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#1
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Mars images update
Inspired by Martin Taylor's composite linked to in an earlier post, I
decided to do one for myself including last nights effort (before being clouded out). You can see the result via my website. Click on the mars composite image on the front page for more information/images. -- Pete Homepage at http://www.pbl33.co.uk CCD/digicam astronomy |
#2
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Mars images update
You can see the result via my website. Click on the mars composite
image on the front page for more information/images. Nice! Are all the images of Mars (except for the last one, I guess!) to the same scale? i.e. really showing Mars getting closer/bigger? Das |
#3
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Mars images update
You can see the result via my website. Click on the mars composite
image on the front page for more information/images. Nice! Are all the images of Mars (except for the last one, I guess!) to the same scale? i.e. really showing Mars getting closer/bigger? Das |
#5
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Mars images update
On 24 Jul 2003 13:09:10 -0700, (Das) wrote:
You can see the result via my website. Click on the mars composite image on the front page for more information/images. Nice! Are all the images of Mars (except for the last one, I guess!) to the same scale? i.e. really showing Mars getting closer/bigger? The scales are as I have captured them with my system at full magnification apart from the first image which is a tiddler because I had no idea what I was doing! The last image is bigger because it's the first one where I've been able to bump down the focal length of the eyepiece I'm using (from 20mm to 5mm). I'll admit that this image was taken after a visit to the local pub. I wasn't going to image but the call of Mars was strong that night. Perhaps it was the beer, but the seeing was incredible. The left hand image taken on the 19th is a bit small for some reason. I may have set the system up incorrectly. Now who's going to be kind and offer to calculate my focal ratio for me. (Someone else is kindly looking into this for me behind the scenes.) Setup #1 (Afocal): Objective diameter 101.9mm Objective focal length 902mm Barlow x2 Eyepiece focal length 20mm Camera lens focal length 70mm Setup #2 (Afocal): Objective diameter 101.9mm Objective focal length 902mm No Barlow Eyepiece focal length 5mm Camera lens focal length 70mm -- Pete Homepage at http://www.pbl33.co.uk CCD/digicam astronomy |
#6
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Mars images update
Pete
Setup #1 (Afocal): Magnification: 902*2/20=90.2x System focal length=70*90.2=6314 mm System focal ration = 6314 /101.9=f 61.96 call it f 62!! Setup #2 (Afocal): Magnification: 902/5=180.4x System focal length=70*180.4=12628 mm System focal ration = 12628 /101.9= f 124 But I wish I was more a a practician than a theoretician when it comes to astrophotography - I'm still stuck between (1) Buying a digital camera and wading through the minefield of adapters and supports. (2) Using my SLR with eyepiece adaptor / T adaptor and waiting "ages" for the results. I have tried camera supported by separate tripod offered up to the eyepiece but I find this very tricky to get square and focussed. -Russell Healey Orion Optics Europa 200mm f6 "Pete Lawrence" wrote in message ... Now who's going to be kind and offer to calculate my focal ratio for me. (Someone else is kindly looking into this for me behind the scenes.) Objective diameter 101.9mm Objective focal length 902mm Barlow x2 Eyepiece focal length 20mm Camera lens focal length 70mm Objective diameter 101.9mm Objective focal length 902mm No Barlow Eyepiece focal length 5mm Camera lens focal length 70mm |
#7
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Mars images update
Pete
Setup #1 (Afocal): Magnification: 902*2/20=90.2x System focal length=70*90.2=6314 mm System focal ration = 6314 /101.9=f 61.96 call it f 62!! Setup #2 (Afocal): Magnification: 902/5=180.4x System focal length=70*180.4=12628 mm System focal ration = 12628 /101.9= f 124 But I wish I was more a a practician than a theoretician when it comes to astrophotography - I'm still stuck between (1) Buying a digital camera and wading through the minefield of adapters and supports. (2) Using my SLR with eyepiece adaptor / T adaptor and waiting "ages" for the results. I have tried camera supported by separate tripod offered up to the eyepiece but I find this very tricky to get square and focussed. -Russell Healey Orion Optics Europa 200mm f6 "Pete Lawrence" wrote in message ... Now who's going to be kind and offer to calculate my focal ratio for me. (Someone else is kindly looking into this for me behind the scenes.) Objective diameter 101.9mm Objective focal length 902mm Barlow x2 Eyepiece focal length 20mm Camera lens focal length 70mm Objective diameter 101.9mm Objective focal length 902mm No Barlow Eyepiece focal length 5mm Camera lens focal length 70mm |
#8
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Mars images update
Very pleasing images, too, Pete.
-Russell |
#9
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Mars images update
Very pleasing images, too, Pete.
-Russell |
#10
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Mars images update
On Fri, 25 Jul 2003 07:51:14 +0100, "Russell Healey"
wrote: Setup #1 (Afocal): Magnification: 902*2/20=90.2x System focal length=70*90.2=6314 mm System focal ration = 6314 /101.9=f 61.96 call it f 62!! Setup #2 (Afocal): Magnification: 902/5=180.4x System focal length=70*180.4=12628 mm System focal ration = 12628 /101.9= f 124 My behind-the-scenes helper (I'll keep Mr Tonkin's identity hidden) pointed me to the formula yesterday. I wanted someone else to do the calculations independently though because to me f62 & f124 are figures that jump out at me as being rather extreme. Any imagers out there care to comment - or am I worrying about nothing? But I wish I was more a a practician than a theoretician when it comes to astrophotography - I'm still stuck between (1) Buying a digital camera and wading through the minefield of adapters and supports. Yes - it's easy for those of us who have slogged through the minefield and come out on the other side to forget just how many options there are out there. (2) Using my SLR with eyepiece adaptor / T adaptor and waiting "ages" for the results. Film vs digital. Go argue that one on rec.photo.digital. Astronomers are regarded as a minority on there and the arguments we put forward for digital over film don't carry much weight as a consequence. Cherry picking of arguments I think. What really amazes me are the images that were taken with really big scopes back in the mid-late 70's early 80's. By big, I'm talking 1.3m reflecators and 0.4m refractors. The images I saw in one of my old Mars books last weekend were made using film. What can I say? Imaging has come on a lot ;-) I have tried camera supported by separate tripod offered up to the eyepiece but I find this very tricky to get square and focussed. Russell Healey Orion Optics Europa 200mm f6 Seperate tripod to the eyepiece isn't going to work very well at all. If I can be so bold... I have an Orion Optics 250mm f4.8 (IIRC!). It's an older model and came on one of Orion's early GEM mounts. Although the mount is fine for visual work, it's pushing the limit photographically. You need a steady mount, and a decent RA drive (preferably DEC as well to help you get things set up correctly). I bought the accessory pack for my Europa which included a camera adapter. That's the same adapter I now use to attach my digicam to my Vixen refractor. Unfortunately, Mr naive here was a bit stupid and glued a coupling thread to the end of the adapter to allow it to fit my camera's thread. All I needed to get was a step-down ring for the camera. We live an learn g. Details of the adapter coupling can be found here... http://homepage.ntlworld.com/p.lawre...icoupling.html I don't know it this helps at all - if you need any additional info. about my set-up please just ask. -- Pete Homepage at http://www.pbl33.co.uk CCD/digicam astronomy |
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