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Short wish list for 2004
Here's a few of what I'd like to see in amateur astro optics, to whatever extent these don't already exist. I can't afford it all, but it shows what I think would be cool to be available. 1. Questar 5. It should have a 1600mm f.l., to go with 127 or 128mm clear ap., for f/12.5 (a bit less than the others; better for deep sky but still keeping central ob. small.) It would be portable but better than minimal 89mm version. Also, rounded mags. with 32, 16mm etc. standard eyepieces. (Aside: why aren't Brandon's seen much in the usual magazine spreads of eyepieces, or offered with other brands of telescopes?) Put in built-in finder with 21mm ap. and 128mm f.l. I'm dropping them a line about this. 2. 12 X 70 binoculars, to get better use of most people's pupils and the rarity of dark skies, but still wide field. All I've seen is 10, 15,16,20,...X. (How many know that our pupil max. d. gets smaller with age? Few can fully use 7 X 50 or 10 X 70, especially when sky brightness is considered.) Is f1 = 360mm OK or color correction? Is glass better now? See 3. for comments. I think 12X is the upper limit for easy satellite observation, and 70mm pieces about enough for most people to hand hold even at peak technical optimization. Yet 12 X 80 would be good also, more efficient for most than 11X. 3. 70mm refractor with 900mm f.l., for decent beginner use and good color correction. (How can mfrs. get away with so many short-focus non-apochromats? Do they have better glass, or are they just putting out color-smudging rubbish?) 4. I wish someone would (has?) tried to make a reflector with a design I thought of, if not originally: Put a Barlow between a Newtonian primary and the secondary mirror, to allow using a smaller secondary (because of extending of light cone) and longer f.l. with short tube. I posted about this on 3/12/02 as "New telescope design?" There were quite a few responses of varying enthusiasm. I would have put 36mm, 1.25 O.D. eyepiece for getting between the 32mm and 40mm, but it and 35mm are out there. A 36mm should allow a wider field than 40mm but still low magnifications. Neil Bates, Virginia |
#2
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Short wish list for 2004
correction. (How can mfrs. get away with so many short-focus non-apochromats? Do they have better glass, or are they just putting out color-smudging rubbish?) Have you looked through a scope such as the ST-80, 80mm F5? There are some good reasons why these scopes are popular. An 80mm F11 scope will have less color but it will also have a limited field of view. Rather than pushing 80mm to high powers where the exit pupil is too small to be effective, the ST-80 scopes are optimized for views that are not possible with larger scopes. A 4 degree FOV at 12.5X is quite interesting and false color is not an issue. While these fast scopes are not optimal on planets they will show the rings of Saturn and maybe even a shadow transit of Jupiter and even the Cassini division. They are reasonable on double stars as well, on a decent night, one can split the double-double. They also make reasonable spotting scopes and bird watching scopes. With a 25mm Plossl an ST-80 works at 16X and a FOV of over 3 degrees, pretty nice for general use. Add the compactness of a 14 inch OTA (compared with close to 3 feet for the F11 version) and one has a scope that is easy to transport, easy to find stuff with and versatile. They make a good companion for a larger scope and a good travel scope. I posted about this on 3/12/02 as "New telescope design?" There were quite a few responses of varying enthusiasm. Its been done, one fellow apparently has designed a scope with lenses between the primary and secondary as well as in the focuser. This is rumored to work quite well. I owned a 125mm Japanese made refector with a lens between the primary and secondary. The optics were very poor. Splitting castor was a major accomplishment. I currently own an Orion 130mm F5 Newtonian with decent optics, nice sharp views of Saturn at over 200X, splits all the standard double stars in the 2 arc second range and with a 2 inch focuser it will do a 3 plus degree FOV. If one wants to use a smaller secondary, I think the best plan is just to use one and live with the lesser illumination, after all by lengthening the effective focal length, one is limiting the FOV. Rather than being afraid of a fast mirror, I prefer taking advantage of it and realizing that if the mirror is decent one can have both nice widefield views and good high power capabilities at the same time. Jon Isaacs |
#3
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Short wish list for 2004
