Long time *VERY* amateur astrophotographer intro.

[CharonPDX]

First, I've never owned a decent telescope - and definitely nothing with a camera mount, or a motor. All manual-operation for me!

And I just got my first interchangable-lens digital camera - A Nikon 1 AW1. (I had a Canon AE-1 Program back in the 35mm days, with a decent long lens, but did little astrophotos back then.)

All of my photos are either "camera with stock lens on tripod pointed at sky" or "camera on tripod pointing in to eyepiece of mediocre telescope". So I'm not going to approach anywhere near the awesomeness of many of your pictures. But it's a fun hobby. And maybe, possibly, someday, I'll get a telescope I can mount the camera to, with a proper motorized tracking system.

Last night I got a picture of Comet Lovejoy, but by the time I remembered it was in the sky, the sky was already too bright from the moon to get a good shot. It's just a green smudgy-blob.

I live in the city, one famous for being cloudy, at that, so I don't often get a good chance at star pictures. But I've gotten a few decent ones over the years.

I have made a gallery here that I will strive to keep up to date. Although, because of the weather, I may not get any new pictures for months at a time: http://www.dpreview.com/galleries/9821563049/albums/stellar-cartography

 

[starman1969]

Some decent pics there. Orion looks nice and sharp & along with a very good capture of Comet Lovejoy.

It looks like you caught a piece of the Teapot asterism with the pic taken from your backyard. The famous Lagoon Nebula can be seen just above it's 'spout'

 

[Andy C Knight]

All of my photos are either "camera with stock lens on tripod pointed at sky" or "camera on tripod pointing in to eyepiece of mediocre telescope". So I'm not going to approach anywhere near the awesomeness of many of your pictures. But it's a fun hobby. And maybe, possibly, someday, I'll get a telescope I can mount the camera to, with a proper motorized tracking system.

One thing you can try now is... "Camera taped to mediocre telescope tube, with stock lens attached".

Using Wide to normal focal lengths on the camera (i.e. equivalent 28-50mm), look through the Scope with a high power eyepiece on a defocused bright star and carefully keep it centered.

Back in the late 80's, I used this method to do time exposures on the night sky with film. I only had a 60mm Tasco "department store 575x" Telescope, but with practice I could expose for up to a minute or so with a 55mm lens.

Note the scope had no slow motion controls. I just sat comfortably and carefully moved the eyepiece by hand. I used a cable release to start/end the exposure, but you could use the 10 sec timer.

I live in the city, one famous for being cloudy, at that, so I don't often get a good chance at star pictures. But I've gotten a few decent ones over the years.

I know what you mean living in the 'not so' sunny UK! - Although I never did work out, how the clouds always knew when I had a new Telescope or lens to try ;-)

I have made a gallery here that I will strive to keep up to date. Although, because of the weather, I may not get any new pictures for months at a time: http://www.dpreview.com/galleries/9821563049/albums/stellar-cartography

Nice... Keep up the good work.

Good Luck and Clear Skies

Regards

Andy.

 

[Yowie Wowie]

Would reversing my 50mm lens on the camera taped to the cheap telescope tube work better? As in, I would get more of the image on the sensor right?

I don't have a reverse ring to try it out yet.

 

[Andy C Knight]

Would reversing my 50mm lens on the camera taped to the cheap telescope tube work better? As in, I would get more of the image on the sensor right?

I don't have a reverse ring to try it out yet.

I'm not sure why you would want to reverse the 50mm lens... The only reason to do this (as far as I know), would be to do something like macro work with (say) little critters.

I was not very clear, in my previous mail.

The camera lens would be attached to the camera as normal. The camera would only be attached to the telescope tube, such that the camera looks in the same direction as the Telescope. It does not look through the telescope - it just rides 'piggyback' on the tube.

In the case of my 'cheap and nasty' 60mm Telescope - In the end I made a little wooden platform, which used some plastic drain pipe clamps to attach it to the telescope tube. In the center was a hole and a suitable bolt for the camera tripod mount screw.

