[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

Re: [APML] 2 inch adapter and now focusers and such

To: Discussion of Film Astrophotography <astro-photo@seds.org>
Subject: Re: [APML] 2 inch adapter and now focusers and such
From: George Anderson <georgea@cam.org>
Date: Fri, 07 Mar 2003 22:55:17 -0500
List-Archive: <http://seds.org/mailman/private/astro-photo>
List-Help: <mailto:astro-photo-request@seds.org?subject=help>
List-Id: Discussion of Film Astrophotography <astro-photo.seds.org>
List-Post: <mailto:astro-photo@seds.org>
List-Subscribe: <http://seds.org/mailman/listinfo/astro-photo>,<mailto:astro-photo-request@seds.org?subject=subscribe>
List-Unsubscribe: <http://seds.org/mailman/listinfo/astro-photo>,<mailto:astro-photo-request@seds.org?subject=unsubscribe>
References: <9A1AD03DD29ED4119CA900104BCD40384362@CC><000b01c2e28e$38ad2560$5345fea9@rocinante2><002201c2e2a3$93603e60$0100a8c0@mshome.net><006201c2e2c1$f0b42ae0$5345fea9@rocinante2><001f01c2e333$752cc220$5345fea9@rocinante2><00d101c2e50b$cb8cd2c0$5345fea9@rocinante2>
Reply-To: Discussion of Film Astrophotography <astro-photo@seds.org>
Sender: astro-photo-bounces@seds.org

Hi Brian

The only place I know of that does magnesium flouride coatings (and
remember I live in the frozen wasteland called Canada) is Moonward
Coatings in Sudbury Ontario. I am sure that there are places in the US
that also do lens coatings though.
I doubt if Roland will sell just the objective lens and cell for a
scope, but I could be wrong. You may want to try dropping him a line at
his e-mail address. I have had good luck with him answering messages
sent to him.
I suspect that Roland's lenses are better than the Vixen flourites but I
have no proof for that statement. The lens and cell are only part of the
cost of the scope from AP though. The tube is made to tight tolerances
and the focusers are a dream (and they can be purchased seperately.
I know that Roland handles the final phase of figuring of every lens
that goes oot of the AP factory, which is why the production runs are so
small and the price so high. Vixen is probably able to procure glass of
the same quality and types as AP, but it is that black magic touch that
makes the difference. 
If you do decide to go the Vixen route you may want to contact Joe
O'neil from the APML list, he was a Vixen dealer and is very honest (he
even tells customers that his mounts are no good for AP work) and he may
be able to give you the scoop on buying a Vixen Flourite lens assembly.
If you can handle the additional e-mail traffic (about 50+ e-mails a
day) you might want to join the Amateur Telescope Makers list and lurk
for a while to get some ideas and sources.

