NGC104 and eta carinae nebula

[Costavar (Costa)]

My first attempts to take some photos, through my 8 inch non guided dob and a compact dital camera attached.

13 secs f2.8 for NGC104
5 secs f2.8 for eta

Also posting processed version of a 13 sec exposure of eta.

Nowhere near good but perhaps a start.

[peter_4059 (Peter)]

They are a good start Costa considering you are using a Dob. You will be battling with stars trailing with the dob. One way to get around this is to take lots of shorter exposures and stack them.

[David Fitz-Henr]

Not bad for such short exposures and on a Dob! When you say unguided, I take it that you mean no tracking? It will be hard to get detail even taking lots of shorter exposures on deep sky objects without tracking of some kind. Do you have motors on your axes? Maybe the next step could be an equatorial platform to provide tracking, or a StellarCat?

[Costavar (Costa)]

Thanks David, no motors or anything. I am not sure if I should consider eq mount or the stellarcat option. the latter seems interesting but not sure how fiddlly it is to install. Do u have any exprience with it?

[telecasterguru (Frank)]

Costa,

A dob will not give you the platform for imaging deep space objects such as nebula or clusters. Unless you invest in a servo cat or the like. These are very expenxive though.

An equatorial mount with tracking would be more cost efective.

You obviously have the passion so keep it up.

Frank

[David Fitz-Henr]

Originally Posted by Costavar

Thanks David, no motors or anything. I am not sure if I should consider eq mount or the stellarcat option. the latter seems interesting but not sure how fiddlly it is to install. Do u have any exprience with it?

I have only seen them at the SPSP star parties, where they are often used in conjunction with an ArgoNavis. The ServoCat works very well I believe, however it is not really suited to imaging due to the problem of field rotation. This is due to the fact the a Dob has its fixed axis pointing at the zenith instead of the pole. An equatorial platform is a simple way of providing limited tracking time (I think a half hour to an hour) for a Dobsonian. The whole Dob sits on the platform which is fairly compact and has a "virtual" axis pointed at the pole (it is basically part of a much larger cone shape on rollers / bearings). I'm not sure how much they are compared to an equatorial mount - I think they are usually home made. An equatorial mount would be the ideal solution if you can afford it - get a good quality one though or you may regret not spending the extra dollars!