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2010-07-03 #7887 平場減焦鏡到貨

0.85x平場減焦鏡，下週有少量抵港。
港幣2723元 (內地同好2443元人民幣，另付香港至內地運費，可匯款至廣州工行)：
http://www.sciencecenter.net/hutech/pri ... l/7887.htm

建議同時選購M57相機接環，與平場鏡本身的M57縲紋匹配外，亦符合後焦點要求，增大通光孔徑有效改善漸暈問題，備有Nikon及Canon EOS接環現貨。
港幣195元 (內地同好175元人民幣，另付香港至內地運費，可匯款至廣州工行)：
http://www.sciencecenter.net/hutech/pri ... l/5003.htm

平場鏡M57至常規望遠鏡2"接環，接環可用M48濾鏡如LPS-V4、LPS-P2。
港幣305元 (內地同好273元人民幣，另付香港至內地運費，可匯款至廣州工行)：
http://www.sciencecenter.net/hutech/pri ... l/7425.htm

Interested!

Looking forward to seeing the detail. Thanks.

yes, will do.

we are now finalizing the price, hopefully a special discount for cafe members. Expected delivery date Mar or Apr in limited quantity, will also offer to cafe member first.

Hi 社長, any technical / spec data you may provide for reference? or even any informative website? Thanks. Looked like the flattener is for 500mm - 800mm APO. Feeling interested in getting one for a newbie of field astrophotography. Thanks much.

You are welcome Horace, BORG/Hutech remove that as this is a discontiued product, but I am able to get a batch. I do have one on hand and may be I can scan the manual and upload here.

what telecope you are using?

Some people find this flattner is even good for Equinox 120 ED (900mm focal length), but doesn't mean that it work well for all telescope at 500 to 800mm, it really depends on the telescope design.

horace 寫:Hi 社長, any technical / spec data you may provide for reference? or even any informative website? Thanks. Looked like the flattener is for 500mm - 800mm APO. Feeling interested in getting one for a newbie of field astrophotography. Thanks much.

The Borg 7887 is a well known reducer/flattener. It works well in Equinox 80ED & 120ED. It is a must item!!!
http://www.skynews.ca/PDFs/Review_PDFs/ ... EDso08.pdf
http://bbs.astron.ac.cn/thread-54511-1-1.html

willis 寫:The Borg 7887 is a well known reducer/flattener. It works well in Equinox 80ED & 120ED. It is a must item!!!
http://www.skynews.ca/PDFs/Review_PDFs/ ... EDso08.pdf
http://bbs.astron.ac.cn/thread-54511-1-1.html

Hi Willis, thanks. Sound like you introduce me the SK telescopes too ... Your recommendation is always welcomed, anyway.

Hi 社長, what if the flattener matchs with a Tak Sky-90? Yep, instead of a proprietary one from Tak. Thanks.

horace 寫:

willis 寫:The Borg 7887 is a well known reducer/flattener. It works well in Equinox 80ED & 120ED. It is a must item!!!
http://www.skynews.ca/PDFs/Review_PDFs/ ... EDso08.pdf
http://bbs.astron.ac.cn/thread-54511-1-1.html

Hi Willis, thanks. Sound like you introduce me the SK telescopes too ... Your recommendation is always welcomed, anyway.

Hi 社長, what if the flattener matchs with a Tak Sky-90? Yep, instead of a proprietary one from Tak. Thanks.

Hi Horace, to be honest, you should go for a corresponding Tak flatterner for the Sky 90, that's a safer and guaranteed choice. There could be chance that you can find a third party flattener works better but no one knows until you really do a star test.

there are test on Cloudynights that, BORG 7887 reducers flatteners works better than Televue 0.8x one on APM-LOMO 80/480.

horace 寫:

willis 寫:The Borg 7887 is a well known reducer/flattener. It works well in Equinox 80ED & 120ED. It is a must item!!!
http://www.skynews.ca/PDFs/Review_PDFs/ ... EDso08.pdf
http://bbs.astron.ac.cn/thread-54511-1-1.html

Hi Willis, thanks. Sound like you introduce me the SK telescopes too ... Your recommendation is always welcomed, anyway.

Hi 社長, what if the flattener matchs with a Tak Sky-90? Yep, instead of a proprietary one from Tak. Thanks.

I don't know u are using SKy90. But Borg 7887 seems an all rounded reducer. It is once discontinued. But due to the huge demand, Borg starts the production again. A few month ago, I sent an e-mail to Borg & asked if they still have stock. They replied me that they will produce 7887 again as the market demand is huge.

fyi, a side topic for your reference, may get a hints on how flattener behave.

