Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.



New Members
  • Content Count

  • Joined

  • Last visited

Community Reputation

2 Neutral

About astolpho

  • Rank

Profile Information

  • Gender
  1. Thanks for the input guys. Yes I do use the Orion TOAG and if that 0.5mm won't affect it then I should be fine. I'll test it out when I have some clear skies. Thanks again guys!
  2. Hey guys, So after checking some diagrams, the distance is 0.5mm not 1.5mm. Does that affect the back focus distance on a SCT? Does it have to be EXACTLY at the 133 or 105mm with the reducer or that 0.5mm is ok to work with? Thank you!
  3. Hey guys quick question, I own a Celestron EdgeHD 8" OTA and I have a question on the back focus for AP. Originally the back focus is set at 133mm (5.25 in). Adding the focal reducer brings it to 105mm (4.133 in). I'm setting up a OAG with the system and my distance is basically 1.5mm more than the 133 or 105 distances. Does that affect it at all or is there a "margin of error" on that? I'm using the EdgeHD T Adapter and a thin off axis guider ring (from Orion) for my system. The OAG is identical to a T-Ring for a camera except that is normally at M48 threads on the scope side and adding the step down ring to a T-Thread adds the 1.5mm. Is the EdgeHD T Adapter longer than the regular one for a C8? If yes, could maybe getting the regular one and adding t thread spacers to get to 105 or 133 work? Thanks in advance everyone!
  4. Alex I wanted to give you an update on the OAG. Now yours is a different brand than mine but you might run into this small predicament. The OAG I got can be disassembled almost entirely. The OAG itself has M48 threads on both sides. The camera side is fine; the EOS bayonet fits right in and it goes into the camera. The other side however, also being M48, you cannot screw the Celestron EdgeHD 8" T-Adapter, just as you would normally do to the T-Ring. So the kit I got comes with a step-down ring from M48 to T2 so then I can attach either the whole T-Adapter or unscrew the smaller piece and thread the longer one directly when using the focal reducer. You don't need to use that step-down ring in a regular T-Ring because it's already a T-Ring and while that ring is thin, I didn't get a chance to measure it, it adds distance to the whole "keeping back focus at 133 or 105 mm with the reducer." Using Celestron's T-Adapter directly on the OAG there are 2 issues: first I checked and the threads are long enough so that if you screw it in all the way it does actually hit the bar where the prism is. I removed the prism part, screwed it all the way in and tried to slide it back in and it wouldn't go. Second, the M48 to T2 step down ring adds to the length of the OAG throwing the back focus off (I'm assuming since I haven't tested it) Now without the focal reducer, I was doing some measurements on the Celestron smaller t-adapter piece and from the beginning of that "lip" it has to the end of it is about 29 mm from what I could tell. The Orion OAG came with a 20 mm t-adapter extension, so I'm missing the 9 mm and I found an Orion T-thread extension kit which comes with a 5 mm, 10 mm and a 25 mm extension. I'm thinking that if add the 10 mm extension and be at 30 mm I believe I should be fine since there's a +1, -1 error margin on the back focus from what I've read. Now, with the focal reducer where you remove that shorter piece and only use the longer one, I'd have to get another one identical to it, minus the length of the step down ring that goes into the OAG to get the back focus at 105 mm or I'll be possibly at 106 or so (the step down ring is reaaaaallly thin). The plus on using just the longer part of the adapter is also the threads are not as long as the shorter piece and screwed all the way in does NOT hit the prism bar like the shorter part of it does, or I could live with threading it directly onto the OAG and since the step down ring is so thin I think I would be ok, but hitting that prism bar not only adds just a bit more to the length but also might damage it (the reason I'm getting that T extension kit). Anyways, long read! Let me know how your OAG is and if you run into similar issues. I think the 1 mm difference won't matter but I'm not experienced enough to answer that..
  5. Tell me about it.. They love to complicate things don't they.. But let me know how yours work out!
  6. So I got the OAG today and while I didn't get a chance to try it out on the field it looks perfect. Only thing is the nose piece it came with. It seems standard for most scopes (the length of it) but it is shorter than the T-Adapter that you get with the Celestron T-Ring for the EdgeHD 8". So I attached the EdgeHD T-Adapter directly to the OAG and it seems to fit perfectly. There is more thread on the Celestron T-Adapter than the one it arrived with that is shorter but it doesn't hit the prism piece so it looks fine. Tried the setup with the focal reducer by removing the shorter half of the Celestron T-Adapter (which is the one that is a bit longer than the one the OAG came with) and threaded the longer T-Adapter piece directly to the OAG and it was a perfect fit. Same situation as far as the amount of thread on the adapter, more than what the threads are on the OAG rings but doesn't hit the prism. Looks like that once I get it up and running it will be just a matter of minutes to find the correct height for the guider piece of the OAG to get them both in focus! Will update here once I try it out.
  7. From what I read, the EOS adapter goes in camera thread all the way just as a regular T-Ring and the size of the OAG is identical to a regular T-Ring so it's a "T-Ring with a OAG". I'll see how it works out Monday when I get it.
  8. Sounds good! Let me know how it works out! I was close to hitting the submit button to order it and ended up finding this: http://www.telescope.com/Orion-Thin-Off-Axis-Guider-for-Astrophotography/p/102812.uts Seems identical to those 2 but for us here in the US! Comes with all adapters too, including one for the EOS! I receive it Monday and then I'll post a review of it.
  9. Alex, I also found this: http://www.teleskop-express.de/shop/product_info.php/info/p1188_Off-Axis-Guider---only-9mm-length---with-Canon-EOS-adaptation---Special-Offer.html Same design of the OAG, but this one you can also choose 3 different locations for the guider to be set to. A bit cheaper on the price as well (at least for me here in the US). I'll keep this thread updated once I get it!
  10. Alex, That is awesome! I did see that before but I didn't know they had it with an EOS adapter directly attached to it. It's basically a "very expensive t-ring" from what I see but it definitely would work like the Celestron diagram shows I'm in the US and can't find anywhere out here to buy it but saw it at teleskop's website in Germany for about 245 U.S. dollars shipped to here. The site you mentioned said it works with the Orion SSAG but I'm thinking it's not going to be sensitive enough to get some stars and from the looks of it, being so thin, it's not like you can freely rotate the guider axis around. Anyone that has that "OAG ring" that could share the experience you've had with it? But definitely a way to do it! Thanks Alex!
  11. Thank you for the quick replies guys! I happen to live "across the pond" as a fellow astronomer here in the Forum delicately put and astrobuysell seem to work pretty much in the UK, Australia and Canada. Someone else mentioned Astromart for us here in the US so I'll be checking that out. Thanks a lot!!
  12. Hey guys, Just out of curiosity, for those of us that end up upgrading our setup and such, is there a particular website that most of us astronomers go to post things like classifieds? I know eBay exists for auctions but maybe something more astronomy-only? Thank you
  13. astolpho