correction. (How can mfrs. get away with so many short-focus non-apochromats? Do they have better glass, or are they just putting out color-smudging rubbish?) Have you looked through a scope such as the ST-80, 80mm F5? There are some good reasons why these scopes are popular. An 80mm F11 scope will have less color but it will also have a limited field of view. Rather than pushing 80mm to high powers where the exit pupil is too small to be effective, the ST-80 scopes are optimized for views that are not possible with larger scopes. A 4 degree FOV at 12.5X is quite interesting and false color is not an issue. While these fast scopes are not optimal on planets they will show the rings of Saturn and maybe even a shadow transit of Jupiter and even the Cassini division. They are reasonable on double stars as well, on a decent night, one can split the double-double. They also make reasonable spotting scopes and bird watching scopes. With a 25mm Plossl an ST-80 works at 16X and a FOV of over 3 degrees, pretty nice for general use. Add the compactness of a 14 inch OTA (compared with close to 3 feet for the F11 version) and one has a scope that is easy to transport, easy to find stuff with and versatile. They make a good companion for a larger scope and a good travel scope. I posted about this on 3/12/02 as "New telescope design?" There were quite a few responses of varying enthusiasm. Its been done, one fellow apparently has designed a scope with lenses between the primary and secondary as well as in the focuser. This is rumored to work quite well. I owned a 125mm Japanese made refector with a lens between the primary and secondary. The optics were very poor. Splitting castor was a major accomplishment. I currently own an Orion 130mm F5 Newtonian with decent optics, nice sharp views of Saturn at over 200X, splits all the standard double stars in the 2 arc second range and with a 2 inch focuser it will do a 3 plus degree FOV. If one wants to use a smaller secondary, I think the best plan is just to use one and live with the lesser illumination, after all by lengthening the effective focal length, one is limiting the FOV. Rather than being afraid of a fast mirror, I prefer taking advantage of it and realizing that if the mirror is decent one can have both nice widefield views and good high power capabilities at the same time. Jon Isaacs |
#4
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Short wish list for 2004
correction. (How can mfrs. get away with so many short-focus non-apochromats? Do they have better glass, or are they just putting out color-smudging rubbish?) Have you looked through a scope such as the ST-80, 80mm F5? There are some good reasons why these scopes are popular. An 80mm F11 scope will have less color but it will also have a limited field of view. Rather than pushing 80mm to high powers where the exit pupil is too small to be effective, the ST-80 scopes are optimized for views that are not possible with larger scopes. A 4 degree FOV at 12.5X is quite interesting and false color is not an issue. While these fast scopes are not optimal on planets they will show the rings of Saturn and maybe even a shadow transit of Jupiter and even the Cassini division. They are reasonable on double stars as well, on a decent night, one can split the double-double. They also make reasonable spotting scopes and bird watching scopes. With a 25mm Plossl an ST-80 works at 16X and a FOV of over 3 degrees, pretty nice for general use. Add the compactness of a 14 inch OTA (compared with close to 3 feet for the F11 version) and one has a scope that is easy to transport, easy to find stuff with and versatile. They make a good companion for a larger scope and a good travel scope. I posted about this on 3/12/02 as "New telescope design?" There were quite a few responses of varying enthusiasm. Its been done, one fellow apparently has designed a scope with lenses between the primary and secondary as well as in the focuser. This is rumored to work quite well. I owned a 125mm Japanese made refector with a lens between the primary and secondary. The optics were very poor. Splitting castor was a major accomplishment. I currently own an Orion 130mm F5 Newtonian with decent optics, nice sharp views of Saturn at over 200X, splits all the standard double stars in the 2 arc second range and with a 2 inch focuser it will do a 3 plus degree FOV. If one wants to use a smaller secondary, I think the best plan is just to use one and live with the lesser illumination, after all by lengthening the effective focal length, one is limiting the FOV. Rather than being afraid of a fast mirror, I prefer taking advantage of it and realizing that if the mirror is decent one can have both nice widefield views and good high power capabilities at the same time. Jon Isaacs |