George

Clear skies and good health from the land of Geddy Lee
Brian Larmay wrote:
> 
> Thanks George!
> 
> Speaking of abnormal glass, if I were to grab a lens from somewhere and
> wanted it coated, where would I have to send it to to have that done?
> Does Astrophysics deal in anything like that?
> Is one able to buy an Objective just by itself from there?
> 
> What are the major differances in lets say an Vixen flourite over an
> Astrophysics flourite?.... Glass? The workers? Testing?
> 
> Thanks,
> Brian
> 
> ----- Original Message -----
> From: "George Anderson" <georgea@cam.org>
> To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
> Sent: Wednesday, March 05, 2003 9:31 PM
> Subject: Re: [APML] 2 inch adapter and now focusers and such
> 
> > Hi Brian
> >
> > What you have is an achromat, the number of elements does not determine
> > APO vs Achro. An apochromatic lens uses abnormal glass (eg flourite) for
> > one of the elements so that all colours fall into focus on the same
> > plane.
> > The 4 element copy lens is sort of like a very large Kellner eyepiece,
> > two identical achromats placed back to back.
> > To Roland and the others, please correct any misleading information
> > above.
> >
> > George Anderson
> > Montreal Canada
> >
> > Clear skies and good health
> >
> > Brian Larmay wrote:
> > >
> > > Hi Clay,
> > >
> > > Its just a 280mm f 1:4.5 tominon copy lens, which appears to be a four
> > > element objective with a stop in the middle.
> > > I read somewhere and found only one bit of literature that it is a six
> > > element, but I doubt that from what I can see.
> > > Being a four element, wouldnt that make this an apochromatic instead of
> > > achromatic?
> > >
> > > I know its just a copy lens, but hey, why not<g>!
> > >
> > > As far as facilities are concerned, notta..Im at the mercy of a very
> limited
> > > budget right now, and I have access to nothing.
> > >
> > > So as far as the 2" focuser...
> > >
> > > I went to ace yesterday and brought my t ring with so I could find some
> thin
> > > metal tubing to thread to it but with no availe..
> > > I even went as far as...Hey...I can try to weld or solder this thing  to
> a
> > > makeshift drawtube over the whole T-ring itself so I get no
> > > obstruction...again..lol.
> > > By that time my wheels were turning too fast and I was getting ahead of
> > > myself without draw plans...I need to make one of these....probably
> going to
> > > end up with a few of them.
> > >
> > > Well my brain is on overload due to no sleep last night so Im going to
> give
> > > it a rest for a few hours
> > >
> > > Thanks for your support Clay, Im sure I'll have more questions and Ill
> > > contact you off list.
> > >
> > > Thanks again,
> > > Brian
> > >
> > > > Brian,
> > > >
> > > > I know the feeling.  What objective are you using for this scope?
> And, if
> > > > you don't mind my asking, what facilities do you have access to to
> make
> > > the
> > > > various "parts and pieces".  I went through a lot of the same decision
> > > > processes that you are doing now when I built my first refractor.  It
> was
> > > > well worth it.  It has become my most used astrograph to date and can
> take
> > > > much better astrophotos that I can - even if it is a "lowly achromat".
> > > >
> > > > I second Don's recommendation for a larger than 2" focuser if
> possible.
> > > > Don't forget - you may want to try medium format sometime in the
> future.
> > > I
> > > > did not find a large format commercial focuser at a reasonable price
> when
> > > I
> > > > was building my scope but there are more choices out there now.
> > > >
> > > > I don,t know where you are located.  If I can be of help drop me a
> line
> > > > "off-list".
> > > >
> > > > Clay
> > > >
> > > > ----- Original Message -----
> > > > From: "Brian Larmay" <astrobri@ameritech.net>
> > > > To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
> > > > Sent: Tuesday, March 04, 2003 9:50 PM
> > > > Subject: Re: [APML] 2 inch adapter and now focusers and such
> > > >
> > > >
> > > > > Hi Clay,
> > > > >
> > > > > Im starting to get picky on how Im building this thing now..
> > > > > Im getting the itch to make this scope into superscope, but I need
> to
> > > > start
> > > > > from scratch starting with the tubeing first so that I can adapt a
> > > decent
> > > > > focuser...maybe a megrez.
> > > > > I hear those are nice little focusers.
> > > > > I opened the B shutter with the film door open to see how much the
> frame
> > > > > gets cut between 1.25-2" and theres a huge differance.
> > > > >
