Newbie needs help - focus problem

[PKay (Peter)]

Hi All
Firstly, thank you for a very informative and interesting forum.
I cannot focus my camera / lens set up on the stars. All I get is noise either using live view, or through the laptop.
I shone my red torch into the scope and I could see the red light in the image, so that says I haven't left a cap on.
I tried during the day and I could focus on a target about 1km away.

Camera settings: I tried full idiot mode, Program mode, Manual mode (30", F00, ISO 3200)

Any ideas?

[Mickoid (Michael)]

Are you changing anything when you try to focus at night? Apart from your exposure settings, I would have thought if you can focus on something 1km away during the day, then that position should also focus on stars at night. I notice you have an eyepiece in your T adapter. Do you plan to do some planetary work? If you just want to shoot DSOs then it's best to remove it unless you have some amazing tracking setup.Once you introduce an eyepiece into the ootical chain, your effective f ratio rises sharply and the amount of light that reaches your sensor is reduced.

The fact you can focus during the day and not at night could simply be because you can see the image a lot brighter as apposed to the darkness of the night sky. Try to get focus on the moon, it's bright and big, much easier than trying to focus on a star. Use liveview rather than the optical yiewfinder of your camera, that way not only can you focus more easily but you can change the camera settings to make the object you're focussing on bright enough to see.

[billdan (Bill)]

Hello Peter,

I'm not sure what you are trying to do by leaving the Hyperion lens on.

For prime focus photography with a telescope all you need is a T-adapter attached to the camera and the telescope then becomes your lens.

This is a photo from the Bintel website that shows what is required.

https://www.bintel.com.au/product/t-rings-dslrs/

Cheers
Bill

[rustigsmed (Russell)]

not sure peter, most people don't use any lenses for photography unless they are doing planetary work, as it increases the magnification and increases the f ratio quite a bit (and make things very dark). I think with a 13mm it would be substantial but I haven't done the maths.

might be best to try it on the moon. or go to prime focus.

and welcome to the forum!

Russ

[glend (Glen)]

Whoa there. That seems to be a Hyperion Projection EP and thus should be suitable for imaging provided you have the infocus or outfocus necessary for the eyepiece to reach the focal point. The important question is does the Hyperion EP reach focus ok if you use it visually. If it does then the only issue should be the spacing to the camera sensor from the top of the Hyperion. Baader has a paper on their website on how to set up Hyperions. I used to have that EP and i know it works. The Canon requires 55mm of spacing between the top of the Hyperion to the sensor.
Now if the Hyperion does not work visually you may have a focal point problem.
You could do the "paper test" to establish where the scope focal point is (basically hold a piece of paper above the focuser tube, with the scope aimed at the Moon, move the paper in and out to see if you can find a focal point where the Moon's image appears sharp on the paper - that is your native focal point). If you cannot achieve that, then it is likely that the focal point is too far inward for the use of any T-Adaptor and extension tube. A projection eyepiece (like the Hyperion) might still be able to pick it up further down the focuser tube but if you see nothing racked fully inward then I would suggest you can't reach focus with either technique.
If your determined to do it, you could try moving the primary mirror up the tube towards the focuser (this will move the focal point further up the focuser tube) ; this can be done somewhat by simply letting out the mirror springs so that they push the mirror more towards the focuser, but there are limits to this travel of course. If you let the springs out to max travel and redo the test, it may allow you to achieve focus. Do not let the springs out so much that the mirror comes loose because you lose adjustment screw range. There are ways to move further, longer screws, longer springs, but you need to ask yourself is it worth the effort, as any visual use is likely to require constant extension tube use in the future if setup that way.

[Nebulous (Chris)]

Hi Peter,

As others have said, there looks to be more than you need in the chain there (but that's just a newbie guess on my part).

I've also just started to try and get shots through a telescope and had exactly the same trouble as you. Initially I couldn't see anything but noise through live view.

As Russell said, the moon was a far easier target to begin with. Plenty of light and easy to focus on. I had no trouble there.

With live view of general stars it was just persistence. The regular lens found focus at a completely different position and I had to slowly work through the range before I found the sweet spot. This wasn't helped by the weight of the camera affecting the efficiency of the adjuster, until I changed the tension a bit.

I also experimented with different ISO settings (1600 was a good starting point) and exposure times (much shorter than I first thought - only a couple of seconds through my 150/750 Newtonian). I had almost given up on getting live view to work at all, when - bingo - I found the right spot. It also helped to boost the image magnification in live view. My camera gives the options of x5 or x10. x5 seemed good.

Keep experimenting and you should find it. Good luck. And

[PKay (Peter)]

Thank you all for replying.
I have ordered a camera adapter that will take the eyepiece out of the chain.
I can't wait to get some images!

[PKay (Peter)]

More to this discussion (or the plot thickens).
I just found that with the hyperion modular lens, the end (or adapter) screws out!
It would have been blocking most of the light.
Maybe that's why they call it modular??

Will try tonight...

[rustigsmed (Russell)]

Originally Posted by PKay

More to this discussion (or the plot thickens).
I just found that with the hyperion modular lens, the end (or adapter) screws out!
It would have been blocking most of the light.
Maybe that's why they call it modular??

Will try tonight...

just remember you probably wont get anything stellar because of the magnification, stick to planets and the moon

[glend (Glen)]

Yes removing the 1.25" adaptor and inserting the 2" tube in the focuser will move the camera sensir closer.