Anyone imaging with a fast reflector?

[MidnightSun]

I know I can't be the only one, so I am wondering what kind of setup you have as far as getting to focus. I have an 8", 1000mm fl, f/4.9, with a 2" focuser. I wound up fabricating my own lo-profile adapter that screws into the housing of the 2" focuser ( after removing the E.P. adapter) by using half of an OM-1 T-ring I had and half of an EOS adapter. This gives me about 1/4" of focusing, which is fine, but it is a pain to have to screw the whole camera into the housing, (as opposed to using a T-ring and popping it in like an E.P.) plus I cannot put any filters in it. I haven't been able to find one that will adapt the 350D to the 2" focuser and also accept a filter, and actually come to focus. . The one I made from the OM-1 doesn't have threads for filters. So......

Without moving the mirror...., how have you worked around this? New focuser? I've been asking around for 2 yrs. now and really haven't found any info except maybe getting a new focuser. If there would be enough difference from my "stock" focuser that I could use a T-ring and just drop in the camera like an E.P. and not have to screw it in, I'd buy it in a minute. Just wanted to hear from someone else who has run across this. Thanx...

__________________

[ngc2403]

i have not had this problem but i would not think that a new focusser would solve all the problems unless it is particulary large? moving the mirror seems like a better idea to me that way you know it will work

[philsail1]

Hello Dave,

I have an 8" Orion Optics f4.5 "Europa" reflector. My tube length is 850mm.

I only do "afocal" astrophotography so don't have any problems with achieving focus or using filters etc.

I know nothing about imaging, so can only suggest, possibly considering changing your astrophotography method to a webcam or other imaging system?

Regards,

philsail1

[Neil I]

Hi Dave

I have a similar OO scope as Philsail1. It's fitted with a 2' crayford focuser and I use a Canon 1000d on a t-ring directly in the focuser. Never had any problem getting to focus. Let me know if you want more info.

Cheers

Neil

[ngc2403]

Hello again, Dave,

FYI, Orion Optics tend to make there reflectors with extra back focus to allow DSLR's to focus along with Filter wheels and the like am not sure that Orion USA do that?

Question do you need an extender to focus up your EP's? My 10'' f/4 Newt needs one and the result is the EP is about 8'' to 10'' from the tube.

can you post an image of a EP focussed in the telescope? to see how big the focusser is? and how far out it is

ally

[dark knight]

To save having to screw the camera to the 2" focuser I use an extension tub which houses an eyepiece, camera via T - Ring at one end and a spare 2" to 1.25" with the 1.25" bit removed at the other. The extension tube is telescopic so allows for plenty of outward travel. Telescope is 200p f5. pm me if you want a picture. This is essentially afocal but the advantage is the weight of the camera is held more robustly and does not put strain on the focuser eyepiece. I tried the other way by screwing directly to the focuser (ala prime focus) but could not get enough inward travel to get focus. My camera is a Nikon D80 btw.

[MidnightSun]

Hello again, Dave,

FYI, Orion Optics tend to make there reflectors with extra back focus to allow DSLR's to focus along with Filter wheels and the like am not sure that Orion USA do that?

Question do you need an extender to focus up your EP's? My 10'' f/4 Newt needs one and the result is the EP is about 8'' to 10'' from the tube.

can you post an image of a EP focussed in the telescope? to see how big the focusser is? and how far out it is

ally

Thx...First pic is an EP at focus distance, about an inch of travel from bottom. 2nd pic is what must be screwed out, and camera screwed in, with silver showing on focuser how close to bottoming out until focus w/camera is reached.

[MidnightSun]

And here is the camera attached, at focus...

[ngc2403]

Hmmm, i have never seen anything like that before.

i think that a new focusser (assuming that it was the same width) would solve that problem. in that it would mean that the focusser tube would have screws in it already just like the EP adapter that you pictured has, and you could just slide in EP or Camera and tighten the screws.

However i think i like the look of what you have there, if the camera is screwed in then there is less chance it will move over time and that is something i find happens to me after a slew of the scope i need to refocus.

maybe if it is not causing you to many problems then you should keep it? if buying a new focusser is going to be about the same as a new scope then perhaps you might want to just save your money for a new scope?

also given that you can get clip in filters for the Canon, they go inside the camera,

Astronomik CLS Light Pollution Filter for Canon EOS Cameras - 8H001C - OPT Telescopes

then there might be no need for the new focusser?

[ngc2403]

or this on which shows you were and how to use it

Astronomik 6nm H-Alpha CCD Filter for Canon EOS Cameras - 8H00IO - OPT Telescopes

[MidnightSun]

maybe if it is not causing you to many problems then you should keep it? if buying a new focusser is going to be about the same as a new scope then perhaps you might want to just save your money for a new scope?

I am looking at focusers because I still can't believe I'm the only one with this issue.... The only pain is after centering an object, then I have to unscrew the focuser adapter and then screw in the camera with as little disturbance as possible, then get the autoguider going. I have gotten pretty good at it, but it is a pain just the same, especially in winter, that seems like it shouldn't be that much trouble.

And thx for the filter tip, I'm gonna look into those....