Rocksolid Light

Welcome to novaBBS (click a section below)

mail  files  register  newsreader  groups  login

Message-ID:  

Whoa...I did a 'zcat /vmlinuz > /dev/audio' and I think I heard God... -- mikecd on #Linux

tech / sci.astro.amateur / How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.

SubjectAuthor
* How much light does a refractor let through (in percentage)? 60% 70%Jean Mario Charest
+* Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90Chris L Peterson
|`* Re: How much light does a refractor let through (in percentage)? 60%StarDust
| +* Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90%Chris L Peterson
| |`* Re: How much light does a refractor let through (in percentage)? 60%StarDust
| | +- Re: How much light does a refractor let through (in percentage)? 60%Jean Mario Charest
| | `- Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90%Chris L Peterson
| `- Re: How much light does a refractor let through (in percentage)? 60%W
+- Re: How much light does a refractor let through (in percentage)? 60%W
`- Re: How much light does a refractor let through (in percentage)? 60%StarDust

1
How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.

<9c96c1d8-26be-4d7b-8410-9d74a0ebf185n@googlegroups.com>

  copy mid

https://www.novabbs.com/tech/article-flat.php?id=10846&group=sci.astro.amateur#10846

  copy link   Newsgroups: sci.astro.amateur
X-Received: by 2002:a05:620a:4007:b0:773:ad95:aa16 with SMTP id h7-20020a05620a400700b00773ad95aa16mr450478qko.4.1699043551407;
Fri, 03 Nov 2023 13:32:31 -0700 (PDT)
X-Received: by 2002:a05:6808:4191:b0:3ac:a02d:708f with SMTP id
dj17-20020a056808419100b003aca02d708fmr6922554oib.1.1699043551186; Fri, 03
Nov 2023 13:32:31 -0700 (PDT)
Path: i2pn2.org!i2pn.org!weretis.net!feeder8.news.weretis.net!proxad.net!feeder1-2.proxad.net!209.85.160.216.MISMATCH!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.astro.amateur
Date: Fri, 3 Nov 2023 13:32:30 -0700 (PDT)
Injection-Info: google-groups.googlegroups.com; posting-host=166.62.178.220; posting-account=hrCbwAoAAACpQkeyo_zNw5eVaL6rQ0dN
NNTP-Posting-Host: 166.62.178.220
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <9c96c1d8-26be-4d7b-8410-9d74a0ebf185n@googlegroups.com>
Subject: How much light does a refractor let through (in percentage)? 60% 70%
80% 90% Etc.
From: ve2...@gmail.com (Jean Mario Charest)
Injection-Date: Fri, 03 Nov 2023 20:32:31 +0000
Content-Type: text/plain; charset="UTF-8"
 by: Jean Mario Charest - Fri, 3 Nov 2023 20:32 UTC

How much light does a refractor let through (in percentage)?

60%
70%
80%
90%
Etc.

Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.

<iuqaki5nh5jos67o38fiufdbab6cvqdel1@4ax.com>

  copy mid

https://www.novabbs.com/tech/article-flat.php?id=10847&group=sci.astro.amateur#10847

  copy link   Newsgroups: sci.astro.amateur
Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!diablo1.usenet.blueworldhosting.com!peer03.iad!feed-me.highwinds-media.com!news.highwinds-media.com!fx15.iad.POSTED!not-for-mail
From: clp...@alumni.caltech.edu (Chris L Peterson)
Newsgroups: sci.astro.amateur
Subject: Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.
Message-ID: <iuqaki5nh5jos67o38fiufdbab6cvqdel1@4ax.com>
References: <9c96c1d8-26be-4d7b-8410-9d74a0ebf185n@googlegroups.com>
X-Newsreader: Forte Agent 6.00/32.1186
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Lines: 13
X-Complaints-To: abuse@easynews.com
Organization: Forte - www.forteinc.com
X-Complaints-Info: Please be sure to forward a copy of ALL headers otherwise we will be unable to process your complaint properly.
Date: Fri, 03 Nov 2023 15:55:36 -0600
X-Received-Bytes: 1031
 by: Chris L Peterson - Fri, 3 Nov 2023 21:55 UTC

On Fri, 3 Nov 2023 13:32:30 -0700 (PDT), Jean Mario Charest
<ve2mcj@gmail.com> wrote:

>How much light does a refractor let through (in percentage)?
>
>60%
>70%
>80%
>90%
>Etc.

