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Post by Deleted on Aug 23, 2014 8:11:36 GMT
They look to be the same scope but just produced for different companies. Same spec as the Skywatcher ED80mm. Both will perform very well for astrovideo when used with a focal reducer. The ED80mm is probably the most used scope for AP, and very good for visual. I doubt you would be disappointed with either of these two scopes.
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Post by Deleted on Aug 23, 2014 19:42:03 GMT
now i look. i think your right.. i went and asked my local hobby shop about the price for the celestron. i get lots of stuff with him. so he might give a good deal.. i guess if i can get it under 450 i might go with it .. he will let me know next week ..
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Post by davy on Aug 23, 2014 19:59:38 GMT
ask him if he will take your plank of wood in as a trade in . lol seriously im really glad you have listened to the advice the guys have given you..these guys know what they are talking about,and most probably have one..it really is worth holding on till you can afford one makes a BIG difference to your images. davy
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Post by Deleted on Aug 24, 2014 3:07:23 GMT
i asked him . he said mmm noo!! lol .... will heres a lil funny thing to me .. but i ask the ones who know.. you guys hehhe .. the focal reducer i got .. its a antares 0.5.. seems sort of worthless.. like it isnt doing anything..
when i 1st got it. i pointed it at window far away. sized up what i seen with out it. then put the reducer on. and sized up again.. not much.. i got 1st lil over 3/4 of the width of the window.. with it i got about 1/8 more outside the window frame. from left side to rite. so not a big amount ..
will i didnt think as so far . i havent reshot anything i been seeing more or less.. so for the fun of it i put the cam on the big dob. out of boardum i guess. with out the FR . it didnt have enough infocuse. ok no big deal . i could fix it. i have longer bolts for the prime mirror.. so i could push the prime up the ota if i wanted to.. to fix the focse issue..
so i put the reducer on.. for the fun of it.. and same thing. there wasnt a big diff in the star i was using.
so here is my ? i guess... the focal reducer works better in refractors ? then newts ? if so ok i wont send it back. if no then the one i got sort of worthless to start with ?
digs in the back of my mind. goin to find the funds for the 80 edapo ehhehe ... sooner then i planed.. lol
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Post by Deleted on Aug 24, 2014 3:59:44 GMT
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Post by davy on Aug 24, 2014 9:11:58 GMT
not familiar with the make. .maybe lee can help..looks ok..I would want to know more about the lens's type of glass and coatings. ..if unshure stick to celestron or orion..davy
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Post by Deleted on Aug 24, 2014 10:39:22 GMT
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Post by Dragon Man on Aug 24, 2014 15:14:29 GMT
Yep, Explore Scientific are a good brand. But as Hemmi said, it's only an Achromat. I have several Achromats of good quality and in all honesty, I find all of them frustrating and disappointing because of the Chromatic Aberration (false colours at the sides of objects). To help you understand, I will give you a report on my findings, using my 120mm f5 Saxon/Skywatcher Achromat and my 6" f5 Skywatcher Achromat: On Planets and the Moon, both Achromats are woeful! On Star Clusters they range from mildy woeful to terribly annoying. On DSO's they range from disappointing to mildly bearable, depending on the DSO. But many galaxies are OK. Also with the type of cameras we use, the sensors are extremely sensitive to IR, which causes star Bloat and the bright Violet fringing around bright objects like the Moon and Planets and bright stars. Medium stars will have less Violet fringing, but it's still there. The use of very high quality IR and IR/UV cut filters only reduce the problem a small amount. I then experimented with Yellow filters (recommended to reduce Violet Fringing) and had a small success in removing the Violet fringing, but also ruined the colour of everything else too. Using both at the same time (IR and yellow) reduced the amount of light gathering too much to be useful. Most DSO's disappeared! Some say they get reasonable results when using a 'Fringe Killer' filter. Even though both of my Achromats are great Telescopes for Richfield viewing, they are a total pain in the rear for Video Astronomy. So I reverted back to using an ED80 and the results are spectacular. The ED scopes give no false colour, no Chromatic Aberration, pinpoint stars, and lovely colour in DSO's. Obvioulsy the shorter the focal length the better. The ED80 I use (Saxon/Skywatcher) is f7.5 and I always use a Focal Reducer to get it down to around f3.2 which gives a nice 1 degree FOV. There is an ED80 which has an even shorter focal length but I can't remember it's name at the moment. The next step up in the ED range is the unpopular ED100. They have a long focal length making it harder to get sharp starts and a wide FOV. They are also expensive. I can highly recommend the ED80's and they are within a similar price range as the Explore Scientific you linked us to. Here are 2 examples of Violet Fringing: and this is an example of the common Chromatic Aberration caused by Achromats:
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Post by Deleted on Aug 24, 2014 15:53:18 GMT
ok so i guess ill go for the celestron. seems ok price its a 80 ed apo. at least comes with a 45 deg so if i wanna look thur it i can a lil easier.. lite weight..
yeah d man . that purple might drive me nuts after awhile lol .. thank you for the info tho.. helps a lot for sure..
hemmi: do you have any photos from your scope? 600 thats not to much above the celestron. and its a triplet.. as to the celestron bein a doublet..