#5
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Short wish list for 2004
On Thu, 1 Jan 2004 16:30:16 -0500, Neil wrote:
Here's a few of what I'd like to see in amateur astro optics, to whatever extent these don't already exist... .. .. .. 4. I wish someone would (has?) tried to make a reflector with a design I thought of, if not originally: Put a Barlow between a Newtonian primary and the secondary mirror, to allow using a smaller secondary (because of extending of light cone) and longer f.l. with short tube. On point four, see the following: http://capenewise.co.uk/ gregory -- Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/ |
#6
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Short wish list for 2004
On Thu, 1 Jan 2004 16:30:16 -0500, Neil wrote:
Here's a few of what I'd like to see in amateur astro optics, to whatever extent these don't already exist... .. .. .. 4. I wish someone would (has?) tried to make a reflector with a design I thought of, if not originally: Put a Barlow between a Newtonian primary and the secondary mirror, to allow using a smaller secondary (because of extending of light cone) and longer f.l. with short tube. On point four, see the following: http://capenewise.co.uk/ gregory -- Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/ |
#7
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Short wish list for 2004
On Thu, 1 Jan 2004 16:30:16 -0500, Neil wrote:
Here's a few of what I'd like to see in amateur astro optics, to whatever extent these don't already exist... .. .. .. 4. I wish someone would (has?) tried to make a reflector with a design I thought of, if not originally: Put a Barlow between a Newtonian primary and the secondary mirror, to allow using a smaller secondary (because of extending of light cone) and longer f.l. with short tube. On point four, see the following: http://capenewise.co.uk/ gregory -- Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/ |
#8
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Short wish list for 2004
1. Questar 5. It should have a 1600mm f.l., to go with 127 or 128mm clear ap., for f/12.5 (a bit less than the others; better for deep sky but still keeping central ob. small.) It would be portable but better than minimal 89mm version. I wish Questar would charge a resonable amount for thier puny ass scopes. Lets say around a few hundred. Anyone who buys a Questar is a stupid moron. 3. 70mm refractor with 900mm f.l., for decent beginner use and good color correction. (How can mfrs. get away with so many short-focus non-apochromats? Do they have better glass, or are they just putting out color-smudging rubbish?) I wish people would stick refractors where the sun don't shine. They would go up there easy since they are small. A good beginner scope would be a 6 or 8 inch dob something large enough where they can see something. |
#9
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Short wish list for 2004
1. Questar 5. It should have a 1600mm f.l., to go with 127 or 128mm clear ap., for f/12.5 (a bit less than the others; better for deep sky but still keeping central ob. small.) It would be portable but better than minimal 89mm version. I wish Questar would charge a resonable amount for thier puny ass scopes. Lets say around a few hundred. Anyone who buys a Questar is a stupid moron. 3. 70mm refractor with 900mm f.l., for decent beginner use and good color correction. (How can mfrs. get away with so many short-focus non-apochromats? Do they have better glass, or are they just putting out color-smudging rubbish?) I wish people would stick refractors where the sun don't shine. They would go up there easy since they are small. A good beginner scope would be a 6 or 8 inch dob something large enough where they can see something. |
#10
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Short wish list for 2004
1. Questar 5. It should have a 1600mm f.l., to go with 127 or 128mm clear ap., for f/12.5 (a bit less than the others; better for deep sky but still keeping central ob. small.) It would be portable but better than minimal 89mm version. I wish Questar would charge a resonable amount for thier puny ass scopes. Lets say around a few hundred. Anyone who buys a Questar is a stupid moron. 3. 70mm refractor with 900mm f.l., for decent beginner use and good color correction. (How can mfrs. get away with so many short-focus non-apochromats? Do they have better glass, or are they just putting out color-smudging rubbish?) I wish people would stick refractors where the sun don't shine. They would go up there easy since they are small. A good beginner scope would be a 6 or 8 inch dob something large enough where they can see something. |
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