    Hello everyone!

    Hey Michigander! Not really! Lol! I'm originally from Brazil so major soccer fan. Also basketball.
  14. Thank you for the suggestions guys! I did think about going CCD, I believe the imaging chip is a lot closer than the regular 55mm of a DSLR. I don't want to break the bank though, what are some recommendations? The OAG is already 250 plus a new CCD and an another one for guiding (since my Orion SSAG isn't sensitive enough..) and it gets quite pricey. What do you guys think of the Orion G3 Deep Space color for imaging and the ASI120mm for guiding? Or any other suggestions on that price range? The back focus from the t thread on the G3 according to Orion's website is 19mm so that might work? But using the t thread isn't it more of a fixed distance once I screw it in? Probably won't add up to the exact 103mm and forgive my stupidity, I don't know the name of the other thread which just sides in and out like an eyepiece and I tighten the knobs once I reach 103mm and then adjust the guiding camera accordingly? I'm learning as I go along but what do you guys think?
  15. I'm in the United States but I'm interested in this OAG for one reason: I have a Celestron EdgeHD 8 with the .7x focal reducer. Celestron's OAG is too long for me to be able to achieve the required 105mm back focus when using the reducer. I'm using a Canon 700D (T5i) Could anyone help me figure out to see if this OAG would work? And which adapters would I need to achieve focus with and without the focal reducer? Maybe a stupid question but does the length of the back focus has to be exactly at the 105 with the focal reducer or 133 without or could it be shorter and then I can adjust the focus knob? Or are they different things focus knob and back focus distance? Thanks in advance!
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.