Arp 13, NGC 7448

[Mike JW]

Hi folks

During the summer I have converted my 15 inch Dob from a push to, to a GOTO. So last night I took the opportunity to put the Ultrastar onto it. (Tracking and alignment not as good as my iEQ45 pro mount).

Arp 13 is a spiral galaxy, 84 million lyrs away, 60,000 lyrs across. The inner disk region appears to be tightly wound spiral fragments which are bright. The outer regions are much dimmer with individual arm segments and dust lanes. There is a definite boundary between the inner section and the much fainter outer section of the galaxy. Various brighter H111 regions picked up, one of which at the top right is almost as bright as the core - must be some real action on the go in this region - not the place to be for life to get started on a rocky planet?. Arp classified this as galaxy with detached segments.

This shot is 14 x 10 sec subs and tweaked in photoshop.

 

Mike

 

[Bill S]

Great shot and explanation. Your Dobsonian must be well mounted and aligned. How have you set it up?

 

[Mike JW]

Hi Bill,

The dob is  a standard design truss tube Dob and reasonably well made but annoyingly is not truly orthogonal so GOTO is fine visually but once the camera is fitted with such a narrow fov it is pot luck as to whether  the object is in the fov. I have tried to improve alignment by accurately leveling the scope each time, doing extra alignment stars after the initial two star alignment, with the final star being reasonably close to the intended object. Compared to my equatorial set up it is inaccurate and a slow process.

Mike