If it's a good quality refractor, I'd figure about 0.5% loss per
air-to-glass surface.

Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.

<b3ff2664-9484-4062-87f8-1b77f86a86a8n@googlegroups.com>

  copy mid

https://www.novabbs.com/tech/article-flat.php?id=10848&group=sci.astro.amateur#10848

  copy link   Newsgroups: sci.astro.amateur
X-Received: by 2002:a05:620a:5306:b0:775:810b:2ec with SMTP id oo6-20020a05620a530600b00775810b02ecmr379217qkn.1.1699062848685;
Fri, 03 Nov 2023 18:54:08 -0700 (PDT)
X-Received: by 2002:a05:6808:418c:b0:3b2:f197:950a with SMTP id
dj12-20020a056808418c00b003b2f197950amr8117232oib.9.1699062848463; Fri, 03
Nov 2023 18:54:08 -0700 (PDT)
Path: i2pn2.org!i2pn.org!weretis.net!feeder8.news.weretis.net!newsreader4.netcologne.de!news.netcologne.de!feeder1.cambriumusenet.nl!feed.tweak.nl!209.85.160.216.MISMATCH!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.astro.amateur
Date: Fri, 3 Nov 2023 18:54:08 -0700 (PDT)
In-Reply-To: <iuqaki5nh5jos67o38fiufdbab6cvqdel1@4ax.com>
Injection-Info: google-groups.googlegroups.com; posting-host=2600:1010:a010:aa44:950b:1833:c358:8d2a;
posting-account=q0dsSgoAAAAV0Xmlj0Dt_FOS5sPk02Ml
NNTP-Posting-Host: 2600:1010:a010:aa44:950b:1833:c358:8d2a
References: <9c96c1d8-26be-4d7b-8410-9d74a0ebf185n@googlegroups.com> <iuqaki5nh5jos67o38fiufdbab6cvqdel1@4ax.com>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <b3ff2664-9484-4062-87f8-1b77f86a86a8n@googlegroups.com>
Subject: Re: How much light does a refractor let through (in percentage)? 60%
70% 80% 90% Etc.
From: csok...@gmail.com (StarDust)
Injection-Date: Sat, 04 Nov 2023 01:54:08 +0000
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
 by: StarDust - Sat, 4 Nov 2023 01:54 UTC

On Friday, November 3, 2023 at 2:55:44 PM UTC-7, Chris L Peterson wrote:
> On Fri, 3 Nov 2023 13:32:30 -0700 (PDT), Jean Mario Charest
> <ve2...@gmail.com> wrote:
>
> >How much light does a refractor let through (in percentage)?
> >
> >60%
> >70%
> >80%
> >90%
> >Etc.
> If it's a good quality refractor, I'd figure about 0.5% loss per
> air-to-glass surface.

So, it means a doublet refractor let's more light through than a triplet?
🤔

Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.

<9bec1fa4-fae1-4a55-a020-1e0ee21496a6n@googlegroups.com>

  copy mid

https://www.novabbs.com/tech/article-flat.php?id=10849&group=sci.astro.amateur#10849

