M51 WHIRLPOOL GALAXY

(Canes Venatici 13h30m 4715')

M51 Whirlpool galaxy

Niet alle objecten in Messier's lijst zijn ook daadwerkelijk door hem zelf ontdekt. M51 (NGC 5194) echter wel, en wel in oktober 1773. William Parsons, beter bekend als Lord Rosse, was met zijn telescoop met 180cm bronzen spiegel als eerste in staat de spiraalstructuur te herkennen (zie zijn tekening rechts). Een indicatie dat deze 'nevel' anders was dan de tot dan toe onderzochte emissie- en reflectienevels. M51 staat op een slordige 35 miljoen lichtjaren afstand en is in interactie met NGC5195 (ook wel aangeduid als M51B). Enkele miljoenen jaren geleden zijn door nauwe passage van dit satellietstelsel de spiraalstructuur van M51A ontstaan alsmede de vage uitlopers van gas en sterren rond NGC5195. NGC5195 bevindt zich nu achter een van de spiraalarmen van M51A.

Not all Messier objects were discovered by Messier himself, M51 however, was (october, 1773). M51 (NGC5194), with its pronounced spiral arms, was the first 'nebula' in which William Parsons, the Third Earl of Ross, recognized a spiral structure, proofing it to be more than just a nebula. The discovery was made in 1845 with his telescope with 6 foot metal mirror (see his drawing on the right).
M51 is some 35 million light-years distant and interacting with its near companion NGC5195 (sometimes designated by M51B), which now lies well behind one of the dusty arms of M51. In fact it is beleaved that the gravitational interaction with NGC5195 caused tidal waves of compressed gas causing large-scale star formation resulting in its spiral structure.

IMAGE INFORMATION
Date:19 may 2004 (MYC-colors) and 20 may 2004 (b/w images)
CCD:FTT1010-M (non-binned)
Optical:Prime focus 25cm Newton, f/D=5.7
Filters:M,Y,C
Exposure:Each color 20x90sec.
Luminance is sum of MYC-images and 32 images of 90 seconds without filters
Processing:Slightly unsharp masked



M51 - 10 Years progress in equipment and technique

From my location (The Netherlands), M51 is near Zenit and has been a frequently photographed object using the CCD-camera's and telecopes I have build. The images below present a short history of progress in technique and equipment.

M51 with TC211 CCD 1994 M51 with TC211 CCD 1995
M51 with FT800 1998
M51 with FT800 2001
M51 with FTT1010-M 2004
May 1994
11cm Newton
f/D=4.6
TC211 CCD
192x165 pixels
Exposure: 8x60 sec
April 1995
15cm Newton
f/D=6.3
TC211 CCD
192x165 pixels
Exposure: 6x50 sec
June 1998
25cm Newton, f/D=5.7
FT800 CCD
300x390 pixels
Exposure: 19x90 sec
April 2001
25cm Newton, f/D=5.7
FT800 CCD
300x390 pixels
Exposure: 24x120 sec
May 2004
25cm Newton, f/D=5.7
MYC-color filter wheel
FTT1010-M CCD
1024x1024 pixels
Each color: 20x90sec
Luminance: 32x90sec