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  #21  
Old 31-08-2012, 10:57 AM
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glenc (Glen)
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William Herschel's 24"

Next time you are in Madrid stop in to the Real Observatorio de Madrid (ROM) and see a replica of William Herschel's 24" aperture 25' long telescope.
Herschel sold the 24" to the King of Spain for 3150 pounds. It was delivered in 1801, erected in 1804 and destroyed by Napoleon's troops in 1808.
http://upload.wikimedia.org/wikipedi...jpg?uselang=es
http://www.flickr.com/photos/surveyo...ry/6790147664/

my new avatar
http://www.cielosboreales.com/wp-con...ioherschel.jpg

http://www.flickr.com/photos/luiyo/7036124529/
http://www.flickr.com/photos/surveyo...n/photostream/

Last edited by glenc; 06-09-2012 at 06:00 PM.
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  #22  
Old 06-09-2012, 05:37 PM
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glenc (Glen)
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1,088 John Herschel Objects

This 15.1 Mb pdf file contains images of 1,088 deep sky objects that were found by John Herschel with an
18.5 inch aperture speculum reflector when he was at the Cape, South Africa between 1834 and 1838.
https://docs.google.com/open?id=0B9I...0d1NWx5eEo0OHc
I like NGC 646. The galaxy trio NGCs 6769, 6770, 6771 is only 1.1 degrees SE of the bright globular NGC 6752

The images were copied from http://www.ngcicproject.org/dss/dss_ngc.asp
http://www.ngcicproject.org/dssack.htm

Last edited by glenc; 06-09-2012 at 06:48 PM.
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  #23  
Old 07-10-2012, 03:29 AM
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Maps and Pictures

William Herschel observed from
Bath (1773-82) http://binged.it/RlqCWg
Datchet (1782-85) http://binged.it/R1lFo6
Clay Hall (1785-86) http://binged.it/RlqfuS
Slough (1786-1802) http://binged.it/Wz7xDn

John Herschel observed from
Slough (1823-1832)
Feldhausen (1834-38) http://binged.it/T7Fx5u
John also lived at Hawkhurst http://binged.it/RluKFU

See also
Bath http://en.wikipedia.org/wiki/File:He..._Bath_2005.jpg
Datchet http://www.datchethistory.org.uk/Her...e_herschel.htm
Clay Hall http://www.gettyimages.com.au/detail...Language=en-US

Slough (large file) http://www.sopse.org.uk/asset_arena/...e-i-00-000.jpg
Feldhausen http://assa.saao.ac.za/html/his-obs-...all_Hersc.html
Hawkhurst http://www.thesoul-space.com/the-spa...ngwood-history

Family Tree (John and Margaret had 12 children) http://members.dodo.com.au/~tr0j/tree/gp17.html

Last edited by glenc; 07-10-2012 at 04:31 AM.
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Old 11-10-2012, 02:20 AM
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Magnitude Limits

How faint were the galaxies that the Herschels saw?
How good was their speculum reflector compared to the refractors used by others?

The answers are in the attached table.
Columns
Observers that found more than 50 NGC and IC galaxies
Number of galaxies found, visual not photographic
Sorted by aperture in inches, speculum reflectors in yellow
5% of galaxies are brighter than magnitude
25% of galaxies are brighter than magnitude
50% of galaxies are brighter than magnitude
75% of galaxies are brighter than magnitude
95% of galaxies are brighter than magnitude
Faintest galaxy seen ?? The faintest galaxy magnitudes may not be reliable.

95% of the galaxies found by William Herschel were brighter than magnitude 13.9.
95% of the galaxies found by John Herschel were brighter than magnitude 14.1.


Speculum only reflects 65% of the light.
William Herschel used the front view with no secondary after 13 Oct 1786.

Bigourdan did an amazing job with a 12.4" refractor!
Attached Files
File Type: pdf Gxy vis mags.pdf (21.6 KB, 15 views)
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  #26  
Old 14-04-2015, 04:17 PM
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ebook Sir William Herschel: His Life and Works

An ebook about William Herschel
http://www.gutenberg.org/files/29031...-h/29031-h.htm

Title: Sir William Herschel: His Life and Works
Author: Edward Singleton Holden
Release Date: June 3, 2009 [EBook #29031]

In the following account of the life and works of Sir William Herschel, I (Edward Singleton Holden) have been obliged to depend strictly upon data already in print—the Memoir of his sister, his own scientific writings and the memoirs and diaries of his cotemporaries. The review of his published works will, I trust, be of use. It is based upon a careful study of all his papers in the Philosophical Transactions and elsewhere.
A life of Herschel which shall be satisfactory in every particular can only be written after a full examination of the materials which are preserved at the family seat in England; but as two generations have passed since his death, and as no biography yet exists which approaches to completeness, no apology seems to me to be needed for a conscientious attempt to make the best use of the scanty material which we do possess.
[Pg vi]
This study will, I trust, serve to exhibit so much of his life as belongs to the whole public. His private life belongs to his family, until the time is come to let the world know more of the greatest of practical astronomers and of the inner life of one of its most profound philosophers,—of a great and ardent mind, whose achievements are and will remain the glory of England.
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  #27  
Old 05-03-2019, 11:52 PM
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The latest Australian Sky & Telescope has an article about observing all the objects found by William Herschel. If you want a shorter list of William and John Herschel objects see post #2.
393 of these objects are south of declination +45 and 30 of those are visible in March at 10pm..

The William & John Herschel 450 deep sky object (DSO) list is made up of:
73 Herschel open clusters brighter than magnitude 7.0
74 Herschel globular clusters
66 Herschel nebulae (some are also clusters)
58 Herschel planetary nebulae
161 Herschel galaxies brighter than magnitude 10.5 and
18 objects in the LMC, SMC, M31 and M33.

Last edited by glenc; 07-03-2019 at 03:16 PM.
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  #28  
Old 06-03-2019, 12:55 AM
Saturnine (Jeff)
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Good of you to revive this thread Glen, also received my S & T today and saw the article about the Herschel Hunt and thought to myself that it makes an interesting observing mission to hunt down the objects on the lists.
After the Lacaille , Dunlop and Messier lists it makes sense that the next mission could be the Herschels lists. A lot of the objects would obviously have already been ticked off as pat of the NGC / IC catalogues. Definitely will keep this in mind when pushing the dob around.
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