me days to get it all attached and it looks a mess, but it did work.

Just need to refine things.

http://stargazerslounge.com/topic/210904-increasing-the-image-scale/

So in the image train is

Scope, eyepiece projection tube with 12mm Hutech EP, various adapter to connect threads together, DMK21.

If you think of eyepiece projection as projecting the image from the eyepiece directly onto the camera chip. All the bits in between are just there to hold everything square.

Cheers

Ant

[Ant]

Here was the difference between the two methods projection on the left and normal prime focus on the right. I do have quality issues as the image was so feint, just introduced noise.

But I'm working on that.

Cheers

Ant

[wxsatuser]

Here was the difference between the two methods projection on the left and normal prime focus on the right. I do have quality issues as the image was so feint, just introduced noise.

But I'm working on that.

image.jpg

Cheers

Ant

The image gets fainter as more extension is added, as well.

[Cornelius Varley]

This web page gives the maths behind eyepiece projection http://geogdata.csun.edu/~voltaire/ann/projection.html

[Langy]

This all sound pretty interesting

However I feel that the real downfall in this after you have spent all the time and money on getting your DSLR to work with EP Projection and focusing will be the EP.

So where a prime focus image should be pretty flat in the focus range there could be some major issues with the curvature from the EP resulting in only the very centre of the image actually being the only useful part.

Perhaps someone can comment on the above.

Also is there a big difference in size / quality of doing EP Projection compared to AFocal?

For example I have a very good digital compact camera even though it is 10 years old. Shoots in RAW if required, has just about all the controls you would find on most DSLRs and fits to the EP rather well. You can buy a mount like this for any camera that has the tripod thread allowing you to be precise with your alignment to the EP.

Below are a couple of images that I did with AFocal on that camera, the moon was hand held and Jupiter I stuck the compact camera on a tripod so spent ages tracking Jupiter and moving the camera / tripod to line up with the EP. Having the mount I linked above would have solved all that.

AFocal seems to be the first thing everyone has a go at, in most cases the first time we look through a scope and get the phone out. So I was wondering how they both compare and if using that method could be used more by using the above linked mount.

Sorry for taking over the thread, but hopefully it just puts some comparisons on the original question and gives a good reason to choose which ever path.

[Si Rollett]

My scope is only a Cel 70az, so as you can imagine its not got much poke with just prim so I need to put a ep in between.

[Peter Drew]

I think you might struggle a bit with the stability of the 70AZ mount so don't go overboard on the magnification.     

[Si Rollett]

Max usable is about 10mm ep unless I am in the middle of Africa :-) thinking might just add a barlow

[Si Rollett]

Max usable is about 10mm ep unless I am in the middle of Africa :-) thinking might just add a barlow

between the scope and camera?

[Si Rollett]

Think just a simple cele x2 barlow adapter?

[PeterCPC]

Sometimes just a simple extension tube can add to the magnification but I also have concerns about whether the mount would be able to cope with it. You are adding weight to the end of the scope which should be balanced out with added weight at the other end.

It might be possible to increase the image during post capture processing. 

Peter