One of my first galaxies taken, M101 is a large galaxy sitting over twenty-one million Ly away in the constellation of Ursa Major. Due to its location, M101 is generally always high in the sky for the Northern Hemisphere and viewable with a large scope, dark skies, and a low power eyepiece. For Astrophotography (AP) a smaller diameter scope is good to get the whole galaxy in one frame.
The galaxy is 170,000Ly in diameter, in comparison to our galaxy at 100,00Ly, it is near twice the size with an approximation of 1 trillion stars (Plait, 2006) and has large volumes of HII gas regions, enough to give each an NGC number. The apparent Magnitude for M101 is 7.8
Gravitational interactions are compressing the interstellar gas which is triggering star-forming regions and can be seen in Ultraviolet images (Waller et al., 1997)
M101 has six companion galaxies NGC 5204, NGC 5474, NGC 5477, NGC 5585, UGC8837 and UGC 9405 all are gravitationally linked and some of distorted due to M101 (Sandage & Bedke, 1994)
The galaxy is 170,000Ly in diameter, in comparison to our galaxy at 100,00Ly, it is near twice the size with an approximation of 1 trillion stars (Plait, 2006) and has large volumes of HII gas regions, enough to give each an NGC number. The apparent Magnitude for M101 is 7.8
Gravitational interactions are compressing the interstellar gas which is triggering star-forming regions and can be seen in Ultraviolet images (Waller et al., 1997)
M101 has six companion galaxies NGC 5204, NGC 5474, NGC 5477, NGC 5585, UGC8837 and UGC 9405 all are gravitationally linked and some of distorted due to M101 (Sandage & Bedke, 1994)
To photograph this target does not require long hours or long exposure times. But, obviously, the more you put in the more you will get out of the picture. The recommendation of 3 min exposures using a UV/ IR filter or the Optolong L-Pro filter is needed, or the stars bloat out (As can be seen in the pictures above). If you are not using UV/ IR filter or Optolong L-Pro, then reduce the exposure time to about ninety secs.
An average of about 3hours will be fine as a starting point on this target the pictures above were both 7hours of exposure time (with two different processing styles done on each) Since m101 is Circumpolar, you can photograph this target all year round.
An average of about 3hours will be fine as a starting point on this target the pictures above were both 7hours of exposure time (with two different processing styles done on each) Since m101 is Circumpolar, you can photograph this target all year round.
The galaxy was discovered by one of Charles Messier's colleagues Pierre Méchain in 1781, describing it as a 'nebula without a star'. William Herschel in 1784 wrote 'in my 7, 10 and 20-feet focal length reflectors showed a mottled kind of nebulosity, which I shall call resolvable' with Lord Rosse observing the galaxy in the late 19th century and being the first to make extensive notes and documentation on the spiral structure.
The location of M101 - 14h 03m 12.6s +54° 20′ 57″
The location of M101 - 14h 03m 12.6s +54° 20′ 57″
A recent chance to capture this target again came along. But this time with the RASA8. What a difference (shame about some of the bigger stars). This was 1hr 15 mins total exposure at 30-sec sub-exposures. The Image is heavily cropped.
Details of the setup are below the picture.
Details of the setup are below the picture.
Scope – Celestron RASA 8
Mount - Skywatcher EQ6 R Pro
Guide scope – ZWO 30mm
Guide Camera – ZWO ASI 120mm mini
Main Camera – ZWO Asi 533mc Pro
Control box – ZWO ASIAIR Pro
Filter – Baader 2" UV/IR filter
Starizona Filter drawer next to the camera sensor
Fox Halo 96k power bank
Dew heater with its own power bank on the guide scope
Main scope Celestron ring dew heater powered though ASIAir at 15%
Mount - Skywatcher EQ6 R Pro
Guide scope – ZWO 30mm
Guide Camera – ZWO ASI 120mm mini
Main Camera – ZWO Asi 533mc Pro
Control box – ZWO ASIAIR Pro
Filter – Baader 2" UV/IR filter
Starizona Filter drawer next to the camera sensor
Fox Halo 96k power bank
Dew heater with its own power bank on the guide scope
Main scope Celestron ring dew heater powered though ASIAir at 15%