強悍的 APM-Riccardi Super ED 0.75x 平場減焦鏡

[Nebulas]

对130780严重中毒了！

老顾童鞋，期盼你上130了，好像最近130特别火！

[社長]

的確是，昨天才有同好買了一台，下月到的那批也有一台訂了。日本也訂了一批130，是目前最暢銷的型號。

[willis]

Still waiting for the report of Super reducer on APM-TMB 100/800...

[社長]

今天收到Dr Massimo Riccardi的Spot Diagram, 是這個減焦鏡配合APM-TMB 130/1200APO，於16803晶片的表現。這是一個可能被認為是奇怪得很的組合，但對我來說可能有另一番意義。

這台130/1200被Thomas Back生前評為市場上同口徑生產型折射鏡的最高水準，超可見光波段達至繞射極限，所以他稱這台鏡為Super Planetary。在香港我們也有一台：
viewtopic.php?f=12&t=234

很明顯，這台鏡因為焦比達f9.25，正常來說拍深空太慢了。但若配合這減焦鏡，便可獲得900mm f6.9的有效焦距，並覆蓋36x36mm片幅的STX16803晶片，即2.3x2.3度天區，在這麼大的片幅下，像場角上失光才22%。論星點大小，以35mm全片幅計，星點是10至20um大小，16803片幅計，角上約25um，是十分銳利了。

若要拍攝星系等高解像度深空，因為是追求軸上解像度，乾脆不加平場鏡，直接以1200mm直焦拍攝便可以，但曝光時間會長得要命，例如：

http://www.stargazer-observatory.com/660-tao.html
http://www.stargazer-observatory.com/draco3.html
http://www.stargazer-observatory.com/4449.html
http://www.stargazer-observatory.com/ngc3718.html
http://www.stargazer-observatory.com/ngc4490.html
http://www.stargazer-observatory.com/m63.html

[社長]

APM 發報，我可以接受訂單了，我應會三月初會收到一個樣版作個人樣版測試，甚至可以四月份帶到西藏用105/650拍攝了。
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New Product : Triplet Super Redcuer/Flattner F/0.75 for 52 mm Image circle

Technical Specs:
- focuser side connection M82 x 1 male thread
- Camera side connection M82 x 1 female thread
- Backfocuse : depends on the telescope, about 90 mm
- Reducer Housing OD : 90 mm
- Reducer Length : 84 mm
- Image circle : 52 mm diameter

Price : US $ 700 ex Germany
Delivery time : 2 month

Optional accessories:
- Adapters for your focuser
- Adapters for your DSLZ or CCD Camera


Massimo Riccardi/Italy
-designer of the largest apo of the world (improvement of the TMB design)
-developer of the Riccardi-Honders Astrograph (did you see it at Roland's stand latest Neaf? I'm sure you noticed it)
-Author of two well-known programs : ATMOS and ATMOSFRINGE software

designed for APM 107 and all LZOS a new triplet Super Redcuer/Flattner F/0.75 with follow specs:

Designed reducer for the 24x36 mm format (21 mm off-axis). It has 20 micron spot at the edge with a very low 3% vigneting

For 26 mm off axis (52mm diameter) then the spotdiagram increase only 5 microns (25 instead of 20) the only problem is the vignetting
that increase from a very low 3% at 21 mm off-axis up to 25-26 % at 26 mm off axis.

with the 2.5" Flattner from TS and our new 0.75 x Reducer we have a real powerfull astrograph available , with the 107 combined rather inexpensive, with expensive LZOS of course more expensive

This Reducer will also perfect work on the 105 to 107 apos from Astrotech ( Astronomy Technologies Astro-Tech AT106LE "Limited Edition" 106mm f/6.5 FPL-53 ED triplet APO refractor ), Handsonoptics ( AstroTelescopes 107mm APO f/6.5 Air-Spaced Triplet ) and Stellarvue (Raptor 105) , since they use the same optical design.


we accepting order now

clear skies

APM-Telescopes

[funoooo]

Please count to me. I want one too.
Do I need any extra adapter for my APM 130/780? Please confirm.
Thanks!

[willis]

At the moment, I need no Super ED 0.75X reducer. But may be one day I need it. Anyway, the spec seems very attractive.

[社長]

Please count to me. I want one too.
Do I need any extra adapter for my APM 130/780? Please confirm.
Thanks!