This 'piggyback' method allows longer exposures (than normally possible) with 'wide angle' to 'normal' lenses. (i.e. equiv. 28-50mm) 1 to 2 minute exposures are possible (near the celestial equator) where normally the limit is only about 10-20 secs, before trailing occurs.

Note: At the celestial equator image rotation will spoil shots longer than about 2 mins. At higher latitudes, exposure time must be reduced. (the limit at the north/south pole is about 30 secs) However you can take multiple shots and 'stack the best' using 'Deep Sky Stacker" (free software available on the net).

Regards

Andy.

 

[Yowie Wowie]

I'm not sure why you would want to reverse the 50mm lens... The only reason to do this (as far as I know), would be to do something like macro work with (say) little critters.

Probably because I have no real understanding of what I am doing yet. I am used to being able to pop out an eyepiece and stick a digicam with optical zoom down the tube of a microscope, and I assume the same with a basic telescope. But the DSLR is slightly too large for that

So, I removed the focus slider, and pointed the DSLR down the tube. The problem is, I had to stick the camera quite far away in order to focus through the optics of the toy scope, and I only get a small magnified part of the image. It looks like using an occluded eye ACOG scope. At night time, I found it impossible. I figured using it in macro mode will allow me to move the camera much closer to the point I need to be to focus, and see more of the telescopic image.

 

[Andy C Knight]

I'm not sure why you would want to reverse the 50mm lens... The only reason to do this (as far as I know), would be to do something like macro work with (say) little critters.

Probably because I have no real understanding of what I am doing yet. I am used to being able to pop out an eyepiece and stick a digicam with optical zoom down the tube of a microscope, and I assume the same with a basic telescope. But the DSLR is slightly too large for that

So, I removed the focus slider, and pointed the DSLR down the tube. The problem is, I had to stick the camera quite far away in order to focus through the optics of the toy scope, and I only get a small magnified part of the image. It looks like using an occluded eye ACOG scope. At night time, I found it impossible.

OK - now I think I understand... There are two different things trying to be done here!!

My previous posts have been how to mount a camera 'piggy back' (i.e. NOT looking through the scope) such that you can follow the motion of the night sky and hence expose for longer.

You appear to be interested in how to do 'prime focus' photography with a toy telescope. (Although your description seems a little different)

I don't know how bad the optics are, so there may well be other limitations you will come across... But you have already discovered the first two - limited backfocus and image circle size.

Both of these can be improved upon by fitting a 'barlow lens' - do you have one? Note this will give more magnification, so the image will be both dimmer and less detailed... But worth a try I suppose.

To get better results, you really need to shorten the tube and use a focuser of a much larger diameter. (and even then you may find the telescope lens has a too curved field of view). It would be better to get another Telescope, but I'm sure you have already worked this out... unless you enjoy the challenge! ;-)

I figured using it in macro mode will allow me to move the camera much closer to the point I need to be to focus, and see more of the telescopic image.

Yes this would technically work, not sure how good the results would be though. You will probably need a reasonable spacing between the front of the camera lens and the sensor. You would also ideally set the focus of the camera lens (unless it's a simple focusing prime) to the correct distance.

(i.e. with lens fitted to camera normally, focus the camera on something at this 'sensor to front element' spacing before reversing.)

If you have a good eyepiece (e.g. say a 25mm Plossl) - you can try 'eyepiece projection'. Here you fit the eyepiece to the telescope as normal and attach the camera to the eyepiece without a lens fitted on the camera. The spacing between the eyepiece and camera sensor sets the magnification. The more distance, the more magnification and more of the sensor will be illuminated. It's basically doing the same job as your idea with the reversed camera lens.

Regards

Andy.

 

[Yowie Wowie]

Thank you, a very informative reply, you have given me much to look into, it helps a lot!