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Pages: 1 | 2 | 3 | (show all) Orion64 professor emeritus Reged: 11/29/09 Loc: Western Cape, South Africa Ready to give up on AP       #5631286 - 01/19/13 10:37 AM Edit   Reply   Quote Quick Reply   Hi folks, I know this seems a bit drastic, but I am really tired of struggling with the same issue for over a year. I have now spent almost 6000USD on my equipment upgrade. Since then it was only trouble. My system actually only has one flaw, but this makes it impossible to take photos. I have a carbon fiber 10inch f/4 newtonian. I purchased the ASA korr reducer/ corrector. My spacing is perfect, although I tried a lot of spacings. Stars in all corners are perfect, EXCEPT one. The one corner is drastically out of focus with lots coma. I dont think its the ccd. When rotating, the corner gets better but others get worse. The only answer I get is orthogonality. but I have changed everything in my system now. Nothing gets the problem better. I have calculated my correct offset of secondary and used how glatters tools in combo with Jason Khadder's colimation steps to colimate my system. No difference. Should I maybe colimate without offset??????? I must add that I have some focusser sag, but I have tried improving it to see the effect and no change to my problem. The only solution I have to continue my hobby is to do mosaics. This way I can overlay the good part of my 2nd image over my bad part of the 1st image. Post Extras:       vpcirc Carpal Tunnel Reged: 12/09/09 Loc: Merced CA Re: Ready to give up on AP [Re: Orion64]       #5631346 - 01/19/13 11:10 AM Edit   Reply   Quote Quick Reply   Newts are very sensitive to collmanation. The faster the optics the more flaws will show. I wonder if you have a defect in a mirror? Post Extras:       fetoma Carpal Tunnel Reged: 09/26/06 Loc: Southern New Jersey Re: Ready to give up on AP [Re: vpcirc]       #5631588 - 01/19/13 01:32 PM Edit   Reply   Quote Quick Reply   If you have focuser sag, try imaging with the focuser on top of the tube. Post Extras:       guyroch Vendor (BackyardEOS) Reged: 01/22/08 Loc: 3rd rock from the sun, Canada Re: Ready to give up on AP [Re: fetoma]       #5631601 - 01/19/13 01:38 PM Edit   Reply   Quote Quick Reply   Quote: If you have focuser sag, try imaging with the focuser on top of the tube. I have to agree. How much weight do you have from hanging on the focuser? I have the same issue right now with my AT8RC. I put the same gear/weight on my AT6RC and all is fine. But on the AT8RC I can't seem to fix it. I understand your frustration first hand. Guylain Post Extras:       Orion64 professor emeritus Reged: 11/29/09 Loc: Western Cape, South Africa Re: Ready to give up on AP [Re: guyroch]       #5631609 - 01/19/13 01:42 PM Edit   Reply   Quote Quick Reply   I found an adapter that adjusts any tilt that one has in the optical path. So I wihl place my order on monday and try this out. Its not expensive, so its definitely worth giving a go. Tonight is one of those clear wind still nights, however my equipment stays in doors until my adapter arrives. Post Extras:       jjongmans super member Reged: 02/11/12 Loc: The Netherlands Re: Ready to give up on AP [Re: guyroch]       #5631611 - 01/19/13 01:42 PM Edit   Reply   Quote Quick Reply   Are you sure that the sensor is correctly mounted in the camera housing? Post Extras:       SANDRO78 super member Reged: 06/12/12 Loc: RP PARIS Re: Ready to give up on AP [Re: Orion64]       #5631672 - 01/19/13 02:29 PM Edit   Reply   Quote Quick Reply   Effectively, there is a problem on the set up, but I hope that you will arrive has to solve your concern(marigold)?? You have ask advice has ASA or to the manufacturer of the CCD? Go courage!! Post Extras:       Orion64 professor emeritus Reged: 11/29/09 Loc: Western Cape, South Africa Re: Ready to give up on AP [Re: SANDRO78]       #5631746 - 01/19/13 03:22 PM Edit   Reply   Quote Quick Reply   I cannot confirm that there is no fault with the sensor, however,as I stated when I rotate the camera, the unfocussed corners shift to another spot. Post Extras:       zerro1 Postmaster Reged: 08/02/09 Loc: Smokey Point , 48.12°N 122.25°... Re: Ready to give up on AP [Re: Orion64]       #5631785 - 01/19/13 03:40 PM Edit   Reply   Quote Quick Reply   Quote: I cannot confirm that there is no fault with the sensor, however,as I stated when I rotate the camera, the unfocussed corners shift to another spot. I take that to mean that the defocussed location does not rotate with the camera... Do you have this problem without the reducer/corrector? Post Extras:       Orion64 professor emeritus Reged: 11/29/09 Loc: Western Cape, South Africa Re: Ready to give up on AP [Re: zerro1]       #5631847 - 01/19/13 04:47 PM Edit   Reply   Quote Quick Reply   Could not test this because I only have the one reducer. Wouldnt I have horrible coma all over when testing without a reducer? Post Extras:       jmasin Carpal Tunnel Reged: 12/22/08 Loc: Murphy, TX (DFW) Re: Ready to give up on AP [Re: zerro1]       #5631851 - 01/19/13 04:50 PM Edit   Reply   Quote Quick Reply   Brett, Others gave good advice and it seems you have something to try. Don't give up, I have known that level of frustration before, so can relate. It is worth it when you get it