> > > > > This is turning into a little bit of fun here:)
> > > > >
> > > > > I have 2 more main objectives to work with so the last two Ill be
> > > thinking
> > > > > of a bigger game plan.
> > > > > Hopefully Ill have this project done in time for summer.
> > > > >
> > > > > Thanks again,
> > > > > Bian
> > > > >
> > > > >
> > > > >
> > > > > > Brian,
> > > > > >
> > > > > > The length of the focus tube can hav an effect on vignetting and
> > > > exposure
> > > > > IF
> > > > > > it blocks part of the objective (forming an effective apature
> mask).
> > > > When
> > > > > I
> > > > > > built my 4" f6 refractor I wanted it to focus both a camera and my
> > > range
> > > > > of
> > > > > > eyepieces.  This dictated a rather long draw tube.  I used a 2"
> > > focuser
> > > > > for
> > > > > > a while but I eventually built a 3" crayford focuser.  In this I
> have
> > > a
> > > > > > drawtube with a large inside diameter.  I bring this to 2" at the
> end
> > > > > only.
> > > > > > This has worked out well.  I have some pictures of the focuser
> parts
> > > and
> > > > a
> > > > > > description of the build process here:
> > > > > > http://www.gatecom.com/~ckessler/ATM%20Focuser.htm
> > > > > >
> > > > > > The refractor kit is described here:
> > > > > > http://www.gatecom.com/~ckessler/bw_optik_4.htm
> > > > > >
> > > > > > I hope this helps
> > > > > >
> > > > > > Clay Kessler
> > > > > >
> > > > > > ----- Original Message -----
> > > > > > From: "Brian Larmay" <astrobri@ameritech.net>
> > > > > > To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
> > > > > > Sent: Tuesday, March 04, 2003 3:39 PM
> > > > > > Subject: Re: [APML] 2 inch camera adapter question
> > > > > >
> > > > > >
> > > > > > > Thanks Frank,
> > > > > > >
> > > > > > > Does the length of focus, such as the focusing barrel/tube have
> > > impact
> > > > > on
> > > > > > > vignette or how long to expose for also?
> > > > > > >
> > > > > > > or....
> > > > > > >
> > > > > > > Should I make the main barrel of the refractor tube as close as
> > > > possibe
> > > > > to
> > > > > > > prime focus, so I dont have to have a long focusing barrel?
> > > > > > >
> > > > > > > This is hard to explain because Im making this refractor from
> > > scratch
> > > > > and
> > > > > > > Ive never built one before.
> > > > > > > I should really be going to ATM, but being that this scope is
> > > > > photographic
> > > > > > > in nature, I will ask here.
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Brian
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > ----- Original Message -----
> > > > > > > From: "Frank Parrotta (Navy Yard)" <FParrotta@TSC.COM>
> > > > > > > To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
> > > > > > > Sent: Tuesday, March 04, 2003 10:09 AM
> > > > > > > Subject: RE: [APML] 2 inch camera adapter question
> > > > > > >
> > > > > > >
> > > > > > > > Brian,
> > > > > > > >
> > > > > > > > As John has said, you really can't use the 1.25" if you want
> to
> > > > > > illuminate
> > > > > > > > as much of the 35mm frame as you can.  However, you're still
> not
> > > > home
> > > > > > > free.
> > > > > > > > The camera T-ring will also vignette the frame as well - the
> > > amount
> > > > > > > > depending on the focal ratio.  I find that the corners get
> pretty
> > > > dark
> > > > > > but
> > > > > > > > the central core of the frame is usable with some vignetting
> > > removal
> > > > > > > > processing.  If you want to get an idea of just how much light
> > > > falloff
> > > > > > > > you'll have to content with, set up your scope with the camera
> > > > > attached
> > > > > > > and
> > > > > > > > aim it at an evenly illuminated source (e.g., blue sky, white
> > > > painted
> > > > > > > wall,
> > > > > > > > etc.).  Set the shutter to "B" and open the camera back.  Fire
> the
> > > > > > shutter
> > > > > > > > and look through the camera back opening (where the film would
> be)
> > > > and
> > > > > > > > notice the illuminated circle produced by the objective.  Move
> > > your
> > > > > eye
> > > > > > > > around to the frame's edges and corners - the amount of the
> > > > > illuminated
> > > > > > > > circle that is obscured at each location will be proportional
> to
> > > the
> > > > > > > amount
> > > > > > > > of vignetting you will get at those locations.  Hope this
> helps.
> > > > > > > >
> > > > > > > > Frank
> > > > > > > >
> > > > > > > > -----Original Message-----
> > > > > > > > From: Brian Larmay [mailto:astrobri@ameritech.net]
> > > > > > > > Sent: Sunday, March 02, 2003 3:40 PM
> > > > > > > > To: astro-photo@seds.org
