Click here if you are having trouble logging into the forums Cloudy Nights - Official Forums of the 2009 International Year of Astronomy Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User   You are not logged in. [Login] Entrance · Main Index · Search · New user · Who's Online FAQ · Calendar Equipment Discussions >> Video and Electronically Assisted Astronomy Previous   Index   Next   Threaded   Pages: 1 gavbray sage Reged: 12/31/06 Posts: 232 Loc: Gold Coast, Australia MFR4 field of view       #2364870 - 05/01/08 05:40 PM Attachment (36 downloads) Edit   Reply   Quote Quick Reply   I use TheSky6 and setup some field of view indicators for the Mallincam. My understanding is the PAL chip size is 7.4mm x 5.95 mm (768 x 494 pixels). I also understand that the Mallincam's FOV is roughly equivalent to an 8mm 50 degree eyepiece and that the MFR4 will reduce my F10 LX200R to F3. Now, I'm not sure if setting up a FOV indicator makes sense for the Mallincam but when I compare its FOV indicator with that of an 8mm 50 degree eyepiece they're roughly the same. When I compare these FOV indicators in TheSky with what I actually see the actual FOV is quite a bit smaller. Here's what TheSky shows. This is centred on NGC3312. The circle represents the FOV of an 8mm 50 degree eyepiece in a 14" LX200R operating at F3. The rectangle represents the FOV of the Mallincam though the same scope and with the MFR4. -------------------- 14" LX200R + SV90T + AP1200GTO 31mm, 22mm, 17mm Naglers, 13mm Ethos, 10mm Pentax XW, 2X Powermate, AP MaxBright Mallincam Hyper Plus Color, DFG/1394 video converter, Optec 0.33 & 0.7 FRs IDAS LPS, DGM NPB & OIII, Lumicon Deep Sky Post Extras:       gavbray sage Reged: 12/31/06 Posts: 232 Loc: Gold Coast, Australia Re: MFR4 field of view [Re: gavbray]       #2364874 - 05/01/08 05:41 PM Attachment (33 downloads) Edit   Reply   Quote Quick Reply   And here's the captured image. Is this a valid comparison? If so, should there be this discrepency? If not, what might be causing this discrepency? If there's something I can do to increase the current FOV then I'm interested in finding out. My setup is MCHP > MFR4 > FT focuser > LX200R. I'm not really sure what the difference is between the MFR3 and MFR4 but most people seem to have the MFR3. Would I be better off getting an MFR3? Regards Gavin -------------------- 14" LX200R + SV90T + AP1200GTO 31mm, 22mm, 17mm Naglers, 13mm Ethos, 10mm Pentax XW, 2X Powermate, AP MaxBright Mallincam Hyper Plus Color, DFG/1394 video converter, Optec 0.33 & 0.7 FRs IDAS LPS, DGM NPB & OIII, Lumicon Deep Sky Post Extras:       midway199 super member Reged: 04/21/04 Posts: 108 Loc: Illinois Re: MFR4 field of view [Re: gavbray]       #2364911 - 05/01/08 06:02 PM Edit   Reply   Quote Quick Reply   Gavin, Someone with a better feel for the numbers can speak with more accuracy, but it's my impression that the amount of focal reduction varies by how far away from the chip the reducer is. So, one might have an f/3.3 focal reducer and calculate a certain field size, but a few millimeters toward or away from the reducer would change things a bit on the screen. When I take calculations into consideration, for instance a program might indicate a 29 arc-minute field of view for my camera/reducer/scope setup, I take that with a grain of salt. I figure it will be close, but may vary somewhat depending on factors of spacing (or even electronic discrepancies) that the program may not be aware of or even capable of factoring in. -------------------- Matthew Sherman StellaCam 3 Celestron NexStar 11 @ f/3.3 Starmaster 12.5" Starmaster 18" Tom Osypowski Equatorial Platform Butterfield East Video Observatory Post Extras:       gavbray sage Reged: 12/31/06 Posts: 232 Loc: Gold Coast, Australia Re: MFR4 field of view [Re: midway199]       #2364943 - 05/01/08 06:22 PM Edit   Reply   Quote Quick Reply   Matthew I think you're right about the spacing but the MFR4 to CCD spacing is fixed and is supposed to bring the FR down to 3.0. I could understand a small discrepancy but not the amount that I'm seeing. Regards Gavin -------------------- 14" LX200R + SV90T + AP1200GTO 31mm, 22mm, 17mm Naglers, 13mm Ethos, 10mm Pentax XW, 2X Powermate, AP MaxBright Mallincam Hyper Plus Color, DFG/1394 video converter, Optec 0.33 & 0.7 FRs IDAS LPS, DGM NPB & OIII, Lumicon Deep Sky Post Extras:       Chris Schroeder Postmaster Reged: 12/11/04 Posts: 5098 Loc: N.E. WI Sky Glow Re: MFR4 field of view [Re: gavbray]       #2365573 - 05/01/08 11:05 PM Edit   Reply   Quote Quick Reply   I thought I read that the MFR4 is to be used with a diagonal. -------------------- Chris Mallincam Color Hyper Plus 10" DSH with SC DSC, CPC 800 XLT M102ED S.V., ZS 80FD 10th Anniv, ZS 66SD, PST POD XL3 http://POD.SchroederCity.com Post Extras:       gavbray sage Reged: 12/31/06 Posts: 232 Loc: Gold Coast, Australia Re: MFR4 field of view [Re: Chris Schroeder]       #2365838 - 05/02/08 03:01 AM Edit   Reply   Quote Quick Reply   I've read that the MFR4 can be used with a diagonal. I'm not sure if that means has to be used with a diagonal. I will try it with a diagonal to see if it makes any difference. Gavin -------------------- 14" LX200R + SV90T + AP1200GTO 31mm, 22mm, 17mm Naglers, 13mm Ethos, 10mm Pentax XW, 2X Powermate, AP MaxBright Mallincam Hyper Plus Color, DFG/1394 video converter, Optec 0.33 & 0.7 FRs IDAS LPS, DGM NPB & OIII, Lumicon Deep Sky Post Extras:       gavbray sage Reged: 12/31/06 Posts: 232 Loc: Gold Coast, Australia Re: MFR4 field of view [Re: gavbray]       #2366003 - 05/02/08 07:24 AM Edit   Reply   Quote Quick Reply   I tried it with a diagonal and saw no difference in the field of view. -------------------- 14" LX200R + SV90T + AP1200GTO 31mm, 22mm, 17mm Naglers, 13mm Ethos, 10mm Pentax XW, 2X Powermate, AP MaxBright Mallincam Hyper Plus Color, DFG/1394 video converter, Optec 0.33 & 0.7 FRs IDAS LPS, DGM NPB & OIII, Lumicon Deep Sky Post Extras:       sabir sage Reged: 06/23/07 Posts: 467 Loc: Pune (India) Re: MFR4 field of view [Re: gavbray]       #2366146 - 05/02/08 09:08 AM Edit   Reply   Quote Quick Reply   WOW!!!.... I'd be happy with what your setup already shows!!!.... Thats awesome!! Post Extras:       gavbray sage Reged: 12/31/06 Posts: 232 Loc: Gold Coast, Australia Re: MFR4 field of view [Re: sabir]       #2366180 - 05/02/08 09:25 AM Edit   Reply   Quote Quick Reply   I am happy but perhaps I could be even more happy. I have a feeling I'm not at F3 and, if that's the case, I'd like to know why. -------------------- 14" LX200R + SV90T + AP1200GTO 31mm, 22mm, 17mm Naglers, 13mm Ethos, 10mm Pentax XW, 2X Powermate, AP MaxBright Mallincam Hyper Plus Color, DFG/1394 video converter, Optec 0.33 & 0.7 FRs IDAS LPS, DGM NPB & OIII, Lumicon Deep Sky Post Extras:       mielejr sage