Now people in Germany found the William Optics TMB 68mm flattener is so good for APM-TMB APO of f6 to f7, so they even offer this instead of the 3.5" TMB flattener, as a lower cost alternative, of course the field coverage is different. May be they have the same DNA (designed by TMB).

now I am working with famous Italian optical designer Massimo Riccardi (the one who developed the RH astrograph for Astrophysics and A&M) on the new universal 0.75x reducer flattener for APM APO, as long as we adjust the interlens and back focal length (with provided spacers), it can correct all the model from 100 to 203 aperture, and deliver spotsize of ~15um on axis and ~25um at edge of 135 format. We are now transferring further data to see how larger and smaller models behave.

There are discussions that some people use BORG, Televue or other reducers, and found sometimes for a certain model of telescope, they can get surprising good result at far from "optimal spacing" as recommended by manufacturers.

社長 寫:
Hi Horace, to be honest, you should go for a corresponding Tak flatterner for the Sky 90, that's a safer and guaranteed choice. There could be chance that you can find a third party flattener works better but no one knows until you really do a star test.

there are test on Cloudynights that, BORG 7887 reducers flatteners works better than Televue 0.8x one on APM-LOMO 80/480.

社長, certainly, I will gather good enough information from you guys before take action. Thanks again.

willis 寫:I don't know u are using SKy90. But Borg 7887 seems an all rounded reducer. It is once discontinued. But due to the huge demand, Borg starts the production again. A few month ago, I sent an e-mail to Borg & asked if they still have stock. They replied me that they will produce 7887 again as the market demand is huge.

Hi Willis, but you are an all-around veteran as well. I learnt a lot from your posts and blog. Please don't discontinue.
Sound like the choices of sort of reducer flatteners are limited in the market. In fact, there are two flatteners ordered on the way to my house ... TeleVue 0.8X Reducer and Astro-Tech 2" field flattener (you see the World is so small!!!)
I'm pretty interested in the middleware, in the term of IT jarjon.
Thanks.

I don't know why, recently I found myself keep collecting flatteners, my strategy is less telescopes and more flatteners

horace 寫:

willis 寫:I don't know u are using SKy90. But Borg 7887 seems an all rounded reducer. It is once discontinued. But due to the huge demand, Borg starts the production again. A few month ago, I sent an e-mail to Borg & asked if they still have stock. They replied me that they will produce 7887 again as the market demand is huge.

Hi Willis, but you are an all-around veteran as well. I learnt a lot from your posts and blog. Please don't discontinue.
Sound like the choices of sort of reducer flatteners are limited in the market. In fact, there are two flatteners ordered on the way to my house ... TeleVue 0.8X Reducer and Astro-Tech 2" field flattener (you see the World is so small!!!)
I'm pretty interested in the middleware, in the term of IT jarjon.
Thanks.

Not really... I bought my first binocular in last Feb. Most of the photos in my blog are bright objects. They are relatively easier to be captured. u just need to get the right instrucments and spend enough time on processing, u can do it. No magic...

I fully agree with Willis, there is no magic in astrophotography, telescope technique... etc.

Practice (and learning) make perfect.

there is a saying, if we invest 10,000 hrs seriously in anything we can be master of that subject.

willis 寫:Not really... I bought my first binocular in last Feb. Most of the photos in my blog are bright objects. They are relatively easier to be captured. u just need to get the right instrucments and spend enough time on processing, u can do it. No magic...

At least, you have proved that the enthusiasm on this hobby with your professions on sort of the topics overrided the fact of which the first binocular joined with your life even as late as last year. It's truly no magic at all. Time can prove your hardship.

社長 寫:I fully agree with Willis, there is no magic in astrophotography, telescope technique... etc.

Practice (and learning) make perfect.

there is a saying, if we invest 10,000 hrs seriously in anything we can be master of that subject.

Certainly, except practice and time spending, a full set of good-matching equipment combination is one of the critical factors to do the best on imaging. Looking forward to learning more from you and purchasing here. Thanks.

horace 寫:

社長 寫:I fully agree with Willis, there is no magic in astrophotography, telescope technique... etc.

Practice (and learning) make perfect.

there is a saying, if we invest 10,000 hrs seriously in anything we can be master of that subject.

Certainly, except practice and time spending, a full set of good-matching equipment combination is one of the critical factors to do the best on imaging. Looking forward to learning more from you and purchasing here. Thanks.

you are welcome Horace.

nice to meet you today, yes, let's learn together.....

我團購一個　7887平場減焦鏡　　敬告知最後價格