Astronigel Posted March 14, 2017 Share Posted March 14, 2017 I thought I'd give a go at fitting my DSLR to scopes... Do I have to move my main mirrors up their tubes to aquire a focus ? I've tried a 2x Barlow also as I think I read/saw somewhere they can be used to help get a focus without moving primary mirror up the tube but it was still out of focus with that. Link to comment Share on other sites More sharing options...
Guest Posted March 14, 2017 Share Posted March 14, 2017 I find the focal length of a DSLR is about 10cm and probably varies a bit through models. I did not need to make any big adjustments with my telescopes. You can do a lot with telescopes and DSLRs, especially the Moon. Link to comment Share on other sites More sharing options...
+Graham Posted March 14, 2017 Share Posted March 14, 2017 3 hours ago, Astronigel said: I thought I'd give a go at fitting my DSLR to scopes... Do I have to move my main mirrors up their tubes to aquire a focus ? I've tried a 2x Barlow also as I think I read/saw somewhere they can be used to help get a focus without moving primary mirror up the tube but it was still out of focus with that. What scope are you attempting to use. Astronigel 1 Link to comment Share on other sites More sharing options...
+Ibbo Posted March 14, 2017 Share Posted March 14, 2017 https://en.wikipedia.org/wiki/Flange_focal_distance don't forget the T ring adds a bit from the T ring to the chip is about 55mm for a canon depending on the t ring dimensions if you move the mirror "up a bit " you will need an extention to be able to get focus with your eyepieces Astronigel 1 Link to comment Share on other sites More sharing options...
Guest Posted March 14, 2017 Share Posted March 14, 2017 One telescope I find difficult to get focus with is a Coronado PST. Link to comment Share on other sites More sharing options...
Perkil8r Posted March 14, 2017 Share Posted March 14, 2017 Yes, with the PST and dslr there are quite a few issues to overcome. Lack of back focus being one of the main ones. With a reflector though most will probably allow focus as standard albeit very close to the fully inward focus position. Using filters then becomes rather difficult. I've had some quite pleasing results with my 200p and DSLR combo on both DSO's as well as Sun and Moon. Issues arise with reflectors though in that you need a good solid mount if you are going for DSO's with a DSLR. Astronigel 1 Link to comment Share on other sites More sharing options...
Astronigel Posted March 15, 2017 Author Share Posted March 15, 2017 Well, I've been specifically after a canon DSLR for ages now, but...spotted a cheap Sony lol.. With a short holiday coming up I went for the Sony :-/ thinking I can still have a go at astro pics with that for now and if I take to it I could get a canon at a later date The 2 scopes I've tried it on so far are a little cheap 4.5" reflector. And a 12" , which I did think would struggle with focusing as for some unknown reason it finds difficulty focusing with some eyepieces ?? Again it doesn't allow enough travel so do really need adjust the mirror on it or something. It could even be just needing adjustment screws turning, maybe there's enough travel on them to move mirror up a few mm's.. I'm hoping that's the case.. Link to comment Share on other sites More sharing options...
stash Posted March 15, 2017 Share Posted March 15, 2017 Or do you mean Afocal images keeping the eyepiece in place and then using the DSLR ? Astronigel 1 Link to comment Share on other sites More sharing options...
Astronigel Posted March 15, 2017 Author Share Posted March 15, 2017 6 minutes ago, stash said: Or do you mean Afocal images keeping the eyepiece in place and then using the DSLR ? Im trying the way without the eyepiece.. But I suppose I could try this way, saves moving mirrors about their tubes at least for now perhaps. Link to comment Share on other sites More sharing options...
Daz Type-R Posted March 15, 2017 Share Posted March 15, 2017 1 hour ago, Astronigel said: The 2 scopes I've tried it on so far are a little cheap 4.5" reflector. And a 12" , which I did think would struggle with focusing as for some unknown reason it finds difficulty focusing with some eyepieces ?? Again it doesn't allow enough travel so do really need adjust the mirror on it or something. I probably should not be inputting into this conversation as I am just a visual monkey (don't dabble with the dark arts) but in my opinion, if you are struggling for focus with an EP, then trying to get a camera (any camera) to focus would be a nightmare. Focusing an EP is always easier than a camera, if you cant get an EP to focus it could mean there is an issue somewhere, making your task of focusing a camera even more difficult? Astronigel 1 Link to comment Share on other sites More sharing options...