Reged: 05/29/05 Posts: 311 Re: MFR4 field of view [Re: gavbray]       #2366457 - 05/02/08 11:44 AM Edit   Reply   Quote Quick Reply   Just curious. Why do you think the MFR4 is supposed to give you f3? I guess I always thought it was supposed to be more equivalent to the Meade f3.3 in redcution ability. Another factor is that you may not really be at f/10 when you start out. Depending on how back the focal plane is from the rear of the tube, your nominal system may be more like f/10.5 or f/11. Post Extras:       gavbray sage Reged: 12/31/06 Posts: 232 Loc: Gold Coast, Australia Re: MFR4 field of view [Re: mielejr]       #2367470 - 05/02/08 07:08 PM Edit   Reply   Quote Quick Reply   Take a look at the Mallicam yahoo group post #4299. In that Rock says: "Using the MFR-4 which was design for Schmidt-Cassegrain, Mak, R-C, ARC type optical system with a diagonal, the MFR-4 focal length is 36.8. With a F/10 optical tube, the MFR-4 will have a F ratio of F/3.0. Add a 5 mm spacer ring and the F/ratio is now F/1.6." Thanks for the suggestion. I'll check the FOV without the reducer. -------------------- 14" LX200R + SV90T + AP1200GTO 31mm, 22mm, 17mm Naglers, 13mm Ethos, 10mm Pentax XW, 2X Powermate, AP MaxBright Mallincam Hyper Plus Color, DFG/1394 video converter, Optec 0.33 & 0.7 FRs IDAS LPS, DGM NPB & OIII, Lumicon Deep Sky Post Extras:       mielejr sage Reged: 05/29/05 Posts: 311 Re: MFR4 field of view [Re: gavbray]       #2367869 - 05/02/08 10:28 PM Edit   Reply   Quote Quick Reply   Ahhh...that would indicate it can give f3 all right! I looked on the Mallincam website and did not see anything about the MFR4. Let us know what you come up with. Post Extras:       gavbray sage Reged: 12/31/06 Posts: 232 Loc: Gold Coast, Australia Re: MFR4 field of view [Re: mielejr]       #2368016 - 05/02/08 11:38 PM Attachment (16 downloads) Edit   Reply   Quote Quick Reply   Here's what TheSky says the Mallincam with my scope operating at F5.5 would show. This looks very similar to the actual view so perhaps I'm only down to F5.5 and not F3. I also used TheSky to compare F3 with F3.3 and the difference is small. Similarly the difference between my scope operating at F10 and F11 is small. So, unless I'm doing something wrong, and I'm happy for someone to point out what that is, it appears that with the MFR4 I'm only getting down to around F5.5. Gavin -------------------- 14" LX200R + SV90T + AP1200GTO 31mm, 22mm, 17mm Naglers, 13mm Ethos, 10mm Pentax XW, 2X Powermate, AP MaxBright Mallincam Hyper Plus Color, DFG/1394 video converter, Optec 0.33 & 0.7 FRs IDAS LPS, DGM NPB & OIII, Lumicon Deep Sky Post Extras:       gavbray sage Reged: 12/31/06 Posts: 232 Loc: Gold Coast, Australia Re: MFR4 field of view [Re: gavbray]       #2368193 - 05/03/08 01:59 AM Attachment (23 downloads) Edit   Reply   Quote Quick Reply   Here's something more familiar. -------------------- 14" LX200R + SV90T + AP1200GTO 31mm, 22mm, 17mm Naglers, 13mm Ethos, 10mm Pentax XW, 2X Powermate, AP MaxBright Mallincam Hyper Plus Color, DFG/1394 video converter, Optec 0.33 & 0.7 FRs IDAS LPS, DGM NPB & OIII, Lumicon Deep Sky Post Extras:       gavbray sage Reged: 12/31/06 Posts: 232 Loc: Gold Coast, Australia Re: MFR4 field of view [Re: gavbray]       #2368196 - 05/03/08 02:01 AM Attachment (17 downloads) Edit   Reply   Quote Quick Reply   And the FOV indicators in TheSky. It still looks like F5.5 