right. Jon Post Extras:       zerro1 Postmaster Reged: 08/02/09 Loc: Smokey Point , 48.12°N 122.25°... Re: Ready to give up on AP [Re: Orion64]       #5631916 - 01/19/13 05:29 PM Edit   Reply   Quote Quick Reply   Quote: Could not test this because I only have the one reducer. Wouldnt I have horrible coma all over when testing without a reducer? I would think it should be fairly uniform with well focused good looking stars in the center region and increasing coma radiating to the edge of field. If it looks like a normal uncorrected field then it's possible the reducer/corrector is introducing the distortion You may want to consider just a coma corrector without the focal reduction... Edit:: I'm pretty sure that moonlite sells a really nice focuser assembly that would solve sag without buying a whole new "APO" scope, for somewhere in the $300 dollar range. Edited by zerro1 (01/19/13 10:03 PM) Post Extras:       mmalik Carpal Tunnel Reged: 01/13/12 Loc: USA Re: Ready to give up on AP [Re: Orion64]       #5632228 - 01/19/13 09:15 PM Edit   Reply   Quote Quick Reply   Quote: Ready to give up on AP Don't; here are some thoughts/suggestions, I am afraid you'll have to spend just a bit longer. 1. Ditch your Newtonian; buy or test your setup on an APO if you have access to one. That will rule out the scope. Personally, I am for APOs when it comes to AP; rest are just half measures in my opinion. 2. To rule out it’s not the scope, try a DSLR on the same setup if you have access to one. May borrow one if you can or just buy a good one that you may also keep using alongside the CCD. 3. You seem to have too much weight for your focuser; changing scope with an APO may bring a solid focuser into the picture. 4. Orthogonality of the sensor, if true, will require fixing or swapping your existing CCD with a different one. One of the above should help to confirm/reject that conjecture. 5. Last, but not least; start salvaging your entire setup in favor of starting fresh and recouping some of your losses. Weakest link in your setup are your scope/focuser in my opinion. Some useful links in light of the above: •APO consideration... •DSLR consideration... •DSLR image processing instructions... •Other CCD alternatives... Post Extras:       blueman Vendor Blue Sky Accessories Reged: 07/20/07 Loc: California Re: Ready to give up on AP [Re: Orion64]       #5632327 - 01/19/13 10:16 PM Edit   Reply   Quote Quick Reply   I had my years of frustration with reflectors. Flexure, coma, field curvature all of the problems that you can face, I wrestled with in spades. I finally went to a good APO refrator and never had to deal with these issues again. Am I saying reflectors are bad? No. I am saying they can be very difficult to deal with and life is too short. Blueman Post Extras:       vpcirc Carpal Tunnel Reged: 12/09/09 Loc: Merced CA Re: Ready to give up on AP [Re: blueman]       #5632353 - 01/19/13 10:34 PM Edit   Reply   Quote Quick Reply   I'd ditch the CGEM before anything else! Post Extras:       JWalk scholastic sledgehammer Reged: 06/06/10 Loc: San Antonio, TX Re: Ready to give up on AP [Re: vpcirc]       #5632460 - 01/19/13 11:49 PM Edit   Reply   Quote Quick Reply   Quote: I'd ditch the CGEM before anything else! Don't knock the CGEM!!! It is capable. Couldn't resist Mikey Post Extras:       elbee professor emeritus Reged: 05/02/09 Loc: Arizona Re: Ready to give up on AP [Re: JWalk]       #5632556 - 01/20/13 01:46 AM Edit   Reply   Quote Quick Reply   Quote: Don't knock the CGEM!!! It is capable. uhhh, Paramount? is that the consequence of a close relationship with a CGEM Post Extras:       Orion64 professor emeritus Reged: 11/29/09 Loc: Western Cape, South Africa Re: Ready to give up on AP [Re: elbee]       #5632711 - 01/20/13 07:46 AM Edit   Reply   Quote Quick Reply   Thanks for the replies guys. I have access to an apo refractor. I will try my setup on this in the mean while Post Extras:       vpcirc Carpal Tunnel Reged: 12/09/09 Loc: Merced CA Re: Ready to give up on AP [Re: elbee]       #5632771 - 01/20/13 09:15 AM Edit   Reply   Quote Quick Reply   Quote: Quote: Don't knock the CGEM!!! It is capable. uhhh, Paramount? is that the consequence of a close relationship with a CGEM Yea I started with one those &$$@@%~} mounts. Jimmy is giving me a hard time because he shot beautiful images on one. (He got a good one) I hadn't read Wodaski's book when I started telling me most of money should be in the platform. I was also doing a typical beginner mistake and going for the most aperture I could afford, then reality set in! Once I bought my first AP, I'd never go back to a low end mount. I'd image with a 15 year old APO and a 5 year old camera before I'd image with a poor platform! Jimmy why don't you send that AP1600 with encoders back and put that new RC 16" on a CGEM deluxe? Lol In all fairness, CGEMs have gotten better since I owned one 4 years ago. Post Extras:       JWalk scholastic sledgehammer Reged: 06/06/10 Loc: San Antonio, TX Re: Ready to give up on AP [Re: vpcirc]       #5632818 - 01/20/13 09:41 AM Edit   Reply   Quote Quick Reply   I wouldn't put much on top of the CGEM. I think my FSQ was about at the limit of one. Post Extras:       Pages: 1 | 2 | 3 | (show all)

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