  copy link   Newsgroups: sci.astro.amateur
X-Received: by 2002:a05:6214:8d2:b0:66d:3d6:2d10 with SMTP id da18-20020a05621408d200b0066d03d62d10mr430163qvb.11.1699092734918;
Sat, 04 Nov 2023 03:12:14 -0700 (PDT)
X-Received: by 2002:a05:6808:bc6:b0:3a9:a49f:d6b8 with SMTP id
o6-20020a0568080bc600b003a9a49fd6b8mr8751353oik.0.1699092734604; Sat, 04 Nov
2023 03:12:14 -0700 (PDT)
Path: i2pn2.org!i2pn.org!weretis.net!feeder6.news.weretis.net!usenet.blueworldhosting.com!diablo1.usenet.blueworldhosting.com!peer03.iad!feed-me.highwinds-media.com!news.highwinds-media.com!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.astro.amateur
Date: Sat, 4 Nov 2023 03:12:14 -0700 (PDT)
In-Reply-To: <9c96c1d8-26be-4d7b-8410-9d74a0ebf185n@googlegroups.com>
Injection-Info: google-groups.googlegroups.com; posting-host=2600:1700:47f7:2800:81f0:931e:8a0a:c91a;
posting-account=tS_DdwkAAABh2_lUXXZvPfbiutm4lA38
NNTP-Posting-Host: 2600:1700:47f7:2800:81f0:931e:8a0a:c91a
References: <9c96c1d8-26be-4d7b-8410-9d74a0ebf185n@googlegroups.com>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <9bec1fa4-fae1-4a55-a020-1e0ee21496a6n@googlegroups.com>
Subject: Re: How much light does a refractor let through (in percentage)? 60%
70% 80% 90% Etc.
From: wsnel...@hotmail.com (W)
Injection-Date: Sat, 04 Nov 2023 10:12:14 +0000
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Received-Bytes: 1691
 by: W - Sat, 4 Nov 2023 10:12 UTC

On Friday, November 3, 2023 at 4:32:32 PM UTC-4, Jean Mario Charest wrote:
> How much light does a refractor let through (in percentage)?
>
> 60%
> 70%
> 80%
> 90%
> Etc.
For an old uncoated objective the number would be in the 85% range.

For many modern coated objectives the number would be in the 95% range.

The best anti-reflection coatings bring the number into the high 90s.

Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.

<3ngcki1ilcs2vebhkf8hisesj13k2deolu@4ax.com>

  copy mid

https://www.novabbs.com/tech/article-flat.php?id=10850&group=sci.astro.amateur#10850

  copy link   Newsgroups: sci.astro.amateur
Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!diablo1.usenet.blueworldhosting.com!peer03.iad!feed-me.highwinds-media.com!news.highwinds-media.com!fx46.iad.POSTED!not-for-mail
From: clp...@alumni.caltech.edu (Chris L Peterson)
Newsgroups: sci.astro.amateur
Subject: Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.
Message-ID: <3ngcki1ilcs2vebhkf8hisesj13k2deolu@4ax.com>
References: <9c96c1d8-26be-4d7b-8410-9d74a0ebf185n@googlegroups.com> <iuqaki5nh5jos67o38fiufdbab6cvqdel1@4ax.com> <b3ff2664-9484-4062-87f8-1b77f86a86a8n@googlegroups.com>
X-Newsreader: Forte Agent 6.00/32.1186
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Lines: 22
X-Complaints-To: abuse@easynews.com
Organization: Forte - www.forteinc.com
X-Complaints-Info: Please be sure to forward a copy of ALL headers otherwise we will be unable to process your complaint properly.
Date: Sat, 04 Nov 2023 07:11:58 -0600
X-Received-Bytes: 1510
 by: Chris L Peterson - Sat, 4 Nov 2023 13:11 UTC

On Fri, 3 Nov 2023 18:54:08 -0700 (PDT), StarDust <csoka01@gmail.com>
wrote:

>On Friday, November 3, 2023 at 2:55:44?PM UTC-7, Chris L Peterson wrote:
>> On Fri, 3 Nov 2023 13:32:30 -0700 (PDT), Jean Mario Charest
>> <ve2...@gmail.com> wrote:
>>
>> >How much light does a refractor let through (in percentage)?
>> >
>> >60%
>> >70%
>> >80%
>> >90%
>> >Etc.
>> If it's a good quality refractor, I'd figure about 0.5% loss per
>> air-to-glass surface.
>
>So, it means a doublet refractor let's more light through than a triplet?
>?

Depends on the design. Not all doublets or triplets have all of their
surfaces facing air.

Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.