to me. Gavin -------------------- 14" LX200R + SV90T + AP1200GTO 31mm, 22mm, 17mm Naglers, 13mm Ethos, 10mm Pentax XW, 2X Powermate, AP MaxBright Mallincam Hyper Plus Color, DFG/1394 video converter, Optec 0.33 & 0.7 FRs IDAS LPS, DGM NPB & OIII, Lumicon Deep Sky Post Extras:       gavbray sage Reged: 12/31/06 Posts: 232 Loc: Gold Coast, Australia Re: MFR4 field of view [Re: gavbray]       #2369385 - 05/03/08 06:28 PM Edit   Reply   Quote Quick Reply   Has anyone else got an MFR-4 and, if so, have you measured the FOV? -------------------- 14" LX200R + SV90T + AP1200GTO 31mm, 22mm, 17mm Naglers, 13mm Ethos, 10mm Pentax XW, 2X Powermate, AP MaxBright Mallincam Hyper Plus Color, DFG/1394 video converter, Optec 0.33 & 0.7 FRs IDAS LPS, DGM NPB & OIII, Lumicon Deep Sky Post Extras:       Jack Huerkamp Vendor - Waning Moon Reged: 10/13/05 Posts: 519 Loc: Louisiana Re: MFR4 field of view [Re: gavbray]       #2369628 - 05/03/08 08:53 PM Edit   Reply   Quote Quick Reply   Gavin, I have one, but I have not used it in a while. If it ever clears and dries up, I will take a scope out and see what I measure. In the interim I have asked Rock to review what you have posted and comment. Jack -------------------- Orion ED80 Coulter CT-100 Celestron 6" f/8 Refractor 8" Newtonian/Cassegrain on Byers 812 Mount Classic C-8 Celestron 11" CPC 100 with HyperStar Tricked-out 17.5" AstroSystems TeleKit Life Member and ALCOR - PAS New Orleans Waning Moon II Observatory Post Extras:       gavbray sage Reged: 12/31/06 Posts: 232 Loc: Gold Coast, Australia Re: MFR4 field of view [Re: Jack Huerkamp]       #2369774 - 05/03/08 10:22 PM Edit   Reply   Quote Quick Reply   Thanks Jack. I appreciate that. Gavin -------------------- 14" LX200R + SV90T + AP1200GTO 31mm, 22mm, 17mm Naglers, 13mm Ethos, 10mm Pentax XW, 2X Powermate, AP MaxBright Mallincam Hyper Plus Color, DFG/1394 video converter, Optec 0.33 & 0.7 FRs IDAS LPS, DGM NPB & OIII, Lumicon Deep Sky Post Extras:       gavbray sage Reged: 12/31/06 Posts: 232 Loc: Gold Coast, Australia Re: MFR4 field of view [Re: gavbray]       #2547820 - 07/29/08 07:56 AM Edit   Reply   Quote Quick Reply   After using and measuring the focal reduction of the Optec 0.33x FR I'm certain that I'm not getting anywhere near a 0.33 reduction with the MFR-4. Using the same setup and performing the same measurement I get a focal reduction of 0.33 for the Optec but only about 0.5 for the MFR-4. The MFR-4 will be assigned to my box of unused equipment. Gavin -------------------- 14" LX200R + SV90T + AP1200GTO 31mm, 22mm, 17mm Naglers, 13mm Ethos, 10mm Pentax XW, 2X Powermate, AP MaxBright Mallincam Hyper Plus Color, DFG/1394 video converter, Optec 0.33 & 0.7 FRs IDAS LPS, DGM NPB & OIII, Lumicon Deep Sky Post Extras:       mielejr sage Reged: 05/29/05 Posts: 311 Re: MFR4 field of view [Re: gavbray]       #2549321 - 07/29/08 10:00 PM Edit   Reply   Quote Quick Reply   Gavin, Thanks for that information. It will be of use to many I'm sure. I have been using an ATIK .5 reducer on my C11 and get good results. I also use the meade f3.3 reducer and that works well too. I need to measure my actual reductions as you did but viewing time is sooo scarce these days! Post Extras:       Pages: 1 Previous   Index   Next   Threaded   Extra information 1 registered and 0 anonymous users are browsing this forum. 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