Guest Posted March 15, 2017 Share Posted March 15, 2017 11 hours ago, Perkil8r said: Yes, with the PST and dslr there are quite a few issues to overcome. Lack of back focus being one of the main ones. With a reflector though most will probably allow focus as standard albeit very close to the fully inward focus position. Using filters then becomes rather difficult. I've had some quite pleasing results with my 200p and DSLR combo on both DSO's as well as Sun and Moon. Issues arise with reflectors though in that you need a good solid mount if you are going for DSO's with a DSLR. I've been known to use a camera tripod to provide extra support but this cannot work with a driven mount. Link to comment Share on other sites More sharing options...
Astronigel Posted March 15, 2017 Author Share Posted March 15, 2017 Its only the high power short fl eyepieces that dont focus as there's not quite enough travel with the focuser. Its a bit of a case of maybe I should move mirror up.. Take account of possibly using a DSLR with it and solve the high mag eyepiece issue at same time ? Link to comment Share on other sites More sharing options...
stash Posted March 15, 2017 Share Posted March 15, 2017 3 hours ago, Astronigel said: Im trying the way without the eyepiece.. But I suppose I could try this way, saves moving mirrors about their tubes at least for now perhaps. OK - IMO you shouldn't need to move any mirrors no matter which way you choose Afocal or prime focus. Your scope should have a focusing tube and some knobs that allow this tube to be moved in and out - this should be used to focus on an object. The first mistake I made was to do too much movement - as the saying goes "slowly slowly catchy monkey". I would also suggest try focusing on distant objects during the day(its alot easier!) and when you have found focus mark the draw tube. So long as you use the same bits and bobs you will not be far out. All you have to do then is (ALL ) is to set the exposures and ISO settings - remember to use "manual" auto exposure will not help especially at night. Hopefully you camera will have a live view screen as this helps to focus during the testing day time shots. Remember adjustments should be small as its easy to miss focusing. Once you have mastered day time use progress to something like the moon which is big and bright and is not easily missed ( i did lots of times so dont worry). As the moon is very bright you will need to adjust your settings so that the exposure is short say 1/200 and use iso 100 - you can always adjust the settings once focused. And the biggest hint is have patience ( I haven't much!) but this will help. Even using Eye pieces ,buy especially high power, again its small movements with the Focuser is the key IMHO If all else fails go to your local Astro club night they will gladly help - we are started at the same point and it will get better. Good luck and clear skies. Astronigel 1 Link to comment Share on other sites More sharing options...
tuckstar Posted March 15, 2017 Share Posted March 15, 2017 Not an imager but i used to have a 130 skywatcher newt and those people that have used for imaging had to move the mirror up the tube as there wasn't enough inward travel to achieve focus, a friend had to do the same to a Tal-1. Astronigel 1 Link to comment Share on other sites More sharing options...
Astronigel Posted March 15, 2017 Author Share Posted March 15, 2017 Yes it actually gets no where near into focus with camera ... Focuser all way in and image fully blurred still Link to comment Share on other sites More sharing options...
stash Posted March 15, 2017 Share Posted March 15, 2017 I stand corrected http://astronomy.stackexchange.com/questions/11709/astrophotography-unable-to-achieve-focus-with-current-setup Astronigel 1 Link to comment Share on other sites More sharing options...
Astronigel Posted March 15, 2017 Author Share Posted March 15, 2017 46 minutes ago, stash said: I stand corrected http://astronomy.stackexchange.com/questions/11709/astrophotography-unable-to-achieve-focus-with-current-setup Thankyou, bit depressing read tho, almost a " scrap your idea and buy a new one " lol... But no... I'm not giving in, I'm going to get an image somehow... I going to have a play about with my scope, see if I'm able get the mirror moved up via its adjusting screws firstly ...before I take a saw to it haha Link to comment Share on other sites More sharing options...
+Bino-viewer Posted March 15, 2017 Share Posted March 15, 2017 With my Orion Optics 10" Newt, i can reach focus quite easily using my Canon DSLR. There is also a provision for raising the mirror up the tube if required, but its on the bottom setting. Standard Orion focusers won't allow most eyepieces to come to focus, so they supply an extender. Link to comment Share on other sites More sharing options...
Perkil8r Posted March 15, 2017 Share Posted March 15, 2017 42 minutes ago, Bino-viewer said: With my Orion Optics 10" Newt, i can reach focus quite easily using my Canon DSLR. There is also a provision for raising the mirror up the tube if required, but its on the bottom setting. Standard Orion focusers won't allow most eyepieces to come to focus, so they supply an extender. Likewise with Skywatcher. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now