<c77850d6-f2f9-4383-a4e0-ccc3fc26f21dn@googlegroups.com>

  copy mid

https://www.novabbs.com/tech/article-flat.php?id=10851&group=sci.astro.amateur#10851

  copy link   Newsgroups: sci.astro.amateur
X-Received: by 2002:a05:620a:4007:b0:773:ad95:aa16 with SMTP id h7-20020a05620a400700b00773ad95aa16mr517708qko.4.1699150476275;
Sat, 04 Nov 2023 19:14:36 -0700 (PDT)
X-Received: by 2002:a9d:6b1a:0:b0:6bc:fb26:499e with SMTP id
g26-20020a9d6b1a000000b006bcfb26499emr7258812otp.2.1699150475773; Sat, 04 Nov
2023 19:14:35 -0700 (PDT)
Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!diablo1.usenet.blueworldhosting.com!peer01.iad!feed-me.highwinds-media.com!news.highwinds-media.com!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.astro.amateur
Date: Sat, 4 Nov 2023 19:14:35 -0700 (PDT)
In-Reply-To: <b3ff2664-9484-4062-87f8-1b77f86a86a8n@googlegroups.com>
Injection-Info: google-groups.googlegroups.com; posting-host=2600:1700:47f7:2800:39a0:1994:46ef:2166;
posting-account=tS_DdwkAAABh2_lUXXZvPfbiutm4lA38
NNTP-Posting-Host: 2600:1700:47f7:2800:39a0:1994:46ef:2166
References: <9c96c1d8-26be-4d7b-8410-9d74a0ebf185n@googlegroups.com>
<iuqaki5nh5jos67o38fiufdbab6cvqdel1@4ax.com> <b3ff2664-9484-4062-87f8-1b77f86a86a8n@googlegroups.com>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <c77850d6-f2f9-4383-a4e0-ccc3fc26f21dn@googlegroups.com>
Subject: Re: How much light does a refractor let through (in percentage)? 60%
70% 80% 90% Etc.
From: wsnel...@hotmail.com (W)
Injection-Date: Sun, 05 Nov 2023 02:14:36 +0000
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Received-Bytes: 2038
 by: W - Sun, 5 Nov 2023 02:14 UTC

On Friday, November 3, 2023 at 9:54:10 PM UTC-4, StarDust wrote:
> On Friday, November 3, 2023 at 2:55:44 PM UTC-7, Chris L Peterson wrote:
> > On Fri, 3 Nov 2023 13:32:30 -0700 (PDT), Jean Mario Charest
> > <ve2...@gmail.com> wrote:
> >
> > >How much light does a refractor let through (in percentage)?
> > >
> > >60%
> > >70%
> > >80%
> > >90%
> > >Etc.
> > If it's a good quality refractor, I'd figure about 0.5% loss per
> > air-to-glass surface.
> So, it means a doublet refractor let's more light through than a triplet?
> 🤔

The triplet will probably have better coatings.

Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.

<ce1b0c34-6cb6-4489-917a-c3aef231f74an@googlegroups.com>

  copy mid

https://www.novabbs.com/tech/article-flat.php?id=10852&group=sci.astro.amateur#10852