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Post by Deleted on Aug 25, 2014 3:46:02 GMT
Yep, Explore Scientific are a good brand. But as Hemmi said, it's only an Achromat. I have several Achromats of good quality and in all honesty, I find all of them frustrating and disappointing because of the Chromatic Aberration (false colours at the sides of objects). To help you understand, I will give you a report on my findings, using my 120mm f5 Saxon/Skywatcher Achromat and my 6" f5 Skywatcher Achromat: On Planets and the Moon, both Achromats are woeful! On Star Clusters they range from mildy woeful to terribly annoying. On DSO's they range from disappointing to mildly bearable, depending on the DSO. But many galaxies are OK. Also with the type of cameras we use, the sensors are extremely sensitive to IR, which causes star Bloat and the bright Violet fringing around bright objects like the Moon and Planets and bright stars. Medium stars will have less Violet fringing, but it's still there. The use of very high quality IR and IR/UV cut filters only reduce the problem a small amount. I then experimented with Yellow filters (recommended to reduce Violet Fringing) and had a small success in removing the Violet fringing, but also ruined the colour of everything else too. Using both at the same time (IR and yellow) reduced the amount of light gathering too much to be useful. Most DSO's disappeared! Some say they get reasonable results when using a 'Fringe Killer' filter. Even though both of my Achromats are great Telescopes for Richfield viewing, they are a total pain in the rear for Video Astronomy. So I reverted back to using an ED80 and the results are spectacular. The ED scopes give no false colour, no Chromatic Aberration, pinpoint stars, and lovely colour in DSO's. Obvioulsy the shorter the focal length the better. The ED80 I use (Saxon/Skywatcher) is f7.5 and I always use a Focal Reducer to get it down to around f3.2 which gives a nice 1 degree FOV. There is an ED80 which has an even shorter focal length but I can't remember it's name at the moment. The next step up in the ED range is the unpopular ED100. They have a long focal length making it harder to get sharp starts and a wide FOV. They are also expensive. I can highly recommend the ED80's and they are within a similar price range as the Explore Scientific you linked us to. Here are 2 examples of Violet Fringing: and this is an example of the common Chromatic Aberration caused by Achromats: Hi,
A small Newtonian OTA is the best option to eliminate the problems associated with achromatic lenses. I started making my own back in the early 60's for that very reason. A good quality semi apo 80mm refractor is not cheap either. After using my various Takahashi/William Opics APO scopes, anything else is very disappointing. You get what you pay for, sad to say, it's the way of life in astronomy. Well, that's my cents worth anyway. Even a good camera lens is a better option, great on deep sky because at f/2.8 they are very fast, and useful for everyday photography.
Clear skies... Shevill
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Post by Deleted on Aug 25, 2014 5:51:29 GMT
what cam lens would you say is a half way good one ? astrotasmania. it would have to be c/cs mountable.
i have thought about that way also. but so much info. hard to figure it all out. i asked on a local photo club site. they didnt seem to wanna share info.. like it was witch voodoo or something.. lol
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Post by Deleted on Aug 25, 2014 7:48:15 GMT
Almost any camera lens can be put to good use with a video cam. The faster the lens the better. You need a C mount to lens adapter to fit the brand of lens you want to use, there are many types available. Typical useful lenses are Canon 200mm f2.8, 50mm f1.4, 50mm f1.8. The shorter the focal length, the wider the view. The faster the lens, the brighter the view for the same exposure time. You can even get satisfactory results with cheap lenses, but you may have to contend with coma around the edges.
Just be aware that a lot of the better lenses can cost as much or more than a scope, and you can't put an eyepiece in them.
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Post by Deleted on Aug 25, 2014 8:11:00 GMT
what cam lens would you say is a half way good one ? astrotasmania. it would have to be c/cs mountable. i have thought about that way also. but so much info. hard to figure it all out. i asked on a local photo club site. they didnt seem to wanna share info.. like it was witch voodoo or something.. lol Hi,
A really good source of lenses well suited to video astro can be bought via S/H shops. Good ones to look out for are manual lenses especially the early screw thread Pentax Super Takumar in all focal lengths can be had for a song, and in most cases excellent quality. I have at least a dozen or more from my Pentax film camera days, now it's Canon & Nikon. Buy a 'C' To lens type adaptor for the lenses you have or might buy, many good astro stores sell them If you are already a SLR/DSLR user, you have suitable lenses. Remember with a 1/2" video chip you are only using the small centre part of the 35mm lens, so basically, quality is not an issue, and you can stop the lens down a stop or two if you want and still have a fast lens.
