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Gamma Virgo - Interesting double

文章發表於 : 2011-05-28, 23:14
benben88
Hi all,

Pls take a look to Gamma Virgo (bright star just next to Saturn) , it is a double with separation of 2 arc sec. now . It was resolved in my 106mm refractor at 265X .

Ben

Re: Gamma Virgo - Interesting double

文章發表於 : 2011-05-29, 07:28
社長
Ben, thanks for sharing.

沒看過這個,我猜以100ED折射鏡來說應該很容易。

因為10年前我們搞學生活動,用一批114/900球面鏡的牛頓鏡及廉價Plossl,都能解分解Epsilon double double的,若用APO則四星完全分離。

http://en.wikipedia.org/wiki/Epsilon_Lyrae

但我有個心願還是想用203APO在香港看天狼B,那次在檳城用228APO很容易看到,但香港過去幾次我看時的視寧度都不配合,現在Paramount的三腳又賣了,203APO又要發到西藏去做深空,所以可能要一兩年後發回來香港才能再看。

Re: Gamma Virgo - Interesting double

文章發表於 : 2011-05-29, 12:09
benben88
Yes , I must be ok for a 4 inch telescope (2" separatiion) . However , I missed this object as I\it could not be resolved in 6 inch APO few years ago , accoring to CN - it would be quite interesting to see the changes of the double from a "snowman" to a clearly splitted double in few years .

However , I could not 100% confirm the Antares B in the 4 inch even using the ultra sharp mono 4 (sharper than LE 5 :) ) ... I could see it in my 10 inch newtonian couple of years ago.

Besides , Sirius B is also my target in the coming year . I failed this year :(

Re: Gamma Virgo - Interesting double

文章發表於 : 2011-05-29, 15:06
社長
對,這是一個很有趣的現象,其實雙星也不是靜態的,就算我們唸書時跟現在比,北極星也走近了北天極很多呢。按理恆星是最高對比度的目標,大口徑反射鏡還是有優勢的,當然前題是光軸及視寧度許可。

Antares B.... 有機會拿台105來試試 :roll:

用了8年Mono目鏡,總體感覺像80年代用f12長焦折射鏡配Or目鏡看行星月面的一樣高對比度,當你用80APO推上216倍,就算我在上水這種天空背景光,我仍是看不到光欄的,因為眩光壓得太低了。

對大部人來說,除非他的望遠鏡特別大口徑焦距超長,否則就是Mono 4, 5, 6已足夠,加起來就是一個Ethos 21多點。我個人不喜歡在目鏡上花太多時間(望遠鏡也是)。

Re: Gamma Virgo - Interesting double

文章發表於 : 2011-05-29, 16:08
David
benben88 寫:It was resolved in my 106mm refractor at 265X .


Great! I saw a discussion about this in Sky & Telescope a few months before but never remembered to look in that direction.

Re: Gamma Virgo - Interesting double

文章發表於 : 2011-05-29, 17:20
David
社長 寫:但香港過去幾次我看時的視寧度都不配合,現在Paramount的三腳又賣了,203APO又要發到西藏去做深空,所以可能要一兩年後發回來香港才能再看。


我讓C8給你用吧,很久沒有用這支鏡了,我用它看Sirius B的! :lol:

Re: Gamma Virgo - Interesting double

文章發表於 : 2011-05-29, 18:04
社長
若我肯再用折反射的,從貨架上拿台Maksutov 180/2700便可以了.... :lol:

Re: Gamma Virgo - Interesting double

文章發表於 : 2011-05-29, 18:52
willis
What about 80mm APM? Theoretically, it is marginal... Anyway, I will try all 80APM, 120ED & M8 etc. :lol: :lol: :lol:

Re: Gamma Virgo - Interesting double

文章發表於 : 2011-05-30, 08:42
社長
I can lend you my 203APO, but get yourself an equatorial mount.