  copy link   Newsgroups: sci.astro.amateur
X-Received: by 2002:a05:6214:169:b0:670:7ac7:ec28 with SMTP id y9-20020a056214016900b006707ac7ec28mr361532qvs.6.1699150984195;
Sat, 04 Nov 2023 19:23:04 -0700 (PDT)
X-Received: by 2002:a05:6808:1529:b0:3ad:f525:52bf with SMTP id
u41-20020a056808152900b003adf52552bfmr10632779oiw.1.1699150983897; Sat, 04
Nov 2023 19:23:03 -0700 (PDT)
Path: i2pn2.org!i2pn.org!weretis.net!feeder8.news.weretis.net!proxad.net!feeder1-2.proxad.net!209.85.160.216.MISMATCH!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.astro.amateur
Date: Sat, 4 Nov 2023 19:23:03 -0700 (PDT)
In-Reply-To: <3ngcki1ilcs2vebhkf8hisesj13k2deolu@4ax.com>
Injection-Info: google-groups.googlegroups.com; posting-host=2600:1010:a010:aa44:149f:7bef:d38:fe90;
posting-account=q0dsSgoAAAAV0Xmlj0Dt_FOS5sPk02Ml
NNTP-Posting-Host: 2600:1010:a010:aa44:149f:7bef:d38:fe90
References: <9c96c1d8-26be-4d7b-8410-9d74a0ebf185n@googlegroups.com>
<iuqaki5nh5jos67o38fiufdbab6cvqdel1@4ax.com> <b3ff2664-9484-4062-87f8-1b77f86a86a8n@googlegroups.com>
<3ngcki1ilcs2vebhkf8hisesj13k2deolu@4ax.com>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <ce1b0c34-6cb6-4489-917a-c3aef231f74an@googlegroups.com>
Subject: Re: How much light does a refractor let through (in percentage)? 60%
70% 80% 90% Etc.
From: csok...@gmail.com (StarDust)
Injection-Date: Sun, 05 Nov 2023 02:23:04 +0000
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
 by: StarDust - Sun, 5 Nov 2023 02:23 UTC

On Saturday, November 4, 2023 at 6:12:05 AM UTC-7, Chris L Peterson wrote:
> On Fri, 3 Nov 2023 18:54:08 -0700 (PDT),
> >On Friday, November 3, 2023 at 2:55:44?PM UTC-7, Chris L Peterson wrote:
> >> On Fri, 3 Nov 2023 13:32:30 -0700 (PDT), Jean Mario Charest
> >> <ve2...@gmail.com> wrote:
> >>
> >> >How much light does a refractor let through (in percentage)?
> >> >
> >> >60%
> >> >70%
> >> >80%
> >> >90%
> >> >Etc.
> >> If it's a good quality refractor, I'd figure about 0.5% loss per
> >> air-to-glass surface.
> >
> >So, it means a doublet refractor let's more light through than a triplet?
> >?
>
> Depends on the design. Not all doublets or triplets have all of their
> surfaces facing air.

Your telescopes Chris are oil filled, isn't it?

Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.

<0452d186-b17a-4ac5-a43e-d048472a5139n@googlegroups.com>

  copy mid

https://www.novabbs.com/tech/article-flat.php?id=10853&group=sci.astro.amateur#10853

  copy link   Newsgroups: sci.astro.amateur
X-Received: by 2002:ad4:4b24:0:b0:66d:6179:8e18 with SMTP id s4-20020ad44b24000000b0066d61798e18mr447595qvw.11.1699194308935;
Sun, 05 Nov 2023 06:25:08 -0800 (PST)
X-Received: by 2002:a9d:4795:0:b0:6c8:f9bc:f768 with SMTP id
b21-20020a9d4795000000b006c8f9bcf768mr7753887otf.1.1699194308709; Sun, 05 Nov
2023 06:25:08 -0800 (PST)
Path: i2pn2.org!rocksolid2!news.neodome.net!news.mixmin.net!proxad.net!feeder1-2.proxad.net!209.85.160.216.MISMATCH!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.astro.amateur
Date: Sun, 5 Nov 2023 06:25:08 -0800 (PST)
In-Reply-To: <ce1b0c34-6cb6-4489-917a-c3aef231f74an@googlegroups.com>
Injection-Info: google-groups.googlegroups.com; posting-host=166.62.178.220; posting-account=hrCbwAoAAACpQkeyo_zNw5eVaL6rQ0dN
NNTP-Posting-Host: 166.62.178.220
References: <9c96c1d8-26be-4d7b-8410-9d74a0ebf185n@googlegroups.com>
<iuqaki5nh5jos67o38fiufdbab6cvqdel1@4ax.com> <b3ff2664-9484-4062-87f8-1b77f86a86a8n@googlegroups.com>
<3ngcki1ilcs2vebhkf8hisesj13k2deolu@4ax.com> <ce1b0c34-6cb6-4489-917a-c3aef231f74an@googlegroups.com>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <0452d186-b17a-4ac5-a43e-d048472a5139n@googlegroups.com>
Subject: Re: How much light does a refractor let through (in percentage)? 60%
70% 80% 90% Etc.
From: ve2...@gmail.com (Jean Mario Charest)
Injection-Date: Sun, 05 Nov 2023 14:25:08 +0000
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
 by: Jean Mario Charest - Sun, 5 Nov 2023 14:25 UTC