Remember any lens over 8 mm (standard FL lens) - (telephoto 12 mm and upwards FL used on a 1/2" video camera is a telephoto lens. So you do not have to spend big dollars to get quality optics for video astronomy. So many people spend money of focal reducers to get their f/10 SCT's and f/8 refractors down to shorter faster scopes, which they are not designed to do, and all the time the answer is often in a camera lens!
For folks wanting quality still images on a cooled expensive CCD, they will be looking at the more expensive range, however, standard entry level video is mostly looking-. Horses for courses.
picasaweb.google.com/109921669020426367250/VideoAstronomy1988Present?authuser=0&feat=directlink
picasaweb.google.com/109921669020426367250/CameraLensesAdaptersForAstroUseASmallSelection?authuser=0&feat=directlink
I have been doing video astro since 1988 and I don't think there is not a lens type I have not attached to a video camera during that time.
Clear skies, Shevill
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Post by Deleted on Aug 25, 2014 8:48:50 GMT
what cam lens would you say is a half way good one ? astrotasmania. it would have to be c/cs mountable. i have thought about that way also. but so much info. hard to figure it all out. i asked on a local photo club site. they didnt seem to wanna share info.. like it was witch voodoo or something.. lol Hi,
One point I forgot to mention, I have bought tele lenses with a Pentax 42 mm screw thread up to 600 mm focal length at about f/6.3 they are low cost S/H, no market for them but I have had excellent results from a $20 lens. Makes a good solar scope with a Baader solar film filter over the front and you can reduce the aperture to control brightness (not possible with a scope). If you have access to a machine shop it is a piece of cake to make an eyepiece fitting to use your 1.25" eyepieces. Lateral thinking and a bit of shopping around and you do not need to spend a fortune.
With the appropriate 'C' mount adaptor any of these lenses can be used, which I do.picasaweb.google.com/lh/photo/qYwmeLRpMyinu1fF5Cl7ItMTjNZETYmyPJy0liipFm0?feat=directlinkClear skies... Shevill
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Post by Deleted on Aug 25, 2014 8:50:09 GMT
what cam lens would you say is a half way good one ? astrotasmania. it would have to be c/cs mountable. i have thought about that way also. but so much info. hard to figure it all out. i asked on a local photo club site. they didnt seem to wanna share info.. like it was witch voodoo or something.. lol Hi, Just check my two recent posts.
Clear skies... Shevill
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Post by Deleted on Aug 25, 2014 16:28:29 GMT
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Post by Deleted on Aug 25, 2014 17:45:14 GMT
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Post by Deleted on Aug 25, 2014 18:49:09 GMT
ok ill check them out. but i love to play with tings. sooo here is my playing around lol it works... i do have to extend about 1/2 inch. from cam.. but heck it works at full mag. lol i cut a hole in the back side dust cap.. god iam nuts lol .. but hey for test it works. as said above. i need to move it out about 1/2 inch maybe lil less... but ill figure something out lol
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Post by Deleted on Aug 25, 2014 19:57:34 GMT
ok ill check them out. but i love to play with tings. sooo here is my playing around lol it works... i do have to extend about 1/2 inch. from cam.. but heck it works at full mag. lol i cut a hole in the back side dust cap.. god iam nuts lol .. but hey for test it works. as said above. i need to move it out about 1/2 inch maybe lil less... but ill figure something out lol Hi,
I my early days I even made adapters/items out of hardwood and painted them black or silver, a good sanding some sealer and a coat or two of paint, ... if it works what the heck. Hardwood is easy to get hold of and a lot easier to work than metal. Also today we have all these wonderful PVC pope tubing & fittings. Nothing is impossible, the ingenuity of ATMer's is legendary. Trouble is sometimes folks get stuck into a fixed line of thought and often overlook the obvious. A camera is one side of the equation the glass in front is the other, just needs an interconnecting bit and the apparatus does not know what it is being used for except to produce images. Telescopes are not the only optic that can be used for astronomy and believe me, their are some pretty good old tele lenses out there better than a lot of telescopes on the market.
Clear skies... Shevill
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Post by Deleted on Aug 25, 2014 22:28:02 GMT
funny u say PVC. lol iam almost done with my adpt.. waiting for epox to dry. then ill photo it togther ... this is funnnnn heres some pix..i used a 1 1/4 to 1 1/2 adpture for sink drains.. cut it to fit.. one of the caps for the back side of lens is glued into it. total cost so far with lens and plumbing parts.. $57 bucks.. not to bad .. and yep i got it on a goto mount. love wood.. lol this lens says .. Kalimar MC auto zoom 1:3.5 35-135mm 58 no k87141644 then have a super albinar 1:2.8 F135mm 52deg i think No 837934 olympus 50mm 1:1.8 stard mc 1:2.8 f28mm 52 not to bad for 50 bucks i dont think?? got it focusing some buildings. now ill find out tonite if it will work.. cant wait. lol
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