要造一片約10mm的厚的連接環 (M82x1 OD, M57x0.75 ID)，然後把你那套BORG濾鏡盒及相機接環旋上去便是了。

有進一步消息告訴你。

[社長]

收到最後兩個Spot diagram，分別為100/800及180/1260型號的。

100/800是Thomas Back生前最鍾愛的一個型號，是一台目視極品，那台99.7% Strehl的也是其遺物之一，透過這個減焦鏡，愛好者又可以600mm f6作深空拍攝了。從Spot diagram看到，拍攝成像表現出色，軸上成像10um、35mm全片幅角上成像也少於25um (比例方格為25um)，角上失光才2至3%。由此看到，一台極級目視鏡，配上匹配的平場鏡，也一樣化為出色的攝星儀。

180/1260亦表現出色，LZOS在其物鏡採用了第三片不一樣的玻璃....

[neodeemer]

关于180/1260，社长的意思是第三片是特殊玻璃还是三片都是特殊的？

[社長]

关于180/1260，社长的意思是第三片是特殊玻璃还是三片都是特殊的？

抱歉，我修改了一下，180/1260的第三片玻璃跟其他APM-APO不一樣。

以下附上兩幅新的Spot Diagram，可見100/800及180/1260配合這個減焦鏡，可照顧16803片幅(36x36mm)。

[社長]

Massimo Riccardi傳來好消息，為80小鏡設計的版本，也可用在APM-TMB較大口徑的折射鏡上，只是成像圈略小，在135片幅的角上失光約20%水平，和高橋FSQ106相若，比FSQ85好。

而3.5"版本的0.75x減焦鏡，在135片幅的角上失光約2至3%水平，16803晶片角上稍多於20%。

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Markus,

the small corrector works in the apo you mention (only slightly less good than the larger one).

The only problems are that the bfl is shorter and there is some vignetting at the edge of a 40 mm field (while the larger one is without vignetting). Vignetting at the edge is in general about 20 % in any model.

Here are the list of the parameter you need:

APO model Optical BFL Best field diameter

100/800 87.2 mm 40 mm
105/650 89.3 40 mm
107/700 88.4 40
115/805 87.1 40
130/780 87.3 40
130/1200 84.1 40
152/1200 84 40

If you want to know the mechanical bfl simply subtract 13.6 mm from the optical bfl .

Ex: 87.2mm -13.6mm= 73.6 mm (for the 100/800 apo)

Massimo

[willis]

Massimo seems very productive in optical design. In the past two yrs, he designed lots of good stuff. I cannot enumerate all of them, at least I know RHs & Super reducers... Does the small version work for APM-LOMO 80/480 & 80/600?

[社長]

今天收到APM的電郵，外國的新用戶對這個減焦鏡評價很高，我訂的一批稍後會到。這個減焦鏡用戶包括了香港內地台灣，也包括STX16803用戶，片幅36x36mm，屆時不同市場都會有獨立用戶報告了。

Quote :
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2 imagers did imaging and confirmed perfection in performance to the edge, super sharp and tight stars, better then anything they have seen so far

Markus

[社長]

配合各個型號下的Spot diagram以及相應的後焦點(APM提供相應墊片)，成像圖採用RMS Spot Size，看來銳些，但也更直接反映星點成像。

[社長]

繼續....

[社長]

繼續....

[willis]

For some APMs, there are two sets of back foci which result in different spot diagrams. Take 105/650 as an example, the two sets of back foci result in different spot size & vignetting. When the back focus is 80.7mm, the spot sizes are larger, but the vignetting is smaller (3% at 21mm). When the back focus is 75.85mm, the spot size is smaller, but the vignetting is larger (19% at 21mm). (19% is only half of some well know astrographs, which has 40% vignetting at the FF corner). It seems that the spot size & vignetting are completing. Does it mean one can tune according to needs? Anyway, from the figures the design tolerance is quite big. (80.7 - 75.85 = 4.85mm). If it is tested the stars are still round at the extreme corner of FF for the quoted range, 75.85mm to 80.7mm, it would be great!

[社長]

不，請參考圖片名稱，上面是兩款不同的減焦鏡。

Riccardi small 0.75x 是用在2.5"調焦筒上，接口是M63縲紋，用在全片幅相機上可以，四角有些掉光，後焦點也短些，若你是用APS片幅當然沒問題，全片幅相機的表現也比很多攝星儀好。這個減焦鏡比較小巧，用在80小鏡上拍星剛好。

Riccardi 0.75x 要求3.5"調焦筒，接口是M82縲紋，在全片幅四角上接近100%照明度，16803片幅則掉了1/2級光圈，若你的望遠鏡是100或以上的，無謂省些丁點錢，應該用這個了。

因為鏡片是固定的，但鏡頭不一樣，若追求理想表現，平場鏡的鏡間距離或後焦點都要調過才可獲得最優化成像，所以買這套平場鏡時APM會附上墊片，即你日後可以用在不同的APM鏡上，當然你也可以拿Equinox 120來試試效果如何

[willis]

Sorry overlooked the small size & full size versions! About the Equinox 120ED, the problem is how to mount the reducer on it. Some modifications are needed.