Le samedi 4 novembre 2023 à 22 h 23 min 05 s UTC-4, StarDust a écrit :
> On Saturday, November 4, 2023 at 6:12:05 AM UTC-7, Chris L Peterson wrote:
> > On Fri, 3 Nov 2023 18:54:08 -0700 (PDT),
> > >On Friday, November 3, 2023 at 2:55:44?PM UTC-7, Chris L Peterson wrote:
> > >> On Fri, 3 Nov 2023 13:32:30 -0700 (PDT), Jean Mario Charest
> > >> <ve2...@gmail.com> wrote:
> > >>
> > >> >How much light does a refractor let through (in percentage)?
> > >> >
> > >> >60%
> > >> >70%
> > >> >80%
> > >> >90%
> > >> >Etc.
> > >> If it's a good quality refractor, I'd figure about 0.5% loss per
> > >> air-to-glass surface.
> > >
> > >So, it means a doublet refractor let's more light through than a triplet?
> > >?
> >
> > Depends on the design. Not all doublets or triplets have all of their
> > surfaces facing air.
> Your telescopes Chris are oil filled, isn't it?
Thank you for your advice. It's a 156mm achromatic doublet that I bought this spring. I didn't have the chance to observe with it. Also I want to buy a used Newton 200mm/1000mm f5.0 SkyWatcher but it doesn't have the cranford 10:1 just plain. but I doubt it needs to be coating on the primary mirror and the secondary mirror. How many years does a coating need to be redone?
It seems to me to be an old model.... Do you have a price for this tube and also it has a small dovetail for an 8''!!!!

Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.

<lm9fki5a5lg9v97h85rrc6885om1cj05ac@4ax.com>

  copy mid

https://www.novabbs.com/tech/article-flat.php?id=10854&group=sci.astro.amateur#10854

  copy link   Newsgroups: sci.astro.amateur
Path: i2pn2.org!i2pn.org!newsfeed.endofthelinebbs.com!usenet.blueworldhosting.com!diablo1.usenet.blueworldhosting.com!peer03.iad!feed-me.highwinds-media.com!news.highwinds-media.com!fx18.iad.POSTED!not-for-mail
From: clp...@alumni.caltech.edu (Chris L Peterson)
Newsgroups: sci.astro.amateur
Subject: Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.
Message-ID: <lm9fki5a5lg9v97h85rrc6885om1cj05ac@4ax.com>
References: <9c96c1d8-26be-4d7b-8410-9d74a0ebf185n@googlegroups.com> <iuqaki5nh5jos67o38fiufdbab6cvqdel1@4ax.com> <b3ff2664-9484-4062-87f8-1b77f86a86a8n@googlegroups.com> <3ngcki1ilcs2vebhkf8hisesj13k2deolu@4ax.com> <ce1b0c34-6cb6-4489-917a-c3aef231f74an@googlegroups.com>
X-Newsreader: Forte Agent 6.00/32.1186
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Lines: 30
X-Complaints-To: abuse@easynews.com
Organization: Forte - www.forteinc.com
X-Complaints-Info: Please be sure to forward a copy of ALL headers otherwise we will be unable to process your complaint properly.
Date: Sun, 05 Nov 2023 07:30:44 -0700
X-Received-Bytes: 2031
 by: Chris L Peterson - Sun, 5 Nov 2023 14:30 UTC

On Sat, 4 Nov 2023 19:23:03 -0700 (PDT), StarDust <csoka01@gmail.com>
wrote:

>On Saturday, November 4, 2023 at 6:12:05?AM UTC-7, Chris L Peterson wrote:
>> On Fri, 3 Nov 2023 18:54:08 -0700 (PDT),
>> >On Friday, November 3, 2023 at 2:55:44?PM UTC-7, Chris L Peterson wrote:
>> >> On Fri, 3 Nov 2023 13:32:30 -0700 (PDT), Jean Mario Charest
>> >> <ve2...@gmail.com> wrote:
>> >>
>> >> >How much light does a refractor let through (in percentage)?
>> >> >
>> >> >60%
>> >> >70%
>> >> >80%
>> >> >90%
>> >> >Etc.
>> >> If it's a good quality refractor, I'd figure about 0.5% loss per
>> >> air-to-glass surface.
>> >
>> >So, it means a doublet refractor let's more light through than a triplet?
>> >?
>>
>> Depends on the design. Not all doublets or triplets have all of their
>> surfaces facing air.
>
>Your telescopes Chris are oil filled, isn't it?

I mainly image with an RC, so no lenses. I have a small refractor I
use for occasional projects... a well corrected doublet, and I'm not
sure of the details of the objective.

Re: How much light does a refractor let through (in percentage)? 60% 70% 80% 90% Etc.

<b3fbea62-e13a-4982-bf4d-b2978b4d5cc4n@googlegroups.com>

  copy mid

https://www.novabbs.com/tech/article-flat.php?id=10857&group=sci.astro.amateur#10857

  copy link   Newsgroups: sci.astro.amateur
X-Received: by 2002:a05:620a:674a:b0:77a:296:f81b with SMTP id rq10-20020a05620a674a00b0077a0296f81bmr487907qkn.9.1699323754755;
Mon, 06 Nov 2023 18:22:34 -0800 (PST)
X-Received: by 2002:a05:6870:d394:b0:1dd:ac4:bc14 with SMTP id
k20-20020a056870d39400b001dd0ac4bc14mr597651oag.1.1699323754521; Mon, 06 Nov
2023 18:22:34 -0800 (PST)
Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!diablo1.usenet.blueworldhosting.com!peer03.iad!feed-me.highwinds-media.com!news.highwinds-media.com!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.astro.amateur
Date: Mon, 6 Nov 2023 18:22:34 -0800 (PST)
In-Reply-To: <7fffee04-6507-4bd0-9591-19a45d301091n@googlegroups.com>
Injection-Info: google-groups.googlegroups.com; posting-host=2600:1010:a000:ecff:646e:78c7:d232:ac14;
posting-account=q0dsSgoAAAAV0Xmlj0Dt_FOS5sPk02Ml
NNTP-Posting-Host: 2600:1010:a000:ecff:646e:78c7:d232:ac14
References: <9c96c1d8-26be-4d7b-8410-9d74a0ebf185n@googlegroups.com> <7fffee04-6507-4bd0-9591-19a45d301091n@googlegroups.com>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <b3fbea62-e13a-4982-bf4d-b2978b4d5cc4n@googlegroups.com>
Subject: Re: How much light does a refractor let through (in percentage)? 60%
70% 80% 90% Etc.
From: csok...@gmail.com (StarDust)
Injection-Date: Tue, 07 Nov 2023 02:22:34 +0000
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Received-Bytes: 2052
 by: StarDust - Tue, 7 Nov 2023 02:22 UTC

On Monday, November 6, 2023 at 5:47:55 PM UTC-8, Rich wrote:
> On Friday, 3 November 2023 at 16:32:32 UTC-4, Jean Mario Charest wrote:
> > How much light does a refractor let through (in percentage)?
> >
> > 60%
> > 70%
> > 80%
> > 90%
> > Etc.
> Depends on the frequency and the angle the light hits the lens at. Perpendicular rays of green light would loose about 0.5% per coated surface. So for an air-spaced triplet apo, about 3% or so. Light rays in blue or red end of the spectrum would lose more percentages and light hitting a curved lens at the edge (partially glancing blow) could lose as much as 20%.

What if I leave the cover on by accident?
😃

1
server_pubkey.txt

rocksolid light 0.9.81
clearnet tor