> > > > > > > > Subject: [APML] 2 inch camera adapter question
> > > > > > > >
> > > > > > > >
> > > > > > > > Hi!
> > > > > > > >
> > > > > > > > What are the advantages photographically of a 2 inch camera
> > > adapter
> > > > > over
> > > > > > a
> > > > > > > > 1.25.
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Brian
> > > > > > > >
> > > > > > > >
> > > > > > > > My Photography
> > > > > > > > Nature: http://www.astrobri.com/nature_photography.htm
> > > > > > > > Astrophotography:
> http://www.astrobri.com/astrophotography_ind.htm
> > > > > > > > Storm chasing photography:
> > > > > > > > http://www.astrobri.com/weather_pictures_2002_season.htm
> > > > > > > > Northern Lights: http://www.astrobri.com/northern_lights.htm
> > > > > > > > Miscellaneous: http://www.astrobri.com/miscellaneous.htm
> > > > > > > >
> > > > > > > >
> > > > > > > > ---
> > > > > > > > Outgoing mail is certified Virus Free.
> > > > > > > > Checked by AVG anti-virus system (http://www.grisoft.com).
> > > > > > > > Version: 6.0.456 / Virus Database: 256 - Release Date: 2/18/03
> > > > > > > >
> > > > > > > > _______________________________________________
> > > > > > > > Astro-Photo mailing list
> > > > > > > > Astro-Photo@seds.org
> > > > > > > > http://seds.org/mailman/listinfo/astro-photo
> > > > > > > > _______________________________________________
> > > > > > > > Astro-Photo mailing list
> > > > > > > > Astro-Photo@seds.org
> > > > > > > > http://seds.org/mailman/listinfo/astro-photo
> > > > > > >
> > > > > > >
> > > > > > > ---
> > > > > > > Outgoing mail is certified Virus Free.
> > > > > > > Checked by AVG anti-virus system (http://www.grisoft.com).
> > > > > > > Version: 6.0.456 / Virus Database: 256 - Release Date: 2/18/03
> > > > > > >
> > > > > > > _______________________________________________
> > > > > > > Astro-Photo mailing list
> > > > > > > Astro-Photo@seds.org
> > > > > > > http://seds.org/mailman/listinfo/astro-photo
> > > > > >
> > > > > >
> > > > > > _______________________________________________
> > > > > > Astro-Photo mailing list
> > > > > > Astro-Photo@seds.org
> > > > > > http://seds.org/mailman/listinfo/astro-photo
> > > > >
> > > > >
> > > > > ---
> > > > > Outgoing mail is certified Virus Free.
> > > > > Checked by AVG anti-virus system (http://www.grisoft.com).
> > > > > Version: 6.0.456 / Virus Database: 256 - Release Date: 2/18/03
> > > > >
> > > > > _______________________________________________
> > > > > Astro-Photo mailing list
> > > > > Astro-Photo@seds.org
> > > > > http://seds.org/mailman/listinfo/astro-photo
> > > > >
> > > >
> > > >
> > > > _______________________________________________
> > > > Astro-Photo mailing list
> > > > Astro-Photo@seds.org
> > > > http://seds.org/mailman/listinfo/astro-photo
> > >
> > > ---
> > > Outgoing mail is certified Virus Free.
> > > Checked by AVG anti-virus system (http://www.grisoft.com).
> > > Version: 6.0.459 / Virus Database: 258 - Release Date: 2/25/03
> > >
> > > _______________________________________________
> > > Astro-Photo mailing list
> > > Astro-Photo@seds.org
> > > http://seds.org/mailman/listinfo/astro-photo
> > _______________________________________________
> > Astro-Photo mailing list
> > Astro-Photo@seds.org
> > http://seds.org/mailman/listinfo/astro-photo
> 
> ---
> Outgoing mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.459 / Virus Database: 258 - Release Date: 2/25/03
> 
> _______________________________________________
> Astro-Photo mailing list
> Astro-Photo@seds.org
> http://seds.org/mailman/listinfo/astro-photo
_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo

Follow-Ups:
- Re: [APML] 2 inch adapter and now focusers and such
  - From: "Brian Larmay" <astrobri@ameritech.net>

References:
- RE: [APML] 2 inch camera adapter question
  - From: "Frank Parrotta (Navy Yard)" <FParrotta@TSC.COM>
- Re: [APML] 2 inch camera adapter question
  - From: "Brian Larmay" <astrobri@ameritech.net>
- Re: [APML] 2 inch camera adapter question
  - From: "Clayton Kessler" <ckessler@gatecom.com>
- Re: [APML] 2 inch adapter and now focusers and such
  - From: "Brian Larmay" <astrobri@ameritech.net>
- Re: [APML] 2 inch adapter and now focusers and such
  - From: "Brian Larmay" <astrobri@ameritech.net>
- Re: [APML] 2 inch adapter and now focusers and such
  - From: "Brian Larmay" <astrobri@ameritech.net>

Prev by Author: Re: [APML] 2 inch adapter and now focusers and such
Next by Author: Re: [APML] Leo Duet
Prev by thread: Re: [APML] 2 inch adapter and now focusers and such
Next by thread: Re: [APML] 2 inch adapter and now focusers and such
Index(es):
- Author
- Thread